VITAMIN D AND YOUR IMMUNE SYSTEM
LOW IN VITAMIN D?–probably, if you are one of these people in Britain:-
Often wear sunblock or face creams
Work indoors or don’t go outside during the middle of the day
Darker skinned or wear outdoor clothes that cover the face and body
Don’t supplement with Vitamin D during the winter months
Older people with thinner skin
Those who live in the far North of the country
Our main natural source of Vitamin D is from the synthesis of UVB sunlight rays on the skin, and thus the amount of Vitamin D synthesised can be dramatically reduced during winter, and by use of sunblock creams or other bodycare creams. Darker skins with higher melanin content will produce less Vitamin D. The higher the latitude then the lower the UVB light reaching the earth’s surface. In Winter the levels of UVB light in Britain is insignificant, Even in Summer UVB is only significant between 10:00am and 2 pm. The further North the available UVB levels drop lower. Hence, those whose working daytime lives are indoors will produce less Vitamin D. As our skin ages it becomes thinner and absorbs less UVB light. Vegans who do not eat oily fish or eggs can be low because they do not get Vitamin D in their food.
Food sources of Vitamin D are limited and we are evolved to produce most Vitamin D from sunlight on the skin and its interaction with cholesterol. The Vitamin D hormone is made active by the liver and kidney and the classic action of Vitamin D is its enhancement of calcium absorption in the intestine and the mineralisation of bone. Clearly Vitamin D affects many other organs and physiological effects. Many of our degenerating diseases or conditions seem to be worse for those with low Vitamin D in their body. It affects also the commonest of health problems colds and ‘flu’.
Vitamin D receptors are found on immune cells (B cells, T cells and antigen presenting cells). Vitamin D can modulate the innate and adaptive immune system. Deficiency in Vitamin D is associated with susceptibility for autoimmune diseases and general infections. Immune cells are in general responsive to Vitamin D additions, absorbed from sunlight, food or supplementation, and produce beneficial reduction in immune effects or infection.
Influenza epidemics occur in the winter, and vitamin D levels are dramatically lower in the winter as well. Since influenza is seasonal, it is thought that vitamin D might be a factor that can affect your chances of getting the flu. Many studies that have been done about influenza have shown that people who have lower levels of vitamin D are more likely to get influenza. Some research has shown a relationship between higher levels of vitamin D and shorter duration of the influenza infection. Experiments have shown that taking vitamin D supplements can reduce your chances of getting influenza in the first place.
It pays for your good health to get as much Vitamin D from sunlight during the summer but avoid getting sunburn from UVA sunlight. As little as ½ hour on a sunny summers day (in the middle of the day) is needed to get all the Vitamin D that your body can produce on that day. The amount you can produce is about 10,000 to 20,000iu (international units). During the winter we suggest that your body’s levels of Vitamin D should be supported by eating oily fish and eggs regularly, and probably supplementing with Vitamin D. If you have a degenerating disease, or frequently suffer from colds or infections ask your GP to assess your Vitamin D levels.