Iron: Essential for healthy blood cells, iron becomes especially important when girls begin to menstruate. With each period, a woman loses small amounts of iron. “About 10% of American women are iron deficient,” says Dorothy Klimis-Zacas, PhD, a professor of nutrition at the University of Maine and co-editor of Nutritional Concerns of Women (CRC Press, 2003). “About 5% have iron deficiency anemia.” Symptoms of low iron include fatigue, impaired immunity, and poor performance at school or work.
The tiny gender differences in minerals other than calcium and iron depend on body size. But while the dietary requirements for selenium fit this rule, men may benefit from supplements of about 200 micrograms a day, a level about four times above the RDA. That's because both a clinical trial and an observational study suggest that selenium may reduce the risk of prostate cancer. It's far from proven, but it's something for men to consider.
Most experts recommend 1,300 mg of calcium a day for girls aged 9 through 19. Natural sources of calcium, such as low-fat dairy products, are the smartest choice, because they also contain vitamin D and protein, both required for calcium absorption. Milk, yogurt, and cheese contribute most of the calcium in our diets. Some vegetables are also good sources, including broccoli, kale, and Chinese cabbage. Many foods are supplemented with calcium, including some brands of orange juice and tofu. The daily intake for Vitamin D is 600 IU per day for most children and healthy adults.
Not everyone who is underweight suffers from an eating disorder, but anorexia and bulimia are serious health problems in this country; an estimated 500,000 women suffer from anorexia, and 1 to 2 million women struggle with bulimia. Women with anorexia nervosa starve themselves and/or exercise excessively, losing anywhere from 15 percent to 60 percent of their normal body weight. Some die. Women with bulimia nervosa binge on large quantities of food—up to 20,000 calories at one time—and then try to get rid of the excess calories. Some purge by inducing vomiting, abusing laxatives and diuretics or by taking enemas. Others fast or exercise to extremes.
Use MyPlate (PDF – 281 KB) as a guide to build a healthy diet. Think about filling your plate with foods from the five food groups — fruits, vegetables, grains, proteins, and dairy — at each meal. Snacks can be a good way to fill in fruits and whole grains you might have missed at meals. Most of us don’t need complicated calorie counting programs or special recipes for healthy eating.