Vitamin D can apparently significantly reduce the risk of dying from the flu. A study on influenza epidemics showed that vitamin D has an extraordinary regulatory effect on the immune system. According to the researchers, the more pronounced the vitamin D deficiency is in winter, the higher not only the number of people suffering from the flu increases but also the risk of dying from the flu. So make sure you have a good supply of vitamin D.
Flu: a consequence of vitamin D deficiency
Flu outbreaks are likely due to a lack of vitamin D. Vitamin D is only ingested in small amounts through food. However, we cover the majority of our vitamin D requirements in-house. But we need the sun for that. Vitamin D can only be formed in our skin under UVB radiation.
It is well known that influenza outbreaks tend to occur in the autumn and in winter months. It has long been suspected that an insufficient vitamin D supply could be largely responsible for this. In winter, firstly, the sun rarely shines and secondly, even when the sky is cloudless, the winter sun’s power in Central Europe is not sufficient to get the body’s own vitamin D production going.
In winter, people from northern climes live mainly from their vitamin D stores, which their bodies built up in summer. But even in summer, it is not always sunny. In addition, there is the massive use of sunscreens, which prevent vitamin D production in the skin, as well as modern working life, which often simply does not leave any time to soak up the sun. It’s no longer easy these days, even in the summer, to stock up on those sorely needed vitamin D supplies.
Influenza death rate increases with vitamin D deficiency
A study by Norwegian scientists on influenza epidemics now clearly shows that the lower the vitamin D level in the body has fallen, the greater the risk of contracting influenza and dying if you do get it. The researchers found a 20- to 600-fold increase in mortality when vitamin D levels were low.
According to this study, a sharp increase in the number of infections and deaths can be observed during influenza outbreaks whenever the exposure to sunlight (and thus the formation of vitamin D) is reduced. This applies not only to the outbreak of an influenza epidemic but also to its course, i.e. whether the influenza epidemic survived well or whether it claims many lives.
Does Vitamin D work like antibiotics?
Vitamin D acts like an antibiotic and boosts the immune system, according to Professor Johan Moan, who led the study.
UV radiation stimulates the production of vitamin D in the skin. In the winter months, the sun is so low, even at its zenith, that the production of vitamin D in the skin does not take place at all. This results in a drop in the vitamin D level in the body and thus only a moderate protective effect of this vitamin.
But now we know that antibiotics do not always have a positive effect, but can also have a number of side effects – especially on the immune system. Antibiotics massively affect the intestinal flora of humans. However, the intestinal flora is a significant part of our immune system, so that it is often significantly weakened at the end of antibiotic therapy.
However, vitamin D as a natural sun vitamin does not have these side effects – when dosed correctly – which is why the comparison with antibiotics is a bit unfortunate. Professor Moan simply wanted to express how strongly he judges the protective effect of vitamin D against influenza.
Vitamin D plays an important role in the immune system
It has long been known that vitamin D plays an important role in the immune system. It is not for nothing that a vitamin D deficiency is associated with the development of a number of autoimmune diseases, cancer, and increased susceptibility to infections. Professor Moan’s research now shows how specifically vitamin D can affect the immune system. This happens on several levels.
Vitamin D regulates the immune system
In this way, vitamin D downregulates the acquired immune response, which is particularly overactive in autoimmune diseases, while it strengthens the innate, i.e. non-specific, immune response. The latter happens, for example, when vitamin D strengthens the so-called AMPs. AMPs are antimicrobial proteins that can kill microorganisms efficiently and quickly – long before the acquired immune system can react by activating specialized defense cells. The prey spectrum of AMPs includes not only bacteria but also viruses, including influenza viruses (flu viruses).
Does vitamin D make you resistant to the flu?
In addition, vitamin D inhibits the production of the so-called NF-κB transcription factor, which is particularly advantageous with regard to fighting off the flu. For example, studies by Nimmerjahn et al. demonstrated that those human cells that showed low levels of NF-κB were resistant to influenza infection. At the same time, the risk of dying from the flu increases with the amount of NF-κB transcription factors in the body. Conclusion: The more vitamin D, the fewer NF-κB transcription factors, the better the flu defense and the lower the risk of death.
Vitamins in autoimmune diseases
On top of that. Vitamin D also activates the so-called TLRs (Toll-Like Receptor). TLRs are structures of the innate immune system. They work on the front lines of the body’s defenses, recognizing which cells and substances belong to the body and which are dangerous invaders. The better the TLRs are formed, the more efficiently the immune system can work without overreacting.
According to the scientists, the fact that vitamin D strengthens the non-specific (innate) immune response and at the same time – as mentioned above – slows down the acquired immune response or prevents an excessive reaction, is the reason for the reduced mortality in flu patients who take good care of the vitamin D are supplied. So we know that the risk of dying from the flu is higher, and more pro-inflammatory messenger substances are released.
Vitamin D now inhibits the release of these pro-inflammatory messenger substances (cytokines) and activates the release of anti-inflammatory messenger substances at the same time. This, in turn, not only ensures that the flu progresses smoothly but also regulates the body’s own defenses with regard to autoimmune diseases in such a way that the immune system cannot go haywire.
Vitamin D prevents influenza
If sun exposure in temperate zones is not sufficient to achieve the required vitamin D status, then taking vitamin D supplements is a good idea. But in what dose?
A number of studies have examined vitamin D preparations with regard to their anti-flu effect. The first randomized controlled study was actually about the bone protective effect of vitamin D in postmenopausal women. It turned out that not only did vitamin D protect the women’s bone health, but those women who took 800 IU of vitamin D daily were three times better protected against colds and flu than the women in the placebo group.
In the group that took even higher doses of vitamin D (2000 IU per day) for a whole year, only one participant developed a cold during this period.
School children also benefit from the protective effect of vitamin D, as was shown in another randomized, double-blind, and placebo-controlled study. Those children who took 1200 IU of vitamin D per day during the winter and early spring were significantly less likely to get the flu than children who took the placebo supplement.
Vitamin D is therefore an important factor in the healthy regulation of the immune system and must therefore not only be taken into account in flu prevention but also in the therapy of autoimmune diseases.