Bottom Line: Diets that contain many fruits and vegetables rich in carotenoids like lycopene can help prevent some types of cancers and heart problems. However, not enough research has been done to say whether lycopene supplements have the same effect.
Lycopene is a natural pigment that is produced by plants and microorganisms. Laboratory experiments with lycopene confirm that it acts as an antioxidant and affects the way cells grow and communicate with each other, although it is not as potent as beta-carotene. Scientists have proposed several different mechanisms by which lycopene might fight cancer. These include inhibition of cancer cell growth, prevention of DNA damage, and enhancement of enzymes that break down cancer-causing products. Studies in healthy elderly patients suggest that consumption of lycopene or tomato juice does not stimulate the immune system. In general, diets rich in carotenoids like lycopene have been associated with decreased risk of macular degeneration, cataracts, some types of cancers, and some heart problems.
To prevent and treat cancer Lycopene is an antioxidant. One clinical trial suggested that preventative use of lycopene supplements reduces the spread of localized prostate cancer, but there is no other proof from clinical trials that lycopene can treat cancer. Diets rich in carotenoids like lycopene are generally associated with a decreased risk of certain types of cancers.
To treat asthma One clinical trial showed that daily lycopene supplementation protected against exercise-induced asthma, but no additional studies have been performed to confirm this.
As an antioxidant Laboratory studies support this use.
To treat heart disease Diets rich in carotenoids like lycopene are generally associated with a decreased risk of some cardiovascular events. However, there is no proof that lycopene supplements have the same effect.
To prevent and treat macular degeneration Diets rich in carotenoids like lycopene are generally associated with a decreased risk of macular degeneration. However, there is no proof that lycopene supplements have the same effect.
Prostate cancer: A small clinical trial examined the use of lycopene supplements in patients with localized prostate cancer who planned to undergo radical prostatectomy. For three weeks before surgery, 15 men received 15 mg of lycopene daily, while 11 received a similar-looking placebo. At the time of surgery, it was found that men who had been taking lycopene had less cancer spread to areas surrounding the prostate. No side effects of lycopene were reported. Though these results are promising, they need to be validated by larger studies in which the patients are randomly assigned to take lycopene or placebo.
Benign prostatic hyperplasia (BPH): Forty participants with BPH received lycopene or placebo for 6 months. Symptoms of BPH including prostate specific antigen (PSA) levels and prostate enlargement were measured. Patients who took lycopene had decreased PSA levels and no further prostate enlargement. Patients given placebo had no changes in their PSA levels and further prostate enlargement. Larger, long-term studies needed to validate whether lycopene supplementation is useful for BPH treatment.
Asthma: The role of lycopene in preventing exercise-induced asthma was studied in a clinical trial with 20 patients. Patients were randomly assigned to receive 30 mg of lycopene or placebo pill daily for one week. After four weeks of a "wash-out" period, patients were switched to the other group for another week of treatment. Their lung function after exercising was measured before and after each week of treatment, and it was found that lycopene was able to protect against exercise-induced asthma in 11 patients when compared to the placebo pill. This study is too small to inform us of the effects of lycopene in the general population.
This product is regulated by the FDA as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
A recent analysis of six commercially available brands revealed that their actual lycopene content varied considerably from the labeled dosage. Brand-name vitamins contained as little as 62% of the claimed dosage to as much as 143% over the stated amount.
A large study in the Netherlands suggested that alcohol consumption may affect the anti-cancer properties of lycopene.
No adverse effects have been reported at normal dosages.
After long-term ingestion of large quantities of lycopene-rich foods (i.e. tomato products), some individuals may develop lycopenodermia, a deep orange discoloration of the skin.
A natural pigment synthesized by plants and microorganisms, lycopene is used primarily as an antioxidant and also to prevent and treat cancer, heart disease, and macular degeneration. Lycopene has antioxidant activity and is classified as a nonprovitamin A carotenoid, other examples being lutein and zeaxanthin. Alpha-carotene, beta-carotene, and beta-cryptoxanthin are classified as provitamin A carotenoids because they can be converted into retinol. Small clinical trials suggest possible benefit against exercise-induced asthma (1), benign prostatic hyperplasia (BPH) (2), and cancer, but no optimal dosage has been established.
Epidemiologic studies suggest an inverse relationship between lycopene consumption and risk of cancer (3), particularly lung (4), stomach (5), and prostate (6) and estrogen receptor (ER) and progesterone receptor (PR)-positive breast cancers (7). Consistent association between lycopene consumption and endometrial cancer risk has not been detected (8)(9). Low intake of tomato sauce may be associated with advanced prostate cancer in patients with low-grade cancer at diagnosis (10) although results from a large prospective study indicate that lycopene or tomato-based regimens may not prevent prostate cancer (11), and variable results were reported for lycopene supplementation in prostate cancer patients (12).
No adverse effects or drug interactions are known for lycopene. A possible interaction between lycopene and alcohol has been reported, high doses of lycopene plus alcohol induced cytochrome P450 (CYP) 2E1 expression (13). An analysis of six commercially available brands revealed that lycopene content varied from the labeled dosage by as much as 43% (14).
Lycopene is a natural pigment synthesized by plants and microorganisms. Referred to as a nonprovitamin A carotenoid, it is not known to have any vitamin A activity. Biological actions include antioxidant activity via singlet oxygen quenching and peroxyl radical scavenging, induction of cell to cell communication, and growth control, although less efficiently than beta-carotene (15). Proposed mechanisms of action in cancer prevention include inhibition of cancer growth, induction of differentiation by modulation of cell cycle regulatory proteins, alterations in insulin-like growth factor-1 (16) or vascular endothelial growth factor (17) levels, prevention of oxidative DNA damage, and possible enhancement of carcinogen metabolizing enzymes (18). Other possible actions for all carotenoids include immunoenhancement, inhibition of mutagenesis and transformation, and inhibition of premalignant lesions. Carotenoids have also been associated with decreased risk of macular degeneration and cataracts, decreased risk for some types of cancers, and decreased risk of some cardiovascular events (19).
Absorption: Intestinal absorption of carotenoids, including lycopene, is facilitated by the formation of bile acid micelles containing carotenoids. The presence of fat in the small intestine stimulates the secretion of bile acids from the gall bladder and improves the absorption of carotenoids by increasing the size and stability of the micelles, thus allowing more carotenoids to be solubilized. Bioavailability of lycopene is affected by the dose and presence of other carotenoids such as Beta carotene (20). Distribution: Concentrations of lycopene in serum and body tissues are highly variable and are dependent on food source, efficiency of absorption, and amount of fat in the diet. The serum concentration after a single dose peaks at 24 to 48 hours post dose (21). Lycopene is primarily stored in adipose and liver. In both serum and tissue storage, lycopene cis-isomers constitute greater than 50 percent of the total lycopene present. Metabolism/Excretion: It is assumed that lycopene is excreted through the bile and kidneys (20).
A recent analysis of six commercially available brands revealed actual lycopene content to vary considerably from the labeled dosage, from 62% to 143% of the stated amount (14).
A possible interaction between lycopene and alcohol consumption was reported, indicating that cytochrome P450 (CYP) 2E1 expression (13) is induced by high doses of lycopene plus alcohol.
No adverse effects have been reported at normal doses. (20) Toxicity: Lycopenodermia has resulted following chronic ingestion of large quantities of lycopene-rich foods (i.e. tomato products) and is characterized by a deep orange discoloration of the skin.
Schwarz S, et al. Lycopene inhibits disease progression in patients with benign prostate hyperplasia. J Nutr. Jan 2008;138(1):49-53. Because epidemiological studies suggest that dietary intake of lycopene is associated with decreased prostate cancer risk, this study sought to determine if lycopene supplementation improved benign prostatic hyperplasia (BPH), which may be a risk factor for prostate cancer development. Forty participants with BPH received lycopene (15 mg/day) or placebo for 6 months after which prostate specific antigen (PSA) levels and prostate enlargement was assessed. Decreased PSA levels were detected in the intervention group whereas there were no changes in the placebo group. Furthermore, although prostate enlargement was detected in the placebo group, no changes from baseline measurements were seen in the lycopene group. Larger, long-term studies are necessary to determine if lycopene supplementation could influence prostate cancer in men with BPH.
Kucuk O, et al. Phase II randomized clinical trial of lycopene supplementation before radical prostatectomy. Cancer Epidemiol Biomarkers Prev 2001;10:861-8. A prospective evaluation of 15 mg lycopene (n=15) or placebo (n=11), administered twice daily, in patients with localized prostate cancer undergoing radical prostatectomy 3 weeks following supplementation. Study endpoints included cell growth and differentiation, plasma levels of IGF-1 and PSA, and tumor pathology. There was no difference in baseline demographics between treatment groups. Following surgery and analysis of data, it was shown that serum levels of IGF-1 and involvement of surgical margins and/or extra-prostatic tissues with cancer was significantly lower in the lycopene group. No adverse events were noted. Although beneficial trends were seen for patients supplemented with lycopene, larger randomized studies are required to validate results.
Neuman I, Nahum H, Ben-Amotz A. Reduction of exercise-induced asthma oxidative stress by lycopene, a natural antioxidant. Allergy 2000;55:1184-9. A small randomized, double-blind evaluation of lycopene (LYC-O-MATO) supplementation on airway hyperreactivity in 20 patients with exercise-induced asthma (EIA). The test was based on the following sequence: measurement of baseline pulmonary function, 7-min exercise session on a motorized treadmill, 8-min rest and again measurement of pulmonary function, 1-week, oral, randomly administered, double-blind supplementation of placebo or 30 mg/day of lycopene, measurement of pulmonary function at rest, 7-min exercise session, and 8-min rest and again measurement of pulmonary function. A 4-week washout interval was allowed between each protocol. All patients given placebo showed significant postexercise reduction of more than 15% in their forced expiratory volume in 1 s (FEV1). After receiving a daily dose of 30 mg of lycopene for 1 week, 11 (55%) patients were significantly protected against EIA. These results must be substantiated by a larger trial.
Institute of Medicine, Food and Nutrition Board. Beta-carotene and other carotenoids. Dietary reference intakes for vitamin C, vitamin E, selenium, and carotenoids. Washington, D.C.: National Academy Press; 2000:325-400.
