Laboratory studies have previously shown that omega-3 fatty acids inhibit the disease while a 30-year study by Sweden's Karolinska Institute, carried out on over 6,000 Swedish men revealed in 2001 that there was a strong association between fish consumption and lower risk of the disease.
The new study, published in the July issue of the American Journal of Clinical Nutrition, looks at specific dietary fats and the risk of prostate cancer.
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intakes were related to both lower total prostate cancer risk and advanced prostate cancer risk. However alpha-linolenic acid (ALA), an omega-3 fatty acid found primarily in dark green leafy vegetables and certain vegetable oils, may raise the risk of advanced prostate cancer, suggests the study, supporting previous findings.
The team from the US National Cancer Institute and Harvard Medical School, with Karolinska researchers, followed a cohort of 47 866 men aged 40-75 years without cancer at the study start date, for 14 years. Among the 2965 new cases of prostate cancer during this time, 448 were advanced prostate cancer.
Men with the highest quintiles of EPA and DHA combined had an 11 per cent lower total prostate cancer risk and advanced prostate cancer risk was 26 per cent lower, according to the risk analysis.
ALA, which can be turned into EPA and DHA by animals, from both non-animal sources and meat and dairy sources significantly raised the risk of prostate cancer, (non-animal ALA doubled the risk), however.
The findings offer further evidence of the anti-cancer action often reported for omega-3 fatty acids and contributing to fast-growing sales of the ingredient in supplements.