A low-carbohydrate diet may be more effective than reducing fat intake for prevention of prostate cancer, suggests a laboratory study by researchers in the US.
Previous studies have suggested a link between the amount of saturated fat in the diet and the risk of progression to advanced prostate cancer.
But Ada Elgavish and colleagues from the University of Alabama at Birmingham found that carbohydrate intake may be more significant for men wishing to delay progression to advanced prostate cancer.
"In the low-fat versus low-carbohydrate debate, we're finding that under conditions in which diet is provided ad libitum, a diet with fewer carbohydrates may be more effective in preventing progression to advanced, lethal prostate cancer than a diet with low fat content," said Dr Elgavish, lead author of the study, presenting the research at this week's AACR meeting, Frontiers in Cancer Prevention Research.
"However, the results of this study are preliminary. Men should talk to their doctors before changing their diets," she added.
The investigators compared the relative risk of developing advanced prostate cancer with a low-carbohydrate or a low-fat diet provided ad libitum (as much as wished), beginning before tumours developed and continuing until middle age.
The study was carried out in TRAMP mice, biologically engineered to develop prostate cancer after puberty, developed by Dr Greenberg and associates at Baylor College of Medicine in Houston. Two groups of TRAMP mice were fed diets containing the same amount of calories, with either 10 per cent or 45 per cent fat (mostly lard). Carbohydrates, mostly corn starch and sucrose, replaced fat in the low-fat diet.
Researchers measured food intake and body weight throughout the 23-week study.
After the onset of middle age, mice fed the 45 per cent fat diet had a consistently higher body weight due to higher body fat. When the study ended, 95 per cent of the mice fed the 45 per cent fat diet had survived, compared with only 68.2 per cent of those fed with the 10 per cent fat diet.
In addition, the percentage of mice with advanced prostate cancer in the 45 per cent fat group was one-third of that in the group fed the 10 per cent fat diet, reported the researcher.
If the results are confirmed in humans, they could provoke a shift in thinking on prostate cancer prevention. Last year researchers from the Fred Hutchinson Cancer Research Center reported finding decreased risk for late-stage prostate cancer in men on low-fat and moderate calcium diets. Numerous other studies support a low-fat, high fibre diet, (advised by the Pritikin programme), to keep prostate cancer at bay. The new study suggests more research is needed to clarify advice for prostate cancer patients.