Micronutrient requirements in pregnancy (I)

While extra calories during pregnancy should be moderate, vitamin and mineral requirements increase in much higher proportions; therefore, it is important to select foods that are very rich in micronutrients to meet daily requirements.

Even if the woman has an adequate nutritional status that generally satisfies the demands for vitamins and minerals, specialists generally consider it prudent to recommend some micronutrient supplements to avoid deficient serum levels.

Plasma concentrations of all vitamins and minerals do not behave in the same way as gestation progresses: some show a slow reduction while others do not alter or even increase.

Among the vitamins and minerals that pregnant women should pay more attention to because their deficiencies are more likely to affect the final outcome of pregnancy are: vitamins A, D, E, B9 (folic acid), B12 and the minerals iron, calcium, iodine and zinc.

Vitamin A needs

Vitamin A is related to the support of human reproduction, the mechanism of vision and the functioning of the immune system. It is very important for the synthesis of hormones involved in gestation; for embryonic development and for the growth and protection of mucous membranes.

Vitamin A deficiencies during pregnancy increase the risks of low birth weight, premature delivery, preeclampsia and maternal mortality. On the other hand, very high doses of vitamin A supplements have been associated with congenital malformations, so the recommended intakes of 800 ug/day -micrograms per day- should be respected.

Foods that provide vitamin A (retinol) are of animal origin. For example: liver, meats, fish, eggs and milk. Foods that provide provitamin A (carotene) are of vegetable origin. For example: spinach, carrots, parsley, broccoli leaves, pumpkin and sweet potato.

Vitamin D needs

Vitamin D is essential for the correct absorption and utilization of calcium, which gives it a prominent role in bone mineralization; therefore, its presence is essential during the stages of formation and growth of the bone tissue of the child.

Vitamin D levels depend mainly on the exposure of the skin to sunlight; its deficiencies are frequent during pregnancy, especially in vegetarian women, dark skin, scarce sun exposure or who present absorption disorders.

Vitamin D deficiencies during pregnancy cause calcium metabolism disorders in mother and child, intrauterine growth retardation, rickets and dental enamel alterations. 15 ug/day, -micrograms per day- of vitamin D is recommended during pregnancy.

It should be obtained mainly by exposing the skin to sunlight for more than 15 minutes daily; although it can also be obtained in some foods such as cod liver oil, egg yolk, liver and dairy products.

Vitamin E needs

Vitamin E acts as an antioxidant in cells, facilitating their proper nutrition and tissue regeneration. It also intervenes in the synthesis of enzymatic systems that modulate hemoglobin formation.

Vitamin E deficiencies during pregnancy increase the risk of fetal death, miscarriages and congenital malformations.

The recommended intake for a healthy adult woman is 12 mg/day -milligrams per day-; this amount should be increased in the second half of pregnancy to 15 mg/day, -milligrams per day-.

Foods that provide vitamin E are oils rich in unsaturated fats, such as olive oil, sunflower oil, soybean oil, corn oil, etcetera. Egg yolk, liver, olives, broccoli and spinach are also vitamin E sources.

Important: Cooking foods can destroy much of the vitamin E contained in them.

Folic acid (Vitamin B9) requirements

Folic acid is necessary for the production and maintenance of new cells, so it is especially important during periods of rapid cell growth such as pregnancy and early childhood.

Adequate intakes of vitamin B9 before and during the first weeks of pregnancy reduce the risks of neural tube defects -chronic malformations in the spine, skull and brain of the baby-; and during the rest of the gestational stage contribute to fetal growth and development, reduce the risks of miscarriage, low birth weight, the occurrence of maternal anemia due to folate deficiencies and preeclampsia.

The recommended intake of vitamin B9 during all stages of pregnancy is 600 ug/day -micrograms per day-.

Specialists recommend taking at least 0.4 milligrams per day of folic acid supplements at least one month before conception and continuing during pregnancy to reduce the risks caused by folate deficiencies.

Foods that provide folate are spinach, chard, lettuce, legumes (lentils, chickpeas, etc.), nuts and some fruits.

These foods should be consumed fresh and uncooked since cooking and long storage periods easily destroy folates.

Vitamin B12 requirements

Vitamin B12 is essential for the functioning of the brain, nervous system, blood and cell formation in the human body; it is involved in cell metabolism, especially in DNA synthesis and regulation.

Vitamin B12 deficiencies increase the risks of maternal anemia and growth retardation of the child; some authors also point out that they constitute an independent risk factor for the occurrence of neural tube defects.

The recommended intake of vitamin B12 for a healthy adult woman is 2 ug/day -micrograms per day-; this amount should be increased in the second half of pregnancy to 2.2 ug/day -micrograms per day-.

Foods that provide vitamin B12 are exclusively of animal origin -liver, kidney, meat, eggs, dairy and fish- making it a critical nutrient for pregnant women who follow strictly vegetarian diets.

Vitamin C needs

As a potent antioxidant, vitamin C is associated with many health benefits for the pregnant woman and her baby. Women who are smokers or regular drinkers may be more at risk of deficiencies.

The recommended intake of vitamin C during the second half of pregnancy is 80 mg/day, -milligrams per day-; this is higher than that of a non-pregnant young adult woman, which is 60 mg/day.

The recommended intake of vitamin C for a healthy adult woman is 60 mg/day -milligrams per day-; this amount should be increased in the second half of pregnancy to 80 mg/day -milligrams per day-.

Foods that provide vitamin C are fresh fruits - kiwi, guava, lemon, orange, grapefruit, tangerine - and vegetables - lettuce, tomatoes, peppers, carrots, etcetera.

Important: Foods rich in vitamin C should be consumed fresh and uncooked since cooking and prolonged storage periods considerably reduce the levels of vitamin C contained in them.