Support the immune system with micronutrients

The immune system – highly complex interaction

The human immune system (lat. immunis = untouched, free, pure) is highly complex and sensitive. It is a close interplay of various organs (e.g. bone marrow, thymus, lymph nodes, (intestinal) mucous membranes), special white blood cells called leukocytes (e.g. granulocytes, macrophages, natural killer cells) and hormones. The immune defence consists of a non-specific, innate part and a specific, acquired part, which complement and support each other. From birth, the non-specific immune defence is able to react to various foreign substances and intruders as the first instance and render them harmless on first contact. However, it can hardly differentiate between the various intruders. In contrast, the specific immune defence only builds up in the course of life and continues to develop. So-called memory cells recognise pathogens with which the organism has already come into contact and trigger a specific immune response. However, our immune system is not only responsible for dangers “from outside”, but is also armed to fight against altered body cells on a daily basis. It also keeps cancer cells in check in the vast majority of cases.

The intestine – central organ of the immune system

The intestine is not “only” responsible for digestion and the absorption of nutrients from food, but also plays a very important role in the immune system. Apart from the skin, our intestines have the largest contact surface with the outside world and therefore have to defend themselves against all kinds of intruders. With a length of around eight metres and an internal surface area of 400-500 square metres, it is the largest immune organ. Around 80 per cent of all defence cells are found in the intestinal immune system. The intestine harbours the central training camp of the immune system, so to speak. This is modulated by the intestinal microbiome and is of great importance for the functioning of the defence system. There is a lively interaction between the gut microbiome and the immune system. The microbiome influences both the innate and the acquired immune system and plays a decisive role in the body’s own defences. This clearly explains why a healthy gut is essential for a well-functioning immune system. If the immune system is weakened, if you are struggling with frequent infections, allergies or autoimmune diseases, you should always think about your gut health!

How can you strengthen the immune system?

As complex as the immune system is, the measures we should take to support our body’s own defences to ensure they function smoothly are just as varied. This definitely includes a healthy and balanced life; a good life balance! A wholesome diet, moderate exercise, sufficient sleep and enough rest and relaxation. Positive social contacts, enjoyment and avoiding stress as much as possible are also important.

However, we will only go into more detail here about nutrition and supplements.

Immune-healthy diet

Our immune system loves a diet that provides a sufficient amount of macronutrients (proteins, fats, carbohydrates) and micronutrients such as vitamins, minerals and phytochemicals. In order to meet these requirements as far as possible, seasonal and organic fruit and vegetables, as well as wholemeal products, pulses and healthy fats should often be included in the diet. A healthy and varied diet is the basis for supporting the immune system and can be supplemented with food supplements if necessary. Good intestinal function is a prerequisite for good absorption of nutrients.

Important nutrients for the immune system

A supply of various nutrients is essential to strengthen the body’s defences. The following substances support the body’s own protective shield and thus maximise the body’s defences. In this way, the body is strengthened from the inside out. As the name suggests, dietary supplements are used to supplement a healthy and balanced diet, but are by no means a substitute for it. However, if there are deficiencies in individual micronutrients, these can hardly be replenished through diet alone.

Vitamin A

The skin and mucous membranes are an important barrier against unwanted intruders. The skin and mucous membranes are strengthened by vitamin A, among other things. If the skin and mucous membranes function optimally, this prevents many pathogens from entering the body in the first place. In order to produce vitamin A ourselves, provitamin A – better known as beta-carotene – is necessary. It is found in carrots, tomatoes, spinach, apricots and sea fish.

B vitamins

The B vitamins include eight different vitamins:

• Vitamin B1: Thiamine
• Vitamin B2: Riboflavin
• Vitamin B3: Niacin
• Vitamin B5: pantothenic acid
• Vitamin B6: pyridoxine, pyridoxamine and pyridoxal
• Vitamin B8: Biotin
• Vitamin B9: Folic acid
• Vitamin B12: cobalamin

They are all different and also differ greatly in their effect on the body. What they have in common is that we need them every day, as our body cannot or can hardly store them as they are water-soluble. They also contribute to a normal energy metabolism and can reduce tiredness and increase performance. Another positive effect that directly affects the immune system: the vitamins help to recognise pathogens as such so that the body can better defend itself against them. They also protect against oxidative stress and help to keep the mucous membranes intact. To get enough B vitamins, you should eat meat and fish, cheese, cereals, pulses and wholemeal products.

Vitamin C

Vitamin C, also known as ascorbic acid, is well known and well researched. It is considered an immune booster and is therefore contained in various products that are supposed to help strengthen the immune system. It has antioxidant properties and protects cells from oxidative damage caused by free radicals. It also promotes the formation of white blood cells. Fruits and vegetables rich in vitamin C include citrus fruits, kiwi, blackcurrants, cabbage, chilli peppers, spinach and broccoli.

Vitamin D

If you want to support your immune system, you should also make sure you have good vitamin D levels. Vitamin D is considered a key hormone for a functioning immune system. This is basically because it activates the so-called T-cells, the body’s defence cells, and regulates the immune system. However, this is not the only effect associated with vitamin D intake. The vitamin also has a positive effect on the genes involved in the development of autoimmune diseases. The human body is able to produce vitamin D in the skin itself with the help of the ultraviolet (UV) component of sunlight. However, a sufficient amount is not usually produced in summer to be able to draw on it in winter. In our latitudes, there is not enough sunlight between October and April. According to the FOPH, at least half of the population has a deficiency(Federal Office of Public Health 2012. Vitamin D deficiency: data, safety and recommendations for the Swiss population). Only a small proportion of the vitamin can be absorbed through food; it is contained in small amounts in mushrooms, eggs, cheese, salmon, herring and tuna.

Vitamin E

Vitamin E also protects cells from oxidative damage. The following cells are positively influenced by vitamin E:

• Dendritic cells: so-called cellular “outposts” of the immune system

• Macrophages (scavenger cells): kill pathogens

• Natural killer cells: directly eliminate virus-infected cells and tumours

• T lymphocytes: fight viruses, bacteria, fungi and other foreign substances; regulate the immune defence system

• B lymphocytes: produce defence substances

If you want to absorb vitamin E through food, you should choose vegetable oils and nuts.

Zinc

Similar to vitamin C, the B vitamins and vitamin E, zinc also protects the cells with its antioxidant effect. In fact, it is precisely the combination of the trace element and vitamin C that is so effective. However, zinc itself is also active and is an important component of the defence system. Zinc can be obtained in the diet from seafood, sea fish, milk, beef and poultry. Oatmeal, pumpkin seeds and wheat bran also contain the mineral.

Selenium

Selenium is one of the important trace elements for strengthening the immune system. A selenium deficiency can lead to increased susceptibility to infections. Without sufficient selenium, the immune system is significantly weaker. The T cells become sluggish or there are not enough of them. Selenium is also essential for the metabolism of thyroid hormones. These in turn are important for metabolising food and have an effect on the bones and nervous system. The body therefore needs the trace element for a variety of functions. Tips for selenium-containing foods: meat, fish, eggs, nuts, cabbage and onion vegetables, lentils, asparagus, mushrooms.

Iron

Like selenium, iron is one of the trace elements that the body needs for a strong immune system. An iron deficiency weakens the immune system, which can have a negative impact on health. Incidentally, the nutrient can also be taken during a cold or if you have gastrointestinal complaints. It supports recovery and can prevent other germs from entering the body. Red meat in particular, but also liver, contains a lot of iron.

Copper

Copper is necessary for the body to be able to absorb iron in the first place. It also protects the cell membranes and fends off free radicals. Copper also helps to transport electrons and thus ensures a balanced energy balance in the body. Foods containing copper: liver, nuts, seeds, shellfish and cocoa products.

Essential amino acids

Amino acids fulfil a variety of functions in the human body, but most people are unaware that they also play a role in our immune system. Proteinogenic amino acids are the building blocks of human proteins (proteins). The following amino acids are considered essential (they must be ingested through food and cannot be synthesised by the body):

• Isoleucine
• Leucine
• Lysine
• Methionine
• Phenylalanine
• Threonine
• Tryptophan
• Valine

Individual amino acids can, for example, help to keep the intestinal mucosa healthy or activate the thymus gland, which is part of the immune system. They influence the maturation of lymphocytes (immune cells) and help to form antibodies and antioxidants.

Probiotics

As already mentioned, the intestinal microbiome has a major influence on our immune system. A healthy and balanced diet and lifestyle can support the beneficial microorganisms. If the gut microbiome is out of balance, it is important to rebuild it and support the body in doing so. To this end, fermented foods such as sauerkraut or kefir and plenty of fibre should be included in the daily diet. Food supplements containing beneficial bacteria (probiotics) and their food (prebiotics) and ferments can also be taken.