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Page 1 of 2  Karen Collins, a nationally known nutritionist and dietitian whose work appears on Nubella, MSNBC.com, and other major Web sites, reports on some sobering news to us lycopene fans.
From the American Institute for Cancer Research in Washington, D.C., here is her take: If you look at tomatoes as a delicious way to prevent cancer by getting the compound lycopene, a recent study may have been a shock. Lycopene is widely touted as a protector against cancer in general – and prostate cancer in particular. The study found that higher blood levels of lycopene were not linked with reduced risk of prostate cancer. This may have you wondering whether your efforts to eat tomatoes are a waste.
Although this study raises several interesting research questions, it’s important to remember that we should never change our eating habits based on just one or two studies. The best dietary health advice continues to be to aim for a wide variety of vegetables and fruits in all our meals, tomatoes included. Potent weapon In laboratory studies, lycopene stands out as a potent weapon against cancer. As one of the carotenoid phytochemicals related to beta-carotene, lycopene seems to protect our cells’ DNA with strong antioxidant power and ability to stimulate enzymes that deactivate carcinogens before they can get cancer started. Lycopene is found in reddish fruits and vegetables, including red and pink grapefruit, guava and watermelon. But tomatoes provide by far the majority of most Americans’ lycopene intake, and studies evaluating lycopene consumption almost always mean greater tomato consumption. In research focusing on lycopene and tomato consumption in humans, studies have repeatedly found an association between greater consumption and lower prostate cancer risk. In an analysis of 21 studies, men who ate the highest amounts of raw tomatoes showed 11 percent lower risk for prostate cancer, and those eating the most cooked tomato products showed a 19 percent reduction in prostate cancer risk. Our body absorbs lycopene more readily when it comes from cooked tomatoes. Several smaller studies also show tomato consumption slowing development of prostate cancer that had already developed.
Raising questions Then in 2006 the Prostate, Lung, Colon, Ovarian Cancer Screening Study raised questions. Almost 30,000 men identified how often they ate more than 25 different tomato-based foods.
After eight years, neither the top 20 percent of lycopene or tomato consumers showed any reduced risk of developing prostate cancer. Because absorption of lycopene improves dramatically when it comes from cooked tomatoes, researchers wondered whether looking directly at blood levels of lycopene would show a relationship to prostate cancer risk. But in a follow-up study reported in May, no significant link was seen between lycopene blood levels and reduced cancer risk. (As an aside from yours truly, U.S. Food and Drug Administration researchers said in early July they found little, hard evidence to suggest that tomatoes and lycopene thwart cancer of the prostate, ovary, stomach and pancreas.) Meanwhile, Collins continues: The men in the studies were unusual in at least one respect; they averaged 8 to 9 servings of vegetables and fruits a day. According to a 2007 report by the Centers for Disease Control and Prevention, only 22 percent of men consume the minimum recommendation of 3 servings of vegetables per day and 29 percent of men eat the minimum fruit recommendation – two or more servings per day.
'Synergy' Is it possible that when our total vegetable and fruit consumption reaches recommended levels, the impact of any one phytochemical or food becomes less important or less obvious? Not only do studies suggest a synergy – a multiplying of benefits – from eating tomatoes themselves rather than lycopene supplements alone, research also says a synergy between tomatoes and other vegetables, such as broccoli.
The Prostate, Lung, Colon, Ovarian Cancer Screening Study adds important information as scientists work to understand and defeat cancer. Meanwhile, including tomatoes in our meals makes sense, for their delicious flavor and their many nutrients and phytochemicals. Yet neither lycopene, nor any other single food or phytochemical, is likely to protect us the way an overall healthy diet can.
(My take: I'm still going to eat plenty of tomato sandwiches.)
Find plenty of recipes containing tomatoes and other healthy veggies in Nubella’s 6,000-plus Recipe Database and Healthy Cooking Center.
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