Prenatal Nutrition

This section is compiled by Frank M. Painter, D.C.
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From the February 2000 Issue of Nutrition Science News

by Charles K. Rosenberg, C.N.

Seeing a customer through a healthy pregnancy is a rewarding experience. Whether the woman is a regular natural products shopper or new to the realm of vitamins, there are important things to relay about supplementing.

Often when a woman becomes pregnant, or is trying to get pregnant, she develops a new perspective on her health. For most this means a new or renewed interest in nutrition and healthy food choices. Some women are afraid their diet is insufficient and worry it might affect their baby. Others simply want to do everything in their power to have an easy pregnancy and a normal infant. All are valid concerns. They are also opportunities for you to discuss the reasons to supplement, even for those already eating healthfully.

Supplementing with vitamins to ensure a healthy pregnancy is wise. In fact, because U.S. RDAs for some nutrients double during pregnancy, it may be the only way to guarantee nutrient needs are met. In particular, pregnant women need increased quantities of iron, calcium and folic acid. Supplementing with a quality multivitamin that provides these three nutrients is a necessity because even a well-balanced diet will not provide enough of them for a woman and her growing child.

Pregnant women generally do not get the required nutrients from food alone for a variety of reasons. First, the typical American diet doesn't contain enough iron and folic acid to meet the needs of pregnant women. [1,2] Second, some women fear excess weight gain for cosmetic reasons and limit their food intake during pregnancy. Third, nausea and appetite loss can prevent women from eating enough. Other mothers particularly in need of supplementation are those who are younger than 15, are older than 35, have had previous pregnancies, are expecting a multiple birth or are vegan. Supplementation is even more important if the mother smokes or drinks--behaviors indicative of those with poor nutritional status.

Building Baby

Doctors used to believe the fetus' nutritional needs would be accommodated regardless of what the mother ate. For example, it was believed that even if a mother didn't get enough calcium the baby would take what it needed from her bone stores. The mother would suffer, but not the baby. Now we've come to realize that, with the possible exception of iron, deficiencies in the mother's diet can lead to deficiencies for the baby.

IRON One of the most common complications of pregnancy is anemia. Although inadequate maternal iron stores, unlike other nutrient deficiencies, don't directly harm the growing fetus, they can lead to a difficult labor. Decreased iron increases the mother's risk of preeclampsia (elevated blood pressure and edema) and of death if hemorrhage occurs at delivery. [3] The concern is real because iron deficiency is so prevalent. In fact, 20 percent of non-pregnant women are deficient, [4] and this risk multiplies during pregnancy because iron needs double from 15 to 30 mg/day. [5] More iron is required because the mother's blood volume increases to transport oxygen to the fetus. Iron is part of the hemoglobin molecule that carries oxygen in red blood cells. It is particularly critical in the last trimester of pregnancy when the fetus and the placenta store the mineral. If a pregnant woman complains of tiredness or difficulty concentrating, she should be assessed for anemia and given iron alone or as part of a multivitamin.

Iron supplementation is important because its richest food sources, such as shellfish and organ meats, are not common in the diet and are not present at all in vegetarian diets. In fact, the Food and Nutrition Board of the National Academy of Sciences in Washington, D.C., recommends that pregnant women supplement with 30 mg ferrous iron daily, especially during the second and third trimesters. [2] Ferrous fumarate is the most common form of iron in supplements, and 100 mg of it are needed to provide 30 mg of ferrous iron. Since iron absorption may be inhibited by other minerals in multivitamins, supplements with more than the RDA for iron may be more effective. Alternatively, a woman may take a multivitamin without iron and an iron supplement between meals. The two remaining side effects associated with iron supplementation are nausea and constipation. If a woman experiences nausea as a result of taking iron she can eat a piece of fruit or a drink a cup of ginger tea with her supplement. The ginger, which is effective for morning sickness, will alleviate supplement-induced nausea as well. [6] If constipation becomes a problem, I recommend women add one tablespoon to one-quarter cup of ground flaxseeds to their food each day.

CALCIUM Another important prenatal mineral is calcium. Supplementing with 1­2 g/day has been shown in some studies to prevent the risks of pregnancy-induced hypertension and its more advanced condition, preeclampsia/eclampsia, as well as the risk of preterm birth. [7] Women with inadequate dietary protein, those younger than 20 or older than 30 who are pregnant for the first time, women who have had five or more pregnancies, as well as women with a history of heart disease, diabetes or hypertension are at risk for these conditions. Because these women may not receive all the calcium they need from diet, and because multivitamins may not provide sufficient levels of calcium either, an extra calcium supplement is in order.

Prescription prenatal vitamins contain an average of 212 mg calcium per daily dose. Natural products brands often contain up to 1,000 mg per daily dose. A separate supplement providing 1,000 mg of well-absorbed calcium citrate malate, combined with 500 mg magnesium, may be the best bet. Magnesium relaxes vascular smooth muscle and also helps mobilize calcium in bone. The greatest needs for calcium occur during the period of intense fetal growth in the last trimester, but extra calcium is necessary throughout pregnancy for many other metabolic processes. Insufficient calcium also increases the potential for impaired fetal skeletal growth. This is a greater risk if the mother's diet is also high in protein, as many American diets are, because protein increases urinary calcium excretion.

FOLIC ACID Although calcium is stored in the skeletal reservoir, humans don't have reserves of folic acid. This water-soluble B vitamin is incorporated in the body into a coenzyme necessary for DNA synthesis, which is vital to cell growth and proliferation, both of which are critical to fetal development. Folic acid is recognized as the paramount prenatal supplement because a lack of it can cause neural tube defects in the developing fetus. According to a 1996 FDA folic acid fact sheet, approximately 2,500 infants are born with a neural tube defect in the United States each year. Half of these defects are thought to be related to inadequate folic acid intake by the mother.

The neural tube, the part of the fetus that develops into the brain and spinal cord, is subject to two major types of defects. As the tube develops it may not close properly at the top, leading to anencephaly, or absence of a brain. These babies die at birth. If the closure is incomplete further down the neural tube, leaving the spinal cord exposed, then spina bifida may occur. This usually leads to paralysis and potentially to mental retardation. After reviewing the evidence that folic acid supplementation can prevent such birth defects, FDA in 1998 ordered that enriched grain flours be fortified with folic acid.

To effectively prevent these defects, folic acid must be present in the diet before conception, thus the rationale to fortify the food supply. Folate, the naturally occurring food form of folic acid, is available in legumes and leafy green vegetables including kale and collards. Because food-derived folate is only half as bioavailable as the synthetic folic acid found in supplements, large quantities of folate-rich foods would have to be eaten to achieve the equivalent of 400 mcg folic acid required to prevent birth defects. [8] One 1998 study reported that not one of the 21 women surveyed consumed adequate levels of folic acid. [9]

It makes sense then that the Institute of Medicine of the National Academy of Sciences recommends, "all women capable of becoming pregnant consume 400 mcg of synthetic folic acid from fortified foods and/or supplements in addition to intake of food folate from a varied diet." [8] But not every woman has fortified foods in her diet. For example, a woman who only uses organic flour and whole grain products from a health food store may not be getting any fortified food. Even though her diet may be richer in natural folate, her requirements for folic acid--sufficient to prevent birth defects--may still not be met.

I encourage my clients to eat a diverse, nutrient-rich diet and to take the following supplements: 30 mg iron first thing in the morning before eating; a multivitamin without iron twice a day with meals; and a calcium citrate or citrate malate pill that includes magnesium with a fruit snack in the evening.

A staggering 75 percent of women within the reproductive age range are not taking a multivitamin. [10] That means approximately 45 million American women could become pregnant with less than optimal nutrition. By using a multivitamin, a woman who eats well can increase her odds of providing adequate nutrition for her baby. Although supplements will not prevent all the complications of pregnancy all of the time, they multiply the assurances a healthy diet provides. NSN

Charles K. Rosenberg, M.S., C.N., is an adjunct faculty member in the nutrition department at Bastyr University in Kenmore, Wash., and a certified nutritionist practicing in Seattle.


DHA & The Developing Infant

Prescription Vs. OTC Prenatal Vitamins


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