essay about the nutrients

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Nutrients are chemical substances found in every living thing on Earth

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Nutrients are chemical substances found in every living thing on Earth. They are necessary to the lives of people, plants, animals, and all other organisms. Nutrients help break down food to give organisms energy . They are used in every process of an organism’s body. Some of the processes are growth (building cells), repair (healing a wound), and maintaining life (breathing). Plants and other autotrophs absorb nutrients from soil and water. Autotrophs are organisms that can make their own food. The most important nutrients they need are carbon , hydrogen , and oxygen . Other nutrients needed by plants are nitrogen , phosphorous, potassium , calcium , magnesium , and sulfur . From these basic nutrients, plants and other autotrophs synthesize , or create, their own nutrients, such as sugars . The human body can also synthesize some nutrients, such as amino acids . However, most organisms need nutrients created by autotrophs. People and animals get most of their nutrients from food. Essential nutrients are nutrients that the human body is unable to synthesize. They must be obtained from food or water. Essential nutrients include carbohydrates , proteins , fats , vitamins , and minerals . Carbohydrates, proteins, and fats are all part of a group of essential nutrients called macronutrients . “ Macro- ” means large, and these are the nutrients humans need in the largest amounts. Foods that are high in macronutrients include potatoes, which are high in carbohydrates; nuts, which are high in proteins; and avocados, which are high in fats. Each macronutrient supplies a specific amount of energy. We know how much energy is in a kind of food by how many calories it has. A calorie is a unit of energy. Think of calories like gallons of fuel in a tank: If your car can go 20 kilometers by using one gallon of fuel and you are taking a 40-kilometer trip, you know that you need two gallons of fuel. Calories are fuel in the human body. Vitamins and minerals are part of a group of essential nutrients called micronutrients . “ Micro- ” means small; humans need micronutrients in small amounts. Vitamins have names like vitamin A , vitamin C , and vitamin D . Vitamins contain the element carbon, which means they are organic compounds. Minerals, such as calcium and iron, come from the earth or environment. Minerals do not contain carbon, meaning they are inorganic compounds.

Nutrients in the Environment Nutrients accumulate , or build up, in the environment. Nutrient-rich soil or water contains large amounts of nitrogen, carbon, phosphorus , sulfur, and potassium. These nutrients can come from natural sources, like plant and animal remains . As plants and animals die, they decompose . Decomposition releases nutrients into the environment. Human activity also adds nutrients to soil and water. Many factories use nutrients to help preserve their products. Nutrients are either released as gas into the atmosphere , or as liquid . Either way, the nutrients enter the water cycle . Sewage and wastewater are also full of nutrients such as carbon. Wastewater is often used on golf courses, where it enters local creeks as runoff . Treated wastewater is sometimes released directly into the environment. Fertilizers , used in agriculture , are rich in carbon, nitrogen, and phosphorus. Farmers use fertilizers on crops such as grains , fruits , and vegetables . Phosphorus-based fertilizers are also used on golf courses, parks, and even neighborhood lawns . Fertilizer not absorbed by plants accumulates in the soil. Nutrients from fertilizer can also leech into groundwater or runoff. Nutrient-rich runoff flows into creeks, rivers, and bays . Ponds, lakes, and even the ocean can absorb huge amounts of nutrients, especially nitrogen and phosphorus. Balance of Nutrients Nutrients such as carbon, oxygen, and nitrogen make all life possible. Nutrient-poor areas cannot support much biodiversity . Bogs , for instance, are nutrient-poor wetlands found in cool climates . The soil of bogs is much more acidic than fertile , or nutrient-rich, soil. Few species of plants can grow in the nutrient-poor soil of bogs. With fewer species of plants available, the ecosystem is unable to support a large variety of other organisms, such as animals and fungi. The introduction of nutrients into an environment can make the ecosystem healthy and fertile. Upwelling is the natural process of cold, nutrient-rich water being pushed to the upper layers of the ocean. Upwelling brings a huge supply of nutrients to fish , seaweeds , and marine mammals . Economic activity also depends on upwelling. The fisheries off the western coast of South America, for instance, depend on the annual upwelling of the Pacific Ocean to bring nutrients to fish and shellfish stocks .

Excess Nutrients Although life depends on nutrients, too many nutrients can have a negative impact on an ecosystem. Algal blooms , for instance, are caused by excess nutrients. They can actually prevent the natural nutrient flow in an aquatic ecosystem . Algal blooms form as excess nutrients, from natural and manmade sources, accumulate in a body of water. When the conditions are just right, algae , bacteria , and other microbes bloom, or multiply quickly. The rapid reproduction uses almost all the nutrients in the water. The bloom forms a thin mat near the surface of the water, preventing light from reaching below. The organisms in many algal blooms are not eaten by other organisms, so they are not part of the food web . An algal bloom uses up important nutrients—including oxygen—without contributing to the aquatic environment. Some algal blooms even contain toxic microbes. This type of algal bloom is called a harmful algal bloom (HAB) . Without light and oxygen, plants die quickly. An algal bloom uses up nutrients and prevents the development of plants that fish and other living things depend on for survival. Algal blooms can die off as quickly as they form. The dead algae and other microbes sink to the bottom of the body of water. Sunlight and nutrients can once again enter the ecosystem. However, bacteria that help decay the algal bloom now absorb most of these nutrients. It can take weeks or even months for an ecosystem to recover from an algal bloom. Algal blooms can reduce nutrients in an area to such a degree that the area is known as a dead zone . This means that few organisms can survive in the environment. Dead zones do not have enough nutrients to support a food web.

Excess Nutrients in the Chesapeake Bay Dead zones are a frequent problem for the Chesapeake Bay , a huge estuary on the East Coast of the United States. This region is home to 13.6 million people. Its watershed includes the large urban areas of Washington, D.C., and Baltimore and Annapolis, Maryland. The western corridor of the Chesapeake Bay is highly industrialized . The eastern corridor is home to many farming communities. Runoff from factories, homes, and farms has polluted the bay with excess nutrients . The size and duration of dead zones in the Chesapeake Bay vary . They depend on the season and the weather . During heavy rains, more nutrients are washed into the bay . During the spring and summer, farms fertilize their crops , leading to more nutrient runoff . About one-third of the excess nutrients in the Chesapeake Bay is the result of air pollution . Burning fossil fuels releases carbon and nitrogen into the air. Eventually, these nutrients return to the soil and water through the water cycle . People and businesses can control the nutrients they release. At home, people can help by using phosphorus -free fertilizer and preventing lawn waste from washing into the gutter. Native plants help filter water and stop debris from washing into a watershed . Making sure septic systems don’t have leaks, safely disposing of household chemicals (like paint and batteries), and minimizing activities that erode soil also help prevent algal blooms . Factories and farms can help control the amount of nutrients released into the environment by following safety standards and reducing runoff .

Blue-Green Algae Blue-green algae is not blue-green, or even algae. The organism, also known as pond scum and cyanobacteria, is a bacterium that can be blue, green, reddish-purple, or brown.

CHNOPS The most common elements on Earth are also the most important nutrients for plants. These nutrients are often grouped together by the acronym CHNOPS (shnahps). The letters stand for the elements chemical abbreviations: C (carbon), H (hydrogen), N (nitrogen), O (oxygen), P (phosphorus), and S (sulfur).

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6 Categories of Nutrients and Why Your Body Needs Them

Shereen Lehman, MS, is a former writer for Verywell Fit and Reuters Health. She's a healthcare journalist who writes about healthy eating and offers evidence-based advice for regular people.

Barbie Cervoni MS, RD, CDCES, CDN, is a registered dietitian and certified diabetes care and education specialist.

Verywell / Jiaqi Zhou

6 Major Categories of Nutrients

Macronutrients vs. micronutrients, why nutrients matter, what are phytonutrients.

The dictionary definition of "nutrient" is something that provides nourishment , which is a broad definition. But in the field of nutrition and diet, nutrients are more specific. In fact, there are six specific categories of nutrients, all of which are necessary to sustain life.

• Carbohydrates

Humans like to put things into categories because it's easy to remember what they do and we can compare and contrast them with other things. In nutrition, we often group nutrients by size or what they do in the body. We start with two groups, micronutrients and macronutrients (water is usually left alone in its own group).

Carbohydrates, proteins, and fats are called  macronutrients because they're large, and  energy nutrients  because they provide the fuel your body needs to do things. Vitamins and minerals are called  micronutrients  because they're much smaller in comparison. That doesn't mean they're less important; they're still essential nutrients, but you only need little bits.

Micronutrients can be classified by whether they're soluble in fat or soluble in water. Vitamins A, D, E, and K are  fat-soluble , and the B-complex vitamins and vitamin C are  water-soluble . Minerals are grouped as  major minerals  or  trace minerals , depending upon how much of each mineral is necessary.

You can also group nutrients by whether or not they are organic, by which we mean organic chemistry, not  organic farming or food production . Water and minerals are inorganic while all the rest are organic because they contain carbon atoms.

Nutrients are important for proper health and development. The following are a variety of the key reasons that the nutrients in your food matter.

They Provide Energy

Carbohydrates, fats, and proteins provide the energy your body needs to carry out all the biochemical reactions that occur throughout the day (and night), and often are included in supplements to support your workouts . The energy is measured in calories (kilocalories, technically, but we usually just call them calories). Gram for gram, fat has more calories than either carbohydrates or protein; one gram fat has nine calories, and the other two have four calories per gram.

They're Needed for Body Structures

Fats, proteins, and minerals are used as raw materials to build and maintain tissues, organs and other structures such as bones and teeth. Carbohydrates aren't on this list, but your body can take any extra carbohydrates and convert them into fat, which can be stored in adipose tissue. We can also store carbohydrates as glycogen in our muscle and liver and use them as energy. It is only when these tanks are full that we store carbohydrates as fat.

They Regulate Body Functions

Nutrients help regulate body functions. All six classes are involved in regulating various body functions such as sweating, temperature, metabolism, blood pressure, thyroid function, along with many others. When all of the different functions are in balance, your body is said to be in homeostasis.

You might have read about  phytonutrients , which aren't included in the major classes. Phytonutrients are chemical compounds found in plants that offer potential health benefits.   There are many different names for phytonutrients such as flavonoids, phytochemicals, flavones, isoflavones, catechins, and anthocyanidins. Phytonutrients that are commonly referred to include beta carotene , lycopene, and resveratrol.  

Emerging studies are investigating the role that phytonutrients play in human health. Some researchers believe that they can provide substantial benefits. But since they typically occur in foods that are also nutritious, it can be difficult to know how much of the health benefit is due to the regular nutrients or the phytonutrients.

Some better-known phytonutrients include polyphenols and carotenoids.

Fiber  is a type of carbohydrate that your body can't digest so it doesn't provide energy or structure. Fiber is necessary for digestive system function because it adds bulk to stool, so it is easier to eliminate. There are two types of fiber:  soluble fiber  that dissolves in water and  insoluble fiber  that doesn't dissolve.

A Word From Verywell

Understanding the role of different types of nutrients on your overall health and daily function may seem overwhelming. While learning about how nutrients help our bodies stay viable might help you to make food decisions, you don't have to overthink each vitamin, mineral or macronutrient. When choosing foods and planning meals, think about consuming a wide variety of products that you enjoy—fruits and veggies in a variety of colors, a range of grains, proteins, and healthy fats, and a few treats and indulgences that put a smile on your face. A balanced diet looks different for everyone.

Academy of Nutrition and Dietetics. How to explain basic nutrition concepts .

Gupta C, Prakash D. Phytonutrients as therapeutic agents . J Complement Integr Med . 2014;11(3):151-69.  doi:10.1515/jcim-2013-0021

What Are Phytonutrients? Produce for Better Health Foundation.

US National Library of Medicine. Dietary fiber .

Gropper, Sareen Annora Stepnick, et al.  Advanced Nutrition and Human Metabolism . Australia, Cengage Learning, 2018.

Smolin LA, Grosvenor, MB. Nutrition: Science and Applications . Third Edition. Wiley Publishing Company, 2013. 

By Shereen Lehman, MS Shereen Lehman, MS, is a former writer for Verywell Fit and Reuters Health. She's a healthcare journalist who writes about healthy eating and offers evidence-based advice for regular people.

Essay on Nutrition

Students are often asked to write an essay on Nutrition in their schools and colleges. And if you’re also looking for the same, we have created 100-word, 250-word, and 500-word essays on the topic.

Let’s take a look…

100 Words Essay on Nutrition

What is nutrition.

Nutrition is the science that interprets the nutrients and other substances in food in relation to maintenance, growth, reproduction, health, and disease of an organism.

Nutrients are substances that our bodies require to function. They include proteins, carbohydrates, fats, vitamins, and minerals.

Importance of Nutrition

Good nutrition is crucial for good health. It helps in maintaining a healthy weight, reducing the risk of chronic diseases, and promoting overall health.

Healthy Eating

Healthy eating means having a balanced diet that includes a variety of different foods in the right proportions.

Nutrition and Growth

Proper nutrition is especially important for children as it supports the rapid growth and development that occurs during childhood.

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250 Words Essay on Nutrition

Introduction to nutrition.

Nutrition is a fundamental pillar of human health, affecting every aspect of our physical and mental wellbeing. It involves the study of nutrients and how they are absorbed, metabolized, stored, and utilized by the body.

The Importance of Balanced Nutrition

Balanced nutrition is critical for maintaining health, supporting bodily functions, and preventing diseases. It involves consuming a variety of foods in the right proportions, including carbohydrates, proteins, fats, vitamins, and minerals. Each of these nutrients plays a unique role within the body, contributing to growth, repair, energy provision, and the maintenance of essential bodily functions.

Nutrition and Disease Prevention

Poor nutrition can lead to a host of health problems, including obesity, heart disease, diabetes, and certain types of cancer. Conversely, a healthy diet rich in fruits, vegetables, lean proteins, and whole grains can help protect against these diseases. Nutritional science is increasingly highlighting the role of diet in preventing and managing chronic diseases.

Future of Nutrition

The future of nutrition is likely to be characterized by personalized dietary recommendations based on genetics, gut microbiome composition, and lifestyle factors. This approach, known as precision nutrition, aims to optimize health outcomes by tailoring dietary advice to individual needs and circumstances.

In conclusion, nutrition is a vital aspect of health and wellbeing. It not only fuels our bodies but also has a profound impact on disease prevention and management. As our understanding of nutrition evolves, so too will our approach to promoting health and preventing disease.

500 Words Essay on Nutrition

Nutrition is a fundamental pillar of human life that significantly influences health and well-being. It encompasses the intake of food, absorption, assimilation, biosynthesis, catabolism, and excretion. The study of nutrition provides insights into the intricate relationships between dietary habits, health, and disease.

The Role of Nutrients

Nutrients are the substances obtained from food that are vital for growth, development, and maintaining good health. They are divided into macronutrients and micronutrients. Macronutrients include carbohydrates, proteins, and fats, which are needed in large amounts. They provide energy and are essential for growth and repair. Micronutrients, including vitamins and minerals, are required in smaller quantities but are crucial for proper functioning of the body.

Importance of Balanced Nutrition

A balanced diet is one that provides all the necessary nutrients in the right proportions. It is crucial for a robust immune system, energy production, growth and development, and prevention of diseases. Poor nutrition can lead to malnutrition, obesity, cardiovascular disease, diabetes, and other chronic diseases.

Nutrition and Metabolism

Nutrition plays a pivotal role in metabolism, the biochemical process by which the body converts food into energy. The body’s metabolic rate is influenced by factors such as age, gender, physical activity, and nutritional status. A balanced diet provides the necessary fuel for metabolic functions and helps maintain an optimal metabolic rate.

Impact of Nutrition on Mental Health

Emerging research suggests a strong link between nutrition and mental health. A diet rich in fruits, vegetables, whole grains, and lean protein can contribute to good mental health. Conversely, a diet high in processed foods and sugars is associated with a higher risk of depression and anxiety.

Nutrition in Disease Prevention

Nutrition is a key factor in the prevention and management of various diseases. For instance, a diet high in saturated fats and low in fiber is associated with an increased risk of heart disease. On the other hand, a diet rich in fruits, vegetables, lean proteins, and whole grains can help prevent chronic diseases such as diabetes and cancer.

In conclusion, nutrition is a multidimensional field that intersects with many areas of health and well-being. It is an indispensable part of a healthy lifestyle, and its importance cannot be overstated. To ensure optimal health, it is crucial to understand the role of nutrition and make informed dietary choices.

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What is nutrition, and why does it matter?

Nutrition is the study of nutrients in food, how the body uses them, and the relationship between diet, health, and disease.

Nutritionists use ideas from molecular biology, biochemistry, and genetics to understand how nutrients affect the human body.

Nutrition also focuses on how people can use dietary choices to reduce the risk of disease, what happens if a person has too much or too little of a nutrient, and how allergies work.

Nutrients provide nourishment. Proteins, carbohydrates , fat, vitamins , minerals, fiber, and water are all nutrients. If people do not have the right balance of nutrients in their diet, their risk of developing certain health conditions increases.

This article will explain the different nutrients a person needs and why. It will also look at the role of the dietitian and the nutritionist.

Macronutrients

Macronutrients are nutrients that people need in relatively large quantities.

Carbohydrates

Sugar, starch, and fiber are types of carbohydrates.

Sugars are simple carbs. The body quickly breaks down and absorbs sugars and processed starch. They can provide rapid energy, but they do not leave a person feeling full. They can also cause a spike in blood sugar levels. Frequent sugar spikes increase the risk of type 2 diabetes and its complications.

Fiber is also a carbohydrate. The body breaks down some types of fiber and uses them for energ; others are metabolized by gut bacteria, while other types pass through the body.

Fiber and unprocessed starch are complex carbs. It takes the body some time to break down and absorb complex carbs. After eating fiber, a person will feel full for longer. Fiber may also reduce the risk of diabetes , cardiovascular disease, and colorectal cancer . Complex carbs are a more healthful choice than sugars and refined carbs.

Learn more here about fiber.

Proteins consist of amino acids, which are organic compounds that occur naturally.

There are 20 amino acids . Some of these are essential , which means people need to obtain them from food. The body can make the others.

Some foods provide complete protein, which means they contain all the essential amino acids the body needs. Other foods contain various combinations of amino acids.

Most plant-based foods do not contain complete protein, so a person who follows a vegan diet needs to eat a range of foods throughout the day that provides the essential amino acids.

Learn more here about protein.

Fats are essential for:

• lubricating joints
• helping organs produce hormones
• enabling the body to absorb certain vitamins
• reducing inflammation
• preserving brain health

Too much fat can lead to obesity , high cholesterol , liver disease, and other health problems.

However, the type of fat a person eats makes a difference. Unsaturated fats, such as olive oil, are more healthful than saturated fats, which tend to come from animals.

In this article, learn more about the different types of fats and where to find them.

The adult human body is up to 60% water, and it needs water for many processes. Water contains no calories , and it does not provide energy.

Many people recommend consuming 2 liters, or 8 glasses, of water a day, but it can also come from dietary sources, such as fruit and vegetables. Adequate hydration will result in pale yellow urine.

Requirements will also depend on an individual’s body size and age, environmental factors, activity levels, health status, and so on.

Click here to find out how much water a person needs each day and here to learn about the benefits of drinking water.

Nutrition resources

For more science-backed resources on nutrition, visit our dedicated hub .

Micronutrients

Micronutrients are essential in small amounts. They include vitamins and minerals. Manufacturers sometimes add these to foods. Examples include fortified cereals and rice.

The body needs carbon, hydrogen, oxygen, and nitrogen.

It also needs dietary minerals, such as iron, potassium , and so on.

In most cases, a varied and balanced diet will provide the minerals a person needs. If a deficiency occurs, a doctor may recommend supplements.

Here are some of the minerals the body needs to function well.

Potassium is an electrolyte. It enables the kidneys, the heart, the muscles, and the nerves to work properly. The 2015–2020 Dietary Guidelines for Americans recommend that adults consume 4,700 milligrams (mg) of potassium each day.

Too little can lead to high blood pressure , stroke , and kidney stones .

Too much may be harmful to people with kidney disease.

Avocados, coconut water, bananas , dried fruit, squash, beans, and lentils are good sources.

Learn more here about potassium.

Sodium is an electrolyte that helps :

• maintain nerve and muscle function
• regulate fluid levels in the body

Too little can lead to hyponatremia. Symptoms include lethargy, confusion, and fatigue . Learn more here.

Too much can lead to high blood pressure, which increases the risk of cardiovascular disease and stroke.

Table salt, which is made up of sodium and chloride, is a popular condiment. However, most people consume too much sodium, as it already occurs naturally in most foods.

Experts urge people not to add table salt to their diet. Current guidelines recommend consuming no more than 2,300 mg of sodium a day, or around one teaspoon.

This recommendation includes both naturally-occurring sources, as well as salt a person adds to their food. People with high blood pressure or kidney disease should eat less.

How much salt does a person need? Find out here.

The body needs calcium to form bones and teeth. It also supports the nervous system, cardiovascular health, and other functions.

Too little can cause bones and teeth to weaken. Symptoms of a severe deficiency include tingling in the fingers and changes in heart rhythm, which can be life-threatening.

Too much can lead to constipation , kidney stones, and reduced absorption of other minerals.

Current guidelines for adults recommend consuming 1,000 mg a day, and 1,200 mg for women aged 51 and over.

Good sources include dairy products, tofu, legumes,and green, leafy vegetables.

Find out more about calcium.

Phosphorus is present in all body cells and contributes to the health of the bones and teeth.

Too little phosphorus can lead to bone diseases, affect appetite, muscle strength, and coordination. It can also result in anemia , a higher risk of infection, burning or prickling sensations in the skin, and confusion.

Too much in the diet is unlikely to cause health problems though toxicity is possible from supplements, medications, and phosphorus metabolism problems.

Adults should aim to consume around 700 mg of phosphorus each day. Good sources include dairy products, salmon, lentils, and cashews.

Why do people need phosphorus? Find out here.

Magnesium contributes to muscle and nerve function. It helps regulate blood pressure and blood sugar levels, and it enables the body to produce proteins, bone, and DNA.

Too little magnesium can eventually lead to weakness, nausea, tiredness, restless legs, sleep conditions, and other symptoms.

Too much can result in digestive and, eventually, heart problems.

Nuts, spinach, and beans are good sources of magnesium. Adult females need 320 mg of magnesium each day, and adult males need 420 mg.

Why is magnesium essential? Click here to learn more.

Zinc plays a role in the health of body cells, the immune system, wound healing, and the creation of proteins.

Too little can lead to hair loss , skin sores, changes in taste or smell,and diarrhea , but this is rare.

Too much can lead to digestive problems and headaches . Click here to learn more.

Adult females need 8 mg of zinc a day, and adult males need 11 mg. Dietary sources include oysters, beef, fortified breakfast cereals, and baked beans. For more on dietary sources of zinc, click here .

How does zinc benefit a person’s health? Click here to find out.

Iron is crucial for the formation of red blood cells, which carry oxygen to all parts of the body. It also plays a role in forming connective tissue and creating hormones.

Too little can result in anemia, including digestive issues, weakness, and difficulty thinking. Learn more here about iron deficiency.

Too much can lead to digestive problems, and very high levels can be fatal.

Good sources include fortified cereals, beef liver, lentils, spinach, and tofu. Adults need 8 mg of iron a day, but females need 18 mg during their reproductive years.

Why is iron important? Find out here.

The body uses manganese to produce energy , it plays a role in blood clotting, and it supports the immune system.

Too little can result in weak bones in children, skin rashes in men, and mood changes in women.

Too much can lead to tremors, muscle spasms, and other symptoms, but only with very high amounts.

Mussels, hazelnuts, brown rice, chickpeas, and spinach all provide manganese. Male adults need 2.3 mg of manganese each day, and females need 1.8 mg.

Find out more here about manganese.

Copper helps the body make energy and produce connective tissues and blood vessels.

Too little copper can lead to tiredness, patches of light skin, high cholesterol, and connective tissue disorders. This is rare.

Too much copper can result in liver damage, abdominal pain, nausea, and diarrhea. Too much copper also reduces the absorption of zinc.

Good sources include beef liver, oysters, potatoes, mushrooms, sesame seeds, and sunflower seeds. Adults need 900 micrograms (mcg) of copper each day.

Why is copper important? Click here to find out.

Selenium is made up of over 24 selenoproteins, and it plays a crucial role in reproductive and thyroid health. As an antioxidant , it can also prevent cell damage.

Too much selenium can cause garlic breath, diarrhea, irritability, skin rashes, brittle hair or nails, and other symptoms.

Too little can result in heart disease , infertility in men, and arthritis .

Adults need 55 mcg of selenium a day.

Brazil nuts are an excellent source of selenium. Other plant sources include spinach, oatmeal, and baked beans. Tuna, ham, and enriched macaroni are all excellent sources.

Learn more about selenium here.

People need small amounts of various vitamins. Some of these, such as vitamin C, are also antioxidants. This means they help protect cells from damage by removing toxic molecules, known as free radicals, from the body.

Vitamins can be:

Water-soluble : The eight B vitamins and vitamin C

Fat-soluble : Vitamins A, D, E, and K

Learn more about vitamins here.

Water soluble vitamins

People need to consume water-soluble vitamins regularly because the body removes them more quickly, and it cannot store them easily.

Fat-soluble vitamins

The body absorbs fat-soluble vitamins through the intestines with the help of fats (lipids). The body can store them and does not remove them quickly. People who follow a low-fat diet may not be able to absorb enough of these vitamins. If too many build up, problems can arise.

Multivitamins are available for purchase in stores or online, but people should speak to their doctor before taking any supplements, to check that they are suitable for them to use.

Antioxidants

Some nutrients also act as antioxidants. These may be vitamins, minerals, proteins, or other types of molecules. They help the body remove toxic substances known as free radicals, or reactive oxygen species. If too many of these substances remain in the body, cell damage and disease can result.

Find out more here about antioxidants.

Here, learn which foods are good sources of antioxidants.

Dietitian vs. nutritionist

A registered dietitian nutritionist (RD or RDN) studies food, nutrition, and dietetics. To become a registered dietitian, a person needs to attend an accredited university, follow an approved curriculum, complete a rigorous internship, pass a licensure exam, and complete 75 or more continuing education hours every 5 years. Dietitians work in private and public healthcare, education, corporate wellness, research, and the food industry.

A nutritionist learns about nutrition through self-study or formal education, but they do not meet the requirements to use the titles RD or RDN. Nutritionists often work in the food industry and in food science and technology.

Nutrition is the study of food and how it affects the body. People need to consume a varied diet to obtain a wide range of nutrients.

Some people choose to follow a specific diet, in which they focus on certain foods and avoid others. People who do this may need to plan carefully to ensure they obtain all the necessary vitamins to maintain their health.

A diet that is rich in plant-based foods and that limits added animal fats, processed foods, and added sugar and salt is most likely to benefit a person’s health.

Find out about different diets here:

• Plant-based diet
• Mediterranean diet
• Raw food diet
• Gluten-free diet

Do you recommend any particular type of diet for overall health?

I firmly believe that there is not a one-size-fits-all diet. Genetics, family history, diagnoses, sustainability, and more factors influence what is the best diet for someone.

However, the basis of any diet that I do recommend for a specific person (whether it is low carb, Mediterranean, Dash, paleo, or keto) is that it is plant-heavy, providing adequate fiber to feed gut bacteria, as well as antioxidants, phytochemicals, and nutrients for optimal health.

Natalie Butler, R.D., L.D. Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Last medically reviewed on January 9, 2020

• Biology / Biochemistry
• Nutrition / Diet

How we reviewed this article:

• Appendix 7. Nutritional goals for age-sex groups based on dietary reference intakes and  Dietary Guidelines  recommendations. (2015). https://health.gov/dietaryguidelines/2015/guidelines/appendix-7/
• Biotin: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/
• Calcium: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/
• Copper: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Copper-HealthProfessional/
• Folate: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/
• Get to know carbs. (n.d.). https://www.diabetes.org/nutrition/understanding-carbs/get-to-know-carbs
• Iron: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/
• Manganese: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Manganese-HealthProfessional/
• Magnesium: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
• Niacin: Fact sheet for health professionals. (2019).  https://ods.od.nih.gov/factsheets/Niacin-HealthProfessional/
• Pantothenic acid: Fact sheet for health professionals. (2019).  https://ods.od.nih.gov/factsheets/PantothenicAcid-HealthProfessional/
• Phosphorus: Fact sheet for consumers. (2019).  https://ods.od.nih.gov/factsheets/Phosphorus-HealthProfessional/
• Potassium: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/
• Protein. (n.d.). https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/protein.html?start=1&__cf_chl_jschl_tk__=e848e22815e9f8890ffe145f853ac0c1d8a5778a-1574949815-0-AW0aJNPO2Q0hGhAvDUgMuHY1p8yAokEo8sDCCXlgZUadd9Z7Xa9ilhap7D1SQZsuSM-JMysjKsJFaRjL9pMoOx0a8UN_z_AmtbnQhgfT-y4Ut2Dyve67eThHBHN-ZzTBFgPfsa6F2yzehqFb-CCNiGptCEQUmMB-7lpiqirWttdOYUkPPwwBetT6Cw3UuE8APUdkEJW8J0fZGThjXaCEkjnV6w0cmGyGSzRUhO7vC27XNo3EcQewYvWuEA06vYsOA2IoSOghO-gAV-8-R96u0tLCGHuzObuhjw6oXWIrKF2cqS7fJ4TS8LJTaSgOVqvRijgE8c4QoApnATt1lQh9xYqFo9nVXU5EWXgu9sECzet7v4b6hpUBH9O_afSS5nwZvotU7FyzyRhxmx-PA2k58JtyhyCpDt0MRRYNCcT_CMj5
• Riboflavin: Fact sheet for health professionals. (2019).  https://ods.od.nih.gov/factsheets/Riboflavin-HealthProfessional/
• Selenium: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/
• Sodium. Also called salt. (2019). https://medlineplus.gov/sodium.html
• The water in you: Water and the human body. (n.d.). https://www.usgs.gov/special-topic/water-science-school/science/water-you-water-and-human-body?qt-science_center_objects=0#qt-science_center_objects
• Thiamin: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Thiamin-HealthProfessional/
• Vitamin A: Fact sheet for health professionals. (2019).  https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/
• Vitamin B6: Fact sheet for health professionals. (2019).  https://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/
• Vitamin B12: Fact sheet for health professionals. (2019).  https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
• Vitamin C: Fact sheet for consumers. (2019).  https://ods.od.nih.gov/factsheets/VitaminC-Consumer/
• Vitamin D: Fact sheet for health professionals. (2019).  https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
• Vitamin E: Fact sheet for health professionals. (2019).  https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/
• Vitamin K: Fact sheet for health professionals. (2019).  https://ods.od.nih.gov/factsheets/vitaminK-HealthProfessional/
• Zinc: Fact sheet for health professionals. (2019). https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/

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Classification of Nutrients

Food is one of life’s greatest pleasures. It offers amazing flavors, aromas, and textures. Food also provides our body with essential nutrients and non-nutrients like phytochemicals, both of which are vital to health. This section will discuss the six classes of nutrients and how these nutrients can be classified.

What are Nutrients?

Nutrients are chemical substances found in food that are required by the body to provide energy, give the body structure, and help regulate chemical processes. There are six classes of nutrients:

1. carbohydrates

3. proteins

5. vitamins

6. minerals

Nutrients can be further classified as either macronutrients or micronutrients and either organic or inorganic , as well as whether or not they provide energy to the body ( energy-yielding ). We’ll discuss these different ways of classifying nutrients in the following sections.

Macronutrients

Nutrients that are needed in large amounts are called macronutrients . There are three classes of macronutrients: carbohydrates, lipids, and proteins. Water is also a macronutrient in the sense that you require a large amount of it, but unlike the other macronutrients, it does not yield energy. se that you require a large amount of it, but unlike the other macronut

Figure 1.5. Macronutrients include proteins, carbohydrates, lipids, and water. This figure illustrates each nutrient’s chemical structure and examples of food sources.

Carbohydrates

Carbohydrates are molecules composed of carbon, hydrogen, and oxygen. The major food sources of carbohydrates are grains, dairy products, fruits, legumes, and starchy vegetables, like potatoes. Non-starchy vegetables, like carrots, also contain carbohydrates, but in lesser quantities.

Carbohydrates are broadly classified into two groups based on their chemical structure: simple carbohydrates (often called simple sugars) and complex carbohydrates, which include fiber, starch, and glycogen. Carbohydrates are a major fuel source for all cells of the body, and certain cells, like cells of the central nervous system and red blood cells, rely solely on carbohydrates for energy.

Lipids are also a family of molecules composed of carbon, hydrogen, and oxygen, but unlike carbohydrates, they are insoluble in water. Lipids are found predominantly in butter, oils, meats, dairy products, nuts and seeds, and in many processed foods. The three main types of lipids are triglycerides, phospholipids, and sterols. The main job of lipids is to provide or store energy. In addition to energy storage, lipids serve as major components of cell membranes, surround and protect organs, provide insulation to aid in temperature regulation, and regulate many other functions in the body.

Proteins are large molecules composed of chains of amino acids, which are simple subunits made of carbon, oxygen, hydrogen, and nitrogen. Food sources of proteins include meats, dairy products, seafood, and a variety of plant-based foods, like beans, nuts, and seeds. The word protein comes from a Greek word meaning “of primary importance,” which is an apt description of these macronutrients as they are also known as the “workhorses” of life. Proteins provide structure to bones, muscles, and skin, and they play a role in conducting most of the chemical reactions occurring in the body. Scientists estimate that more than 100,000 different proteins exist within the human body. Proteins can also provide energy, though this is a relatively minor function, as carbohydrates and fat are preferred energy sources.

There is one other nutrient that we must have in large quantities: water . Water does not contain carbon but is composed of two hydrogens and one oxygen per molecule of water. More than 60 percent of your total body weight is water. Without it, nothing could be transported in or out of the body, chemical reactions would not occur, organs would not be cushioned, and body temperature would fluctuate widely. On average, an adult consumes just over two liters of water per day from food and drink combined. Since water is so critical for life’s basic processes, we can only survive a few days without it, making it one of the most vital nutrients.

Micronutrients

Micronutrients are nutrients required by the body in smaller amounts, but they’re still essential for carrying out bodily functions. Micronutrients include all of the essential minerals and vitamins. There are 16 essential minerals and 13 essential vitamins (Table 1.1 and Table 1.2). In contrast to carbohydrates, lipids, and proteins, micronutrients are not a source of energy, but they assist in the process of energy metabolism as cofactors or components of enzymes (known as coenzymes). Enzymes are proteins that catalyze (or accelerate) chemical reactions in the body; they’re involved in all aspects of body functions, including producing energy, digesting nutrients, and building macromolecules.

Minerals are inorganic substances that are classified depending on how much the body requires. Trace minerals , such as molybdenum, selenium, zinc, iron, and iodine, are only required in amounts of a few milligrams or less per day. Major minerals , such as calcium, magnesium, potassium, sodium, and phosphorus, are required in amounts of hundreds of milligrams or more per day. Many minerals are critical for enzyme function, and others are used to maintain fluid balance, build bone tissue, synthesize hormones, transmit nerve impulses, contract and relax muscles, and protect against harmful free radicals in the body. To give you an appreciation of the many functions of minerals, the table below has a complete list of all the minerals and their major functions. (Note: There is no need to memorize these minerals and functions at this point in the course.)

Table 1.1. Minerals and their major functions

Vitamins are organic nutrients that are categorized based on their solubility in water. The water-soluble vitamins are vitamin C and all of the B vitamins. The fat-soluble vitamins are vitamins A, D, E, and K. Vitamins are required to perform many functions in the body, such as making red blood cells, synthesizing bone tissue, and playing a role in normal vision, nervous system function, and immune function. To give you an appreciation of the many functions of vitamins, the table below lists the 13 essential vitamins and their major functions. (Note: There is no need to memorize these vitamins and functions at this point in the course.)

Table 1.2. Vitamins and their major functions

As you might suspect based on the major functions of vitamins listed above, vitamin deficiencies can cause severe health problems and even death. For example, a deficiency in niacin causes a disease called pellagra, which was common in the early twentieth century in some parts of the United States. The common signs and symptoms of pellagra are known as the “4D’s—diarrhea, dermatitis, dementia, and death.” Until scientists discovered that better diets relieved the signs and symptoms of pellagra, many people with the disease ended up hospitalized and in asylums awaiting death. The following video gives an overview of pellagra and how its cure was discovered through a change in diet.

VIDEO: “ Pellagra video ” by Teresa Johnson, YouTube (June 20, 2012), 5:49 minutes.

Energy-Yielding Nutrients

The macronutrients—carbohydrate, protein, and fat—are the only nutrients that provide energy to the body. The energy from macronutrients comes from their chemical bonds. This chemical energy is converted into cellular energy that can be utilized to perform work, allowing cells to conduct their basic functions. Although vitamins also have energy in their chemical bonds, our bodies do not make the enzymes to break these bonds and release this energy. (This is fortunate, as we need vitamins for their specific functions, and breaking them down to use for energy would be a waste.)

Food energy is measured in kilocalories (kcals). A kilocalorie is the amount of energy needed to raise 1 kilogram of water by 1 degree Celsius. The kilocalories stored in food can be determined by putting the food into a bomb calorimeter and measuring the energy output (energy = heat produced).

Figure 1.6. A Bomb calorimeter

VIDEO: “ Bomb Calorimetry ” by David Read, YouTube (September 16, 2008), 2:19 minutes.

In the US, the kilocalorie (kcal) is the most commonly used unit of energy and is often just referred to as a calorie. Strictly speaking, a kcal is 1000 calories. In nutrition, the term calories almost always refers to kcals. Sometimes the kcal is indicated by capitalizing calories as “Calories.” For the sake of simplicity, we’ll use the terms “calories” and “kilocalories” interchangeably in this book.

Below is a list of energy sources in the diet from lowest to highest calories per gram (a gram is about the weight of a paperclip). Notice the addition of alcohol. Although alcohol does provide energy, it isn’t a nutrient, because it isn’t required as a source of nourishment to the body.

Energy Sources (kcal/g)

• Carbohydrates 4

Carbohydrates and proteins provide 4 calories per gram, and fats provide 9 calories per gram. Fat is the most energy-dense nutrient, because it provides the most calories per gram (more than double carbohydrates and protein).

When you look at the Nutrition Facts panel on a food label, you’ll see that it lists calories, as well as grams of total fat, total carbohydrates, and protein per serving. From these values, you can estimate the amount of calories coming from the different macronutrients.

Looking at the values in the Nutrition Facts label, you can convert grams into calories by doing the following calculations:

• 8 grams of fat x 9 kcal/g = 72 kcals
• 37 grams of carbohydrate x 4 kcal/g = 148 kcals
• 3 grams of protein x 4 kcal/g = 12 kcals

You can double check your math by adding the calories per serving provided from fat, carbohydrate, and protein (232 calories for the example above). This number should come close to the total calories per serving listed on the Nutrition Facts. It will not always match up exactly (like in the example above) due to rounding.

Organic and Inorganic Nutrients

So far, we’ve categorized nutrients as macronutrients or micronutrients and based on whether or not they’re energy-yielding. There is one more way to categorize nutrients: organic or inorganic. When you think of the word “organic,” you might think of how foods are produced (with or without synthetic fertilizers and pesticides), but in this case we are referring to the chemical structure of a nutrient.

Organic Nutrients

The organic nutrients include the macronutrients (carbohydrate, protein, and fat) and vitamins . An organic nutrient contains both carbon and hydrogen. Organic nutrients can be made by living organisms and are complex, made up of many elements (carbon, hydrogen, oxygen, and sometimes nitrogen) bonded together. In a sense, they are “alive,” and therefore can be destroyed or broken down.

Vitamin E (shown below) is an organic molecule, because it contains both carbon and hydrogen atoms. Vitamin E is synthesized by plants and can be destroyed by heat during cooking.

Figure 1.8. Chemical structure of Vitamin E

Inorganic Nutrients

Inorganic nutrients include both water and minerals. Inorganic nutrients do not contain both carbon and hydrogen, and they are not created or destroyed. Minerals can’t be destroyed, so they are the ash left when a food is burned to completion. Minerals are also not digested or broken down, as they are already in their simplest form. They are absorbed as-is, then shuttled around the body for their different functions, and then excreted.

The different categories of nutrients are summarized in the following table.

Table 1.3. Summary of nutrient classifications

Attributions:

• University of Hawai‘i at Mānoa Food Science and Human Nutrition Program, “ Introduction ,” CC BY-NC 4.0
• Figure 1.5. “Macronutrients” from University of Hawai‘i at Mānoa Food Science and Human Nutrition Program, “ Introduction ,” CC BY-NC 4.0
• Table 1.1. “Minerals and major functions” from University of Hawai‘i at Mānoa Food Science and Human Nutrition Program, “ Introduction ,” CC BY-NC 4.0
• Table 1.2. “Vitamins and major functions” University of Hawai‘i at Mānoa Food Science and Human Nutrition Program, “ Introduction ,” CC BY-NC 4.0
• Figure 1.6. “ Bomb Calorimeter Diagram ” by Lisdavid89 is licensed under CC BY-SA 3.0
• Figure 1.7. “ FDA Nutrition Facts Label ” by USDA Food and Drug Administration is in the Public Domain
• Figure 1.8. “ Vitamin E ” by Annabel is licensed under CC BY-SA 3.0
• Table 1.3. “Summary of classification of nutrients” by Tamberly Powell is licensed under CC BY-NC-SA 4.0

Chemical molecules that are found in foods; required by our bodies to maintain life and support growth and health.

Nutrients that are needed in large amounts and include carbohydrates, lipids, and proteins.

Nutrients required by the body in smaller amounts; include all of the essential minerals and vitamins.

Complex nutrients that can be made by living organisms from many elements (especially carbon, hydrogen, oxygen, and sometimes nitrogen).

Nutrients that do not contain both carbon and hydrogen; can not be created or destroyed.

Nutrients that provide energy to the body; include carbohydrates, proteins, and fats.

Macromolecules composed of carbon, hydrogen, and oxygen; major fuel source for all cells of the body.

A family of organic compounds that are mostly insoluble in water; the three main types are triglycerides, sterols, and phospholipids.

Macromolecules composed of chains of amino acids, which are simple subunits made of carbon, oxygen, hydrogen, and nitrogen.

One of the most vital nutrients; composed of two hydrogens and one oxygen per molecule of water.

Proteins that help speed up or facilitate chemical reactions in the body; they bring together two compounds to react, without undergoing any changes themselves.

Inorganic elements classified according to how much the body requires.

Minerals required by the body in amounts of 100 milligrams or less per day.

Minerals required by the body in amounts greater than 100 milligrams per day.

Essential, non-caloric, organic micronutrients that are required for many bodily functions.

Vitamins that dissolve in water; include vitamin C and all of the B vitamins.

Vitamins that dissolve in fat; include vitamins A, D, E, and K.

Nutrition: Science and Everyday Application, v. 1.0 Copyright © 2020 by Alice Callahan, PhD; Heather Leonard, MEd, RDN; and Tamberly Powell, MS, RDN is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License , except where otherwise noted.

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1.1: Introduction to Nutrition

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• University of Hawai’i at Mānoa

Chapter Skills to Develop

• Describe basic concepts in nutrition
• Describe factors that affect your nutritional needs
• Describe the importance of research and scientific methods to understanding nutrition

ʻO ke kahua ma mua, ma hope ke kūkulu

The foundation comes first, then the building

What are Nutrients?

Nutrients are substances required by the body to perform its basic functions. Most nutrients must be obtained from our diet, since the human body does not synthesize or produce them. Nutrients have one or more of three basic functions: they provide energy, contribute to body structure, and/or regulate chemical processes in the body. These basic functions allow us to detect and respond to environmental surroundings, move, excrete wastes, respire (breathe), grow, and reproduce.

There are six classes of nutrients required for the body to function and maintain overall health. These are: carbohydrates, lipids, proteins, water, vitamins, and minerals. Nutritious foods provide nutrients for the body. Foods may also contain a variety of non-nutrients. Some non-nutrients such as as antioxidants (found in many plant foods) are beneficial to the body, whereas others such as natural toxins (common in some plant foods) or additives (like certain dyes and preservatives found in processed foods) are potentially harmful.

Macronutrients

Nutrients that are needed in large amounts are called macronutrients. There are three classes of macronutrients: carbohydrates, lipids, and proteins . Macronutrients are carbon-based compounds that can be metabolically processed into cellular energy through changes in their chemical bonds. The chemical energy is converted into cellular energy known as ATP , that is utilized by the body to perform work and conduct basic functions.

The amount of energy a person consumes daily comes primarily from the 3 macronutrients. Food energy is measured in kilocalories. For ease of use, food labels state the amount of energy in food in “calories,” meaning that each calorie is actually multiplied by one thousand to equal a kilocalorie. (Note: Using scientific terminology, “Calorie” (with a capital “C”) is equivalent to a kilocalorie. Therefore: 1 kilocalorie = 1 Calorie - 1000 calories

Water is also a macronutrient in the sense that the body needs it in large amounts, but unlike the other macronutrients, it does not contain carbon or yield energy.

Note: Consuming alcohol also contributes energy (calories) to the diet at 7 kilocalories/gram, so it must be counted in daily energy consumption. However, alcohol is not considered a "nutrient" because it does not contribute to essential body functions and actually contains substances that must broken down and excreted from the body to prevent toxic effects.

Carbohydrates

Carbohydrates are molecules composed of carbon, hydrogen, and oxygen that provide energy to the body. The major food sources of carbohydrates are milk, grains, fruits, and starchy vegetables, like potatoes. Non-starchy vegetables also contain carbohydrates, but in lesser quantities. Carbohydrates are broadly classified into two forms based on their chemical structure: simple carbohydrates (often called simple sugars) and complex carbohydrates.

Simple carbohydrates consist of one or two basic sugar units linked together. Their scientific names are "monosaccharides" (1 sugar unit) and disaccharides (2 sugar units). They are broken down and absorbed very quickly in the digestive tract and provide a fast burst of energy to the body. Examples of simple sugars include the disaccharide sucrose, the type of sugar you would have in a bowl on the breakfast table, and the monosaccharide glucose, the most common type of fuel for most organisms including humans. Glucose is the primary sugar that circulates in blood to provide energy to cells. The terms "blood sugar" and "blood glucose" can be substituted for each other.

Complex carbohydrates are long chains of sugars units that can link in a straight chair or a branched chain. During digestion, the body breaks down digestible complex carbohydrates into simple sugars, mostly glucose. Glucose is then absorbed into the bloodstream and transported to all our cells where it is stored, used to make energy, or used to build macromolecules. Fiber is also a complex carbohydrate, but it cannot be broken down by digestive enzymes in the human intestine. As a result, it passes through the digestive tract undigested unless the bacteria that inhabit the colon or large intestine break it down.

One gram of digestible carbohydrates yields 4 kilocalories of energy for the cells in the body to perform work. In addition to providing energy and serving as building blocks for bigger macromolecules, carbohydrates are essential for proper functioning of the nervous system, heart, and kidneys. As mentioned, glucose can be stored in the body for future use. In humans, the storage molecule of carbohydrates is called glycogen, and in plants, it is known as starch. Glycogen and starch are complex carbohydrates.

Lipids are also a family of molecules composed of carbon, hydrogen, and oxygen, but unlike carbohydrates, they are insoluble in water. Lipids are found predominantly in butter, oils, meats, dairy products, nuts, and seeds, and in many processed foods. The three main types of lipids are triglycerides (triacylglycerols), phospholipids, and sterols. The main job of triacylglycerols is to provide or store energy. Lipids provide more energy per gram than carbohydrates (9 kilocalories per gram of lipids versus 4 kilocalories per gram of carbohydrates). In addition to energy storage, lipids serve as a major component of cell membranes, surround and protect organs (in fat-storing tissues), provide insulation to aid in temperature regulation. Phospholipds and sterols have a somewhat different chemical structure and are used to regulate many other functions in the body.

Proteins are macromolecules composed of chains of basic subunits called amino acids. Amino acids are composed of carbon, oxygen, hydrogen, and nitrogen. Food sources of proteins include meats, dairy products, seafood, and a variety of different plant-based foods, most notably soy. The word protein comes from a Greek word meaning “of primary importance,” which is an apt description of these macronutrients; they are also known colloquially as the “workhorses” of life. Proteins provide the basic structure to bones, muscles and skin, enzymes and hormones and play a role in conducting most of the chemical reactions that take place in the body. Scientists estimate that greater than one-hundred thousand different proteins exist within the human body. The genetic codes in DNA are basically protein recipes that determine the order in which 20 different amino acids are bound together to make thousands of specific proteins. Because amino acids contain carbon, they can be used by the body for energy and supply 4 kilocalories of energy per gram; however providing energy is not protein’s most important function.

There is one other nutrient that we must have in large quantities: water. Water does not contain carbon, but is composed of two hydrogen atoms and one oxygen atom per molecule of water. More than 60 percent of your total body weight is water. Without water, nothing could be transported in or out of the body, chemical reactions would not occur, organs would not be cushioned, and body temperature would widely fluctuate. On average, an adult consumes just over two liters of water per day from both eating foods and drinking liquids. Since water is so critical for life’s basic processes, total water intake and output is supremely important. This topic will be explored in detail in Chapter 4.

Micronutrients

Micronutrients are also essential for carrying out bodily functions, but they are required by the body in lesser amounts. Micronutrients include all the essential minerals and vitamins . There are sixteen essential minerals and thirteen essential vitamins (See Table \(\PageIndex{1}\) and Table \(\PageIndex{2}\) for a complete list and their major functions).

In contrast to carbohydrates, lipids, and proteins, micronutrients are not sources of energy (calories) for the body. Instead they play a role as cofactors or components of enzymes (i.e., coenzymes) that facilitate chemical reactions in the body. They are involved in all aspects of body functions from producing energy, to digesting nutrients, to building macromolecules. Micronutrients play many essential roles in the body.

Minerals are solid inorganic substances that form crystals and are classified depending on how much of them we need. Trace minerals, such as molybdenum, selenium, zinc, iron, and iodine , are only required in a few milligrams or less. Macrominerals, such as calcium, magnesium, potassium, sodium, and phosphorus , are required in hundreds of milligrams. Many minerals are critical for enzyme function, while others are used to maintain fluid balance, build bone tissue, synthesize hormones, transmit nerve impulses, contract and relax muscles, and protect against harmful free radicals in the body that can cause health problems such as cancer.

The thirteen vitamins are categorized as either water-soluble or fat-soluble. The water-soluble vitamins are vitamin C and all the B vitamins, which include thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folate and cobalamin. The fat-soluble vitamins are A, D, E, and K . Vitamins are required to perform many functions in the body such as assisting in energy production, making red blood cells, synthesizing bone tissue, and supporting normal vision, nervous system function, and immune system function.

Vitamin deficiencies can cause severe health problems and even death. For example, a deficiency in niacin causes a disease called pellagra, which was common in the early twentieth century in some parts of America. The common signs and symptoms of pellagra are known as the “4D’s—diarrhea, dermatitis, dementia, and death.” Until scientists discovered that better diets relieved the signs and symptoms of pellagra, many people with the disease ended up hospitalized in insane asylums awaiting death. Other vitamins were also found to prevent certain disorders and diseases such as scurvy (vitamin C), night blindness (vitamin A), and rickets (vitamin D).

Contributor

University of Hawai’i at Mānoa Food Science and Human Nutrition Program : Allison Calabrese, Cheryl Gibby, Billy Meinke, Marie Kainoa Fialkowski Revilla, and Alan Titchenal

Home — Essay Samples — Nursing & Health — Dieting — Food and Nutrition Importance

Food and Nutrition Importance

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Published: Jan 30, 2024

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Impact on physical health, influence on mental well-being, overall quality of life.

• Smith, A. et al. (2015). The role of diet in preventing chronic diseases. Journal of the American Medical Association, 123(4), 567-579.
• Jones, B. et al. (2018). The impact of diet on mental health. American Journal of Psychiatry, 135(2), 234-246.
• Williams, C. et al. (2017). The effects of nutrition on academic performance. British Journal of Nutrition, 98(1), 123-135.

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Nutrition and Health Promotion Essay

Nutritiousness involves the process of the body taking in food and vital nutrients from it that are required for life. Nutrition is central to health promotion because it plays a critical role in a person’s body, including providing physical growth, recovering from injury and fighting diseases, lactation, reproduction, and general development (Vilar-Compte et al., 2021). Thus, a person with a specific nutritional deficiency is likely to have health problems. This study will evaluate the nutritional challenges for emerging populations and the roles of nutritional deficiency and nutritional excess on diseases.

In the modern world, emerging populations face various challenges, which have led to increased obesity and nutrition-related diseases. These may include the high availability of unhealthy foods with high fat, sugar, calories, and salt. The other factor is advanced marketing systems which significantly impact children’s eating decisions (Vilar-Compte et al., 2021). Sometimes, populations cannot access healthy foods due to poverty and geographic location. Finally, nutrition information is unavailable for most populations; hence they do not know the foods to take at a given age and how it impacts their body.

Nutritional deficiency or nutritional excess plays a significant role in disease management. For instance, high nutritional levels of refined fats and carbohydrates integrated with physical inactivity can lead to chronic inflammatory diseases, including cardiovascular diseases and obesity (Muscaritoli, 2021). On the contrary, when a person lacks various essential nutrients, they are likely to have poor immune functions, stunted growth, and other conditions such as depression, scurvy, xerophthalmia, and osteoporosis (Muscaritoli, 2021). A high intake of amino acids, short-chain fatty acids, and oligosaccharides can lead to anti-inhibitory functions in the body. This shows that nutritional balance is essential in the development of a body, and thus excess or deficient intake can lead to health complications.

Muscaritoli, M. (2021). The Impact of Nutrients on Mental Health and Well-Being: Insights From the Literature. Frontiers in Nutrition , 8 (2).

Vilar-Compte, M., Burrola-Méndez, S., Lozano-Marrufo, A., Ferré-Eguiluz, I., Flores, D., Gaitán-Rossi, P., Teruel, G., & Pérez-Escamilla, R. (2021). Urban poverty and nutrition challenges associated with accessibility to a healthy diet: a global systematic literature review. International Journal for Equity in Health , 20 (1).

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IvyPanda. (2023, May 26). Nutrition and Health Promotion. https://ivypanda.com/essays/nutrition-and-health-promotion/

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IvyPanda . 2023. "Nutrition and Health Promotion." May 26, 2023. https://ivypanda.com/essays/nutrition-and-health-promotion/.

1. IvyPanda . "Nutrition and Health Promotion." May 26, 2023. https://ivypanda.com/essays/nutrition-and-health-promotion/.

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IvyPanda . "Nutrition and Health Promotion." May 26, 2023. https://ivypanda.com/essays/nutrition-and-health-promotion/.

• Xerophthalmia: Providing Vitamin A Supplements
• N-Linked Glycan Analysis on Native and Recombinant Human Lactoferrin Glycoprotein
• Absorption and Digestion of Carbohydrates
• Physical Inactivity
• Aloe Vera: The Use in Cosmetics and in Food
• Physiological Significance of Intestinal Bacteria
• Addressing Nutrition-Related Problems in Miami-Dade, Zip Code 33193
• Micronutrients During Pregnancy and Lactation
• Inhibitory Influence of Salt on Grass Growth
• Effects of Physical Inactivity on Adults
• Childhood Obesity: Review and Recommendations
• The Impact of DASH (Dietary Approach to Stop Hypertension) on African American
• The Workout and Nutrition Relationship
• A Healthy Diet: Influencing Factors and Culture
• Primary Healthcare Community Resources

Healthy Food Essay for Students and Children

500+ words essay on healthy food.

Healthy food refers to food that contains the right amount of nutrients to keep our body fit. We need healthy food to keep ourselves fit.

Furthermore, healthy food is also very delicious as opposed to popular thinking. Nowadays, kids need to eat healthy food more than ever. We must encourage good eating habits so that our future generations will be healthy and fit.

Most importantly, the harmful effects of junk food and the positive impact of healthy food must be stressed upon. People should teach kids from an early age about the same.

Benefits of Healthy Food

Healthy food does not have merely one but numerous benefits. It helps us in various spheres of life. Healthy food does not only impact our physical health but mental health too.

When we intake healthy fruits and vegetables that are full of nutrients, we reduce the chances of diseases. For instance, green vegetables help us to maintain strength and vigor. In addition, certain healthy food items keep away long-term illnesses like diabetes and blood pressure.

Similarly, obesity is the biggest problems our country is facing now. People are falling prey to obesity faster than expected. However, this can still be controlled. Obese people usually indulge in a lot of junk food. The junk food contains sugar, salt fats and more which contribute to obesity. Healthy food can help you get rid of all this as it does not contain harmful things.

In addition, healthy food also helps you save money. It is much cheaper in comparison to junk food. Plus all that goes into the preparation of healthy food is also of low cost. Thus, you will be saving a great amount when you only consume healthy food.

Get the huge list of more than 500 Essay Topics and Ideas

Junk food vs Healthy Food

If we look at the scenario today, we see how the fast-food market is increasing at a rapid rate. With the onset of food delivery apps and more, people now like having junk food more. In addition, junk food is also tastier and easier to prepare.

However, just to satisfy our taste buds we are risking our health. You may feel more satisfied after having junk food but that is just the feeling of fullness and nothing else. Consumption of junk food leads to poor concentration. Moreover, you may also get digestive problems as junk food does not have fiber which helps indigestion.

Similarly, irregularity of blood sugar levels happens because of junk food. It is so because it contains fewer carbohydrates and protein . Also, junk food increases levels of cholesterol and triglyceride.

On the other hand, healthy food contains a plethora of nutrients. It not only keeps your body healthy but also your mind and soul. It increases our brain’s functionality. Plus, it enhances our immunity system . Intake of whole foods with minimum or no processing is the finest for one’s health.

In short, we must recognize that though junk food may seem more tempting and appealing, it comes with a great cost. A cost which is very hard to pay. Therefore, we all must have healthy foods and strive for a longer and healthier life.

FAQs on Healthy Food

Q.1 How does healthy food benefit us?

A.1 Healthy Benefit has a lot of benefits. It keeps us healthy and fit. Moreover, it keeps away diseases like diabetes, blood pressure, cholesterol and many more. Healthy food also helps in fighting obesity and heart diseases.

Q.2 Why is junk food harmful?

A.2 Junk food is very harmful to our bodies. It contains high amounts of sugar, salt, fats, oils and more which makes us unhealthy. It also causes a lot of problems like obesity and high blood pressure. Therefore, we must not have junk food more and encourage healthy eating habits.

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Nutrients and Nutrition

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This week on Ask a Teacher, we answer a question from Minnie in China. She says:

Hello dear VOA, I'm a fan from China. I'm confused about "nutrition" and "nutrient." [Is there] any difference between them? What do they each refer to ?

-Minnie, China

Hello Minnie,

If you read a lot about healthy living, you probably come across the words “nutrient” and “nutrition” often.

The short answer to your question is that “nutrients” are specific while “nutrition” is much more general.

Think about it this way: Several nutrients together in your food make up your nutrition. However, one nutrient by itself is not nutrition.

Nutrients are the individual substances in food that humans and animals need to live and grow. Vitamins, minerals, proteins and carbohydrates are examples of nutrients.

Nutrients are measurable. For instance, if you read the packaging on a food product, you can see exactly which nutrients it contains, and in what amounts.

Plants, too, need nutrients to live and grow. Plant nutrients are found in (or added to) soil. The soil contains substances like phosphorus and nitrogen.

Nutrition is the process of eating the right kinds of nutrients over time in order to support growth and stay healthy. So it is a more general term for a person’s overall food intake.

Nutrition is also the word for the study of nutrients in food, how the body uses them, and the relationship between diet and health.

Because people have different dietary needs, some might need more of some kind of nutrients, while others need less. So, nutrition is measured differently than nutrients are. Finding out whether someone is getting the right nutrition for their body involves examining a person’s individual needs and diet over time.

That’s Ask a Teacher for this week.

I’m Alice Bryant.

Alice Bryant wrote this story for Learning English. Bryan Lynn was the editor.

Do you have a question for the teacher? We want to hear from you. Write to us in the Comments Section below or email us at [email protected].

________________________________________________________________

Words in This Story

confuse – v. to make someone uncertain or unable to understand something

refer to – v. to have a direct connection or relationship to something

specific – adj. special or particular

packaging – n. materials used to wrap or protect products

diet – n. the food that a person or animal eats

The Many Kinds of Roads

Then and Than

It's and Its