Proteins are the building blocks of all cells. They are composed of amino acids and are necessary for the growth and repair of tissues, for building bloods and amniotic fluid, and for forming antibodies in both the woman and baby. There are two kinds of proteins—complete and incomplete. A complete protein supplies all eight of the essential amino acids. Protein from amino sources is usually complete. Vegetable protein is usually incomplete. If you are a vegetarian, you will need to learn all about protein composition to plan a diet that is balanced and provides all eight of the essential amino acids. Including both aminal and vegetable sources of protein is the best way to get all of them. Some good sources of protein are meat, fish, poultry, eggs, milk, cheese, dried beans and peas, peanut butter, nuts, and whole-grain breads and cereals.
Carbohydrates also come in two forms. Sugars, the simpler form, are found in fruit and milk. Starches, the more complex form, are found in vegetables and cereals.
Carbohydrates are especially important during pregnancy because they supply the woman with energy, allowing protein to be spared for the important work of building tissues. Many snacks—such as potato chips, cookies, and candy— are largely carbohydrates that supply empty calories and little else. Vegetables and fruit supply not only energy, but vitamins and minerals that benefit both the woman and the developing baby. Some carbohydrates also provide fiber, which helps minimize the problem of constipation. Good sources of carbohydrates are fresh fruits and vegetables, and whole-grain breads and cereals.
A small amount of fat is essential for the body to be able to process vitamins A, D, E and K, which are fat soluble. Nutritionists believe that vegetable fat is more beneficial than animal fat in the human body. Good sources of fat include cooking oil, butter, margarine, nuts, peanut butter, and cheese.
Calcium builds bones and teeth, aids in blood clotting, regulates the body’s use of other minerals, and functions in muscle tone and relaxation. An imbalance of calcium and phosphorus can lead to leg cramps. Just one bottle of a soft drink may contain enough other minerals to have a negative effect on the availability of calcium to the body’s cells. Eliminate soft drinks from your diet and eat good sources of calcium. Decreased amounts of calcium in the diet are associated with decreased strength in infant bones. In addition, a daily intake of 1,500 to 2,000 milligrams of calcium may decrease the risk of developing PIH. Good sources of calcium are dairy products, broccoli, dark green leafy vegetables, and some seafood.
Iron is essential for the formation of hemoglobin, the element that carries oxygen to the tissues and cells. Because of the increase in total blood volume during pregnancy, the ratio of hemoglobin to blood volume goes down is last trimester. This is normal, although it is sometimes confused with true anemia. During pregnancy, iron intake must be increased to build up the baby’s supply while preventing anemia in the woman. If necessary, an iron supplement may be recommended to be taken along with the prenatal vitamins. Iron supplements, however, can cause constipation and nausea. Talk with your caregiver about finding an iron supplement that will agree with your digestive system. Good sources of dietary iron are red meat, egg yolk, shellfish, dried fruit, and enriched whole-grain breads and cereals.
The best way to obtain vitamins is through a diet that includes both the water-soluble B complex and C vitamins as well as the fat-soluble A, D and K vitamins. Vitamin supplements are essentially just that—supplements. They will not compensate for an inadequate diet and should not be thought of as the best way to obtain vitamins. They contain only those vitamins which nutritional recommendations have been established. There are many trace vitamins in a well-balanced diet for which recommendations have not been set or requirements are not even known.
A vitamin for which a supplement is strongly recommended is folic acid, a B vitamin. Studies indicate that daily consumption of 400 micrograms (but not more than 1,000 micrograms) of folic acid, beginning before pregnancy and continuing through the first trimester, can prevent up to 70 percent of neural tube defects in babies. There is also evidence that folic acid may prevent cleft lip and palate, and certain heart and limb defects. Good dietary sources of folic acid include orange juice, green leafy vegetables, beans, peas, liver, and some fortified cereals. The FDA enacted a regulation, beginning in 1998, to require manufacturers to fortify grain products—including breads, flours, cornmeal, pasta, and rice—with folic acid to ensure that women receive this important vitamin.
Not all vitamins are safe. Extra doses of vitamin A, even two or three multivitamins a day, may cause birth defects if taken in early pregnancy. A study published in the New England Journal of Medicine in 1995 cautions that than 10,000 international units of vitamin A each day may be dangerous to the fetus. The problems involve malformation of the face, head, heart, or nervous system. Most prenatal vitamins contain 4,000 units. Some multivitamins, especially those sold in health food stores, contain higher levels, and vitamin A capsules may have as much as 25,000 units. It is also recommended that women be careful combining supplements with large servings of liver, which is high in vitamin A, and with vitamin-enriched cereals, which may contain 5,000 units of vitamin A per bowl.