Vitamin D and infections
The number of infections caused by multi-resistant bacteria (MRSA) has been on the rise for the past years. These infections are now being diagnosed more often in people that are not hospitalized. At the same time research has shown that a large proportion of the worlds population is vitamin D deficient. Could deficiency of vitamin d and infections be related in any way?
It so happens that vitamin D is not really a vitamin but rather a hormone that not only helps boost the immune system but basically controls it. This, among other facts, is revealed in a book by Dr. Michael Holick, The Vitamin D Solution, which was published in 2010. Dr. Holick has studied vitamin D for the past 30 years. Since one of the major roles of vitamin D is to help the body fight all kinds of infections and a large proportion of the population is deficient it is not illogical to speculate if this deficiency could help explain the rise in infections.
Why are so many people deficient in vitamin D? Dr. Holick and many others think there are two basic reasons; we are not getting enough sun exposure, partly secondary to increased use of sunscreen, and we are not getting enough vitamin D from food sources.
Vitamin D and sun exposure
It is common knowledge that our skin produces vitamin D when we are exposed to sunlight. A lot of people don‘t realize though that this production is hampered by the use of sunscreen. Sunscreen with Spf of 30 can thus reduce vitamin D production by 95-99%. Dr. Holick and others are not recommending that we stop using sunscreen altogether but that we let the skin be exposed to sunlight for a short period of time before we put sunscreen on in order for us to be able to produce this important vitamin. The amount of vitamin D that we can produce through the skin is much larger than the amount that we can get through our food or through supplements and lasts much longer in the bloodstream. Dr. Holick is not promoting suntanning and warns strongly against sunburn.
Vitamin D in food
There are not a lot of food sources that contain vitamin D, mostly oily fish such as herring, salmon, trout, sardines and halibut. Vitamin D is also found in eggyolks and in some amount in mushrooms. Cod liver oil is also rich of vitamin D and research has shown that people living in the northern countries such as Iceland that consume cod liver oil on a daily basis are not as vitamin D deficient as those who do not take cod liver oil. Mushrooms are remarkable for the fact that if they are exposed to ultraviolet light of B type during the cultivation process they will produce vitamin D in their “skin“ and thus can increase their vitamin D amount markedly. Such vitamin D rich mushrooms are now available in Australia and the US.
Living above 35°north latitude
People that live in the northern hemisphere of the world, defined by living above 35° north latitude, have less opertunity to produce vitamin D from sunlight than people living further south. Therefore they need to supplement on vitamin D in order not to become deficient. Research has shown that people living in northerly countries, e.g. Iceland, are not getting enough vitamin D from their food. That indicates a need for taking vitamin D supplements. How much is needed has been debated and people are getting mixed messages. In Iceland for example the official guidelines are that grownups should take 400 international units (iu) per day or 10 micrograms while Dr. Holick and others recommend that grownups need to take 1000 -2000 iu per day. Some experts recommend even higher doses.
What should we do?
We need to come up with clear recommendations for the public about both sensible exposure to sunlight as well as amounts of vitamin D to consume. The sun is the source of all life on this earth and we have to be able to be exposed to it to such a degree that we will be able to produce enough vitamin D without increasing our changes of getting skin cancer. Diseases like rickets in children that were thought to be extinct are on the rise secondary to vitamin D deficiency. Vitamin D not only protects us against all kinds of diseases and infections but also can protect us from high blood pressure, heart disease, certain kinds of cancer (e.g. breast- and colon cancer), autoimmune diseases, arthritis and fibromyalgia as well as increasing our life expectency. We live in times where the cost of health care is constantly on the rise so cutting down on infections and diseases with simple measures like supplementation of vitamin D and sensible sun exposure can prove invaluable, both financially as well as to improve the quality of our lives.