DR. MARK’S INTEGRATIVE MEDICINE CABINET: Antioxidants: A doubled-edged sword
JACKSON HOLE, WYO – Can you hear it? That crashing sound? No, it’s not another hailstorm here to strip your flowerbeds. It’s an unpaired electron from an oxidation reaction bombarding your DNA, trying to inflict permanent damage.
Sound like a good sci-fi movie? Actually, this is the main process of aging and may be at the root of all disease, including cancer. Let’s find out how to stop this devastation.
Free radicals are groups of atoms with an unpaired electron formed when oxygen interacts with certain molecules. Once formed, these highly reactive radicals start a chain reaction, inflicting damage to DNA and cell membranes, causing cells to die or transform into cancer cells. This is bad.
To prevent free-radical damage, the body has a defense system of antioxidants, molecules that terminate the chain reaction before vital DNA is damaged. These are good, although there are several enzyme systems within the body that scavenge free radicals, the main protective antioxidants are vitamin E, beta-carotene, vitamin C and selenium. The body cannot manufacture these micronutrients, so they must be supplied in the diet. Are you taking any of these?
Vitamin E is a fat-soluble vitamin present in nuts, seeds, vegetable and fish oils, whole grains, fortified cereals and apricots. A recent study discouraged the use of vitamin E, but very high doses were used and there were other factors that clouded the results. There have been more than 30 heart and stroke clinical trials using vitamin E, and the only positive study utilized the gamma and mixed tocopherols. My recommendation is for a mixed tocopherol, not just alpha-tocopherol. Check the label. There does not seem to be any benefit for more than 400 IU, and possible harm from higher doses, as there are case reports of patients having severe bleeding that could not be stopped with megadoses. That’s another good reason to discuss your supplements with a knowledgeable physician prior to any surgery.
Vitamin C, or ascorbic acid, is a water-soluble vitamin present in citrus fruits and juices, green peppers, cabbage, spinach, broccoli, kale, cantaloupe, kiwi and strawberries. A recent study linked vitamin C to DNA damage, though they used fungi cells and megadoses, with damage likely from an osmotic effect. Supplementing with 500 to 1,000 mg seems to be a wise choice, as suggested by an Italian study that showed reductions in stroke rates for patients at such dosages.
Beta-carotene is a precursor to vitamin A (retinol) and is present in liver, egg yolk, milk, butter, spinach, carrots, squash, broccoli, yams, tomato, cantaloupe, peaches and grains. Beta-carotene is converted to vitamin A by the body, but you must be careful, because vitamin A has no antioxidant properties and can be toxic at high doses. Interestingly, only one valid study has been done with beta-carotene, which had to be stopped due to more deaths in the group taking beta-carotene than placebo, though this was only true for smokers. So is beta-carotene good for the non- smoker? We still don’t know.
Selenium is a trace metal required for proper function of many other antioxidant enzyme systems. A large study in Sweden suggested selenium may also help prevent prostate cancer; to date it’s the only cancer-prevention factor discovered. Dean Ornish is also releasing data suggesting a specific dietary/lifestyle approach may reverse prostate cancer.
That other crashing sound is from all the surgical instruments being dropped as patients take charge again of their health. Remember: Medicine is what the doctor does to you; health is what you do for yourself.
There are lower cancer rates in people whose diets are rich in fruits and vegetables, suggesting that these diets contain antioxidants that protect against cancer. There is intense scientific investigation into this topic. Many large clinical trials have not shown that dietary supplementation with extra antioxidants reduce the risk of developing cancer. Antioxidants are necessary for good health, yet no one knows if additional supplements should be taken and if so, how much. Antioxidant supplements were once thought to be harmless, but we are becoming increasingly aware of interactions and potential toxicity.
Here is the double-edged sword: vitamin C and beta-carotene are antioxidants at normal concentrations, but at higher concentrations they are pro-oxidants and may cause DNA damage. We just don’t know about the long-term consequences of megadoses of antioxidants. Taking chemicals without a complete understanding of all of their effects may disrupt this balance.
As always, we give you just enough to confuse you. Integrative medicine is your source for answers that combine good science with individualized care. Start with healthy, whole food-based nutrition, ideally organic. As Jenny reminds me every day, remember to eat a fruit and vegetable with every meal and snack to be sure to get the five-plus servings of each per day. This is a good base, but we may need more.
Man is a food-dependent creature. If you don’t feed him, he will die. If you feed him improperly, part of him will die.