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  • Writer's pictureShruti GOCHHWAL

Nutrients And Their Functions And Sources

What are Nutrients?

The World Health Organization (WHO) note that essential nutrients are crucial in supporting a person’s reproduction, good health, and growth. The WHO divide these essential nutrients sources into two categories: micronutrients and macronutrients.

Six essential nutrients include- protein, fat, carbohydrate, vitamins, minerals and water.

Nutrients sources can be classified into macronutrients and micronutrients

‘Macro’ means large; as their name suggests these are nutrients which people need to eat regularly and in a fairly large amount. They include carbohydrates, fats, proteins, fibre and water. These substances are needed for the supply of energy and growth, for metabolism and other body functions.

Macronutrients provide a lot of calories but the amount of calories provided varies, depending on the food source.


As their name indicates (‘micro’ means small) micronutrients are substances which people need in their diet in only small amounts. These include minerals and vitamins.

In this section let us learn about the macronutrients: carbohydrates, fats, proteins, water and fibre, and how they nourish the body.


Nutrients, sources, functions

protein, Credits: pexels

Protein is a macronutrient that every cell in the body needs to function properly.

Proteins carry out a variety of functions, including:

  1. ensuring the growth and development of muscles, bones, hair, and skin

  2. forming antibodies, hormones, and other essential substances

  3. serving as a fuel source for cells and tissues when needed

  4. A person can take in proteins through their diet.

The following foods are good sources of protein:

  1. red meats (limit their use and choose lean cuts)

  2. poultry, including chicken and turkey

  3. fish and other seafood

  4. beans and legumes

  5. eggs

  6. dairy products

  7. soy

  8. nuts

  9. some grains, including quinoa


Nutrients sources, functions

fish, Credits: pexels

People often associate high fat foods with bad health. However, a person needs certain fats to help maintain optimal health.

Fats provide the body with energy and help it carry out a range of functions. However, it is essential to consume healthful fats, such as monounsaturated and polyunsaturated fats and limit or avoid saturated and trans fats.

Healthful fats help with the following functions:

  1. cell growth

  2. blood clotting

  3. building new cells

  4. reducing the risk of heart disease and type 2 diabetes

  5. muscle movement

  6. balance blood sugar

  7. brain functioning

  8. mineral and vitamin absorption

  9. hormone production

  10. immune function

According to recent Dietary Guidelines for Americans, a person should consume 20–35% of their calories from healthful fats.

A person can find healthful fats in several foods, including:

  1. nuts

  2. fish, such as salmon and tuna

  3. vegetable oils

  4. coconut oil


Nutrients sources, functions

carbohydrate, Credits: pexels

Carbohydrates are essential to the body. They are sugars or starches that provide energy for all the cells and tissues in the body.

There are two different types of carbohydrates: simple and complex. People should limit their intake of simple carbohydrates, such as white bread, pasta, and rice. However, the body needs complex carbohydrates to support the following:

  1. the immune system

  2. brain function

  3. the nervous system

  4. energy to perform tasks

  5. digestive function

The Dietary Guidelines for Americans recommend a person consumes 45–65% of their daily calories from complex carbohydrates.

The following foods contain complex carbohydrates:

  1. quinoa

  2. brown rice

  3. vegetables

  4. whole grain pasta, bread, and other baked goods

  5. oatmeal

  6. fruits

  7. barley

People should avoid overly processed products that contain bleached, white flour, and foods with added sugar.


Nutrients sources, functions

Water, Credits: pexels

Water is probably the most important essential nutrient that a person needs. A person can only survive a few days without consuming water. Even slight dehydration can cause headaches and impaired physical and mental functioning.

The human body is made up of mostly water, and every cell requires water to function. Water helps with several functions, including:

  1. flushing toxins out

  2. shock absorption

  3. transporting nutrients sources

  4. preventing constipation

  5. lubrication

  6. hydration

The best source for water is to drink natural, unsweetened water from the tap or bottled sources. For people who do not like the taste of plain water, they can add a squeeze of lemon or other citrus fruits.


Nutrients sources, functions

Fibre, Credits: pixabay

Fibre is a mixture of different carbohydrates which are not digested like other nutrients sources but pass through the gut nearly unchanged. Foods rich in fibre are ‘kocho’; vegetables like cabbage, ‘kosta’, carrots, cassava; fruits like banana and avocado; peas and beans; whole-grain cereals like wheat flour and refined maize or sorghum.

Including fibre in the diet

Fibre should be included in the diet for the following reasons:

  1. Fibre makes food bulky or bigger — this can help a person who is overweight to eat less food

  2. Fibre makes the faeces soft and bulky; this can help prevent constipation

  3. Fibre slows the absorption of nutrients sources, so it helps nutrients to enter the blood stream slowly. This is important for patients with diabetes mellitus.

Lets learn about the micronutrients now-


Nutrients sources, functions

Fruits, Credits: pexels

Vitamins are micronutrients that offer a range of health benefits, including:

  1. boosting the immune system

  2. helping prevent or delay certain cancers, such as prostate cancer

  3. strengthening teeth and bones

  4. aiding calcium absorption

  5. maintaining healthy skin

  6. helping the body metabolize proteins and carbs

  7. supporting healthy blood

  8. aiding brain and nervous system functioning

Fat soluble vitamins are:

  1. vitamin A

  2. vitamin D

  3. vitamin E

  4. vitamin K

Water soluble vitamins are:

  1. vitamin B-1 (thiamine)

  2. vitamin B-12 (cyanocobalamin)

  3. vitamin B-6

  4. vitamin B-2 (riboflavin)

  5. vitamin B-5 (pantothenic acid)

  6. vitamin B-3 (niacin)

  7. vitamin B-9 (folate, folic acid)

  8. vitamin B-7 (biotin)

  9. vitamin CVitaminsFunctionFood sourcesVitamin ANight vision

Healing epithelial cells

Normal development of teeth and bonesBreastmilk, tomatoes, cabbage, lettuce, pumpkins

Mangoes, papaya, carrots

Liver, kidney, egg yolk, milk, butter, cheese creamVitamin DNeeded for absorption of calcium from small intestines

Calcification of the skeletonUltra violet light from the sun

Eggs, butter, fish

Fortified oils, fats and cerealsVitamin KFor blood clottingGreen leafy vegetables

Fruits, cereals, meat, dairy productsB complexMetabolism of carbohydrates, proteins and fatsMilk, egg yolk, liver, kidney and heart

Whole grain cereals, meat, whole bread, fish, bananasVitamin CPrevention of scurvy

Aiding wound healing

Assisting absorption of ironFresh fruits (oranges, kiwi, mango, grapefruits, lemons)


Nutrients, sources, functions

vegetables, Credits: pexels

Minerals are the second type of micronutrients. There are two groups of minerals: major and trace minerals. The body needs a balance of minerals from both groups for optimal health.

Major minerals are:

  1. magnesium

  2. calcium

  3. phosphorus

  4. sulfur

  5. sodium

  6. potassium

  7. chloride

Major minerals help the body to do the following:

  1. balance water levels

  2. maintain healthy skin, hair, and nails

  3. improve bone health

Trace minerals are:

  1. iron

  2. selenium

  3. zinc

  4. manganese

  5. chromium

  6. copper

  7. iodine

  8. fluoride

  9. molybdenum

Trace minerals help with:

  1. strengthening bones

  2. preventing tooth decay

  3. aiding in blood clotting

  4. helping to carry oxygen

  5. supporting the immune system

  6. supporting healthy blood pressure

A person can ensure they consume enough minerals by including the following foods in their diet.

  1. red meats (limit their use and choose lean cuts)

  2. seafood

  3. milk and other dairy products

  4. nuts and seeds

  5. vegetables

  6. leafy greens

  7. fruits

  8. poultry

  9. fortified bread and cereals

  10. egg yolks

  11. whole grains

  12. beans and legumesMineralsFunctionFood sourcesCalciumGives bones and teeth rigidity and strengthMilk, cheese and dairy products

Foods fortified with calcium, e.g. flour, cereals. eggs, fish cabbageIronFormation of haemoglobinMeat and meat products

Eggs, bread, green leafy vegetables, pulses, fruitsIodineFor normal metabolism of cellsIodised salt, sea vegetables, yogurt, cow’s milk, eggs, and cheese

Fish; plants grown in iodine-rich soilZincFor children to grow and develop normally; for wound healingMaize, fish, breastmilk, meat, beansFluorineHelps to keep teeth strongWater

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