A study by Dutch and German researchers has provided evidence that lycopene may be able to inhibit the growth of prostate tumours and that its effect may be enhanced if it is combined with vitamin E. A number of studies already show that high intake of lycopene – a carotenoid that gives the red colour to tomatoes and other fruits – is associated with a reduced risk of prostate cancer.
The new study demonstrates a beneficial effect in human prostate tumours grown in mice. It involved testing one low and one high dose of lycopene alone, one low and one high dose of vitamin E alone and a combination of low dose lycopene and vitamin E or a placebo to see what effect the supplements would have on the tumour growth and PSA levels.
One researcher, Dr Limpens, said that they “found that low dose lycopene suppressed the growth of the human prostate tumours by over half….while all other single treatments had no significant effect. However, the combination of low-dose lycopene and vitamin E produced the greatest tumour inhibition – 73% (at day 42).”
The study also showed that the lycopene and vitamin E were effectively taken up in the mice prostates in the same form as they are in humans, said Dr Limpens.
It was too early, said Dr Limpens, to say whether lycopene and vitamin E could ever be used to prevent prostate cancer in healthy individuals. The first step was to see the results from the studies on men with prostate cancer: changes may, for example, be necessary to optimize the treatment.
European Organisation for Research and Treatment of Cancer, Sept 30, 2004