Vitamins & Minerals in Pregnancy
Jovian Wat, PhD
When we think about the importance of our 'diet', we usually think of carbohydrates, proteins, and fats. However, vitamins and minerals are also central parts of the diet. A balanced diet containing the right levels of vitamins and minerals is essential for maintaining health, especially in pregnancy.
What are vitamins and minerals?
Vitamins are a group of organic molecules essential for nutrition. The term 'organic' refers to compounds that contain carbon, while inorganic refers to compounds that contain other elements. Vitamins play a numerous types of roles in our bodies, especially involving our body's growth and metabolism. Vitamins are not made by our own bodies, they must be ingested from animal, plant, or synthetic sources.
There are at least 13 groups of vitamins: vitamins A, B1, B2, B3, B5, B6, B7, B9, B12, C, D, E, and K. Each group of vitamins could be made up of different compound that function in a similar way in our bodies. For example, vitamin A includes carotenes and xanthophyll (found mostly in plant sources), as well as retinol and retinal (animal sources).
Minerals are inorganic molecules that are also required for health. The term 'inorganic' refers to compounds that elements other than carbon. Calcium, iron, magnesium and phosphate are all minerals.
Let's discuss several vitamins and minerals that have been shown to impact pregnancy health in mom and baby.
Vitamin B9 / Folate
Folate is found in dark leafy greens, legumes, and citrus fruits, as well as fortified cereals. It is an essential vitamin for a healthy pregnancy.
Folate plays a central role in the normal development of the fetal nervous system in the first month of pregnancy. Low levels of folate in the mom's system is linked with increases risk of neural tube defects in the baby. Neural tube defects can result in serious conditions such as spina bifida and anencephaly, with fatal or severe lifelong consequences.
Since many women do not know they are even pregnant in the first month of pregnancy, it is important that the mom has good folate levels before conception. However, the majority of women aged 15 to 44 do not meet the recommended dietary intake of folate.
In an effort to reduce folate deficiency in pregnancy and the rates of neural tube defects, the United States and Canada began fortifying cereal grains with folic acid in 1998. This fortification program successfully reduced neural tube defects by more than 50% in Canada. The United States Preventative Services Task Force recently concluded 'the net benefit of daily folic acid supplementation to prevent neural tube defects in the developing fetus is substantial for women who are planning or capable of pregnancy'.
The Society of Obstetricians and Gynaecologists of Canada and the American College of Obstetricians and Gynecologists provide recommendations for folic acid supplementation in pregnancy.
The main source of vitamin D is exposure to sunlight or UV-B radiation on the skin. Sunlight stimulates the transformation of cholesterol into Vitamin D in the skin. Technically, Vitamin D is not a vitamin; it is a hormone that is not made in the body. Vitamin D is not commonly found naturally in foods but is fortified in certain dairy or fruit products.
Up to 40% of North Americans have low Vitamin D status. Vitamin D deficiency is more common among African-Americans (over 80%) and Hispanics (over 60%). People with darker pigmented skin are more prone to have low levels of vitamin D deficiency, since their skin absorbs less UV-B radiation.
Studies have found that Vitamin D deficiency is linked with placental inflammation, gestational diabetes, preeclampsia, and preterm birth. In a meta-analysis of 27 randomized controlled trials, Vitamin D supplementation reduced the risk of preeclampsia by 50%. However, more research is needed to determine the exact role of Vitamin D in healthy pregnancy.
The Royal College of Obstetricians and Gynaecologists in the United Kingdom recommends Vitamin D supplementation for women who are pregnant or breastfeeding. In contrast, the World Health Organization and the American College of Obstetricians and Gynecologists do not recommend routine Vitamin D supplementation for pregnant women, stating that there is currently not enough data to support Vitamin D supplementation to improve the health of mom and baby.
Calcium is found in dairy products and fortified foods, such as cereals. Calcium is important for bone, dental and heart health, as well as normal hormone function.
A Cochrane Review evaluated if calcium supplementation during pregnancy can reduce the risks of preeclampsia and preterm birth, analyzing data from 13 clinical trials that included over 15,000 pregnant women. High doses of calcium supplementation (more than 1 gram/day) during pregnancy was found to reduce the rates of preeclampsia by as much as 50%. Calcium supplementation reduced the rates of preeclampsia even more in pregnant women with low calcium diets.
There is no clear evidence that calcium supplementation during pregnancy prevent preterm birth or increases birthweight.
The Society of Obstetricians and Gynaecologists of Canada recommends calcium supplementation for women with low calcium diets for the prevention of preeclampsia. The American College of Obstetricians and Gynecologists and World Health Organization also recommend calcium supplementation for pregnant women where calcium intake is low.
Vitamins and minerals, including Vitamin B9, Vitamin D and calcium, play a key role in the health of both mom and baby. It is important to ensure that mom's diet is nutritious and contains balanced levels of vitamins and minerals.
Every woman and every pregnancy is unique. Pregnant women should speak to their healthcare provider to ensure maternal and fetal safety. This article is meant to provide readers with current information and opinions. All medical and treatment decisions should be discussed with your healthcare provider.