|
Vitamins - Dietary Health Benefits
(Page 3)
Carotenoids and Heart Protection. Studies have reported that a high intake of fruits and vegetables containing beta carotene, lycopene, and other carotenoids may reduce the risk of heart attack. For example, lycopene-poor diets (particularly lycopene in tomatoes) were associated with a significantly higher risk of heart disease and stroke. In another study involving animals, lutein protected against early hardening of the arteries.
 Atherosclerosis is a disease of the arteries in which fatty material is deposited in the vessel wall, resulting in narrowing and eventual impairment of blood flow. Severely restricted blood flow in the arteries to the heart muscle leads to symptoms such as chest pain. Atherosclerosis shows no symptoms until a complication occurs.
Phytochemicals and Heart Protection. Several phytochemicals are associated with heart protection.
- Flavonoids. Certain flavonoids, found in both black and green tea, dark chocolate, onions, red wine or red grape juice, and apples, appear to be strongly heart protective. In a 2003 study, people who consumed the most flavonoids in foods had a 20% lower risk for heart disease than those with low consumption. Flavonoids may protect against damage done by cholesterol and help prevent blood clots. A number of studies have now reported heart protection from the flavonoid catechin, which is found in both black and green tea. (Studies on tea-drinking however have been mixed. For example, the British consume a lot of tea but have high rates of heart disease.) The flavonoid resveratrol, which is found in grape skin, appears to be responsible for the well-known heart protective effects in red wine and purple grape juice. A glass or two of red wine a day may be healthful. For people who cannot drink alcohol, juice from red grapes may be beneficial.
- Organosulfurs. Organosulfurs found in onions and garlic have been under investigation for possible beneficial effects on cholesterol levels. Two well-conducted studies found no heart-benefits from taking capsules equivalent to between one and one and a half garlic cloves a day. The preparation of these products, however, may be responsible for the lack of effect. On a more positive note, a 2000 study reported an association between taking garlic capsules and significantly lower cholesterol-build up in the arteries of older women but not in older men. In the study, daily garlic supplements dramatically reduced the build-up of newly formed plaque in the arteries, while having much less effect on older, harder plaque deposits. Garlic supplements for cardiovascular disease may be most beneficial, then, when used during earlier years among men and later years among women.
- Isoflavones. Soy protein is the most studied source of isoflavones (known as phytoestrogens, or plant estrogens). Not all studies are consistent, but the majority has shown an improvement in at least one of the cholesterol components in people who consumed at least 25 grams of soy protein. Soy may also reduce other heart risk factors, at least in certain populations. For example, in one 2002 study, soy was beneficial for controlling blood sugar and lowering LDL in postmenopausal women with type 2 diabetes. In another study, soy protein was associated with lower systolic blood pressure in men. The best sources are soy products (tofu, soy milk) or whole soy protein. Powdered soy protein that contains at least 60 mg of isoflavones may provide similar benefits. Tablets of individual isoflavones found in soy do not appear to offer any advantages and may be harmful.
- Sterols. The plant sterols, including sitosterol, are also proving to be potent cholesterol fighters. Sitostanol, a derivative of sitosterol, is being used in new margarine products to lower cholesterol levels.
| |
