Dairy may protect smokers from prostate cancer - study

The new research, published in the Journal of Nutrition , also reports that an increased intake of omega-6 fatty acids may increase the risk of prostate cancer, adding to an ever-growing body of research suggesting the omega-6-rich Western diet may be detrimental to prostate health.

Over half a million news cases of prostate cancer are diagnosed every year world wide, and the cancer is the direct cause of over 200,000 deaths.

More worryingly, the incidence of the disease is increasing with a rise of 1.7 per cent over 15 years.

Researchers from Fred Hutchinson Cancer Research Center, University of Washington, Roswell Park Cancer Institute, and Swedish Medical Center and Swedish Cancer Institute, report that smokers may benefit from boosting dairy consumption and reducing omega-6 intakes, although expert advice is clearly to avoid tobacco smoke altogether.

"Our findings suggest that associations of dietary fat with prostate cancer risk may vary by type of fat or fat-containing food, and that risk may vary by host factors, including family history and smoking," wrote lead author Marian Neuhouser.

Neuhouser and co-workers investigated the link between dietary fat, meat, and dairy foods with the risk of prostate cancer among 12,025 men in the Carotene and Retinol Efficacy Trial (CARET).

After 11 years of follow-up, the researchers had documented 890 cases of prostate cancers.

Overall, total fat from all sources was not linked to the risk of prostate cancer, but when the researchers considered sub-groups, they found that men with a higher dairy intake had a statistically significant 41 per cent reduced risk of aggressive prostate cancer compared to men with lower dairy intake.

The benefits of dairy foods appeared to be limited to current, rather than former, smokers with increased intake associated with a 58 per cent reduced risk of aggressive prostate cancer.

However, increased omega-6 intake was associated with an increased risk among men with a family history of the cancer (161 per cent).

Further research is needed to further explore these associations, with particular attention paid to the mechanism behind the effects, and why certain types of fats and food matrices may benefit prostate health, compared to others.

One in three Europeans are smokers, while the US figure is one in five.

Tobacco smoke contains over 4,000 compounds, of which 60 are known carcinogens.

The oxidative stress levels of smokers are significantly greater than non-smokers, and as such there is a bigger drain on the levels of antioxidants in the body.

Source: Journal of Nutrition July 2007, Volume 137, Pages 1821-1827 "(n-6) PUFA Increase and Dairy Foods Decrease Prostate Cancer Risk in Heavy Smokers" Authors: M.L. Neuhouser, M.J. Barnett, A.R. Kristal, C.B. Ambrosone, I. King, M. Thornquist and G. Goodman