Women's diets often fall short in vital minerals and vitamins for a variety of reasons.
Here are six nutrients that women are often deficient in, either because they lose too much of a nutrient, don't get enough of a nutrient, or both.
Why you need it: Calcium builds teeth and bones, curbs premenstrual syndrome, helps maintain normal blood pressure, and may protect against colon cancer. It is also needed for muscle contraction, hormones and enzymes, and nervous system function, according to the American Dietetic Association. Nearly all of the body's calcium is stored in the teeth and bones.
Women's risk for bone loss rises at menopause with waning levels of estrogen, a hormone that helps keep calcium in your bones. Getting adequate calcium, vitamin D, and exercise as a child and teen can lessen the impact of bone loss later in life, the National Osteoporosis Foundation says.
What you need: 1,000 mg a day for women of childbearing age; 1,200 mg a day after menopause.
The problem: More than three out of four women don't get the recommended amount of calcium, according to the Office of Dietary Supplements (ODS), part of the National Institutes of Health. Many weight-conscious women forgo dairy products, calcium's richest source. Even when women include dairy products in their diet, however, the amount of calcium they absorb can be affected by age, pregnancy, and the amount of vitamin D they consume, the ODS says. The amount of calcium you absorb declines with age. Although some plant-based foods, such as spinach and collard greens, contain significant amounts of calcium, this source of calcium may not be absorbed as well as the calcium found in dairy products.
The remedy: Choose more dairy foods. A cup of low-fat yogurt, milk, or cottage cheese provides about 300 mg of calcium. Good nondairy choices include kale, turnip greens, almonds, dried figs, and fortified foods, such as breakfast cereals and fruit juices. Weight-bearing exercise like brisk walking prevents calcium loss from bones. Research has shown that for women at risk for fractures, taking calcium and vitamin D supplements alone after menopause is not enough to protect against fractures. Additional medicines may be necessary. A diet rich in fruits and vegetables and regular weight-bearing exercise are essential to bone health for women of all ages.
Why you need it: Vitamin D helps the body maintain normal levels of calcium and phosphorus in the blood, and helps form and maintain strong bones, the ODS says. It also may help maintain a healthy immune system and help healthy cell growth and development. It helps prevent rickets, a condition in children that weakens the bones. There is also evidence that vitamin D may help prevent falls by improving muscle strength.
What you need: 200 IU a day for women up to age 50, 400 IU for ages 51 to 70, and 600 IU for those 71 and older. For women older than 60 and for women with additional risk factors for osteoporosis or a low intake of calcium and vitamin D, 600 to 800 IU may be needed.
The problem: The primary source of vitamin D is your body; your body makes vitamin D when your skin is exposed to the sun's ultraviolet rays. But getting vitamin D this way may be difficult for some women. People who are 50 and older don't make vitamin D as efficiently as younger people; people who live in northern climates may not get enough sun exposure, particularly during the winter months; people who don't spend time outdoors are unable to make vitamin D. Vitamin D levels also have declined because of widespread sunscreen use. Sunscreen blocks the ultraviolet rays that can damage the skin -- but these same rays cause the body to produce vitamin D.
The remedy: Get 10 to 15 minutes of unprotected sun exposure at least two times a week on the face, arms, hands, or back, the ODS says. After that time, you should protect yourself with a sunscreen with an SPF of at least 15. Fortified foods are another source of vitamin D, the ODS says. A cup of skim milk provides about 200 IU of vitamin D; the vitamin is also found in eggs, salmon, and organ meats. A supplement can supply vitamin D, too. Women should begin taking vitamin D supplements as teens and continue throughout life.
Why you need it: Iron is used to help the blood carry oxygen throughout the body. If you don't get enough iron in your diet, you may feel fatigued. Too much iron, however, can be fatal.
What you need: 18 mg a day for menstruating women; 27 mg a day for pregnant women; 9 mg a day for women who are breast-feeding; and 8 mg day for women after menopause.
The problem: Iron deficiency is usually a problem only for women who have not gone through menopause; women mainly lose iron from menstrual bleeding. Iron levels may also fall if you:
Don't eat iron-fortified foods, plant foods that contain iron (such as lentils or beans), or red meat, fish, or poultry
Use aspirin, which causes microscopic bleeding in the gastrointestinal tract
Don't get enough vitamin A; this vitamin helps the body use stored iron
Iron deficiency develops gradually. Anemia from iron deficiency may be caused by too little iron in the diet, inadequate absorption of iron, or excessive blood loss, the ODS says. The type of iron you eat influences how well you absorb iron. Heme iron, which comes from meat, is absorbed efficiently. Nonheme iron, which is found in rice, corn, black beans, soybeans, and wheat, is not absorbed as completely. Absorption of this type of iron also is affected by other foods in the diet.
The remedy: You absorb iron best from meat and fish, so adding grilled chicken to a salad is a plus. Nonmeat eaters can opt for iron-rich combos. Try kale or beet greens tossed with raisins, nosh on dried apricots and nuts, and lace enriched cereals with blackstrap molasses. To boost absorption, combine iron-rich foods with orange juice and other foods that contain vitamin C. Don't take an iron supplement without a doctor's guidance, because excess iron can harm the heart, liver, and other organs.
Why you need it: Folate is a water-soluble B vitamin. It helps make red blood cells, prevent birth defects such as neural tube defects and spina bifida, and lower homocysteine levels.
What you need: 400 micrograms a day; 500 micrograms a day for women who are pregnant; 600 micrograms a day for women who are breastfeeding.
The problem: Although many foods are now fortified with folate, certain medical conditions and medications may increase the need for this B vitamin, the ODS says. (Folate is the form of this vitamin found naturally in food; folic acid is the form found in dietary supplements and fortified foods.) Medical conditions that increase the need for folate include pregnancy and breast-feeding; alcohol abuse; kidney dialysis; liver disease; and anemia. Medications that interfere with folate include drugs to treat epilepsy, diabetes, colitis, and rheumatoid arthritis. Barbiturates also may interfere with folate.
The remedy: Dark greens provide the highest amounts of folate. A cup of cooked spinach provides 200 micrograms. Other foods rich in this B vitamin include navy beans, oranges, and fortified grains. Ask your doctor about supplements.
Why you need it: To help make connective tissues, strengthen blood vessels and gums, and boost infection-fighting cells.
What you need: 75 mg per day; 85 mg a day for pregnant women; 120 mg day for women who are breast-feeding; and an additional 35 mg for smokers.
The problem: Many busy women find it tough to eat enough fruits and vegetables, as recommended by USDA dietary guidelines.
The remedy: Think fresh and raw, then plan ahead to include citrus fruits and dark veggies for every meal and snack. On the run, grab salads and fruit bowls that feature cantaloupe, papaya, kiwi, green peppers, or broccoli.
Why you need it: Magnesium helps produce the energy in your cells, keep your muscles and nerves working, keep heart rhythm steady, keep your immune system healthy, and build bone, the ODS says. It regulates blood pressure and blood sugar.
What you need: Women need 310 to 320 mg; 350 to 360 mg if pregnant.
The problem: Americans tend to fall 100 mg short. That may tip the scales against bone strength. Processed food junkies miss out on magnesium.
The remedy: Switch to whole, fresh, nutrient-dense foods. Trade iceberg lettuce for spinach (a half cup provides 65 mg); chips for nuts (an ounce of almonds provides 86 mg), and white bread for bran (134 mg per slice).