Adelle Davis, the 1960s nutrition guru, provided the mantra for a generation: you are what you eat. Today’s nutrition experts, however, say that you are what you absorb. Swallowing food or supplements is only the first step toward good nutrition. Absorption, how much of a nutrient is actually utilized by the body, depends on many factors, including the form of a supplement (for example, calcium citrate versus calcium carbonate) and the “delivery system” (tablet, capsule, or liquid). Taken improperly, many nutrients are excreted through the kidneys, creating nothing more than “expensive urine”.
Here, Chris Meletis, a naturopathic physician and clinical director and chief medical officer of National College of Naturopathic Medicine in Portland, Oregon, offers guidelines to help you gain the maximum benefit from dietary supplements.
General tip: The words “citrate”, “picolinate”, “aspartate”, “glutamate”, or “amino acid chelate” following the name of a nutrient (chromium picolinate, for example) indicate that a product is easier to absorb than one with the words “oxide” or “carbonate” following the nutrient name.
Multivitamins: Check to see what type of vitamin E your multivitamins contain. Look for D alpha tocopherol, not DL alpha tocopherol—it’s the synthetic version of vitamin E and doesn’t make its way through the body as efficiently as natural vitamin E. All multivitamins (as well as other supplements) should be bottled in dark or opaque containers to prevent degradation by light.
Calcium: Steer away from calcium carbonate and look instead for calcium citrate, the more easily absorbed of the two. The carbonate version is commonly derived from oyster shell and bone, which may have absorbed toxins from the earth or sea, which then may be passed on to you. For some postmenopausal women, calcium carbonate is a poor choice because they may have too little stomach acid to absorb it.
Timing: Meletis recommends that his patients take multivitamins throughout the day, not in one large dose, because the body can only absorb a limited amount of a supplement at one time and the rest is excreted. In addition, the higher the dosage of a supplement taken at one time, the lower the absorption rate. For example, Meletis says, in clinical studies, when a person takes 100 micrograms (mcg) of vitamin B12 in a single dose, about 80 percent is absorbed. That rate drops to 3 percent when the single dose increases to 2,000 mcg.
The best time to take supplements varies according to the nutrient. For example, acidophilus, a strain of bacteria taken therapeutically to change the intestinal flora, is best taken away from meals so that “the friendly bacteria can locate the walls of the intestines without having to fight their way through food,” Meletis says. A multivitamin, on the other hand, is best taken with a meal because food can improve the body’s utilization of the vitamins.
Delivery systems: Capsules were once the most easily absorbed form of supplement. Today’s soft-pressed tablets break down just as easily as capsules, although not all tablets are soft-pressed. Tablets and sprays are quickly absorbed through the oral mucosa into the bloodstream, bypassing the intestinal tract.
Teenagers and dietary supplements: An interview with Leo Galland, M.D.
An internist practicing in New York City, Dr. Leo Galland specializes in working with patients with chronic complex illnesses. Much of his work involves nutrition. His new book, The Four Pillars of Healing (Random House, 1996), documents his use of nutritional supplements in preventive medicine.
Herbs for Health—Why might teenagers need nutritional supplements?
Dr. Galland—Teens are changing hormonally, and they’re growing fast. Some of them are very physically active. It is still a time of building bone density. Both iron and zinc are needed for growth, but teens’ diets are often deficient in these.
HH—Do girls and boys have different nutrient requirements?
DG—Girls need more iron because of menstruation, and boys need more zinc in general. Kids who are heavily reliant on dairy foods for protein may have a zinc-deficient diet because calcium blocks zinc and iron absorption. For both girls and boys, calcium is important, but especially so for girls, who must build bone density to avoid osteoporosis in later life.
HH-Do you recommend calcium supplements for girls?
DG—Because of the complex way in which our bodies absorb and use calcium, I don’t supplement teens’ diets regularly with calcium because it can interfere with absorption of trace minerals and iron and zinc. Actually, taking moderate amounts of calcium is more beneficial than megadoses. If it is needed, for example, when a diet is deficient in calcium, then it is best to give it at bedtime as calcium citrate.
Calcium and exercise, combined with the key cofactor nutrients such as protein, phosphorus, magnesium, manganese, copper, silica, and vitamins A and D, are vital for healthy bone development. Carbonated high-sugar cola drinks are particularly bad for teenage girls due to the excess of phosphorus, which is too much of a good thing and can block the absorption of calcium and magnesium.
HH—What special needs arise from hormonal changes?
DG—There is still much research needed on this, but there is some evidence that estrogen may impair the activation of vitamin B6 in the body, resulting in a variety of mental and physical conditions. Teens on oral contraceptives need to be aware of this. Also, the menstruation cycle may adversely affect the magnesium balance in girls.
HH—What are the most common vitamin and mineral deficiencies in American teens?
DG—Vitamins A and B1, folic acid, magnesium, calcium, and possibly trace minerals such as selenium, manganese, copper, iodine, chromium, and molybdenum. Vitamin B1, for example, is displaced by sugar. Teens consume lots of junk foods on average. Vitamin A, folic acid, and essential fatty acids are vital to teens’ immune systems, but if they aren’t eating lots of fresh vegetables, deficiencies are common.
HH—Are there nutrients that can help teens suffering from acne?
DG—Despite the conventional literature that says diet doesn’t affect acne, I believe all acne could be controlled through diet and supplementation. It is a very individual study, however.
With acne, I advise my patients to eat a low-sugar, low-fat diet with 1 tablespoon of flaxseed oil or 1 teaspoon of cod-liver oil daily; 10,000 units of vitamin A daily; 20 mg of zinc daily; and 50 mg of vitamin B6 (not B complex) daily. If there is no improvement after three weeks, I begin diet modifications such as eliminating all milk products, even in baked goods.