B12: Like folic acid, B12 is essential for healthy nervous system development and function. Pregnant women who are vegans or vegetarians may fall short on B12, since it is present in animal protein and to a lesser extent in dairy. Teenage and adult women need 2.4 mcg. Recommended levels rise to 2.6 mcg for pregnant women and 2.8 mcg for lactating women.
Men who choose to drink and can do so responsibly may benefit from one to two drinks a day, counting 5 ounces of wine, 12 ounces of beer, or 1.5 ounces of spirits as one drink. But women face an extra risk: Even low doses of alcohol can raise their risk of breast cancer. So women who choose to drink might be wise to limit themselves to half as much as men.
No matter how busy you are, eat lunch before 3 p.m., a Spanish study suggests. Researchers placed a group of women on a diet for 20 weeks; half ate lunch before 3 and half consumed their midday meal after 3. Although both groups’ daily caloric intake, time spent exercising and sleeping, and appetite hormone levels were the same, those who lunched late lost about 25 percent less weight than earlier eaters. Being European, lunch was the biggest meal of the day for these women, constituting 40 percent of their calories for the day, so consider slimming down dinner in addition to watching the clock.
Calcium: For adult women aged 19-50, the USDA recommended daily allowance is 1,000 mg/day. For women over 50, the recommended daily allowance is 1,200 mg/day. Good sources of calcium include dairy products, leafy green vegetables, certain fish, grains, tofu, cabbage, and summer squash. Your body cannot take in more than 500 mg at any one time and there’s no benefit to exceeding the recommended daily amount.
You should consume only 25 percent to 35 percent of your total calories per day from fat, with a significant portion from good fats like omega-3 and omega-6 fatty acids. According to the American Heart Association, women should get at least five to 10 percent of their total daily calories from omega-6 fatty acids (equal to 12 to 20 grams), and anywhere from 0.5 to 3 grams of omega-3 fatty acids, depending on individual risk for heart disease.
The best evidence that ALA can protect the heart comes from the Lyon Diet Heart Study, a randomized clinical trial in Europe. It tested the effects of an ALA-enriched Mediterranean diet in 605 patients with coronary artery disease. Over a four-year period, the high-ALA diet produced a 72% reduction in heart attacks and cardiac deaths and a 56% lower risk of dying from any cause (including cancer). The Mediterranean diet differed from the standard Western diet in many respects, but because it contained a special canola oil margarine, the greatest difference was in its ALA content, which was nearly eight times higher in the protective diet.
Salt, caffeine and alcohol intake may interfere with the balance of calcium in the body by affecting the absorption of calcium and increasing the amount lost in the urine. Moderate alcohol intake (one to two standard drinks per day) and moderate tea, coffee and caffeine-containing drinks (no more than six cups per day) are recommended. Avoid adding salt at the table and in cooking
The average woman should get 10 to 35 percent of her daily calories from protein. Protein helps prevent muscle tissue from breaking down and repairs body tissues. Sources of animal proteins include meat, fish, poultry, eggs, milk and cheese. Vegetable proteins include dried beans and peas, peanut butter, nuts, bread and cereal. (A three-ounce serving of cooked chicken contains about 21 grams of protein.)
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 U.S. Department of Agriculture's (USDA) food pyramid system (www.mypyramid.gov) provides a good start by recommending that the bulk of your diet come from the grain group—this includes bread, cereal, rice and pasta— the vegetable group; and the fruit group. Select smaller amounts of foods from the milk group and the meat and beans group. Eat few—if any—foods that are high in fat and sugars and low in nutrients. The amount of food you should consume depends on your sex, age and level of activity.
Dairy. Women should get 3 cups of dairy each day, but most women get only half that amount.6 If you can’t drink milk, try to eat low-fat plain yogurt or low-fat cheese. Dairy products are among the best food sources of the mineral calcium, but some vegetables such as kale and broccoli also have calcium, as do some fortified foods such as fortified soymilk, fortified cereals, and many fruit juices. Most girls ages 9 to 18 and women older than 50 need more calcium for good bone health.