- On September 9, 2019
Pregnancy is a time in a women’s life when there is an increased need for many vitamins and minerals, particularly iron. Iron is an essential micronutrient necessary for the development of healthy red blood cells and to transport oxygen throughout the body. Additionally, iron is necessary for growth, development, cell function, and the synthesis of some hormones. During pregnancy, iron needs increase (recommendation of 27 mg/day) to support the increase in blood plasma associated with the growing baby and placenta, and for the physiological changes occurring in the mother. Due to these increased needs, pregnant women are at risk of developing iron deficiency anemia. Iron deficiency anemia during pregnancy increases the risk of maternal and infant mortality, preterm birth, and low birth weight infants. Effects of iron deficiency anemia include impaired cognitive function, immune function, work/exercise performance, and body temperature regulation. As a result, many doctors recommend a daily prenatal vitamin, which typically contains 30 mg of iron, therefore meeting the recommendations and reducing the risk of deficiency.
What about after the baby is born? Often times women will continue taking their prenatal vitamins thinking that there is no harm and that it is just like any other multivitamin. Unfortunately, there is often a great deal of conflicting recommendations coming from a variety of sources; internet, well-meaning family and friends, and even some doctors! Additionally, there is often confusion as to if prenatal vitamins are needed if you’re breastfeeding. In actuality, the amount of iron contained in prenatal vitamins is typically much higher than the needs of non-pregnant and breastfeeding women. The recommendations for non-pregnant adult females are set at 18 mg/day, and even less for breastfeeding women (10 mg/day).
So, what’s the big deal if I get some extra iron? Too much iron can become toxic with adverse health effects and risks when intake regularly exceeds recommendations. Extra iron from dietary sources is not usually a concern, as iron toxicity from dietary sources is rare, although there is a higher risk of over consuming iron through supplements and multivitamins (such as prenatal vitamins). Symptoms of toxicity include; abdominal pain, nausea, vomiting, constipation, or even organ failure and potentially death. Additionally, large amounts of supplemental iron (about 25 mg/day, less than what is in a typical prenatal vitamin) may impair zinc absorption. Zinc is an essential mineral that is important for immune function, wound healing, cell growth, development, and proper taste and smell. Zinc deficiency can lead to growth retardation, impaired immune function, delayed wound healing, hair loss, diarrhea, and taste abnormalities. Pregnant women and young children are at risk for zinc deficiency as zinc is essential for healthy growth and development during pregnancy and throughout puberty. Also, zinc needs for breastfeeding women are even higher than non-pregnant/non-breastfeeding women.
As it turns out, it is possible to have too much of a good thing! Excessive iron intake after pregnancy, as with prenatal vitamins and other supplements, may not be needed, and in fact may be doing more harm to your body than good. It’s best to have your iron levels checked by your doctor if you feel that you may be at risk for deficiency to determine if there is a need for supplementation. In most cases though, a balanced diet with of lots of vegetables, fruits, whole grains, low-fat dairy (or alternatives), and lean proteins will meet your iron needs after pregnancy. As always, seek the advice of a Registered Dietitian for help with meeting your needs, if needed.
- Gernand AD. The upper level: examining the risk of excess micronutrient intake in pregnancy from antenatal supplements. Annals of the New York Academy of Sciences. 2019;1444(1):22-34.
- Gropper SS, Smith JL. Advanced Nutrition and Human Metabolism. 7th
ed. Boston, MA: Cengage; 2018.
- Office of Dietary Supplements. Iron: Fact Sheet for Health Professionals. National Institutes of Health Office of Dietary Supplements Website. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/. Updated July 9, 2019. Accessed August 11, 2019.
- Office of Dietary Supplements. Zinc: Fact Sheet for Health Professionals. National Institutes of Health Office of Dietary Supplements Website. https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/#en9. Updated July 10, 2019. Accessed August 11, 2019.
- Trumbo P, Yates AA, Schlicker S, Poos M. Dietary reference intakes: vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Journal of the American Dietetic Association. 2001;101(3):294-301.