News flash: Men and women are different.

As the Harvard Medical School Family Health Guide points out, men and women have different nutritional needs. Though for most vitamins, the Recommended Dietary Allowances (RDA) from the Food and Drug Administration are effectively the same for both sexes when adjustments are made to accommodate the fact that men generally weigh more than women, different needs clearly exist.

These differing needs can be attributed to the fact that men and women have different body masses and muscular structures, as well as different hormonal needs. Women have special supplementation needs due to menstruation, pregnancy, and menopause.

Women’s Needs

Both men and women need a good supply of the B vitamins and the antioxidants A, C, and E. However, some nutrients are simply more important for one sex than for the other. A good example is calcium. While a high-calcium diet may significantly lower the risks that women will develop osteoporosis, there is far less research-based evidence that calcium protects men. Too much calcium is suspected of contributing to prostate cancer in men, especially in men whose daily calcium consumption is 2,000 milligrams; in fact, many nutritionists recommend that men consume no more than 800 milligrams of calcium per day.

Women’s multivitamins often contain dong quai (also known as Angelica sinensis or female ginseng), horse chestnut, butcher’s broom, Garcinia cambogia extract, uva ursi, and alpha-lipoic acid, herbal extracts that studies show support female health and well-being.

Men’s Needs

Supplements for men frequently contain ginkgo biloba, Korean ginseng, PABA (para-aminobenzoic acid), and choline (as choline bitartrate), since these substances are believed to support male health. Men, especially those who are athletically active, need more magnesium than women do, as provided in Optimum Nutrition’s Opti-Men, which combines vitamins and essential minerals with a comprehensive array of herbs and other ingredients chosen specifically for males.

Iron Women

Because premenopausal women lose iron with each menstrual period, they also need more iron than men; the iron RDA is milligrams for women and 8 milligrams for men. Women generally need only 500 IU of vitamin A, while men should have 7,500 IU. When it comes to vitamin E, however, the scales tip the other way: Women need 600 IU, but men need only 200 IU daily.

Different Ages and Stages

Increasingly, supplement manufacturers are refining their formulas even further for men or women in specific age groups. Today, many multivitamins formulated especially for women over 50 also contain herbs such as black cohosh and chasteberry to help control hot flashes during menopause and isoflavones to support a good estrogen balance—clearly substances men don’t need. A good example is Optimum Nutrition’s Opti-Women Multi-Vitamin, which blends essential vitamins and minerals with Ostivone and soy isoflavones. Vitamin supplements formulated for premenopausal women now often contain evening primrose, additional calcium, and zinc to help control symptoms of premenstrual tension and discomfort.

Finally, prenatal vitamins, which are formulated for use during pregnancy, typically contain more folic acid than those prepared for other times in a woman’s life, because research indicates that folic acid may prevent birth defects of the brain and spinal cord.

—Julie Crawshaw