Health Horizons : NUTRITION : Vitamin Insurance? : Some researchers believe that such a ‘policy,’ costing only about $50 a year, comes in the form of megadoses of itamins E and C and beta carotene. They believe that the compounds could protect against such things as cancer and heart disease.
We hedge our bets with all kinds of insurance policies. We insure our homes, cars, children, husbands, wives, boats, skis and dogs. Heck, dancers even insure their legs.
So how about a policy that insures good health? Insurance against cancer, heart disease, cataracts, diabetes, high cholesterol, Parkinson’s disease, arthritis and all those ailments that have been accepted as a scourge of aging in today’s world.
A dream? As of now, yes. But some researchers are on the trail of what they say has the potential to protect us--at least partially--against those diseases. The policy costs only about $50 a year, and it comes in the form of itamin E, itamin C and beta carotene, all in huge, or megadoses. (Beta carotene is what turns carrots and sweet potatoes orange. We commonly call it itamin A, which is what it becomes in the body.)
Studies gathering steam in the last few years point to those compounds as ones that might ward off diseases and could boost the power of our immune systems.
Few, however, are ready to prescribe those supplements--called dietary antioxidants--as the Fountain of Youth or anti-aging pills. The federal Food and Drug Administration, which regulates food labeling, including claims about health values of foods and vitamins, says the evidence is too equivocal to approve health claims.
Nevertheless, the federal government has invested millions of dollars in two dozen clinical trials now under way, which signals confidence in the potential of the nutrients, says Jeffrey Blumberg, associate director of the Human Nutrition Research Center on Aging at Tufts University, and chief of the antioxidants research laboratory.
“I can assure you that the government isn’t spending that much money to see what’s not going to succeed,” he says.
In another sign of confidence, conservative researchers around the world, including Blumberg, are already popping one or more of the vitamin supplements themselves. Steven Harris, associate research pathologist in the pathology department at UCLA, says he takes extra doses of itamins E, C and “just enough beta carotene to turn the soles of my feet yellow.”
But Harris, Blumberg and others are quick to point out that swallowing pills isn’t a panacea for living on fast food, puffing on tobacco or being a couch potato. The researchers pop extra pills but they also eat their leafy greens and get their weekly dose of heart-pumping exercise.
So if you obey the low-fat, high-carbohydrate dietary rules issued by the health honchos, the next decision is whether to pursue an insurance policy against, for example, heart disease and cancer, the two biggest killers today.
Here’s what some studies have found about antioxidants taken in doses at least 10 times greater than the ecommended ietary llowance. In most cases, researchers say, results are promising, but more study is needed:
* Daily doses of beta carotene, Vitamin E and selenium reduced cancer deaths by 13%, according to a study reported in September, which was conducted in rural China by U.S. researchers. The five-year study, involving 29,584 people in an area where cancer rates are among the highest in the world, showed that some vitamins and minerals can be of benefit against cancer, according to the National Cancer Institute researchers. The scientists added, however, that the results “don’t automatically translate to the situation in the United States,” which has a much better balanced and more healthful diet.
* Two ongoing studies of more than 120,000 men and women reported in June that initially healthy people with the highest daily intakes of Vitamin E developed coronary heart disease about 40% less often than comparable men and women who took the lowest amount of Vitamin E. The greatest protection was with 100 international units or more of Vitamin E a day for more than two years among participants in the Nurses’ Health Study and the Health Professionals Follow-up Study.
* Getting too little Vitamin A raised the risk of breast cancer in a group of 89,494 nurses tracked for eight years, researchers at Brigham and Women’s Hospital in Boston reported in July. Eating less than one daily serving of vegetables also increased risk.
* Higher levels of Vitamin C in the blood were associated with lower risk factors for heart disease, a study in the Journal of the American College of Nutrition reported last year. Vitamin C apparently increased high-density lipoproteins (HDL), the so-called good cholesterol, lowered low-density lipoproteins (LDL), the bad cholesterol, and lowered blood pressure.
* A 1987 study in London measured levels of Vitamin E in the blood of 22,000 men. The 271 men who were found within one year to have cancer had lower levels in their blood of Vitamin E than in a group of 533 controls matched to the cancer group.
* In a 1990 review of 12 studies of Vitamin C’s influence on breast cancer, Gladys Block, a researcher at the UC Berkeley, concluded that if all post-menopausal women lowered the fat in their diets, their of breast cancer would decline by 10%. However, if they increased the amount of fruits and vegetables they ate to achieve high daily levels of Vitamin C, their risk of breast cancer would decline by 16%. Do both, and the cancer risk would drop 24%, she found.
* In 1990, Simin Nikbin Meydani of Tufts University found that a chemical in the blood responsible for a strong immune system increased nearly tenfold in a group of healthy people 60 years and older after 30 days on Vitamin E pills. Several studies in the 1980s indicated a lower incidence of infectious diseases in people with higher levels of Vitamin E in their blood.
* The Physicians Health Study, an ongoing project administered by the Harvard Medical School, unexpectedly found that a subgroup of physicians with signs of coronary heart disease had half as many heart attacks and strokes after six years on beta carotene than those not receiving the supplements.
“We aren’t talking about some test-tube model and . . . waving flags saying how great this is,” Blumberg says. “The data does make sense; it is consistent.”
Antioxidants appear to work by offsetting cell damage: The body contains an unstable compound called a singlet oxygen. It participates in energy reactions that produce additional unstable electrons called free radicals, which are electrons without partners. These radicals bump around your body, stealing electrons from stable compounds, creating even more destructive free radicals.
If left unchecked, singlet oxygens keep producing free radicals, and the free radicals continue to create more wild radicals until the free radical finds a permanent partner or is deactivated by an antioxidant such as itamins C, E or beta carotene. Those antioxidants calm the singlet oxygen before it has a chance to produce free radicals, effectively halting the destructive process.
The chemical process is clear, but the scientific evidence implicating itamins C, E and beta carotene as protective remains cloudy enough that the FDA won’t allow health claims on labels of dietary supplements, including antioxidants, in its sweeping revision of food labels that went into effect in May. The FDA plans to look now at the kinds of claims that may be made about antioxidants and their role in preventing cancer and other diseases.
In reviewing studies, Hathcock looks for weaknesses. For example, most studies analyzed diets--how much of the antioxidants people get from foods--rather than looking at reactions to supplements. In addition, the studies have latched on to beta carotene as the cure, but fruits and vegetables with beta carotene usually contain other, similar substances called carotenoids, as well as itamin C. It has been impossible so far to say conclusively which of the substances is responsible for the apparent benefits, or if the substances in combination cause the disease reduction, he says.
The recommended doses are also unclear, he says, as well as the effect of a high dose on the body’s delicate chemical balance. For example, an excess of Vitamin C could reduce the body’s ability to absorb iron.
“The answer is we aren’t sure” about the benefits, Hathcock says. “The answer is maybe, and that’s not significant scientific agreement. Even if the answer is probably, that’s still not significant scientific agreement.’
Meanwhile, researchers scurry for answers that will satisfy the skeptics, while pointing out that these three antioxidants aren’t harmful even at the megadoses said to reduce disease. So why not pop a few pills for insurance? they ask.
“The side effects are zip,” Harris says. “It’s kind of a gamble where the downside is absolutely nothing.”
Even the skeptical gatekeepers, such as Hathcock, don’t dispute that the supplements are benign. (One exception: Swallow too much beta carotene and your skin might turn orange, temporarily.) Nevertheless, the government can’t approve health claims based on the lack of negative side effects. Although these substances occur naturally in foods, the megadoses in pills are far above what a person gets from a normal diet and are therefore considered drugs, said James Kenney, nutrition research specialist at the Pritikin Longevity Center in Santa Monica.
“When you take high doses of a supplement, you are taking a drug, and if you’re taking a drug, it’s not something you should do on your own,” Kenney says. He also worries that the public’s attitude will be: “So I’ll just take my Vitamin C and beta carotene in pill form and eat my potato chips and Ding-Dongs and be healthy.”
“That would be the most foolish thing you could do, he says.”
The FDA does not consider megadose vitamins a drug but is considering imposing labeling restrictions that would prohibit any health claims.
The supplements implicated are as much as 10 and 20 times the recommended dietary allowances--known as RDAs--updated in 1989 by the National Research Council’s Food and Nutrition Board. But Blumberg points out that the RDAs are based on the minimal needs to prevent vitamin or mineral deficiency, not on the needs to maintain health or to prevent disease.
The problem, he says, is that money isn’t available to support large-scale, long-term studies. Much of that money comes from private pharmaceutical companies because, with the results, they can patent medications and make money. They can’t patent vitamins and minerals, Blumberg says, so the companies are less willing to hand over money for research.
“If you want to make the claim, ‘If you take this or that, it’ll reduce your risk,’ it’ll take a 20-, 30-year study,” he says. “The data simply isn’t there to do anything more than to suggest.”
That leaves the public to decide for itself whether to pop extra pills, partly based on whether cancer or heart disease runs in the family, Kenney says.
“Read, think, listen, make informed decisions,” Hathcock says. “Those are God, motherhood and apple-pie kinds of recommendations.”
Food Sources of Antioxidant Vitamins E, C and Beta-carotene
The Dietary Guidelines for Americans, updated in 1990 by the U.S. Department of Agriculture, call for us to eat a variety of foods so we get a balance of nutrients in our diet. In addition, the guidelines recommend that Americans eat five servings of fruits and vegetables a day, with at least one Vitamin C-rich and one Vitamin A-rich serving. Serving sizes range from half a cup to a cup.
VITAMIN C
Good dietary sources of Vitamin C are citrus fruits such as oranges and grapefruit, fruit and vegetable juices, tropical fruits such as mangoes and guavas, kiwi fruit, strawberries, plus vegetables such as broccoli, cauliflower and sweet and hot peppers. Recommended Dietary Allowance (RDA): 60 mg. Megadose supplement: 500-1,000 mg.
VITAMIN E
Good sources of Vitamin E are more limited, especially if someone is trying to lower fat and meat intake. The best dietary sources are nuts such as almonds and hazelnuts, sunflower seeds, wheat germ and vegetable oils. RDA: 30 international units. Megadose supplement: 400-800 IU.
BETA-CAROTENE
Good dietary sources of beta-carotene, which the body converts to Vitamin A, are carrots, squash, sweet potatoes, green leafy vegetables such as spinach and kale, mangoes, cantaloupes and apricots. RDA: None established. Megadose supplement: 15-30 mg.
Source: USDA
