Herbs & Supplements:
Lycopene

Principal Proposed Uses
  • Cancer Prevention
Other Proposed Uses
  • Cataract Prevention, Macular Degeneration Prevention, Infertility

Lycopene is a powerful antioxidant found in tomatoes and pink grapefruit. Like the better-known supplement beta-carotene, lycopene belongs to the family of chemicals known as carotenoids. As an antioxidant, it is about twice as powerful as beta-carotene.

There is some evidence that a diet high in lycopene may reduce the risk of cancer of the prostate as well as other cancers. Lycopene may also help prevent macular degeneration and cataracts.

Sources

Lycopene is not a necessary nutrient. However, like other substances found in fruits and vegetables, it may be very important for optimal health.

Tomatoes are the best source of lycopene. Happily, cooking doesn't destroy lycopene, so pizza sauce is just as good as a fresh tomato. In fact, some studies indicate that cooking tomatoes in oil may provide lycopene in a way that the body can use better,^1,2 although not all studies agree.³ Lycopene is also found in watermelon, guava, and pink grapefruit.

Therapeutic Dosages

The optimum dosage for lycopene has not been established. However, one study on lycopene and prostate cancer suggested that about 6.5 mg is an effective daily intake.⁴ Standardized tomato extracts containing lycopene are also available; these should be used according to label instructions.

Therapeutic Uses

Observational studies suggest that foods containing lycopene may help prevent macular degeneration, cataracts, and cancer (particularly cancer of the prostate, but also possibly cancers of the lung, colon, and breast).^5–13

One small study found suggestive evidence that a standardized tomato extract containing lycopene might be helpful for the treatment of prostate cancer, but the study had serious problems that make the results unreliable.²³ Even weaker evidence suggests that tomato extracts containing lycopene might be helpful in breast cancer, while lycopene alone is not.²⁴

Very weak evidence suggests that the same extract may also be helpful for the treatment of infertility²⁵ and for preventing heart disease.²⁶

What Is the Scientific Evidence for Lycopene?

Cancer Prevention

Although there are no double-blind studies on lycopene, the results of observational studies are promising.

One study followed 47,894 men for 4 years.¹⁴ Subjects who ate large amounts of tomatoes or tomato sauce (including that on pizza) had lower rates of prostate cancer. In an evaluation that compared these foods to others that were studied, lycopene appeared to be the common denominator.¹⁵

Preliminary evidence suggests that lycopene may also help prevent lung, colon, and breast cancer as well.^16,17 In one study, elderly Americans who ate a diet high in tomatoes had 50% fewer cancers overall than those who did not.¹⁸ Animal studies have also found some cancer-preventative benefits with lycopene.^19,20

However, other observational studies have not found lycopene to be the key cancer-fighting ingredient in fruits and vegetables.^21,22 What we really need are large double-blind studies in which people are given either pure lycopene supplements or placebo treatment. Unfortunately, none have yet been reported.

Safety Issues

Although lycopene is a normal part of the diet, there has not been a formal evaluation of lycopene's safety when it is taken as a concentrated supplement. Maximum safe dosages for young children, pregnant or nursing women, or those with severe liver or kidney disease have not been established.

Last reviewed March 2002 by Medical Review Board

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