In a study involving almost 2,000 patients with colorectal cancer and over 4,000 disease-free patients (who were admitted to hospital for reasons not related to colorectal cancer), researchers in Italy concluded that a diet rich in folate and methionine – and containing little alcohol – may lower the risk of colorectal cancer. Incidence of colorectal cancer was 40% higher for patients who were both heavy drinkers and had diets deficient in folate and the essential amino acid methionine. For this study, light drinking meant less than one glass of wine daily, while heavy drinking was equivalent to at least two 12-ounce beers a day.

The main sources of folate reported in the Italian diets were green leafy vegetables, whole grains, and liver. Methionine levels were studied because this amino acid plays a key role in regulating the availability of folic acid in the body. Previous studies have shown that high levels of methionine reduce colon cancer risk in people with a family history of the disease.

It is interesting to note that low levels of methionine were slightly associated with colorectal cancer, but the combination of low methionine and low folate had an even stronger association with cancer risk.

The researchers’ recommendations are to exercise regularly, eat a balanced diet with lots of fruit and vegetables and to avoid more than 2 alcoholic drinks per day.

First published in the Inside Tract® newsletter issue 135 – January/February 2003
C La Vecchia, et al. Dietary folate and colorectal cancer. International Journal of Cancer 2002;102:545-547.