Lycopene, zinc linked to better prostate health

Almost 5,000 men were followed for the new study, published online in the American Journal of Epidemiology , which showed a stronger benefit for a vegetable-rich diet, while also indicating that high consumption of red meat may increase the risk of BPH.

"There were no associations of supplemental antioxidants with risk, and there was weak evidence for associations of lycopene, zinc, and supplemental vitamin D with reduced risk," wrote the authors, led by Alan Kristal from the Fred Hutchinson Cancer Research Center in Seattle.

"A diet low in fat and red meat and high in protein and vegetables, as well as regular alcohol consumption, may reduce the risk of symptomatic BPH," they added.

Benign prostatic hyperplasia (BPH) is a non-cancerous swelling in the prostate gland of older men.

It affects approximately 25 per cent of American Caucasians over the age of 50, with the direct cost of BPH in 2000 calculated to be $1.1 billion (€ 0.9 billion).

According to the European Association of Urology, 30 per cent of men older that 65 are affected by BPH.

The "weak evidence" for lycopene does appear inline with previous findings.

Indeed, epidemiological evidence has suggested that tomato-based foods can protect men from prostate cancer.

One study found that men eating four to five tomato based-dishes per week were 25 per cent less likely to develop prostate cancer compared to men eating tomatoes only rarely.

In addition, researchers from the University of Hohenheim recently reported results from a pilot study that showed that levels of prostate-specific antigen (PSA), a marker of prostate health, were reduced in men receiving lycopene supplements showing improvements in health of the tissue.

However, no changes were recorded in the placebo group ( Journal of Nutrition , January 2008, Vol. 138, pp. 49-53).

The new study was epidemiological, and followed 4,770 men participating in the placebo-arm of the Prostate Cancer Prevention Trial.

All the men were free of BPH at the start of the study.

Over seven years of follow-up, 876 incident BPH cases were documented by Kristal and co-workers.

Dietary intakes, assessed using a food frequency questionnaire (FFQ), showed that a high-fat diet was associated with a 31 per cent increase in the risk of BPH, while increased protein intake was associated with a 15 per cent reduction in risk.

Moreover, consumption of four daily servings of vegetables was associated with a 32 per cent reduction in BPH risk, compared to less than one daily serving.

On the other hand, a daily serving of red meat was linked to a 38 per cent increase in risk, compared to less than one serving per week.

Vitamin D, zinc and lycopene were weakly associated with a reduction in the risk of BPH, added the researchers.

The role of lycopene for prostate health has been questioned recently.

A study published last May in published in the journal Cancer Epidemiology Biomarkers & Prevention , reported that the carotenoid may not offer protection for prostates, based on a multi-centre study case-control study including 692 prostate cancer cases, and 844 randomly selected, matched controls.

According to the European School of Oncology, 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.

Source: American Journal of Epidemiology Published online ahead of print, doi:10.1093/aje/kwm389 "Dietary Patterns, Supplement Use, and the Risk of Symptomatic Benign Prostatic Hyperplasia: Results from the Prostate Cancer Prevention Trial" Authors: A.R. Kristal, K.B. Arnold, J.M. Schenk, M.L. Neuhouser, P. Goodman, D.F. Penson, I.M. Thompson