A new review suggests that eating tomatoes and other lycopene-containing foods lowers prostate cancer risk.
Consuming tomatoes, watermelon and other foods containing lycopene – a naturally occurring phytochemical that gives red or pink fruits and vegetables their characteristic color – may protect against prostate cancer, according to new research presented today at the American Institute for Cancer Research (AICR) 25th Research Conference.
The study, one of over 140 posters presented at the conference, is not yet published and has not gone through the peer-review process.
Prostate cancer is the most common form of cancer in men worldwide, after skin cancer. It is the second leading cause of cancer-related death among men in the United States, claiming more than 27,000 lives each year.
Previous studies have shown inconsistent results on the link between eating tomatoes and tomato-based foods, including tomato sauce, tomato juice and pizza, and a lower risk of developing prostate cancer. This may be due to differences in study quality, as well as differences in the population groups studied.
Joe Rowles, III, a doctoral student at the University of Illinois at Urbana-Champaign (UIUC) and his colleagues conducted a systematic review of 66 population-based studies conducted over a period of more than 20 years to identify trends that indicated a relationship between tomato and lycopene consumption and prostate cancer incidence. They included only studies that focused on research related to lycopene from food sources rather than from dietary supplements.
The study found that men who consumed higher amounts of lycopene had an 11 percent reduced risk of prostate cancer compared to those who consumed the least; highest amounts of circulating blood lycopene was also linked to a 17 percent lower risk. There was a 1 percent decrease in prostate cancer risk for each additional 1 milligram of lycopene consumed per day. An average tomato has about 3 milligrams of lycopene.
When focusing on tomatoes alone, men who ate the highest amounts had a 10 percent lower risk of developing prostate cancer than those who consumed the least.
There was no association between lycopene or tomato intake and advanced prostate cancer, although there are only a few studies published on this topic.
This study is the first of its type with regard to lycopene, says John W. Erdman, Jr., a professor emeritus at UIUC and the senior author of the study. “The huge value of this work is that it considered the entire body of past research and when combined, included several thousand men,” said Erdman.
“Because lycopene is present in only a few foods, and approximately 85 percent of lycopene in the American diet comes from tomatoes and tomato products, people can really focus on eating tomato-containing foods,” said Erdman. “That’s a pretty easy way to reduce risk of cancer.”
- Find conference updates on twitter at #aicr16.
- Read more news on our conference press section: aicr.org/research.