Everybody nowadays talks about vitamin D, especially in relation to Covid-19 and its impact to fight this virus.
Vitamin D has changed over the years from a regular vitamin known for it links to rickets and calcium metabolism to an ingredient which is linked to many other health problems like cancer, muscle pain, asthma, obesity, insomnia and so on.
Due to the lockdown during the coronavirus crisis Public Health England’s chief nutritionist recommends taking vitamin D supplements on a daily basis.
Considerable organisations e.g. in Singapore are studying and reviewing now the impact of vitamin D against coronavirus.
So, let’s have a closer look at vitamin D.
What is vitamin D?
Vitamin D is a fat-soluble vitamin that helps to regulate the balance of calcium and phosphate in the body. It regulates immune functions, has an impact on cell growth and development and promotes bone health.
Why do we need vitamin D?
We have seen that a lack of vitamin D can lead to serious health conditions e.g. rickets or bone deformity. Vitamin D might also boost your immune system and help you to fight off infections. The National Institute for Health and Care Excellence reviewed the current research and comes to the conclusion that there is no evidence to support taking vitamin D supplements to specifically prevent or treat Covid-19. Nevertheless, experts do think it may have some broader health benefits during the pandemic.
The Scientific Advisory Committee on Nutrition (SACN) comes to a similar conclusion after reviewing studies on vitamin D for treating or preventing chest infections and say there is insufficient evidence to recommend the vitamin for this.
However, in the article by Lanham-New et al. in BMJ Nutrition, Prevention and Health experts all around the world have a consensus:
“They all agree that avoiding low vitamin D status is important for many health reasons, and possibly also because of the potentially, but not proven lower risk of infection and death from Covid-19, as more studies are needed. They agree that avoiding deficiency can usually be achieved within current national guidelines, highlighting vitamin D-rich foods and moderately dosed vitamin D supplements.”
“Because the infection is still new, there is much that needs to be learned and many investigators are making great strides in understanding the role of specific nutrition factors for resisting infection and for the most effective treatment of ongoing disease.”
“In the end, it is good to emphasize that the authors all agree, that preventing vitamin D deficiency is important for many health reasons, but for the prevention of deficiency the use of supplements with more than 4000 IU vitamin D is rarely necessary or justified and is strongly cautioned against.”
So, evidence is still lacking and further research needs to be undertaken. Nonetheless vitamin D is an important micronutrient for a healthy lifestyle and a deficiency might be linked with poorer results to fight Covid-19 due to its anti-inflammatory effect.
How do I get vitamin D?
Vitamin D is built up by the sun. Alternative sources are a limited number of foods. Fish liver oils are the richest natural sources of vitamin D followed by salt-water fish like tuna fish, salmon or swordfish. Only a small amount can be found in butter, eggs, milk and fortified yoghurts. Although eating a well-balanced diet is highly recommended it is difficult to get enough vitamin D from food alone.
When should I take vitamin D?
People who get not enough sun exposure are advised to get vitamin D supplements to maintain an adequate vitamin D level. During the Covid-19 lockdown this might apply to more people than otherwise.
How much you should take, may differ between countries. The UK NHS recommends 10 mg of vitamin D a day – especially when you spend most of your day inside.