A new review article highlights the many health advantages of eating more tomatoes, which includes a lower risk of prostate cancer and other cancers, and emerging evidence of benefits concerning other diseases. While the good news is Americans eat more tomatoes and tomato products than any other non-starchy vegetable, about 90 percent of adults fail to consume the 2.5 cups of vegetables per day recommended by the 2010 Dietary Guidelines for Americans.
The authors of the new review, which references more than 100 articles and reports, note that much of the initial research regarding tomatoes focused on the vegetable’s high antioxidant content, specifically lycopene. Lycopene has been the subject of many research studies regarding its protective effect against prostate cancer.
Can eating tomatoes decrease your risk of prostate cancer?
In men with prostate cancer, lycopene supplementation has been shown to be safe and tolerated well in doses up to 120 mg per day for up to one year. Toxicity is generally very mild, with diarrhea as a possible side effect at high doses. The authors also point out that the data consistently support a protective effect of tomatoes and tomato products and the risk of prostate cancer as well as improvements in biomarkers of disease status, including insulin-like growth factor (IGF)-1.
A unique characteristic of tomatoes is that unlike the nutrients in other fresh fruits and vegetables, lycopene is more bioavailable after tomatoes are cooked and processed. This fact opens up even more possibilities for individuals to enjoy the benefits of lycopene.
According to the US Department of Agriculture National Nutrient Database for Standard Reference, ½ cup of tomato paste contains 18.84 mg of lycopene, while an equal amount of tomato sauce has 17.12 mg, spaghetti sauce has 15.82 mg, and tomato juice has 10.88 mg (lycopene levels may vary depending on the brand). One-half cup of raw tomatoes, however, contains only 2.32 mg of lycopene. Non-tomato products that contain lycopene include watermelon (1/2 cup has 3.44 mg) and grapefruit (1/2 fruit contains 1.75 mg).
More recent hypotheses have looked at the advantages of whole tomatoes, which are excellent sources of vitamins A and C, fiber, and potassium, and identified other protective elements beyond lycopene. Vitamins A and C are potent antioxidants, while fiber has been shown to reduce cholesterol, and potassium is helpful in lowering blood pressure and possibly reducing bone loss.
Can eating tomatoes reduce risk of other diseases?
In studies of tomato consumption and cardiovascular disease, for example, the addition of tomato products to the diet can increase antioxidant enzyme defenses and reduce susceptibility of low-density lipoprotein (LDL) to oxidation, a factor in cardiovascular disease. Among healthy adults and people with diabetes, tomatoes and tomato products have shown positive results concerning LDL cholesterol. The authors note these findings are not solely attributed to lycopene, but rather illustrate the benefit of the combination of nutrients available in whole tomatoes.
The authors conclude that “Research underscores the relationship between consuming tomatoes and reduced risk of cancer, heart disease, and other conditions.” They also note that even though lycopene has been extensively studied apart from tomatoes, “the preponderance of evidence suggests that consumption of whole tomatoes and tomato products should be preferentially recommended because of greater consistency of documented positive outcomes with the whole tomato and the concomitant supply of other important essential nutrients.”
Given that tomatoes and tomato products are already dietary favorites, increasing their consumption can achieve several goals, including reduction in the risk of prostate cancer and other diseases, and helping Americans achieve the recommended daily intake of 2.5 cups of vegetables.
Read more in our Prostate Cancer Health Center.
Burton-Freeman BB, Reimers K. Tomato consumption and health: emerging benefits. American Journal of Lifestyle Medicine 2010 Nov; DOI: 10.1177/1559827610387488