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That doesn't mean, however, that popping vitamin E pills will stave off heart disease. Previous research had reached a split decision over whether supplementary E could guard against cardiovascular problems. But the study on postmenopausal women, one of the largest yet, concluded that the vitamin was protective only when eaten in foods; in pill form, it didn't seem to do much good at all. This result could mean that the vitamin works in tandem with some other, as yet unidentified, food-borne substance.
Adding lots of fruits and vegetables to the diet is good for the heart in all kinds of ways. It displaces meat and dairy products and thus reduces the intake of saturated fats. It puts more vitamins--not just E but also C and many of the B vitamins--into your body.
Over the past several years, however, researchers have been investigating a whole new class of plant-based substances whose role in preventing heart disease may be even more important than vitamins. Known as phytochemicals, they fall into two classes: carotenoids, found mostly in orange-colored vegetables (beta carotene is the best known of the more than 600 carotenoids); and flavonoids--some 4,000 of them, found in, among other things, onions, broccoli, red wine and tea (green, black and oolong, but not herbal).
Like vitamin E, the flavonoids and the carotenoids appear to act as antioxidants, keeping LDL and triglycerides from being oxidized by free radicals. But they do so in different ways, explains Jeffrey Blumberg, a Tufts University nutritionist: "All those free radicals come in many varieties and affect different parts of the body. So you need many different antioxidants to protect yourself at different levels."
For example, he says, vitamin E, which is fat soluble, is incorporated into the LDL or triglyceride particle, forming a last line of defense against corruption by free radicals. Water-soluble flavonoids, by contrast, can be absorbed by most cells in the body, where they can presumably take free radicals out of circulation. But so far, these are only theories. All scientists know for sure is that people who eat foods rich in these two kinds of chemicals, flavonoids and carotenoids, seem to have less heart disease--and it's not even certain that there is a cause-and-effect relationship.
As for figuring out precisely which of the thousands of phytochemicals is most important, that is decades away, if it's even a legitimate question in the first place. Just as with vitamin E--and with the studies that debunked beta-carotene supplements as cancer fighters a few years ago--it may turn out that phytochemicals work only in tandem with one another or with other chemicals found in foods. Trying to isolate the "active ingredient" might be a fool's errand. Says Dr. Ronald Krauss, a nutrition and cholesterol researcher at the Lawrence Berkeley Lab: "It's premature to interpret that research in any way other than you should eat more fruits and vegetables."
INFECTION AND INFLAMMATION