What Are Micronutrients?

Lucy Bell-Young

by Lucy Bell-Young

29th September 2021

Micronutrients are nutrients our bodies need in very small amounts. They’re better known as the vitamins and minerals that are found in our everyday diets, especially in things like fruits and vegetables. Unlike macronutrients, we don’t derive energy or building blocks for cells and tissues from micronutrients. 

Micronutrients Explained

Maintaining a healthy and normally functioning body isn’t possible without micronutrients. As the “micro” part of the name implies, these nutrients are only needed in trace amounts. Unlike the three major macronutrients (carbohydrates, proteins, and fats), micronutrients aren’t the main sources of energy and raw materials. 

Instead, they mainly serve as coenzymes in several metabolic processes. They facilitate the use of energy and synthesis of many other necessary biochemicals, such as hormones.

Micronutrient deficiency can cause serious health issues, some of which could even become life threatening. Here are some of the serious health issues related to micronutrient deficiency:

  • Vitamin C deficiency: Commonly known as scurvy, this is one of the well-documented health problems faced by sailors on long voyages, when they would have to endure months without eating any fresh fruits and vegetables. Symptoms include bleeding gums, irritability, joint pains, and depression.
  • Vitamin A deficiency: In some poor or developing countries, many people suffer from blindness due to vitamin A deficiency. Other symptoms include a compromised immune system, skin irritations, and stunted growth. Dairy products like cheese and milk are good sources of vitamin A.
  • Vitamin D deficiency: Vitamin D deficiency causes rickets, which is characterised by soft, weak bones, especially among young children. It typically leads to skeletal deformities like bowed legs. Vitamin D deficiency was so common in the 1930s that it prompted some governments to mandate the vitamin D fortification of milk. Other symptoms of rickets include joint pains and dental problems.
  • Iron deficiency: People who are deficient in iron are anaemic. Symptoms include deep fatigue, pale skin, shortness of breath, cold extremities, chest pain, and poor appetite. Some of the best dietary sources of iron are red meat, organ meat, shellfish, beans, and green leafy vegetables.
  • Iodine deficiency: Dietary iodine from fish and other types of seafood, including seaweed, is essential in the production of thyroid hormones, namely thyroxine (T4) and triiodothyronine (T3). These hormones regulate the amount of calories used by the body, and help regulate the basal metabolic rate. Severe iodine deficiency has been found to cause a drop in children’s IQs by more than 12 points.
  • Vitamin B12 deficiency: Vitamin B12 deficiency can cause fatigue, lethargy, pale skin heart palpitations, depression, irritability, and headaches. Great sources of vitamin B12 include organ meat, eggs, shellfish, and milk products.
  • Calcium deficiency: Similar to vitamin D deficiency, calcium deficiency can cause weakness of the bones, which can lead to osteoporosis. Other symptoms include muscle cramps or pains, numbness or tingling in the hands and feet, pain in the thighs when walking, extreme fatigue, dry skin, depression, and dental problems.
  • Zinc deficiency: Children who are deficient in zinc may have stunted growth and weak immune systems. It may also cause hair loss, diarrhoea, and delayed sexual maturation. Some excellent dietary sources of zinc are meat, shellfish, legumes, eggs, and dairy products.
Multivitamins and supplements with fresh and healthy fruits on white wooden background
Micronutrients are mostly found in fruits and vegetables, as well as vitamin supplements

How Many Micronutrients Are There?

Micronutrients are classified into four categories: fat-soluble vitamins, water-soluble vitamins, macrominerals, and trace minerals. Some of these micronutrients are so essential that they shouldn’t be left out of the daily diet.

  • Fat-soluble vitamins: These are vitamins A, D, E, and K. As the name implies, they can be dissolved in fats. They tend to be deposited in the fat tissues of the body and can potentially cause poisoning when taken in large amounts.
  • Water-soluble vitamins: These include vitamin B complex and vitamin C. As the name suggests, they can be dissolved in water. These don’t accumulate in the body, and can easily be metabolised and excreted. Therefore, overdosing with supplements for these vitamins is virtually impossible. The only real side effect is that you would have to urinate a lot!
  • Macrominerals: These are minerals that are needed in larger amounts compared to trace minerals. One example is calcium, which is essential for bone growth and maintenance.
  • Trace minerals: Trace minerals are only needed in small amounts in order for the body to function properly. An example of these is zinc, which is important for immunity and healing wounds.

The human body needs 13 essential vitamins and 14 essential minerals. Therefore, in total, 27 micronutrients are needed by the body.

Examples of Micronutrients

Again, we can divide the micronutrients into four categories. Continue reading for some examples and descriptions of these.

Examples of fat-soluble vitamins

  • Vitamin A: Otherwise known as retinol, this vitamin has an essential role in vision. It has two forms: the retinoids and the beta carotene. The first type is from animals and dairy products, while the other type is from plants. Vitamin A functions as an antioxidant and it also has a role in immunity. Depending on your age, sex, and health conditions, you shouldn’t take more than the reference nutrient intakes (RNI) for vitamins per day. For example, if you’re a male who’s above 50 years of age, the RNI for vitamin A is 700 µg/day
  • Vitamin D: Otherwise known as calciferols, vitamin D is a group of fat-soluble secosteroids that are involved in the absorption of calcium, magnesium, and phosphates in the intestines. This vitamin mainly has a role in promoting healthy bones and teeth, but it also has other roles, such as regulating insulin. Again, you should follow the RNI, or the recommendation of your physician, when taking it

Examples of water-soluble vitamins

  • Vitamin C: This is also known as ascorbic acid, and is arguably the most important vitamin because it has a crucial role as an antioxidant that fights free radicals as an immune system booster. Citrus fruits are rich in this vitamin. Vitamin C also plays a role in building collagen and absorbing iron. Those who are between the ages of 15 and 50 years old need at least 40 mg/day of vitamin C.
  • Vitamin B9 (folate): Folate is important to healthy cell division. A pregnant person must have the proper intake of this vitamin (at least 10 mg/day) during the first few weeks of pregnancy. Seafood, beans, liver, and sunflower seeds are some excellent sources of vitamin B9.

Examples of macrominerals

  • Calcium: This mineral is important in forming and maintaining bones and teeth. It also has a role as a neurotransmitter in muscle movement. Calcium regulates blood pressure through the contraction of blood vessels. The RNI for this is 700 mg/day for those who are 50 years old and above.
  • Phosphorus: This macronutrient is an important component of the cell membrane’s phospholipid structure, and it’s also used in ATP production for energy purposes. The RNI for this is 625 mg/day for those who are between 11 and 14 years old.

Examples of trace minerals

  • Iron: Although this is the central atom of haemoglobin in the blood, which carries oxygen and carbon dioxide, only a small amount is necessary on a daily basis from dietary or supplemental sources. For example, individuals who are between 19 and 50 years old only need 14.8 mg/day based on the RNI table.
  • Selenium: Selenium is important for thyroid health, healthy reproduction, and as an antioxidant. The RNI is 60 µg/day if you’re between 15 years old and 50 years old or older.
3D render of different color glossy vitamin and mineral pills capsules

What Are Micronutrients Measured in?

Micronutrients are typically measured either in milligram of intake per day or in microgram of intake per day. These are based on the RNIs established by the UK’s Committee on Medical Aspects of Food and Nutrition Policy.

How to Calculate Micronutrients in Food

Calculating the micronutrients in food may slightly differ depending on the standards used. For instance, in the UK, you can use the RNI table. This is more of an estimated range depending on the type of food and dietary requirements of an individual.

You can also use an online nutrient calculator to specify the food. You simply need to add the amounts of micronutrients in the meal that you eat each day. You can calculate it for the whole day or just for one meal. Then you can compare it to the RNI table – though this method could also be done the other way around. If you’re a nutritionist, the precise calculation is essential.


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