Where it comes from: Lycopene is a bright red carotene and carotenoid pigment found in the human skin, liver, adrenal glands, lungs, prostate and colon. It's most commonly known for its presence in red fruits and vegetables such as tomatoes, carrots, watermelons and papayas.
Studies have proven that lycopene possesses antioxidant properties and may hold keys to promoting general health. In the late 1980s, when lycopene's antioxidants were found to be twice that of beta-carotene, massive interest and studies were launched to find its role in cancer prevention.
What it'll do for you: Given its antioxidant properties, researchers have been studying (and continue to do so) lycopene's affect on general health. Here, a look at some of the most notable possibilities:
- Antioxidant benefits
Laboratory research with mice found that lycopene, like other carotenoids, may have antioxidant properties. However, it is not clear if lycopene has these effects in the human body. Results of different studies do not agree with each other and better research is needed before a firm conclusion can be drawn.
- Cancer prevention
Population studies have shown that the risk for some types of cancer is lower in people who have diets high in tomato products or who have higher levels of lycopene in their blood. What types of cancer? Evidence strongly suggests lycopene is protective against lung, stomach and prostate cancers. Other evidence says it may also help to protect against cancer of the cervix, breast, mouth, pancreas, esophagus and colon and rectum. Results have credited and discredited lycopene's effects regarding prostate cancer protection. One study gave men at high risk for prostate cancer an ordinary multivitamin either with or without a lycopene supplement and found no difference in PSA levels (prostate-specific antigens) between the two groups. However another controlled study in a small group of men with prostate cancer found that lycopene supplements appeared to reduce the rapid growth of prostate cancer cells. A slew of other studies have replicated both of these outcomes. Obviously, more research is needed but many researchers are optimistic.
- Coronary artery disease prevention
Several studies have suggested that lycopene may be helpful in people with atherosclerosis or high cholesterol. A recent study had healthy humans ingest lycopene in the form of tomato juice, tomato sauce and soft gel capsules for one week. Those patients had significantly lower levels of LDL than the control patients.
- Treatment for male infertility
A 2000 study in India examined 30 men with idiopathic infertility. All the men were given 2000 micrograms of lycopene, twice a day for three months. Their semen was analyzed after the three-month period and twenty patients (66%) showed an improvement in sperm concentration, sixteen (53%) had improved motility and fourteen (46%) showed improvement in sperm morphology.
Suggested intake: Tomatoes are the most concentrated food source of lycopene, although apricots, guava, watermelon, papaya and pink grapefruit are also significant sources. Studies that looked at lycopene levels in the blood found that levels were higher after people ate cooked tomatoes than after they ate raw tomatoes or drank tomato juice. This suggests that lycopene in cooked tomato products—such as tomato sauce or pasta—may be more readily absorbed by the body than lycopene in raw tomatoes. "As a nation, men aren't getting enough fruits and vegetables," says Lisa R. Young, Ph.D., R.D., author of The Portion Teller and adjunct professor of nutrition at New York University. "Luckily when it comes to lycopene and tomatoes, experts suggest a more delicious way—with a small amount of oil or fat, as they increase the amount of lycopene that's absorbed by the intestines." Young suggests eating cooked tomato sauce on pastas or pizzas.
Lycopene is not an essential nutrient for humans and so Young says supplements are unnecessary. "Just make more of an effort to eat a balanced diet—and increase your intake of tomatoes—and there's no need for additional lycopene," she adds.
If you do opt for a supplement, common doses range from 2 to 30 milligrams for up to six months. Consult your doctor before starting a regular oral ingestion.
Associated risks/scrutiny: Lycopene is non-toxic and there are no known serious side effects. The potential side effects of lycopene supplements are not fully known. In one study, some patients who took a lycopene-rich tomato supplement of 15 milligrams twice a day did suffer from nausea, vomiting, diarrhea, indigestion, gas and bloating. When consumed over a long period of time, very large amounts of tomato products can give the skin an orange color; this is reversible and skin will return to its natural color about three weeks after a lyocpene-free diet is begun.
While the risks are minimal, the scrutiny does seem larger. As mentioned earlier, lycopene has been found to possess antioxidant properties in laboratory mice but the positive effects in humans remains controversial. Also, a 2004 study in the Journal of the National Cancer Institute reported that the anti-cancer effects of lycopene in tomatoes stems more from the tomatoes—which also contain vitamin C, folate and potassium—and less from the lycopene itself. "Whether that's true or not, it can't hurt to continue eating more tomatoes since they are full of good nutrients," says Young.