D - The Sunshine Vitamin
Sunshine stimulates the skin to make Vitamin D and we can also get Vitamin D from Cod Liver Oil, oily fish (tuna, sardines, mackerel, salmon), egg yolks and shitake mushrooms. It provides protection against rickets in childhood and is very important for our bone health.
This has all been known for nearly 100 years but the last 25 years has added a whole new dimension to our understanding of the actions of Vitamin D.
The sunshine vitamin also stimulates the immune system and in doing so provides protection against certain types of cancer and infectious diseases.
The problem for us in England is that in winter our skin is not exposed to much UVB light from the sun. We have short days, a lot of cloud and we cover up due to the cold. Studies carried out in many north European countries have shown up lots of vitamin D deficiencies across populations. This may account for the increased incidence of infectious diseases and certain types of cancers in north European areas.
Interestingly, Vitamin D has now been identified as the probable reason that Tuberculosis (TB) could be cured by sending patients to sunnier places. It stimulates the production of a natural anti-biotic that killed off the TB.
The anti-cancer activity of Vitamin D is being worked out by finding the genes with which it acts and activating these genes in cell cultures of cancer cells. Activating these genes has been shown to inhibit growth and reproduction of these cancer cells.
Drug companies are now researching these anti-cancer properties with a view to developing drugs that will stimulate the body’s defences against cancer without causing bone problems. So how can we protect ourselves against a lack of Vitamin D. One of the best ways is to take a daily dose of cod liver oil. I was brought up on it because it was provided for all children in the forties and into the 1950s. It is possible to overdose with Vitamin D but that will not happen if you follow the instructions with cod liver oil. Supplements of vitamin D are also available often supplied in conjunction with Calcium. Finally, a holiday in the sun is probably even better if you can afford it. A woman in a bikini exposed to the sun for just 15 to 20 minutes generates 10,000 international units (IU) of Vitamin D. That is a lot more than you would get from a supplement. Colin Sutherland References: Cell Defenses and the Sunshine Vitamin. L. E. Tavera-Mendoza & J. H. White. Scientific American. November 2007.
Sunshine. It doesn’t just make you feel good
Vitamin D was covered in last month’s newsletter but since then a major piece of research has been published in an American Journal (Proceedings of the National Academy of Sciences).
Research had already demonstrated that Vitamin D provides protection against getting certain cancers. The new research showed that "Increased sun exposure may lead to improved cancer prognosis and, possibly, give more positive than adverse health effects,". This particularly related to improved survival rates of people with cancers of the colon, breast or lung .
The mention of adverse health effects in the quote above refers to skin cancers that can result from too much exposure to the sun. However, it takes only 15 to 20 minutes of sun exposure in a bikini to generate all the Vitamin D required by the body, so it is not necessary to sunbathe for long periods. Also, Vitamin D is available in cod liver oil, sardines, mackerel, salmon, tuna, egg yolks and can be taken as a supplement.