Q. I just bought some supplements, and the clerk at the health food store told me I needed to take 6,000 mg of vitamin C per day. That sounds like an awful lot. What do you recommend?

A. I used to recommend taking 2,000 to 6,000 mg of vitamin C daily (divided into three doses). However, I changed my recommendation in 1999 to 200 to 500 mg (divided into two doses) after examining two well-designed studies showing that lower levels of vitamin C more than saturate the body's tissues, and thus are sufficient to protect against cancer, heart disease and other chronic illnesses. One of the studies that influenced my decision was a review of clinical trials published in the April 21, 1999, issue of the Journal of the American Medical Association. It concluded that 200 mg a day is the maximum amount of vitamin C that human cells can absorb, making higher doses a waste.

The second study came from the Linus Pauling Institute (Pauling himself took 18,000 mg of C per day) and was published in the June 1999 issue of the American Journal of Clinical Nutrition. It identified a similar dose, 120 to 200 mg, as the optimal amount for reducing the risk of cardiovascular disease, cancer, cataracts and other chronic conditions.

I wouldn't worry if you've been taking higher doses. Vitamin C is water soluble and anything not used by the body quickly passes out. In fact, I still recommend higher dosages to those under extra stress, living in smoke-filled or polluted environments, or not getting at least five servings of fruits and vegetables as part of their daily diet.

The rest of my antioxidant recommendations are as follows:

Vitamin E: 400 IUs of mixed natural tocopherols (or at least 80 mg of mixed tocopherols and tocotrienols) a day. Since vitamin E is fat soluble, it must be taken with food to be absorbed. Also, choose natural forms of vitamin E (d-alpha tocopherol with mixed tocopherols, or better yet, mixed tocopherols and tocotrienols) instead of the synthetic form (dl-alpha-tocopherol). I take vitamin E at lunch or dinner. Selenium: 200 micrograms a day. Selenium is a trace mineral with antioxidant and anticancer properties. Selenium and vitamin E facilitate each other's absorption, so take them together. Vitamin C may interfere with the absorption of inorganic forms of selenium (sodium selenite), so take the yeast-bound form instead. Doses of selenium above 400 micrograms a day may not be healthy. Mixed carotenes: 15,000 IUs a day. I recommend a natural form, which is easily found in health food stores. Read the label to make sure it gives you lycopene, the red pigment in tomatoes that helps prevent prostate cancer, and lutein, which protects against cataracts and macular degeneration. I take mine at breakfast.

Q. I am concerned about your recommendations for supplemental vitamin A. Most conventional wisdom and research indicate that 20,000 I.U. of vitamin A can be toxic, even lethal. It scares me to follow this advice.

A. You are right to be concerned about vitamin A toxicity. But first, please note that vitamin A comes in many forms. It is the animal form that is toxic, not plant-derived beta-carotene, which is the form I recommend in the Vitamin Advisor.

The Upper Limit of vitamin A set by the Food and Nutrition Board of the National Academy of Sciences is 10,000 IU per day. Vitamin A can be found in such dietary supplements as palmitate, acetate or fish liver oil, all of which are derived from animal sources. Although vitamin A is an essential nutrient, an excessive chronic intake of these forms of vitamin A can be toxic, leading to hair loss, confusion, liver damage, and — more recently discovered — bone loss.

The form of vitamin A I recommend in our Vitamin Advisor is beta-carotene in addition to other mixed carotenoids. The body can make all the vitamin A it needs from beta-carotene, which is not toxic, unlike the animal forms of vitamin A. Carotenoids are plant pigments found in orange and yellow fruits and vegetables and dark leafy greens. Unlike vitamin a, beta-carotene is water-soluble and does not accumulate in the body (although very high intakes — 100,000 IU or more a day — can cause an orange tint to your skin). Aside from being unsightly, this side effect is innocuous.

Carotenoid-containing fruits and vegetables have great cancer-protective value. In addition to beta-carotene, the antioxidant formulation I recommend contains lycopene, alpha-carotene, astaxanthin, lutein, and zeaxanthin. Lycopene is the red pigment in tomatoes that helps prevent prostate cancer, and lutein has been found to protect against cataracts and macular degeneration.

Taking a mixed carotenoid supplement does not excuse you from eating tomatoes, carrots, fruits, and greens, but it is useful insurance against failing to supply your body with all the antioxidant protection it needs. Read labels carefully to make sure the product you’re using includes lycopene AND lutein and provides at least 20,000 IU of beta-carotene.

Dosage Update, October, 2004
In order to provide the most up-to-date health information, I may change my recommendations from time to time. Due to compelling new research on carotene, I now suggest that you take 15,000 IU of mixed carotenes. (My previous recommendation was 25,000 IU; please adjust your dosage accordingly.)

Q. What is sublingual B12? Is it more effective than B12 bought at a drug store? My niece found out she is anemic and is having trouble handling the iron. Is this a good thing for her to take?

A. Sublingual vitamin B12 is merely a form of the vitamin that is taken under the tongue. The advantage of sublingual vitamins is improved absorption. In the case of B12, this method of administration is often better for seniors who frequently have trouble absorbing the vitamin from the stomach.

Regardless of the form it comes in, vitamin B12 is used to treat pernicious anemia, a much different condition from the more common iron-deficiency anemia. If your niece has pernicious anemia, she needs B12 — not iron. If she has iron-deficiency anemia, she needs iron, not B12. Pernicious anemia is due to vitamin B12 deficiency and is rare in young people — except in strict vegetarians (vegans) who eat no animal products, our only dietary source of B12. The condition can also occur in older men and women who lack sufficient “intrinsic factor,” a protein produced in the stomach that is necessary for B12 absorption (which occurs in the small intestine). Failure to produce intrinsic factor can be genetic in origin or caused by atrophy of the stomach lining (common in older age), or by autoimmunity.

Mild to moderate cases of iron-deficiency anemia can be treated with an over-the-counter iron supplement. If your niece is having trouble taking an iron supplement, she can try the suggestions below for obtaining more iron from her diet:

Cook in cast-iron pots (the cooked food absorbs iron and delivers it to you). Increase your intake of red meat, chicken and fish, all of which provide some iron. Vegetarian sources include whole grains, dried beans, molasses, dried apricots and prunes, and leafy green vegetables such as kale, beet greens and chard, as well as exotic greens such as dandelions, lamb’s quarters, nettles and yellow dock. Eat more foods that enhance iron absorption. These include fruits and vegetables high in vitamin C, or yogurt or sauerkraut, both of which contain lactic acid, which promotes iron absorption. Fermented soy foods can help, too. Avoid caffeinated beverages, eggs, milk and bran, all of which can interfere with iron absorption.

If her physician has prescribed iron and your niece can’t handle the supplement, she should be sure to let the doctor know if she stops taking it and is trying to increase her iron stores via the steps outlined above. These may not be adequate if she is severely anemic.

For more on vitamins, visit Dr.Weil.com.

Copyright © 2005 Weil Lifestyle, LLC. All material provided on the DrWeil.com Web site is provided for informational or educational purposes only. Consult a physician regarding the applicability of any opinions or recommendations with respect to your symptoms or medical condition.

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