Pregnant Women Deficient in Vitamin D
If you are pregnant and taking vitamin D supplements, you still may not be getting enough of this critical nutrient. According to a new study from Northern Ireland, current dosing recommendations do not allow many expectant mothers to achieve adequate blood levels of vitamin D.
Research abounds on the critical need for vitamin D for people of all ages. According to the Vitamin D Council, a deficiency of vitamin D is a major factor in at least 17 varieties of cancer as well as in heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, muscle weakness, muscle wasting, periodontal disease, birth defects, and others. Of particular concern is a deficiency of the vitamin among pregnant women, as low levels can have a negative impact on both the mother and the child.
Unlike the United States, the United Kingdom has specific dose recommendations for vitamin D for pregnant women of 10 micrograms daily. Pregnant women in the United States, however, generally follow the guidelines for adequate intake for all adults at 5 micrograms per day.
Pregnant women who are vitamin D deficient are themselves at increased risk of preeclampsia, gestational diabetes, and bacterial vaginitis. Some studies show that infants born to vitamin D deficient mothers may be at greater risk of low birth weight, lower respiratory tract infections, asthma, and weak bones.
In the current study, the researchers evaluated 99 pregnant women at 12, 20, and 35 weeks of gestation and 38 nonpregnant women. The investigators found that serum concentrations of 25-hydroxyvitamin D (25[OH]D), the non-active form of the vitamin in the body, were deficient at all three testing times. Specifically, at 12 weeks, 35 percent of women were deficient and 96 percent had insufficient levels of vitamin D. By 35 weeks of gestation, 16 percent of women were vitamin D deficient and 75 percent had insufficient levels of the nutrient.
The Vitamin D Council recommends that all adults take a sufficient amount of vitamin D so that blood levels are between 50 and 80 ng/mL (or 125 to 200 nmol/L) year round. In the Northern Ireland study, nearly all the pregnant women had blood levels lower than 80 nmol/L, which is considered to be the cut-off point for vitamin D sufficiency.
The US National Academy of Sciences’ Institute of Medicine, which sets dietary requirements for nutrients, has indicated that it will review the recommendations for vitamin D “in the not too distant future.” The Vitamin D Council advises healthy adults and adolescents, including pregnant women, to take about 125 micrograms and children older than age 2 to take 50 micrograms. The American Academy of Pediatrics has recommended that children consume 10 micrograms daily.
American Academy of Pediatrics
Holmes VA et al. British Journal of Nutrition 2009 Sept; 102(6): 876-81
Institute of Medicine
Vitamin D Council