The Beauty of Tomatoes: Crushed, Diced,
or Stewed
For: Should Women Like Lycopene, Too? August
2002
Lycopene may be the best discovery since vitamin C. A vitamin-like substance that makes tomatoes red, it is a member of the carotenoid family, one of the world's truly functional families. Lycopene may help reduce the risk of prostate cancer and cardio-vascular disease—and other cancers, too, particularly breast and cervical cancer.
Lovers of fresh produce may be surprised to learn that processed tomato products contain more lycopene (and in a more absorbable form) than fresh tomatoes. Processed tomatoes, like fresh, also contain beta carotene and some vitamin C. Tomato products in cans, jars, or even cartons are usually reasonable in price, and they are well worth eating. Even a dollop of ketchup—famed in other days as perhaps the only vegetable in some school lunches—has a little lycopene.
Just be sure to read labels: sodium can be a problem, and so can fats in the form of oils and cheeses in some sauces. Canned tomato juice, including cocktails such as V-8, packs a lot of lycopene, but with a sodium wallop (900 milligrams or more in a cup). Low-sodium or sodium-free versions are available.
Tomato products are not just for spaghetti and pizza. Add them to stews, soups, lentils, and beans. Try poaching fish filets or a skinless chicken breast in crushed or diced tomatoes. Or serve a tomato sauce on the side with chicken and fish.
A primer of tomato products
Diced tomatoes: Peeled and coarsely chopped, usually cooked in tomato juice with seasonings. Many uses. Heated with a few herbs, they make a quick sauce for pasta.
Crushed tomatoes: Chopped fine and simmered in tomato purée. Many uses. Excellent added to vegetable soups.
Stewed tomatoes: Peeled, sliced, simmered with other vegetables and seasonings. For soups and sauces, or as a side dish. Add as a sauce to steamed zucchini.
Whole tomatoes: Sometimes plain, sometimes with onion and added flavorings. Good as a side dish. Seed and chop them for a sauce.
Tomato paste: Thick rich concentrate, obtained by long cooking, straining, and reduction. Small amounts can enrich soups, stocks, and stews. Comes in tubes, too.
Tomato purée: Cooked briefly and strained to a thick liquid, thinner than paste and more versatile.
Tomato soup: Usually high in sodium; if made with cream, high in fat, too. Check labels. Some low-fat, low-sodium, and very tasty soups come in cartons now.
Tomato sauce, spaghetti sauce: Thinner than purée, usually with lots of added sodium, seasonings, and other ingredients, sometimes including meat. Read the labels to avoid fat and minimize sodium.
Pizza sauce: Tomato purée with Italian seasonings. Good for pizza, on bagels, or as a dip.
Sun-dried tomatoes: Often
high in sodium, and those preserved in oil have lots of calories and fat.
The kind you reconstitute yourself is lower in calories. Use sparingly
as a flavoring in sauces or salads. Look for low-sodium and/or low-fat
versions.
Good eating and maybe good medicine
Lycopene may help prevent prostate cancer, and the best source is cooked tomatoes, as we've said. So scientists recently did an experiment to see whether tomato sauce might even help combat existing prostate cancer. They asked a group of men scheduled for prostate-cancer surgery to eat tomato-based dishes (such as lasagna or stuffed shells) once a day during the three weeks before their operations.
The amount of lycopene in these foods was exactly measured; and during the surgery, lycopene levels in the prostate and blood were measured, along with PSA levels (prostate specific antigen, a blood protein that usually rises when prostate cancer is present). They also looked at damage to the genetic material in the cancer cells and compared it with cells removed earlier, at the time of biopsy.
Though the study was admittedly small and preliminary, results were very interesting. Lycopene levels in both the blood and prostate increased, and PSA levels declined. The damage to the genetic material in the cancer cells was less than at the time of biopsy.
This does not mean that pizza and lasagna cure prostate cancer. Still, this study from the Journal of the National Cancer Institute suggests that lycopene may slow the progress of the cancer. More work is underway. Meanwhile, processed tomatoes are a very worthwhile part of a healthy diet, and fresh tomatoes are great, too. Watermelon and pink or red grapefruit also supply lycopene.
What about lycopene and women? The case is less clear-cut,
but we'll report on studies in a future issue.
UC Berkeley Wellness Letter, April 2002
