Saturday, July 19, 2008

Antioxidants: Protection from cancer-causing free-radicals with antioxidants contained in vitamin C, Pycnogenol and various herbs (Part IV)

Rx: To prevent such health problems, physicians and researchers in France suggest 50 mg per day of either grape seed or pine bark extract. Larger doses, between 150 to 300 mg per day, are suggested for treating these conditions.

Milk thistle: The seeds of this blue-purple plant contain potent flavonoids that can protect the liver from damage due to a history of mononucleosis, hepatitis, cirrhosis of the liver, excessive medication, drug or alcohol intake, or exposure to industrial chemicals. In short, its antioxidant properties may "detox" the liver, helping to restore it to normal function, or protect it from further damage.

Rx: "The only way that milk thistle has been shown in clinical studies to work is through a strong, concentrated extract," says Blumenthal. The recommended dosage: 420 mg daily, in capsule or tablet form. Take two to three 140 mg doses.


Zinc: Available in tablets, the trace mineral zinc is known to boost the effectiveness of our immune system. Still being tested is its link to protecting us against macular degeneration (retinal deterioration) and acne. Found mostly in fortified cereals, and protein-dense legumes in plant-based diets, if you're getting enough protein, it's likely you're getting adequate amounts of zinc.

Rx: Stick to the RDA of 15 mg or less (along with two mg. of copper to help your body absorb it better). Excessive doses can be toxic, weaken your immune system, and lower HDL ("good") cholesterol levels.

Selenium: Linked with the ability to fight heart disease and some forms of cancer, this trace mineral is found in wheat germ, whole grains (oats, whole wheat, brown rice, etc.), nuts, and molasses. Says McCaleb, "Because this mineral can be toxic, it helps to know if the soil in your area is high in selenium. If you're in a high selenium soil area, your locally grown vegetables will have a high selenium content."

Rx: If the area in which you live has selenium-rich soil, avoid supplementation. Otherwise, suggested safe amounts for adults is 200 to 400 mg daily.

In the world of supplements, vitamins and minerals are perceived as nutritional insurance; herbs, as having a more therapeutic effect. In the not-too-distant-future, "I think we're going to see more physicians and pharmacists recommending these herbs; more people demanding them," says Blumenthal. Why? In part because they're often gentler, less expensive, and more natural than pharmaceutical drugs. "There's also a presumption that they're safer," says Blumenthal. "This isn't always true, but in the case of herbs, it usually is."

Although the medical community has not reached a consensus about antioxidant supplementation, many well-respected scientific experts believe there is a place for supplemental antioxidants. There is also a consensus that supplements are not a substitute for a healthy diet.

Alliance for Aging Research (AAR): The Alliance is the first national non profit health organization to issue specific public health guidelines on obtaining antioxidants from diet and supplements, based on findings from more than 200 clinical and epidemiologic studies on antioxidants conducted over the past two decades. Their conclusion: First, strive to obtain antioxidants by eating a diet rich in fruits and vegetables.

Supplementation: AAR suggests that people at high risk for cancer, especially asbestos workers and smokers, should not take any beta carotene supplements. For others interested in health promotion and disease prevention, they recommend the following ranges of supplements (in an aging population): vitamin C, 250 to 1000 mg daily; vitamin E, 100 to 400 IUs daily; beta carotene, 17,000 to 50,000 IUs (10 to 30 mg) daily.

UC Berkeley: The UC Berkeley Wellness Letter, with an editorial board that includes some of the top nutrition researchers in the country, supports supplementation "to hedge your bets." But in light of the NCI's findings, they have withdrawn their recommendation for smokers to take beta carotene supplements-though they see no harm or benefit for non-smokers to take low doses if it's not obtained in the diet. Their recommendation: In addition to eating five or more servings of fruits and vegetables daily, 200 to 800 IUs (133 to 533 mg) of vitamin E daily; 250 to 500 mg of vitamin C, but no more than six to 16 mg beta carotene daily for non-smokers not obtaining adequate amounts in their diet (April 1996).

Ornish Institute: Dr. Dean Ornish's Preventive Medicine Research Institute (PMRI) conducts pioneering research on lifestyle (diet, exercise, stress management, and group support) and "reversing" heart disease. Says PMRI's research director, Larry Scherwitz, PhD, "If a three-day nutritional analysis reveals program participants are not obtaining adequate antioxidant levels in the diet, we recommend a range of supplement doses": one to three grams vitamin C; 100 to 400 IUs of dry vitamin E daily; 10,000 to 25,000 IUs of beta carotene. Interpretation: If your dietary intake of antioxidants is low, choose supplement doses at the high end of the recommendation; if your dietary intake is adequate but not optimal, chose supplement doses at the lower end. As "insurance," PMRI suggests taking a multi-vitamin, without iron, each day.

Cooper Center: The Kenneth Cooper Aerobics Center also espouses antioxidant supplementation-as an adjunct to consuming five or more servings of fruits and vegetables daily. "After assessing someone's nutritional intake, we make recommendations," says Dr. Mitchell. If the analysis shows adequate daily intake, defined as 1000 mg vitamin C, 15 mg (25,000 IUs) beta carotene, and 400 IUs vitamin E (specifically d-alpha tocopherol-the natural form of vitamin E), then extra supplements aren't recommended. "But if the intake is below the recommended amounts [to combat free radicals], we now know how much extra each person needs to take each day to meet our 'template'."

(Note: Although there is no hard research evidence [yet] that endurance athletes benefit from higher doses of antioxidants, the Center suggests that anyone exercising more than five hours weekly should double the recommended dosage to combat excess free radical by-products.)

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