A year later, a second Harvard study added to the concern. The Physicians' Health Study of 20,885 men did not evaluate diet per se, but it did measure the blood levels of ALA in 120 men who developed prostate cancer and compared them with the levels in 120 men who remained free of the disease. Men with moderately high ALA blood levels were 3.4 times more likely to develop prostate cancer than men with the lowest levels; curiously, though, men with the very highest levels were only 2 times more likely to get the disease.
Getting enough water also is important. Many experts recommend at least eight 8-ounce glasses of water daily—more if you exercise frequently or are exposed to extremes of heat and cold. The 2010 Dietary Guidelines for Americans emphasize drinking more water and other calorie-free beverages, along with fat-free or low-fat milk and 100 percent fruit juices, instead of calorie-packed regular sodas.
The recommended daily intake for vitamin E is 15 mg. Don't take more than 1,000 mg of alpha-tocopherol per day. This amount is equivalent to approximately 1,500 IU of "d-alpha-tocopherol," sometimes labeled as "natural source" vitamin E, or 1,100 IU of "dl-alpha-tocopherol," a synthetic form of vitamin E. Consuming more than this could increase your risk of bleeding because vitamin E can act as an anticoagulant (blood thinner).
A person's caloric requirement depends on his body size and exercise level. Sedentary people of both genders will keep their weight stable by taking in about 13 calories per pound of body weight each day. Moderate physical activity boosts this requirement to 16 calories a pound, and vigorous exercise calls for about 18 calories a pound. On average, a moderately active 125-pound woman needs 2,000 calories a day; a 175-pound guy with a similar exercise pattern needs 2,800 calories. And like women, men will lose weight only if they burn more calories than they take in.
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.
After menopause. Lower levels of estrogen after menopause raise your risk for chronic diseases such as heart disease, stroke, and diabetes, and osteoporosis, a condition that causes your bones to become weak and break easily. What you eat also affects these chronic diseases. Talk to your doctor about healthy eating plans and whether you need more calcium and vitamin D to protect your bones. Read more about how very low estrogen levels affect your health in our Menopause section. Most women also need fewer calories as they age, because of less muscle and less physical activity. Find out how many calories you need based on your level of activity.
The U.S. Public Health Service recommends that all women of childbearing age consume 400 mcg of folic acid (a B vitamin) daily to reduce their risk of having a pregnancy affected with spina bifida or other neural-tube defects. Women who are actively trying to get pregnant should consume 600 mcg, and lactating women should consumer 500 mcg. Women of childbearing age should also take care to meet the daily requirements for calcium, fiber, iron, protein and vitamin D. Discuss supplements with a health care professional, however. Iron and vitamin D in particular can be dangerous in high amounts.
If you usually head to the gym after work, take heed: Mental exhaustion can make you feel physically exhausted, even when you have plenty of energy, reports a Medicine & Science in Sports & Exercise study. When people played a brain-draining computer game before exercising, they reported a subsequent workout as being harder, yet their muscles showed the same activity as they did doing the same workout after an easy mental game. So if you think you can’t eke out those last 10 minutes on the rowing machine, remember: You can! [Tweet this motivation!]
Foods that contain natural folic acid include orange juice, green leafy vegetables, peas, peanuts and beans. (One cup of cooked kidney beans contains 230 mcg of folic acid.) Fortified foods, such as ready-to-eat breakfast cereals, also contain a synthetic form of folic acid, which is more easily absorbed by your body than the natural form. Folic acid is now added to all enriched grain products (thiamin, riboflavin, niacin, and iron have been added to enriched grains for many years).