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http://www.naplesnews.com/news/2007/...d_sufficiency/

naplesnews.com

Guest commentary: Many getting an ‘F’ in ‘D’ sufficiency

By MARK R. GOLDSTEIN, M.D., Special to the Daily News
Saturday, July 7, 2007
The residents of Southwest Florida and other regions in our vast country suffer from an insufficiency that is arguably a causative factor in more than half of all cancers.
And you would least expect this in sunny Florida — vitamin D insufficiency.
There have been a plethora of population studies over the past two decades showing that vitamin D insufficiency increases and, conversely, vitamin D adequacy decreases the risk of various cancers. They include, but are not limited to, cancer of the breast, lung, prostate, colon, pancreas and lymph glands.
How might vitamin D prevent cancer? It decreases cancer cell growth, proliferation and spread. It increases cancer cell death and decreases blood vessel growth to cancer cells.
A study has been published in the American Journal of Clinical Nutrition, which investigated nearly 1200 postmenopausal women over a four year period. Compared to a placebo pill, vitamin D given at a dose of 1,000 units daily in tablet form decreased total cancer incidence, including breast cancer, by 60 percent.
In absolute numbers, vitamin D supplementation decreased the incidence of cancer from 17 to 7 cases for every 1000 women taking vitamin D each year. There were no side effects from taking the vitamin D.
A 60 percent decrease in cancer incidence is huge! Statistics from the National Cancer Institute have shown that cancer is the major cause of years of life lost in this country, even surpassing heart disease.
The cholesterol-lowering statin drugs decrease coronary heart disease by about 30 percent, if given to the appropriate populations. This cannot compare in magnitude to the potential benefit of vitamin D in preventing cancer.
Besides, vitamin D is cheap. You can purchase 300 vitamin D tablets (1,000 units each tablet) for under $10 at discount stores. If you opt to get it from the sun, it’s free.
I have been routinely measuring the vitamin D blood levels of patients. Vitamin D is measured in nanograms/milliliter (ng/ml). About half of individuals are vitamin D insufficient, with levels below 30 ng/ml. So, why do so many of us have vitamin D insufficiency in the sunshine state?
Vitamin D is obtained from two sources — the skin, when exposed to the sun, and the diet. Early humans, constantly exposed to the sun, probably had vitamin D levels near 60 ng/ml. Many people avoid the sun and use sunscreen for fear of developing skin cancer. Experts argue that the amount of skin cancer prevented by sun avoidance pales in comparison to the amount of other cancers caused by vitamin D insufficiency.
As people age, their skin becomes much less efficient in making vitamin D. Furthermore, dark skinned individuals are much less efficient in making vitamin D and are more commonly vitamin D insufficient.
Dietary sources of vitamin D are limited. Milk is fortified with 100 units of vitamin D for each 8 ounces. Some orange juice is likewise fortified. Salmon has about 100 units and sardines have about 150 units of vitamin D per ounce.
For those with limited or no sun exposure, 1,000–2,000 units of vitamin D need to be consumed daily for optimal health. So, unless you spend 10 to 15 minutes in the sun, a few days a week without sunscreen, and/or consume large amounts of milk and fatty fish, you may be vitamin D insufficient.
In the study previously mentioned, the vitamin D level increased from a baseline average of 28 to an average of 38 ng/ml in the women supplemented with 1000 units of vitamin D daily. This resulted in the 60 percent decrease in cancer incidence over the four year period.
Optimal blood levels of vitamin D are about 40 to 60 ng/ml. Supplementation with 1000-2000 units of vitamin D daily should correct most insufficiency states, and it’s safe.
My advice is to talk to your doctor and have your vitamin D level measured. Supplement with 1000 units of vitamin D daily. If you do this, you should decrease your chance of getting cancer by more than 50 percent — for about $1 per month. I think it’s worth the investment, don’t you?
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Dr. Goldstein practices internal medicine in Bonita Springs.