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How to prevent the virus infections of winter time

How to prevent the virus infections of winter timeLack of vitamin D and selenium increases your risk of catching a cold or the flu or accompanying complications. Many people resort to Echinacea, ginger, and smoothies filled to the rim with vitamin C and secondary immune compounds, but these measures can never replace the two essential nutrients, selenium and vitamin D.

It is a common misconception that catching a cold or the flu is perfectly normal. If your immune system functions optimally, it can easily ward off the bugs that go around during the wintertime. What is necessary, however, is that the white blood cells of the immune system are properly supplied with energy and the different nutrients they need in order to carry out attacks on microorganisms and to produce antibodies. Even if we stick to the official guidelines for healthy eating, it is very difficult to get enough vitamin D and selenium, at least if we want our immune system to function optimally.

Of course, proper hygiene is vital for avoiding disease, but a strong immune defense is normally able to ward off contagions.

Why you should avoid virus infections and its complications

Our innate, nonspecific defense system that consists of special proteins and white blood cells (macrophages, monocytes, and granulocytes) is able to deal with most infectious germs without us ever knowing that they entered our bodies. However, if there are too few available resources, the macrophages get support from our acquired (adaptive) immune system that consists of T and B lymphocytes, and it is this whole battle process and some special compounds called cytokines that make us sick. Under normal circumstances, a virus infection should be over within a week or so, after which we are back to normal with increased immune strength. However, if the immune system is very weak, there is a risk that bacteria from our natural esophageal microflora spread to the bronchi, lungs, or middle ear where they are the cause of complicated infections. This may pose a threat to older people, cancer patients, and others with a compromised immune system, as they risk dying of pneumonia.

The immune system cannot function without vitamin D

All our cells have vitamin D receptors, even the immune cells. Vitamin D produces more than 200 different antibiotic peptides and controls loads of genes that strengthen the immune system and counteract undesirable inflammation. According to Professor Carsten Geisler from the Faculty of Health and Medical Sciences at University of Copenhagen, T-cells are every bit as dependent on vitamin D, as a car depends on its battery in order to run. As soon as the white blood cells recognize a virus or a bacteria, they start multiplying explosively and attack the intruder like an aggressive and highly focused army of soldiers. This, however, requires sufficient amounts of vitamin D in the body.

Lack of vitamin D increases the risk of viral infections

According to American research, the risk of catching a cold or the flu increases by as much as 40 per cent if vitamin D levels are low. People who already suffer from asthma or other lung diseases and are vitamin D-deficient at the same time have a five times greater risk of getting influenza than those with higher vitamin D levels in their body.

Did you know that asthma patients are especially susceptible if they lack vitamin D?

We are only able to produce vitamin D during the summer months

We humans synthesize most of our vitamin D from cholesterol that gets converted in our skin by ultraviolet sunrays. However, at our latitude we are only able to make vitamin D during the summer months when the sun sits sufficiently high in the sky. Vitamin D gets stored in the liver, and many people become deficient once their deposits are used. It is therefore no coincidence that viral infections such as colds and influenza typically spread during the cold winter months.

It is a myth

that we are able to synthesize vitamin D during the winter months if only we spend time in the sun. The sun sits too low in the sky for this to happen

Scientists claim that our actual need for vitamin D is higher

On a sunny summer day, a lightly dressed adult is able to produce around 60 micrograms of vitamin D in about 30 minutes. In comparison, a regular vitamin pill typically provides around 5-15 micrograms of vitamin D. Many researchers claim that the actual need for vitamin D is substantially higher than the DRI (Daily Reference Intake) of around 10-15 micrograms. Their recommendations vary from 30 to 100 micrograms per day. Vitamin D is a lipid-soluble vitamin, which is why we get the best absorption of the nutrient if it is dissolved in vegetable oil in capsules.

A blood sample can show a person’s vitamin D status

Vitamin D deficiencies are widespread

A surprisingly great number of people around the world are vitamin D-deficient, even in sunny countries such as Italy and Portugal. Even if a blood sample shows that levels of vitamin D are adequate during the summer period, they may not be in the autumn and winter, and that may result in a bad case of the flu or a nasty cold.

Vitamin D deficiency and poor utilization of the nutrient may be caused by

  • Lack of sun exposure during the summer period
  • Veiling and dark skin
  • Low-fat diets – especially if they do not contain oily fish and eggs
  • Vegetarian and vegan diets
  • Alcoholism
  • Overweight and diabetes
  • Old age and thin skin
  • Use of sun cream with a factor above 8 (which blocks the synthesis of vitamin D in the skin)
  • Prolonged use of cholesterol-lowering medicine and certain other types of medicine

Flu vaccine or vitamin D supplementation?

In order to prevent one case of the flu, you must vaccinate 71 people, according to a Cochrane review of 90 relevant studies. The review concludes that healthy adults do not need flu vaccines, which are even known to cause side effects. In fact, it appears that supplementing with high doses of vitamin D is more effective and there are no side effects.

Also remember selenium for your immune defense

Lack of the trace element selenium increases the risk of viral infections, inflammation, and cancer, which are characterized by a weak or derailed immune system. Selenium supports more than 30 different selenoproteins that have an array of vital functions. Numerous studies show that an increased selenium intake may help activate and control both the innate and the adaptive immune systems which, as mentioned earlier, include different white blood cells and antibodies. The question is how much selenium we need for optimal protection.

Selenium prevents flu virus and other types of virus from mutating

Studies show that virus mutates as a way of deceiving the immune defense. RNA virus that is known to cause influenza, colds, herpes, and HIV is particularly clever at mutating, which is why selenium plays a crucial role in the prevention and treatment of these infections. Also, it is hardly a coincidence that new and dangerous flu strains typically originate from large, selenium-depleted regions of China.

Selenium supplements strengthen the immune defense

An American study showed that supplementing with 200 micrograms of selenium daily increased the activity of white blood cells (lymphocytes) by 118 per cent and NK cells (natural killer cells) by 82 per cent. This improvement significantly increases your protection against infections.

Selenium supports the ageing immune system

Ageing is a complicated process that involves free radicals and changes in the metabolism, hormonal system, and the immune system. In a study of healthy older (57-84 years) people, the participants were given daily supplements of beta-carotene (45 mg) and/or selenium (400 micrograms) for a period of six months. It turned out that the selenium supplement alone caused the number of white blood cells (CD4 T-cells) to increase by more than 50 per cent. The increase lasted for two months and stopped once the participants discontinued their use of selenium.
Selenium is also a powerful antioxidant, and many studies have shown that selenium plays an important role for maintaining a good immune defense and good health in old age.

How selenium protects against infection

  • Helps white blood cells attack virus and bacteria
  • Contributes to fast cell division and communication between cells
  • Prevents virus from mutating
  • Functions as an antioxidant that protects healthy cells
  • Counteracts inflammation and non-desirable reactions

Selenium, supplements, and sources

Brazil nuts, organ meat, meat, and whole-grain are good selenium sources. However, the agricultural soil in large parts of Europe is nutrient-depleted, and the average selenium intake in European diets lies in the range of 40-50 micrograms, which is below the DRI level (Daily Reference Intake). In comparison, other populations such as the Americans and the Japanese easily get around 100 and 200 micrograms of selenium from the diet. This is the amount that is used in most intervention studies.
Supplementation with selenium yeast that contains many different organic selenium species provides the same natural blend of selenium types that you get from a balanced diet with many useful selenium sources.

Also remember that a good night’s sleep, relevant hygienic measures, and frequent washing of your hands prevent diseases from spreading


Marina Rode vin Essen, Martin Kongsbak, Peter Scherling, Claus Olgaard, Niels Ødum og Carsten Geisler. Vitamin D controls T cell antigen receptor signaling and activation of human T cells. Nature Immunology

Lasse Foghsgaard: D-vitamin er immunforsvarets batteri.

Gombart AF. The vitamin D-antimicrobial peptide pathway and its role in protection against infection. Future Microbiology

Hoffmann Peter R et et al. The influence of selenium on immune responses. Mol Nutr Food Res.

Hertz Niels. Selen et livsvigtigt spormineral. Ny Videnskab

Beck MA, Levander OA. Host nutritional status and its effect on a viral pathogen. J Infect Dis.

Pernille Lund. Styrk immunforsvaret. Hovedland

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