The scientists had previously shown in a rat study that the powerful antioxdiant may kill prostate cancer cells by targeting the male hormone androgen.
Their new study suggests that lycopene, found naturally in red fruits and vegetables like tomatoes, also targets androgens in healthy prostate tissue, suggesting that it not only fights cancer in this way, but also reduces the risk of developing the disease.
The findings are significant for the food and supplement industry, looking to exploit the preventative measures of natural ingredients rather than treating an established disease.
Prostate cancer is one of the biggest cancer killers in industrial countries and affects more than 500,000 men worldwide every year. This number is expected to increase with the ageing population.
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.
Such findings are boosting the lycopene market, with growth rates forecast at over 100 per cent by Frost & Sullivan, albeit from a low base of around $34 million in 2003.
Dr Karin Wertz, laboratory head at DSM Nutritional Products, and colleagues supplemented healthy young male rats with lycopene for up to eight weeks. During this time, lycopene accumulated in the prostate tissue but did not influence normal prostate development, they report in the 15 November online issue of FASEB.
This is important, since children have a relatively high lycopene intake from foods like ketchup, pizza and spaghetti with tomato sauce.
The researchers say they demonstrated for the first time that lycopene reduced the effect of androgen on the healthy prostate tissue, as well as signs of inflammation and expression of the growth factor IGF-I, regarded as a risk factor for prostate cancer.
"All of these mechanisms can contribute to the epidemiologically observed prostate cancer risk reduction by lycopene," they write.
Earlier this year, DSM researchers, in collaboration with the Charité Hospital in Berlin, Germany, found that lycopene increased the killing rate of tumour cells. This effect was accompanied by repressed androgen signaling, reduced expression of IGF-I and of the inflammatory cytokine IL-6.
The new study demonstrates that lycopene influences the same mechanisms in healthy prostate tissue, as found for prostate tumours, giving a mechanistic explanation for previous epidemiological evidence.
"Our research highlights the role for lycopene in primary prevention," Wertz told NutraIngredients.com. "For this you would have to start supplementing early on in life, before the tumour or any altered cells are present."
The trial was done on DSM's synthetic lycopene, not currently available on the European market.
Wertz said the research should also be valid for natural lycopene's effects, since the effects demonstrated in this study reflect the activity of the lycopene molecule, and synthetic lycopene is nature-identical.
But she added: "It can not be predicted from this study, how other components found in the natural-source lycopene, such as other carotenoids or vitamin E, influence the effect of pure lycopene."