Colette's Blog

November 21, 2014

Speaking of color and food (see salmon blog below), let's find out why the same ingredient that gives tomatoes their red color may also help protect you against cancer!

It seems unlikely, but it's true. In a Harvard University study of over 47,000 men, those who ate 10 or more servings a week of tomato products had a reduced risk of prostate cancer. One of the foods most commonly eaten? Pizza!

But don't run out and start gorging on pizza. Researchers believe that at least some of the cancer-protective effect seen in the Harvard study is due to a member of the carotenoid called lycopene. (In the Harvard study, tomato sauce had the highest relationship to a low risk for prostate cancer, though tomatoes and pizza also fared well. And tomato sauce was by far the most related to blood levels of lycopene.) Lycopene is what gives tomatoes, watermelons, grapefruits and papaya their red color. A pigment synthesized by some plants and animals to protect them from the sun, lycopene evolved as a weapon against certain types of free radicals. Lycopene is so effective at quenching free radicals that it beat out vitamin E in one study on oxidized fat. This suggests that lycopene might have importance in preventing heart disease, which involves oxidized LDL ("bad") cholesterol.

Humans get most of their lycopene from tomatoes--by far the richest source--yet tomato products offer a more concentrated source of lycopene than the fresh fruit itself. For example, tomato powder contains approximately 120 milligrams per 100 grams of fruit, whereas fresh tomatoes have about 2 milligrams per 100.

Note: In the Harvard study, the only tomato-based food that showed no relationship to prostate cancer was tomato juice. However, it's been suggested that since lycopene needs some fat to be absorbed, the results might be different if tomato juice were consumed with a digestible oil.

Whether lycopene alone causes reduced cancer risk is uncertain. Some research suggests foods that contain lycopene are more helpful than lycopene by itself; for example, in a dietary supplement pill. Foods that contain lycopene also contain other nutrients, including other antioxidant vitamins. It may be the combination of nutrients found in vegetables and fruits that help reduce cancer, rather than any single nutrient such as lycopene. It is well-established that diets high in fruits and vegetables are associated with lower risk of cancers--just one more reason to adhere to the principles of the Atkins Advantage, which include getting all of your vitamins and minerals and eating plenty of vegetables.

Tip: Research shows that lycopene in foods is more available to the body when it has been heated. Like all carotenoids, it is more available to the body when it consumed in combination with foods or ingredients that contain fat--for example, in the form of spaghetti sauce, tomato sauce or tomato paste.

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