Micronutrients: Definition, Types, Sources, Deficiency

Written by Ahmed Zayed | Last updated on August 4, 2023

Micronutrients are often overlooked in favor of more well-known macronutrients like protein, carbs, and fats. Yet, they play an essential role in maintaining good health.

Vitamins, minerals, and antioxidants, all very small molecules, perform essential roles in our bodies. From helping us grow strong bones and skin to boosting our immune systems and keeping our brains sharp.

Read on to learn everything you need to know about micronutrients and how to get the most out of your diet.

What are Micronutrients?

Micronutrients are substances necessary for growth and development in the body. However, they are required in smaller quantities. They're crucial to the body's metabolic processes. 

Minerals, vitamins, and anti-oxidants fall within this category.

Vitamins and minerals are essential for good health, but the human body is unable to manufacture them on its own. Getting adequate vitamins and minerals requires a varied diet, because the micronutrient concentration varies from meal to meal.

Certain diseases can be avoided or fought off with the aid of these micronutrients. However, they should be taken in sufficient quantities, as either an overdose or a deficiency can cause a variety of health problems.

Why are Micronutrients important?

Micronutrients are important for a multitude of reasons. Micronutrients keep us healthy. They enhance growth and development, immunological function, skin and hair health, cognitive function, and chronic illness prevention despite their modest size.

They’re needed for bone formation and maintenance in children and adults. Micronutrients play a vital role in enhancing immunity and fighting infections.

Other than that, they also help maintain healthy skin, hair, and nails. Certain micronutrients (omega-3 fatty acids, B vitamins, and choline) have a brain-boosting effect.

 Antioxidants (including vitamin E, vitamin C, and selenium) protect cells and may prevent chronic illnesses like heart disease, cancer, and Alzheimer's. Hence, eating a range of micronutrients helps us stay healthy and perform at our best. [1]

Role of Micronutrients in Human Health

Although increasing the intake of micronutrients is important for metabolism and tissue function, doing so won't prevent or treat diseases that aren't due to a lack of micronutrients.

This demonstrates how critical the body considers micronutrients to be. Getting enough is necessary for your body and tissues, but supplying too many micronutrients to those who don't need them might be hazardous.

To identify at-risk individuals and adjust their diets, additional research is needed to establish improved indicators of micronutrient status. [2]

Types of Micronutrients

Micronutrients, in the broadest sense, include all types of vitamins and minerals. [3]

Vitamin A

The body can store vitamin A because it is fat-soluble. Because of this, it may be used for a longer time after being consumed since it is stored in the body's fat.

Vitamin A is necessary for healthy eyesight, immunological function, reproduction, and growth and development in children.

Vitamin A is beneficial for the health of your heart, lungs, and other organs. It is found in a variety of foods, including liver, organ meat, green leafy vegetables, and fruits. Adult males and females should have 700 to 900 mcg daily. [4]

Vitamin B Complex

There are eight different B vitamins that make up vitamin B complex.. They’re all water-soluble, which means that they cannot be stored in the body. Hence, they need to be consumed regularly in the diet.

Vitamin B complex helps with nerve function and promotes healthy brain health. 

The production of energy, proper operation of the nervous system, mental and cardiovascular health, healthy skin, hair, and nails, and the synthesis of red blood cells are all improved by vitamin B complex. [5]

The recommended daily intake of B vitamins varies depending on the kind of B vitamin being discussed; for example, vitamin B12 requires 1.1–2.4 micrograms per day, whereas folate requires 400–800 micrograms per day.

Vitamin C

Ascorbic acid, or vitamin C, is a water-soluble vitamin. It is essential for proper tissue development and repair throughout the body. Collagen is a crucial protein required in the formation of skin, cartilage, tendons, ligaments, and blood vessels, is made with the help of vitamin C.

Healing wounds and rebuilding and preserving bones and teeth, both need vitamin C. It also acts as an antioxidant, preventing damage to the cells caused by free radicals.

Foods such as oranges, broccoli, and tomatoes are good sources of vitamin C. Vitamin C recommendations for adult males and females are 75–90 mg daily.

Vitamin D

As another important fat-soluble vitamin, vitamin D is an essential ingredient for bone development and maintenance. Your body can only absorb calcium in the presence of vitamin D. Vitamin D also regulates a variety of other biological processes in your body.

It helps the body's immune system, muscles, and brain cells. This is due to its antioxidant, anti-inflammatory, and neuroprotective properties.

Fortified milk and cereal, as well as fatty fish like salmon, mackerel, and sardines, are good sources of vitamin D. Your body can make vitamin D through exposure to sunlight.

This converts a chemical in your skin into the active form of vitamin D (calciferol). 600–800 IU (International Units) daily for people younger than 70, and 800–1000 IU daily for those older than 70.

Vitamin E

Many foods, including cereals, poultry, meat, vegetable oil, eggs, and fruits, are good sources of vitamin E. It is also a fat-soluble vitamin.

Vitamin E functions as an antioxidant. Antioxidants are compounds that may protect your cells from the effects of free radicals. There are possible links between free radicals and cancer, heart disease, and other illnesses.

Vitamin E is also an essential component for good eyesight, reproduction, and blood, brain, and skin health. Adult males and females should take 15 milligrams of vitamin E.

Vitamin K

Another member of the fat-soluble vitamin family, vitamin K helps the body in clotting of blood, maintains healthy bone mass, and controls calcium levels in the blood.

A deficiency of vitamin K is uncommon. This is due to the fact that leafy green vegetables also contain vitamin K, which your gut bacteria may also synthesize.

Prothrombin, a protein and clotting factor essential for blood clotting and bone metabolism, cannot be made without vitamin K.


The body's main mineral, calcium, is the most prevalent macromineral. Macrominerals, unlike trace minerals, are required at greater levels for your body to function properly.

 Calcium plays a significant role in the health of bones and teeth. It also initiates smooth muscle contraction and allows smooth nerve-to-nerve communication. It also plays a vital role in activating blood clotting factors.

Green leafy vegetables and dairy products are excellent sources of calcium. Both adult men and women need between 1,000 and 1,300 mg of calcium daily.


The human body needs iron to function properly.. Iron is required for development and growth, and it is also a key ingredient in hemoglobin and myoglobin.

Myoglobin is a protein that transports oxygen to the muscles, whereas hemoglobin transports oxygen from the lungs to the rest of the body.

Therefore, a lack of iron in the diet is one of the leading causes of anemia worldwide. Red meat, poultry, seafood, beans, and legumes are good sources of iron. Adult men and women need between 8 and 18 milligrams of iron per day, depending on their age and sex.


Following iron, zinc is the second most abundant trace micronutrient. Zinc strengthens the immune system and protects against infectious illnesses including malaria, cholera, and dysentery. To have a healthy pregnancy, zinc must be present in normal amounts.

Zinc plays an important role in enzyme function, protein structure, and the control of gene expression.

Beef, poultry, fish, and grains are all good sources of zinc. Adult males should have 8–11 milligrams daily, while adult females should have 8 milligrams daily.


Thyroid hormones include iodine, making it a vital micronutrient. Although an iodine shortage may cause a variety of problems at any point in life, it is especially important during early development since the fetal brain depends so heavily on it.

The thyroid stores 75% of the body's iodine, enabling it to produce hormones essential for growth, reproduction, brain development, healing, energy metabolism, the neurological system, and proper thyroid function.

Seaweed, fish, dairy products, and iodized salt are rich sources of iodine.


The majority of the magnesium in the body is found in the skeleton. The remainder is found in muscle, blood, and soft tissue. It is the 4th most abundant mineral in the body.

Magnesium is essential for many metabolic processes. These include processes such as energy creation, the metabolism of nutrients, and the synthesis of fatty acids and proteins.

It also plays a role in the transmission of nerve and muscle impulses and the regulation of blood sugar and blood pressure.

It has been shown that those with higher magnesium levels in the blood have a lower chance of developing cardiovascular disease. Adult men and women should have 310–420 mg of magnesium each day.


Because of its role as a trace mineral, selenium has a low dietary requirement.

Reproduction, metabolism, thyroid function, DNA synthesis, and immunity to oxidative stress and infection are all enhanced by selenium.

The antioxidant properties of selenium and its influence on DNA repair and the endocrine system suggest that it may be useful in preventing cancer.

Selenium can be found in foods such as Brazil nuts, seafood, poultry, meat, whole grains, and dairy products. Adults should consume 55–70 mcg of selenium daily. 

Micronutrient Deficiencies

Causes of Micronutrient Deficiencies

More than two billion people worldwide are micronutrient malnourished, with iron, zinc, iodine, selenium, and iron being the most often deficient. 

Some of the reasons that contribute to micronutrient deficiencies include poverty, a limited diet, a lack of awareness about healthy eating habits, and a high prevalence of infectious illnesses.

Symptoms of Micronutrient Deficiencies

Even though micronutrient deficiencies often go unnoticed by doctors, they may nevertheless contribute to serious health problems, including fatigue, poor concentration, and weakness. 

This may have a negative impact on a person's ability to learn, their productivity on the job, and their overall health. Some signs to look out for may be:

Thin Hair - Thyroid problems, which may cause either rapid weight gain or loss, or low iron levels, which sap your vitality, might be the cause.

Flaring mouth or feet can be due to a lack of iron or vitamin B12.

Zinc and vitamin C deficiencies can lead to slower wound healing.

Pain in the bones and a feeling of fatigue can point to a vitamin deficiency.

Cardiac arrhythmia (irregular heartbeat), tremors, and muscle twitching are signs of calcium deficiency.

High-risk groups for micronutrient deficiencies

Certain people with specific conditions are at a higher risk of developing micronutrient deficiencies. [6]

1.       Women who are expecting a child have higher dietary requirements, especially for iron, folate, and vitamin D.

2.       Children under the age of five have significant dietary requirements for growth and development, making them more susceptible to micronutrient shortages. This age group has special nutritional needs, especially for iron, vitamin A, and zinc.

3.       Plant-based diets may lack sufficient amounts of B12, iron, and zinc, which might pose health risks for vegetarians and vegans.

4.       The body's absorption and use of several micronutrients decline with age. Vitamin D and B12 deficiencies are especially frequent among the elderly.

5.       Patients Individuals with medical diseases such as celiac disease, Crohn's disease, or other malabsorption disorders may have difficulty absorbing certain micronutrients.

Micronutrient Supplements

Micronutrients should be naturally obtained from a healthy, complete diet. However, due to a number of reasons, you may not be able to obtain your complete nutrients. In such a case, supplements may be consumed on a doctor’s recommendation.

Types of Micronutrient Supplements

The different types of supplements available are:

Multivitamins: They’re a kind of dietary supplement that includes a number of different vitamins and minerals, usually in the levels specified by the RDA. You may get them in pill, capsule, gummy, or even liquid form.

Vitamins and Minerals: Unlike multivitamins, which include a wide variety of nutrients, individual vitamins and minerals only contain the one or two that the body needs. For example, Vitamin D supplements.

Combination: Vitamin and mineral combinations are a kind of supplement that are typically formulated for specific groups or medical conditions. Prenatal vitamins, for instance, are fortified with extra nutrients like folic acid and iron.

Infused Food and Drinks: Foods and drinks that have been fortified with vitamins and minerals to help with deficiencies. Examples are cereals, bread, and dairy products that have been enhanced.

Pros and Cons of taking Micronutrient Supplements

 Advantages of Micronutrients 

  1. Dealing with Malnutrition: Supplements may help eliminate vitamin and mineral deficiencies when diet alone is insufficient or when more nutrients are required by the body. 
  2. Positive Effects On Health: Vitamin supplements have been demonstrated to improve the health and longevity of persons with specific medical conditions including pregnant women. 
  3. Convenience: Vitamin and mineral supplements are a convenient tool to ensure sufficient intake.
  4. Adjustable dosing: Individuals that have different nutritional needs might benefit from taking supplements since they can be formulated with varying concentrations of vitamins and minerals.

Disadvantages of Micronutrient Supplements

  1. Potential Adverse Effects: Possible negative effects include feeling nauseous, throwing up, or having diarrhea if you take too much of certain micronutrients. 
  2. Incompatibility with medicine: Some vitamins have detrimental effects when used with prescription medicines, and the other way around.
  3. Over-usage: If you take supplements instead of eating a balanced diet, you may come to rely too much on them and risk not getting enough of the essential nutrients your body requires. 
  4. Improper Quality Control: Because of concerns with quality control, it's crucial to buy supplements from reputable brands and stores.

Risks of micronutrient supplements

The active ingredients in many supplements are rather potent. Keep an eye out for any adverse effects, especially when trying out new items. 

Negative reactions are more likely to occur if you take many supplements, use excessive doses, or utilize supplements in place of prescriptions.

Taking some supplements before surgery might raise bleeding risks and change how anesthesia works. It is possible for certain nutritional supplements to have an effect on prescribed drugs. 

During pregnancy and while feeding, you shouldn't take any supplements that aren't prenatal. Give kids vitamins only if their doctor says to. Several supplements' safety for use by kids and pregnant/nursing mothers is unclear. 

Vitamins C and E may reduce the effectiveness of several cancer therapies. Some breakfast cereals and beverages now incorporate nutritional supplements including vitamins and minerals. As a result, you could consume more of these chemicals than is required. 

The expenditures and potential side effects of overdosing are not worth it. Migraines, hepatitis, bone loss, and fetal abnormalities have all been linked to vitamin A. Nausea, vomiting, and liver damage are all symptoms of iron excess. [7]

Sources of Micronutrients in Foods

1.       Vegetables and Fruits

Vitamin A and C may be found in abundance in many different fruits and vegetables.

2.       Green Leafy Food

Foods like spinach, kale, and collard greens are great sources of iron and calcium in addition to vitamins A, C, and K.

3.       Seeds and Nuts

Almonds, sunflower seeds, and pumpkin seeds are all excellent dietary sources of vitamin E, magnesium, and zinc, among other minerals.

4.       Seafood

Omega-3 fatty acids, vitamin D, and selenium are abundant in fish like salmon, tuna, and sardines.

5.       Milk

Dairy products, such as milk, cheese, and yogurt, are rich in calcium, vitamin D, and vitamin B12.

6.       Whole Grains

B vitamins, iron, and fiber are abundant in whole grains including brown rice, quinoa, and oats.

Role in Diseases Prevention and Treatment

Micronutrients are important for preventing illness and treating it. Vitamins, minerals, and antioxidants can help prevent cancer, heart disease, and diabetes. 

By eating foods high in micronutrients, you may be able to avoid getting lung, stomach, and breast cancer. With enough vitamin D and calcium, you can keep your bones healthy and strong.

A lack of vitamins could also be bad for your health. If you don't get enough iron, you can get anemia. If you don't get enough vitamin A, you can go blind. Micronutrients help your body fight off infections and improve your immune system.

Micronutrients also help with the healing of a number of illnesses. Vitamins A and C can be used to treat both measles and scurvy. Zinc helps treat diarrhea and asthma in kids, while magnesium is used to treat preeclampsia in pregnant women.

Micronutrients can stop certain illnesses and can even make them go away. Foods that are high in micronutrients might help treat or prevent chronic diseases. To get enough micronutrients, you must eat a healthy, well-balanced diet or take the right supplements. [8]

Micronutrients and aging

Micronutrients play a role in how our cells work and how our bodies use energy. As we get older, they become even more important. Due to changes in food, intake, and use, a person's micronutrient level may go down as they age. 

This degeneration could lead to mental loss, weak bones, and heart disease, among other things.

Antioxidants like vitamins D, E, and C and anti-inflammatory substances like beta-carotene may help prevent diseases that come with getting older. Supplements of micronutrients could be helpful for older people.

Too much iron, copper, or zinc, on the other hand, can cause reactive stress and damage, which speeds up the aging process and makes you more likely to get chronic illnesses. [9]

Micronutrients misconceptions and myths

Some common misconceptions and myths related to micronutrients are:

  • There is a common belief that more is always better. Contrary to what most people think, getting too much of some micronutrients could be bad for your health.
  • Some believe that supplements can be an alternative to a healthy diet. Even though vitamins can help support health, they can't take the place of a well-balanced diet with a variety of healthy foods.
  • People believe that any kind of supplement is safe to consume. There is no way to know for sure that a supplement is safe and will work. Some supplements may mix badly with prescription drugs or have other unwanted side effects.
  • The use of micronutrient supplements instead of medication is a common mistake. A diet high in micronutrients can help avoid and treat diseases, but it can't do this on its own.

Frequently Asked Questions

What are the 7 micronutrients?

The seven essential micronutrients are Vitamin A, Vitamin C, Vitamin D, Vitamin E, Vitamin K, Vitamin B complex (B1, B2, B3, B5, B6, B7, B9, B12) and Minerals (such as calcium, magnesium, potassium and sodium) 

What is the definition of micronutrients?

Micronutrients are nutrients necessary for good health that the body needs in very little quantities.

Vitamins and minerals are examples of these nutrients; they're essential for a wide range of biological processes, including development, immunity, energy generation, and more. 

The human body is unable to generate micronutrients, hence they must be consumed or provided from outside. 


For optimum health and wellness, micronutrients are crucial. A shortage of even a single micronutrient may be harmful because of the widespread roles they play in the body. 

It's easy to achieve your daily micronutrient requirements by simply eating a healthy, well-balanced diet. People may also still benefit from taking micronutrient supplements. 

Micronutrient supplements are not intended to substitute for a balanced diet. They should be used only when prescribed by a doctor. By eating a well-balanced diet that includes a range of nutrient-rich foods, people can help support their general health and comfort.


[1] Brown, K. H., & Rivera, J. A. (2002). Nutrient management for the prevention of childhood stunting: the role of zinc and vitamin A. Journal of Nutrition, 132(9 Suppl), 2636S-435S. Retrieved from https://academic.oup.com/jn/article/132/9/2636S/4687524

[2] The key role of micronutrients - PubMed. (2006, February 1). PubMed. https://doi.org/10.1016/j.clnu.2005.11.006

[3] Gaziano JM, Sesso HD, Christen WG, Bubes V, Smith JP, MacFadyen J, Schvartz M, Manson JE, Glynn RJ, Buring JE. Multivitamins in the Prevention of Cancer in Men: The Physicians' Health Study II Randomized Controlled Trial. JAMA. 2012;308(18):1871–1880. Retrieved from https://jamanetwork.com/journals/jama/fullarticle/1390482

[4] National Institutes of Health. (2021). Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes, Elements. Office of Dietary Supplements. Retrieved from https://ods.od.nih.gov/HealthInformation/Dietary_Reference_Intakes.aspx.

[5] Fairfield KM, Fletcher RH. Vitamins for Chronic Disease Prevention in Adults: Clinical Applications. JAMA. 2002;287(23):3127–3129. Retrieved from https://jamanetwork.com/journals/jama/fullarticle/195751

[6] Prevalence and Consequences of Micronutrient Deficiencies in Low- and Middle-Income Countries retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5986487/

[7] Dietary Supplements and Adverse Event Outcomes in Children and Young Adults, by F. R. Ernst and T. Grizzle, JAMA Network Open, 2018. Retrieved from https://doi.org/10.1001/jamanetworkopen.2018.3627.

[8] Weaver CM. Calcium. In: Shils M, Shike M, Ross AC, Caballero B, Cousins RJ, eds. Modern Nutrition in Health and Disease. 10th ed. Lippincott Williams & Wilkins; 2006: 190-202, retrieved from https://www.ncbi.nlm.nih.gov/books/NBK216793/

[9] Micronutrient (Zn, Cu, Fe)-gene interactions in aging and inflammatory age-related diseases: implications for treatments, retrieved from https://www.sciencedirect.com/science/article/abs/pii/S1568163714000722




About the author 

Dr Ahmed Zayed is a medical resident specializing in plastic surgery with years of experience in the field. He is also a writer for top-rated websites including Washington Post, Chicago Tribune, ConsumerHealthDigest, and Huffington Post

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