If you wish to strengthen your immune system, make sure you get enough vitamins, minerals, and amino acids. Frequent infections as well as allergies strain the immune system and increase the demand for almost every micro-nutrient.

Stress puts additional burden on the immune system, as does the aging process. The amount of vitamins and amino acids required to keep the immune system functioning effectively thus increases significantly. Deficiencies in vitamins, minerals, or amino acids inevitably lead to a diminished immune defense.

As long as our immune system is in balance, it functions unnoticed in the body and carries out the following tasks:

  • Defense against foreign substances and organisms (viruses, bacteria, fungi, and parasites),
  • Wound healing and repair of damaged cells,
  • Rejection of substances foreign to the body,
  • Acceptance of nutrients for consumption by the body,
  • Disposal of destroyed cell material.

The effectiveness of the immune system depends on the proper functioning of several organs. These can be divided into physical defense (skin), general defense (natural killer cells, phagocytes, white blood cells), and the specific, learned immune defense:

  • Skin and intestinal mucosa (incl. gastrointestinal tract) as external protection,
  • Bone marrow (produces white blood cells),
  • Thymus,
  • Spleen,
  • Lymphatic system.

The amino acids, minerals, and vitamins listed below are of particular importance. Deficiencies in these micro-nutrients, as a result of stress and other factors, can have negative effects on the immune system:

  • L-arginine
  • L-cysteine
  • L-methionine
  • Vitamin A
  • Vitamin C
  • Vitamin D
  • Vitamin E
  • B Vitamins
  • Zinc
  • Iron, copper, selenium, manganese

Signs of immune weakness include increased frequency of infections and unusually long periods of illness.

Auto-immune disorders and allergies point to an overactive immune system. Sometimes inflammation is the result of an excessive immune response.

Sugar and white flour are the enemies of a well-functioning immune system. These sources of energy are often referred to as “empty calories”. Unfortunately, in today’s diets, they are increasingly displacing the foods rich in vitamins and amino acids that the human body requires. Just 100 grams of sugar (the sugar content of a liter of soda) can negatively affect the function of white blood cells for a period of five hours. Protection from viruses and bacteria is then less effective.

Amino Acids Strengthen the Immune System

Vitamin C and Zinc are the most recognized natural supporters of a healthy immune system. The importance of amino acids in immune health was not understood until the last twenty years or so. This explains why knowledge regarding the immune functions of amino acids is still not very prevalent.


Strengthening the immune systemL-glutamine is a building block of glutathione and functions as an immunoregulator as well as an antioxidant. Glutamine is a key energy supplier to the cells of the immune system undergoing rapid mitosis (cell division). Taking glutamine has also been found to improve the functioning of intestinal mucosa 1 and thereby contributes to the stabilization of the immune system. 2 Glutamine deficiency increases susceptibility to infections.3

Glutamine is well tolerated and can also be taken in higher doses of several grams per day. People with epilepsy should take higher doses only after consultation with their physician.


L-arginine is an element of white blood cells and can significantly contribute to the effectiveness of the body’s defense against viruses. A study conducted as early as 1991 shows the positive effects of L-arginine on white blood cells.4 Because L-arginine also stimulates collagen synthesis, supplementation with the amino acid can lead to improved wound healing.


L-cysteine can contribute to the elimination of heavy metals. It functions as an immunoregulator and, together with glutathione, forms one of the most powerful antioxidants. Individuals with a compromised immune system often evidence low levels of L-cysteine.

In the form of N-acetyl-cysteine (NAC) and dosages starting at approx. 400 mg – 600 mg per day, cysteine is a medication you can get without a prescription to facilitate active transport across mucosa. Dosages of 100 mg per day and up in the form of cysteine are effective as a nutritional supplement. To improve glutathione synthesis, cysteine should be taken together with vitamin C.

Cysteine is also an important building block of keratin in hair. In addition to diminished immune defenses, a deficiency in cysteine can also lead to hair loss.


Lysine has antiviral properties and is recommended as an inhibitor of herpes viruses and shingles (herpes zoster). 5 Lysine’s immune-stimulating and virus-inhibiting functions in herpes cases has been documented in several studies. 6

Taking lysine in combination with L-arginine is recommended. Lysine is well tolerated and doses of up to 3 grams per day are considered safe for healthy adults.


L-carnitine is known for its functions in fatty acid transport. However, L-carnitine also plays a major role in the immune system. Individuals with weakened immune systems often evidence low levels of L-carnitine. 7 An American study shows that giving these individuals supplementation with L-carnitine improves immune defense on several levels .8

L-Carnitin helps protect cells from oxidative stress and contributes to the protection of nerve cells.

Vitamins and Minerals that Strengthen the Immune System

Almost all vitamins are involved in maintaining immune defenses on some level. Any type of vitamin deficiency thus goes hand in hand with a weakened immune system.

Vitamin C

Immune System and Vitamin CVitamin C (ascorbic acid) is the most well-known and researched supplement. It is safe to take vitamin C in doses of up to several grams per day. With higher dosages, the amount of vitamin C that the body can actually use decreases and the amount that is eliminated increases. Nonetheless, it is widely accepted that Vitamin C in high doses of up to 10 grams per day is not harmful.

According to European agencies, the recommended daily allowance of Vitamin C for a healthy, young non-smoker is 80 mg. More than 30% of the population do not get this amount through a regular diet. 9 This amount is also not enough to restore a compromised immune system. 10

Moreover, vitamin C is used when taking medications such as aspirin®. Smokers need twice the amount of vitamin C that non-smokers require.

Vitamin C controls histamine levels in the body. Deficiencies in vitamin C lead to elevated histamine levels in the blood. Histamine is released in allergic or asthmatic conditions and is the cause of allergic symptoms. If you are suffering from allergies or asthma, daily doses of at least 800 mg of vitamin C are recommended.

Because low levels of vitamin C weaken immune defenses, it is recommended that you take vitamin C together with your medication when fighting the flu.

Vitamin D

Supporting the Immune System with Amino AcidsVitamin D is rarely found in food and is synthesized in the skin through UV radiation. To generate vitamin D in the skin, the sun has to be at least 30 degrees high in the sky, and its rays have to reach a UV index of at least 3. In central Europe, these conditions are only met from March to September around noon. As a result, 9 out of 10 central Europeans have a vitamin D deficiency. Even in southern Europe, the majority of people cannot synthesize sufficient vitamin D.

Vitamin D has extensive functions in the immune system and its effects can be remarkable. In a renowned study, the effectiveness of vitamin D as prevention against the flu was compared to the effectiveness of a flu shot. The result: taking vitamin D provided eight times the protection of the flu shot!

A study conducted in 2007 shows a clear correlation between upper respiratory tract infections / asthma and low blood levels of vitamin D. 11

B Vitamins

In addition to immune functions, vitamins of the B complex play in important role in energy metabolism and nerve function. Niacin (B3) slows the release of histamine and is therefore commonly recommended for allergies. Lack of energy and fatigue, both signs of an overworked immune system and often caused by deficiency in vitamin D, can be effectively addressed by supplementing with a vitamin B complex (B1, B2, B6, B12, folic acid, niacin, pantothenic acid).

Of all the B vitamins, vitamin B12 is particularly important as it is directly associated with a normally-functioning immune system.

Vitamin E

Vitamin E is a strong, fat soluble antioxidant. It is an anti-inflammatory and helps regulate the immune response. High doses of vitamin E may lower cytokine levels. Approx. 50% of the population do not get the recommended daily allowance of vitamin E. 12

Vitamin A

Vitamin A helps regulate immune function. Supplementation with vitamin A should not exceed 100% of the recommended daily allowance, as the first undesirable side effects may become noticeable starting with dosages of 500% of the recommended daily allowance. A better approach is to make carotinoids available to the body. The body can convert these into vitamin A on an as-needed basis. Taking up to 100% of the recommended daily allowance of vitamin A should be sufficient.


Zinc is of central importance to a healthy immune system and is responsible for regulating the immune response. Studies have shown that taking high doses of zinc in combination with vitamin C can cut the duration of a cold in half. 13

For short-term therapy, up to 75 mg of zinc can be taken daily. For longer-term therapy in immune support, only 15 mg of zinc per day are recommended. 14

Copper, Selenium, Manganese, Iron

Zinc should be taken with supplemental copper, because zinc may have negative effects on copper levels. Additionally, copper supports normal functioning of the immune system.

Selenium can help slow the proliferation of viruses and boost the immune system. Manganese is believed to lessen the susceptibility to allergies. Iron is another contributor to effective functioning of the immune system.

Plant Materials

So-called phytochemicals can enhance vitamins and contribute to strengthening the immune system.

Cranberries are known to support urinary tract health (bladder, urethra, kidneys). Several studies have shown that the length and severity of bladder infections can be reduced with cranberries.

Pine bark extract has a high content of proanthocynadins, which can help the body process vitamin C and E. This gives the body a chance to recycle these antioxidants on an as-needed basis. A study on colds confirmed the positive effects on the immune system. Supplementation with pine bark extract, vitamin C, and zinc led to a 50% reduction in the duration of colds.

Additional Tips for a Strong Immune System

Strengthening the immune systemA compromised immune system cannot be restored in a matter of days or weeks. It requires long-term support through a healthy and balanced diet. The following information will help you achieve a strong and balanced immune system:

  • Smoking affects the function of white blood cells. Smokers are therefore far more susceptible to infections.
  • Stress, fear, and sadness also stress the immune system and weaken it. Be sure to get some type of stress release during periods of stress. Boost your immune system even more with a healthy diet.
  • The immune system requires sufficient sleep and exercise.
  • It is important to strengthen your immune system over the summer so that you do not begin winter with an already weakened defense.
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Which products are best for strengthening your immune system?

Good compositions and high-grade raw materials do not have to be expensive. These products with amino acids and vitamins are recommended for every season.
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  1. Benjamin, J, et al.; “Glutamine and Whey protein improve intestinal permeability and morphology in patients with Crohn´s disease: a randomized controlled trial.” Dig Dis Sci 2011, Oct 26
  2. Anderson, PM, et al; “Oral glutamine reduces the duration and severity of stomatitis after cytotoxic cancer chemotherapy”; Cancer 1998; 83, pp 1433-1485
  3. Castell, L.M. “Does glutamine have a role in reducing infection in athletes?”; European Journal of Applied Physiology; 73, (1996); pp 488-490
  4. Park, G, et al “stimulation of lymphocyte natural cytotoxicity by L-Arginine”; The Lancet, March 16, 337 (1991); pp. 645 – 646
  5. Gaby AR, “Natural remedies for Herpes simplex”; Alt Med Rev 2006; 11(2), pp. 93 – 101
  6. Wright, EF; “Clinical effectiveness of lysine in treating recurrent aphtous ulcers and herpes labialis”; Gen Dent 1994; 42; pp. 40-42
  7. De Simone et al., “L-Carnitine depletion in peripheral blood mononuclear cells from patients with aids: effect of oral L-Carnitine”; AIDS, 8, pp 655 – 660; 1994
  8. Uhlenbruck, G., A. van Mill, “Immunbiologische und andere Aspekte der Membranmodulation durch L-Carnitin”; Echo Verlag, Köln, 1993 (“Immuno-biological and other aspects of membrane modulation through L-carnitine”)
  9. Nationale Verzehrsstudie 2008, Teil 2, Ergebnisbericht (National Consumption Study 2008, Part 2, Results Report
  10. Maggini, S. ; “Vitamins and minerals. Contribution to immune function and health”, Watson RR et al: “Dietary components and immune function”; 2010, pp 227 – 252
  11. Ginde et al., “Vitamin D, respiratory infections and asthma”; Curr Allerg Asthma Re; 2009; 9:pp 81 – 87
  12. Nationale Verzehrsstudie 2008, Teil 2, Ergebnisbericht (National Consumption Study, Part 2, Results Report
  13. Prasad AS et al., “Duration of symptoms and plasma cytokine levels in patients with the common cold treated with zinc acetate.”; Ann intern Med; 2000; 133, pp 245 – 252
  14. Singh, M. “Zinc for the common cold”; Cochrane databse of systematic reviews 2011, issue 2
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