| No: 11 | November 2007 |
TOMATO LYCOPENE MAY REDUCE THE RISK OF PROSTATE CANCER OR NOT Lycopene is the pigment that provides the red color of tomatoes. Lycopene and other carotenoids serve as a key source of antioxidants (Antioxidants are substances that can prevent or delay the oxidation of other substances and may protect against chronic disease). Since recent epidemiological studies suggestive of lycopene's role against prostate cancer let's have a look to the related scientific studies and conclusion of FDA: Assessment of Observational Studies There were 13 observational studies evaluating the relationship between tomatoes or tomato products and prostate cancer. Two large cohort studies conducted in the United States evaluated tomato/tomato sauce intake and prostate cancer risk. Both studies received a high methodological quality rating. The Health Professionals Follow-Up Study cohort was used that contained 47,365 males followed for approximately 12 years. In this cohort 2,481 prostate cancer cases were identified during follow-up. Tomato sauce intake was evaluated using three different food frequency questionnaires given at the beginning of the study and at four-year intervals. Consuming one, or greater than one, serving of tomato sauce per week was associated with significant decreased risk of prostate cancer; relative risk 0.80 (95% Confidence Interval (CI) of 0.70-0.91) and 0.77 (95% CI of 0.66-0.90), respectively. Then a cohort of 14,000 Seventh Day Adventist males for six years was followed, 180 prostate cancer cases were identified during the follow-up. Consuming tomatoes one to four times per week, or greater than five times per week was associated with a significant decrease in prostate cancer incidence; relative risk 0.62 (95% CI of 0.40-0.96) and 0.57 (95% CI of 0.35-0.93), respectively. One sub-cohort study evaluated tomatoes and prostate cancer risk in 642 prostate cancer cases and 1,668 random healthy subjects from a cohort in the Netherlands. This study was of high methodological quality. Tomato intake (per 25 grams tomatoes) was not associated with prostate cancer, with a relative risk of 1.05 (95% CI of 0.90-1.22). Tomato juice intake (per 25 grams) was not associated with prostate cancer incidence; relative risk of 1.12 (95% CI of 0.96-1.29). Eight case-control studies evaluated tomatoes and prostate cancer risk and all of the studies received high to moderate methodological quality ratings. It is reported that consuming greater than 109 grams of tomatoes per day was associated with a reduced risk of prostate cancer; odds ratio of 0.64 (95% CI of 0.45-0.91). This case-control study was conducted in Canada with 617 prostate cancer cases and 636 controls. A case-control study was conducted that included 320 prostate cancer cases and 246 controls in Greece. Decreased intake of cooked tomatoes was associated with an increased risk of prostate cancer; odds ratio of 1.91 (95% CI of 1.20-3.04). However, there was no association between raw tomato intake and prostate cancer risk. A case-control study was conducted in 130 prostate cancer cases and 274 controls from China. Tomato intake was associated with a reduced risk of prostate cancer; odds ratio of 0.16 (95% CI of 0.07-0.38). Five of the eight case-control studies found no association between tomato consumption and prostate cancer risk. One case-control study conducted in Canada included 1,623 prostate cancer cases and controls and found no association between prostate cancer and tomatoes or tomato juice consumption; odds ratio of 1.0 (95% CI of 0.7-1.3). Another case-control study conducted in England included 328 prostate cancer cases and controls and found no association between prostate cancer and raw or cooked tomato intake; odds ratio of 1.06 (95% CI of 0.55-1.62) and 0.92 (0.59-1.42), respectively. A case-control study was conducted in the United States with 932 prostate cancer cases and 1,201 controls. Tomato juice and raw/cooked tomato consumption had no association with prostate cancer risk. A case-control study was conducted using 1,619 prostate cancer cases and 1,618 controls from a multi-ethnic population from the United States and Canada. There was no association between tomatoes or cooked tomato consumption and prostate cancer risk. A case-control study was conducted in Hawaii with 452 prostate cancer cases and 899 controls. Tomato consumption had no association with prostate cancer risk. Two ecological studies of moderate methodological quality evaluated tomato consumption and prostate cancer risk. Prostate cancer mortality data were compared from 41 countries to the tomato supply for each country. Of the 28 countries that consumed more than five kilocalories per day from tomatoes, there was a strong protective correlation between tomato intake and prostate cancer mortality. Prostate cancer incidence rates were evaluated and tomato consumption (based on country intake) for 44 countries. There was no correlation between tomato consumption and prostate cancer. Conclusion Very limited and preliminary scientific research suggests that eating one-half to one cup of tomatoes and/or tomato sauce a week may reduce the risk of prostate cancer. FDA concludes that there is little scientific evidence supporting this claim. |
