The natural health news is abuzz with reports that vitamin D lowers the risk of cancer, but in the case of pancreatic cancer, this is not always the case. Smokers do not have the same response to vitamin D as non-smokers.
The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study in Finland followed the vitamin consumption of 29,133 men aged 50 to 69 who smoked at least 5 cigarettes a day. During the nearly 17 years of the study, certain patterns were observed in the participants who developed pancreatic cancer. They were:
- Had lower blood pressure,
- And were about twice as likely as men who did not develop pancreatic cancer to have had asthma or diabetes.
Where pancreatic cancer sufferers showed a marked difference from men who did not develop pancreatic cancer-this being in cohort of all-smokers-was in vitamin D. Men who had the highest concentrations of vitamin D in their bloodstreams had a 150 to 500 per cent greater risk of developing the cancer.
But this was not the only study vitamin D and the risk of pancreatic cancer.
The even larger Nurses Health Study and Health Professionals Follow-Up Study in the USA followed 75,427 women and 46,771 men for 14 years. Their findings?
Men and women with the highest consumption of vitamin D from foods, 600 IU a day or more had a 41 per cent lower risk of pancreatic cancer.
The effect was slightly greater in men.
How can the two conflicting results be reconciled?
The Finnish study measured bloodstream concentrations of vitamin D in male smokers, while the American studies estimated vitamin D consumption in groups of men and women including both smokers and non-smokers. The body makes its own vitamin D when the skin is exposed to sunlight, and it may be that over-production of vitamin D somehow occurs in smokers.
But these massive studies don't really tell us what the difference is. And a third study done at Harvard to be released in April 2008 finds that African-Americans have yet another pattern of pancreatic cancer risk as relates to vitamin D.
I've spent the best part of my working years writing about and formulating herbal and nutritional supplements, but sometimes nutritional supplements simply are not appropriate. It seems sensible to avoid vitamin D supplements if:
- You're a man,
- You smoke, and
- You have a family history of pancreatic cancer.
For everyone else, vitamin D supplements are probably safe, but it's more useful to make sure you get plenty of vitamin B, especially folic acid.
Robert Rister is the author or co-author of nine books on natural health and Folic Acid and Pancreatic Cancer Risk and Alternative Pancreatic Cancer Therapies .