Sunshine makes you feel good and may also help fight cancers

May 22 2005

Although Vitamin D, the sunshine vitamin, gets little media attention, it is, surprisingly, a good tool in the fight against cancer.

Animal and epidemiological studies are suggesting that sufficient vitamin D may prevent or even treat many cancers such as lymphoma, colon, prostate, skin, and lung cancer.

Studies in animals have found that vitamin D can help kill off tumour cells, and epidemiological studies have also found that elderly people with low vitamin D appear to be more susceptible to cancers.

Black people with black pigments which absorb the ultraviolet rays thus reducing vitamin D synthesis, have more cancers, and people in the northern hemisphere, where there is less sunshine, have more cancers.

Even though vitamin D has not been clinically proven to be a cancer-fighter a dispute is unlikely, but there is likely to be a debate on the best way to access vitamin D and how much it is needed to have an anti-cancer effect.

The two easiest ways of getting Vitamin D are exposure to sunshine and eating a vitamin D rich diet. Too much sunshine may promote skin cancer and ordinary diets do not offer enough vitamin D.

Milk is usually fortified with vitamin D-2, which is not as good as D-3 which is best used by the body.

An excellent source for vitamin D is fish oil, particularly fish liver oil, but it is expensive and often not widely available, whereas sunshine is cheap and readily available.

Some experts believe that the risk of life-threatening skin cancer from sunshine exposure is lower, and although 570,000 cases of skin cancer are diagnosed each year in the U.S., only 7,770 are found to be deadly melanoma.

New research by Harvard professor Edward Giovannucci suggests that sunshine-induced vitamin D might prevent much more cancer cases than skin cancer cases caused by sunshine.

Too much vitamin D in the body can do more harm than good, and dietary vitamin D supplements can either offer you too little or too much vitamin D, also many vitamin D supplements come with other vitamins such as vitamin A which lessens the effect of vitamin D.

An added problem is that the only way to assess if your body has an adequate level of vitamin D supplementation is by a blood test, which is impractical on a frequent basis, and the recommended daily allowance is itself a subject of debate.

Government advisers suggest 200 international units (IU) a day for those up to age 50, 400 IUs for those aged 50 to 70, and 600 IUs for those over 70,but scientists now believe that adults should have 1,000 IUs each day.

Dr. Giovannucci goes even further and suggests in order to have an anti-cancer effect, as much as 1,500 IUs of vitamin D might be needed.

The biosynthesis of vitamin D is so suited to your needs that the body will get only what it needs and in this sense, sunshine is a better source for vitamin D.

Dr. Giovannucci is not alone in his belief as other experts concur with his view.

Dr. Michael Holick, of Boston University, who is a noted vitamin D expert is one of the advocates for sunshine exposure. His book,"The UV Advantages" was written to encourage people to get enough vitamin D from sunshine. Holick suggests 15 minutes of sunshine exposure a session three sessions a week should do the trick for most people.

The book caused such a fuss in the academic and professional arenas, that Holick was disciplined by his department,and the American Academy of Dermatology last year called him irresponsible.

Dermatologists who have possibly seen too many skin cancers, are cautious when it comes to exposure to sunshine, and usually encourage that sunscreens are used to protect the skin and often suggest people avoid strong sunshine.

Regardless of the range of opinions surrounding vitamin D and sunshine, there are two things worth remembering, get enough vitamin D and avoid excessive sunshine.