These micronutrients are vital for our immune system

Most of us know how important it is to eat healthy, since nutritional substances keep us in shape. However, the nutrients seem to have something in common with the measures against the spread of the new coronavirus: healthy people have a hard time believing that they are really necessary.

And there is another parallel: nutritional substances are not miracle remedies. And it is that, even with an exemplary nutritional state, we can get sick. However, a well-equipped immune system can fight pathogens more quickly and easily.

While micronutrients, i.e. vitamins and minerals, do not supply the body with energy, they are essential for cellular metabolism and the body's immune response. Which are the most important?

Vitamin A

Vitamin A is a generic term for fat-soluble compounds that exist in different forms in products of animal origin, as well as in fruits and vegetables. The active forms of vitamin A in our body are retinol, retinal and retinoic acid.

This micronutritive substance plays a key role in regulating the growth and specification of virtually all cells in the human body. Vitamin A is necessary for the development of the embryo and the formation of the organs of the fetus. Furthermore, it is essential for the development of the eyes and the visual faculty.

Retinoic acid is found in the skin and mucous cells of the respiratory tract, digestive system, and urinary tract, which represent the body's first battlefront against infection.

Foods rich in vitamin A include liver, carrots, kale, and spinach.

Vitamin C

Vitamin C is soluble and our body eliminates excess of it. Hence, an overdose is not to be feared. It is also an antioxidant, that is, it reduces the damage that free oxygen radicals cause to the body's molecules. These types of radicals form naturally in metabolic processes.

However, when levels increase excessively they cause oxidative stress. This mainly affects smokers. But also other poisons and harmful substances, such as certain chemotherapeutic agents, raise the level of oxidative stress and, with it, the demand for vitamin C.

It also plays an important role in the body's immune response. In the event of an invasion with pathogens, it stimulates the migration of immune cells to the site of infection and drives phagocytosis, the process by which pathogens are removed.

Vitamin D

This fat-soluble vitamin is special because, with the necessary amount of sun, our own body can produce it. Those who are not sure if they are sufficiently exposed to the sun are recommended a blood test to determine the status of vitamin D. Depending on the result, vitamin D supplements may be taken.

This micronutrient regulates the body's calcium and phosphorous levels, strengthening bones and teeth. A vitamin D deficiency is not only related to an increased risk of osteoporosis, but also of certain types of cancer, type 1 diabetes, as well as cardiovascular disease.

Likewise, vitamin D participates in the regulation of a multitude of genes of immunological relevance. For example, it regulates the expression of a gene that encodes an antimicrobial peptide, which participates in the body's non-specific defense mechanisms.

Vitamin E

This vitamin also works as an antioxidant: it protects cell membranes from oxygen free radicals. It plays an important role for our body's defenses because it protects immune cells from attacks and reduces the production of immunosuppressive factors, which suppress the immune system.

Vitamin E is believed to improve the defenses of older people. And some studies indicate that it could reduce the risk of diseases of the respiratory system.

Folate / folic acid

Folate is the generic term for a soluble B vitamin (vitamin B9), which is essential for cell division and cell growth. Since this nutritive substance participates in the production of nucleic acids and amino acids –and with it in the synthesis of DNA–, a deficiency can have serious consequences.

Pregnant women are encouraged to take a folic acid supplement (the synthetic form of folate) in the first trimester of pregnancy to reduce the risk of birth defects such as spina bifida in newborns. Also, folate is important for brain function. In one study, it was observed that sufficient supply of this micronutrient substance reduces the risk of dementia.

Green vegetables like cabbage or spinach, as well as lentils, peas, and beans are foods rich in folate.

B12 vitamin

This vitamin is important for nerve function and is involved in the production of red blood cells, protein, and DNA. Since immune cells have high metabolic activity, they need vitamin B12 to form new immune cells. This way they can react appropriately in the event of an attack. As age advances, the body's ability to absorb vitamin B12 decreases.

Since this is only found in foods of animal origin, vegans, vegetarians, as well as people with chronic digestive diseases are recommended to take supplements.


Iron deficiency is the most common nutritional deficiency in the world, affecting mainly children, women of reproductive age and pregnant women.

Iron plays a central role in the development of the central nervous system, where it participates in the formation of myelin sheaths, which allow the transmission of nerve impulses. In addition, the body needs iron for the synthesis of neurotransmitters, which also go into action in the nervous system.

The body absorbs iron better from some animal products than from plants. Hence, vegetarians and vegans must ingest sufficient amounts of vitamin C, which increases the absorption of iron.

Source: Julia Vergin for DW