The prostate is a male reproductive gland responsible for producing fluid that carries the sperm and lubricates the urethra. The prostate is a common cause of genitourinary symptoms in elderly American men due to benign enlargement, infections and cancer. The National Cancer Institute cites that prostate cancer is the second most common type of cancer among American men, claiming the lives of over 32,000 yearly. Lycopene is a nutrient found in tomatoes and some other fruits that may offer some protective benefit for the prostate gland.
Lycopene Defined
Lycopene is a phytochemical, called a carotenoid, that is red in color and found mainly in tomatoes, but in other red fruits and vegetables too. Lycopene is essential for the production of other carotenoids like beta-carotene that are known for their strong antioxidant behavior. Antioxidants scavenge free radicals, which are products of oxygenation and related to inflammatory responses, tissue and blood vessel deterioration, and potentially, cancer. Carotenoids are vital to plants and vegetables, as they provide color and the ability to photosynthesize. According to "Human Biochemistry and Disease," some research has shown that high tomato consumption reduces cancer risks, so lycopene has been investigated as a possible preventative agent for some cancers, especially prostate cancer.
Lycopene and Prostate Cancer
Observational studies that have noted a correlation between high tomato intake and low cancer rates do not necessarily implicate lycopene as the main factor, because tomatoes are rich in a variety of nutrients. However, according to the American Cancer Society, lycopene supplements have shown the ability to prevent prostate cancer in some human studies and possibly reduce the size of prostate tumors in others. Specifically, lycopene supplements appeared to reduce the rapid growth of prostate cancer cells and lowered PSA levels in the blood, which is considered a good indicator of prostate cancer growth. According to MayoClinic.com, studies of large populations report mixed results as to whether eating tomato products reduce the risk of developing prostate cancer, although there is some evidence that lycopene may slow the progression of prostate cancer. Both sources note that specific research on lycopene supplements is limited.
Sources of Lycopene
The most common source of lycopene is tomatoes, and includes sauces, pastes and even ketchup. With the exception of strawberries and cherries, most red fruits and vegetables contain lycopene, such as red carrots, watermelons, pink grapefruits, guavas and papayas, according to "American Dietetic Association Complete Food and Nutrition Guide." Due to its strong red color and lack of toxicity, lycopene is used as a commercial food coloring. Lycopene is readily absorbed in the stomach and intestines and is stored in the liver, adrenal glands, prostate and testes.
Potential Adverse Effects
Lycopene is considered non-toxic and is commonly found in most diets. Side effects from excessive carotenoid intake are very rare, but have been reported, and primarily involve skin discoloration. Excessive and prolonged consumption of tomato products can turn the skin an orange-yellow color, which is referred to as lycopenoderia. Lycopenodermia is a temporary condition and fully resolves after discontinuing tomato products for a few weeks, according to "Professional Guide to Diseases."
References
- National Cancer Institute: Prostate Cancer
- "Human Biochemistry and Disease"; Gerald Litwack; 2008
- American Cancer Society: Lycopene
- MayoClinic.com: Lycopene Evidence
- "American Dietetic Association Complete Food and Nutrition Guide"; American Dietetic Association; 2006
- "Professional Guide to Diseases: Ninth Edition"; Springhouse Publishing; 2009
