Vegetarians Reap Certain Cancer Benefits
Vegetarians are less likely to develop cancer, according to research published in the June 2009 issue of the British Journal of Cancer.
The researchers from Oxford University conducted two studies, which covered a time span of 12 years, and included over 61,000 British men and women.
32,403 (52%) of the participants were meat eaters, 8,562 (15%) were non-meat eaters who ate fish and 20,601 (33%) were vegetarians.
Over the 12 year period, the researchers tested for one or more than 20 different forms of cancer and diagnosed 3,350 cases.
After controlling for factors such as smoking, alcohol use and obesity, the researchers found that the risk of all cancers combined was 18% lower in fish eaters and 12% lower in vegetarians.
For some forms of cancer, vegetarians saw a much more pronounced reduction. For example, vegetarians were 50% less likely to develop cancers of the blood and lymphatic system such as leukemia and non-Hodgkin lymphoma.
Vegetarians also saw a 64% reduction in stomach cancer risk compared to meat eaters and a 53% reduction in risk of bladder cancer.
The instance of cervical cancer, however, was almost double among vegetarians compared to meat eaters.
This large study confirms the findings of smaller studies which have found that high meat diets may increase the risk of some cancers whereas diets high in vegetables may actually reduce the risk.
The researchers said the reasons for lower cancer rates among vegetarians is not clear, but theorize that it could be due to viruses and mutation-causing compounds found in meat that are known to damage DNA.
Some types of vegetables have particularly high anti-carcinogenic properties such as cruciferous vegetables like broccoli, Brussels sprouts, cabbage, cauliflower, and horseradish. Allium vegetables like onions, garlic, and leeks have also been shown to significantly reduce the risk of some cancers.