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.
If you thought texting changed your love life, imagine what it could do for your waistline. When people received motivational text messages promoting exercise and healthy behaviors twice a week (i.e., “Keep in the fridge a Ziploc with washed and precut vegetables 4 quick snack. Add 1 string cheese 4 proteins”), they lost an average of about 3 percent of their body weight in 12 weeks. Participants in the Virginia Commonwealth University study also showed an improvement in eating behaviors, exercise, and nutrition self-efficacy, and reported that the texts helped them adopt these new habits. Find health-minded friends and message each other reminders, or program your phone to send yourself healthy eating tips.
Vitamin D: Over the past decade, dozens of studies have revealed many important roles for vitamin D, the nutrient that skin cells produce when they are exposed to sunlight. The recommended daily intake of Vitamin D is 600 IU per day, although recommended levels are under review. If you avoid the sun or live in the northern half of the U.S., ask your doctor whether your vitamin D level should be tested.
Calcium may even be harmful for men, at least in large amounts. The worry is prostate cancer, and two Harvard studies have raised the alarm. In 1998, the Health Professionals Follow-up Study found that a high consumption of calcium from food or supplements was linked to an increased risk of advanced prostate cancer. The risk was greatest in men who got more than 2,000 mg a day. More recently, the U.S. Physicians' Health Study reported that a high consumption of calcium from dairy products appeared to increase a man's risk of prostate cancer by up to 37%. A study from the Fred Hutchinson Cancer Research Center in Seattle also found a link between calcium and advanced prostate cancer.
Although growing bodies need plenty of energy in the form of calories, many children and teenagers consume way too many, says Ruth Frechman, RD, a spokesperson for the American Dietetic Association. The latest findings from federal surveys show that 18% of adolescents and teenagers are fatter than they should be. Kids who are obese are 16 times more likely than healthy weight children to become obese as adults, other findings show.
Adopting a plant-based diet could help tip the scales in your favor. A five-year study of 71,751 adults published in the Journal of the Academy of Nutrition and Dietetics found that vegetarians tend to be slimmer than meat-eaters even though both groups eat about the same number of calories daily. Researchers say it may be because carnivores consume more fatty acids and fewer weight-loss promoting nutrients, like fiber, than herbivores do. Go green to find out if it works for you.
What you eat is even more important as you enter your 40s. Women need protein (meat, fish, dairy, beans, and nuts), carbohydrates (whole grains), fats (healthy oils), vitamins, minerals, and water. These foods have been linked to some disease prevention, such as osteoporosis, high blood pressure, heart disease, diabetes, and certain cancers. The American Academy of Family Physicians supports the development of healthy food supply chains in supplemental nutrition programs so as to broaden the availability of healthy food.
Nutrition is particularly important during pregnancy to ensure your health and the health of the baby. It's normal to gain weight during pregnancy—not just because of the growing fetus, but because you'll need stored fat for breast-feeding. The Institute of Medicine (IOM) recommends a gain of 25 to 35 pounds in women of normal weight when they get pregnant; 28 to 40 pounds in underweight women; and at least 15 pounds in women who are overweight when they get pregnant. The IOM has not given a recommendation for an upper limit for obese women, but some experts cap it as low as 13 pounds. If you fit into this category, discuss how much weight you should gain with your health care professional.
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).