You need to stay well nourished for your own health and that of the child developing within. When should you start to eat wisely? Now. Irwin Rosenberg, MD, director of the US Department of Agriculture Human Nutrition Center on Aging at Tufts University, emphasizes that sound nutrition is important not only during pregnancy but at the time of conception. Because the timing of conception is often unpredictable, he says, "Ideally women ought to be maintaining good nutrition throughout their childbearing years."

Should pregnant women take vitamin supplements? Generally, the best way to get vitamins and minerals is by eating a varied diet of whole foods, one that includes an abundance of grains, legumes, fruits, vegetables, food herbs, nuts, seeds, and, if you're not a vegetarian, dairy and lean meats.

Vitamins and minerals from foods tend to be well absorbed and assimilated, with little risk of overdose. "Healthy food is, by far, more important than supplements," says Betsy Walker, MS, who teaches nutrition during pregnancy at the Seattle Midwifery School. "If a woman is getting a very good quality diet, I don't think she absolutely needs supplements. Women who are not receiving good nutritional counseling should be taking a prenatal supplement." Because vitamins and minerals extract easily into vinegar, Cox makes a cider vinegar extract of dandelion leaf, nettles, parsley, burdock root, and violet leaf, which she adds to greens and grains for extra nutrition.

Although the National Academy of Sciences recommends that prenatal vitamins be prescribed on an individual basis, depending on a woman's nutritional status, routine prenatal vitamins have become the standard of care. However, no amount of vitamin pills can substitute for a healthy diet. Furthermore, when it comes to supplements, more doesn't mean better. Unless advised to do so by your health practitioner, don't take megadoses of single vitamins during pregnancy. The main concern is vitamin A, an excess of which has been associated with birth defects. Other vitamins and minerals can also be toxic to the fetus, and an excess of one mineral can unbalance others.

Studies show that diets of pregnant women most often lack four vitamins (folic acid, B-6, D, and E) and four minerals (calcium, magnesium, iron, and zinc).(1) Of these, iron is the most difficult to obtain from diet alone. The recommended daily allowances for pregnancy listed below represent the amount a woman should derive from diet, plus or minus a supplement.

Folic add is necessary for DNA synthesis, and therefore critical in the development of all tissues, particularly the nervous system's. Oral contraceptives may deplete folic acid levels. Diet surveys have found folic acid intake to be low in the US, particularly among women and blacks.(2)

Deficiencies have been linked to megaloblastic anemia and neural tube defects (incomplete development of the brain and spinal cord). Folic acid supplementation has been shown to reduce recurrence of neural tube defects by 72 percent.(3) When a group of more than 2,000 women took a multivitamin that included 800 micrograms of folic acid from the time of conception through the first three months of pregnancy, their babies had 50 percent fewer birth malformations of all types and no neural tube defects.(4)

Because the neural tube forms within the first four weeks of pregnancy, you need to get sufficient folic acid while you're trying to conceive. The US Public Health Service 1992 advisory statement recommends all women of childbearing age get 400 micrograms a day and not exceed 1 milligram a day, except under medical supervision.

RDA: 400 mcg.

Food sources: liver (750 mcg. in 3.5 oz.), whole grains, legumes (358 mcg. in 1 cup lentils), sunflower seeds (317 mcg. in 1 cup), beans (292 mcg. in 1 cup pinto beans), green leafy vegetables (200 mcg. in 1 cup frozen spinach, 171 mcg. in 1 cup turnip greens), citrus fruits (109 mcg. in 1 cup orange juice), broccoli (104 mcg. in 1 cup), and brewer's yeast. Herbal sources include dandelion, amaranth greens, lamb's quarter, nettle, and red clover.

Vitamin B-6 is important in the breakdown and utilization of carbohydrates, fats, and proteins, and in the production of antibodies and red blood cells. Oral contraceptives can deplete this vitamin. A deficiency may aggravate morning sickness, which supplementation can help relieve. In one clinical study, 342 pregnant women were randomly assigned to receive either 30 mg. of vitamin B-6 or a placebo. Compared to the placebo group, the women taking vitamin B-6 reported a significant reduction in nausea and vomiting, although one-third continued to experience gastrointestinal upset.(5)

RDA: 2.2 mg.

Food sources (contents given in mg. per 3.5-oz. serving): torula yeast (3), brewer's yeast (2.5), sunflower seeds (1.25), toasted wheat germ (1.15), legumes (.81 for dry soybeans), walnuts (.73), whole grains (.55 for brown rice), fruits (.51 for bananas), green leafy vegetables such as spinach (.28), and meat, fish, and poultry.

Calcium is vital to the health of bones and teeth in both the fetus and the mother. It's important not to take calcium and iron at the same time because each counters the absorption of the other. For this reason, some practitioners recommend that women take a multivitamin that contains iron and, at another time, a calcium supplement. In addition, a high protein intake depletes calcium stores, which is one reason the RDA is so high (since most Americans consume more protein than they need). If you follow a lower protein vegetarian diet, you may not need this much calcium.

RDA: 1,200 mg.

Food sources: sardines (370 mg. in 3 oz.), dairy products (300 mg. in 1 cup low-fat milk), mackerel, firm tofu processed with calcium, seaweed, tahini, almonds, dark leafy greens (180 mg. in 1/2 cup), salmon (165 mg. in 3 oz. canned with bones), broccoli (70 mg. in 1/2 cup), beans, lentils, blackstrap molasses, and dried fruit. Herbs containing calcium include nettles, red raspberry leaves, oatseed, oatstraw, alfalfa, chamomile, borage, dandelion, and red clover. A cup of lamb's quarters or amaranth greens contains about 400 mg. An infusion of two handfuls of nettle, red clover, raspberry leaf, or oatstraw in 2 to 4 cups boiling water, steeped 4 to 8 hours, contains 250 to 300 mg. per cup. Food herbs rich in calcium generally also contain magnesium in a ratio well utilized by the body.

Vitamin A is essential in building strong bones and teeth, and in the growth and repair of all tissues, especially skin and mucous membranes. Because of the potential toxicity of high doses, which are associated with birth defects, stay within recommended guidelines. Beta-carotene, which the body converts to vitamin A, is considered more beneficial and is not associated with toxicity.

RDA: 4,000 IU

Food sources (given in IU of beta carotene): Orange fruits and vegetables such as carrots (11,000 in 1 large carrot), sweet potatoes, winter squash, (2,700 in 2 to 3 medium), cantaloupe (3,400 in 1/4 melon), peaches (1,330 in 1 medium), and dark leafy greens like mustard and kale (7,400 in 3/4 cup cooked), spinach (7,300 in 1/2 cup cooked). The best herb source is dandelion (3,500 to 6,500 in a 1/2 cup of steamed or flesh dandelion greens), although you do not need that much--just adding a few leaves to your salad will boost your vitamin intake. Other herb sources include alfalfa, cayenne, paprika, and elderberries.

Vitamin C is essential for collagen synthesis, as well as amino acid and thyroid hormone production; it also aids iron and calcium absorption.

RDA: 70 mg.

Food sources: guava (242 mg. in 1 medium), papaya, green peppers (96 mg. in 3.5 oz.), broccoli (90 mg. in 2/3 cup cooked), Brussels sprouts (87 mg. in 6 to 7 cooked), cauliflower (78 mg. in 1 cup), cabbage (47 mg. in 1 cup), turnip greens, strawberries (59 mg. in 10 large), citrus fruits (53 mg. in 1 orange), cantaloupe (33 mg. in 1/4 melon). Herbs include dandelion leaves, nettles, elderberries, rosehips, cayenne, violet leaves, pine needles, and alfalfa.

Vitamin D is important in the absorption of calcium and phosphorous and for the fetus's bone and tooth development.

RDA: 10 mcg. (400 IU)

Sources: sunshine, alfalfa, nettles, dairy, butter, eggs. Deficiency is rare.

Vitamin E is important for red blood cell growth and proper immune function.

RDA: 10 mg. or 10 IU

Food sources: wheat germ, vegetable oils, broccoli, Brussels sprouts, whole grains, eggs, spinach, soybeans, hazelnuts, almonds, and seaweeds. Herbs include alfalfa, rosehips, raspberry leaf, and dandelion.

Vitamin K is necessary for the formation of thrombin--a chemical critical to blood clotting. In the presence of certain intestinal bacteria, our bodies can make this fat-soluble vitamin. Insufficient vitamin K can contribute to postpartum hemorrhaging.

RDA: 65 mcg.

Food sources: (given as mcgs. per 3.5-oz. serving): kale (729), green tea (712), leafy greens such as turnip greens (650) and spinach (415), broccoli (200), lettuce (129), cabbage (125), watercress (57), asparagus (57), oats (20), green peas (19), and whole wheat (17).

Iron requirements double in pregnancy, chiefly to keep up with the production of hemoglobin (the chemical that carries oxygen in red blood cells) in mother and fetus.

RDA: 30 mg. The drawback of supplemental iron is constipation. Absorption is increased by vitamin C.

Food sources: clams (24 mg. in 3 oz.), oysters (11 mg. in 3 oz.), legumes (9 mg. in 1 cup soybeans), tofu (7 to 13 mg. in 4 oz. firm), organ meats (6 mg. in 3 oz. beef liver, 15 mg. in 3 oz. pork liver), whole grains (5 mg. in 1 cup cooked quinoa), beans (4 mg. in I cup cooked pinto beans), dark, leafy greens (3 mg. in a cup cooked spinach), dried fruits (2 mg. in 5 figs), seeds, nuts (especially almonds), egg yolks, rosehips, and blackstrap molasses (6 mg. in 2 tbsp.). Herbs containing iron include yellow dock root, dandelion root, nettles, and alfalfa. According to Cox, these herbs provide an assimilable source of iron that is nonconstipating.

Zinc is important in enzyme function, the formation of insulin, protein synthesis, development of reproductive organs, and immune function. In a study of women with blood zinc levels below the median, the group who took a prenatal vitamin that included a zinc supplement bore infants of greater birthweight and head circumference than the placebo group.(6)

RDA: 15 mg.

Food sources: (given as mg. per 3.5 oz. serving): fresh oysters (148.7), pumpkin seeds (7.5), gingerroot (6.8), nuts (3 to 4), whole wheat (3.2), oats (3.2), lima beans (3.1), green peas (1.6), garlic (.6).