Written by Jessica Patella, ND. In a study of 448,000 white pregnant women in the South of England, 90% had vitamin D levels below the recommended levels and 28% were seriously deficient.
Researchers recently reviewed the history of vitamin D deficiency and rickets in the United Kingdom (1). When vitamin D was discovered in the 1920s, it led to moderate sun exposure for infants and regular cod liver oil supplementation.Vitamin D is a fat-soluble vitamin that is produced naturally when ultraviolet rays from sunlight strike the skin and trigger vitamin D production in the body (4). It is also found naturally in cod liver oil, prompting the recommendations in the 1920s. By the 1930s, rickets had virtually disappeared in the UK (1). In the 1990s, cod liver oil lost favor when there were concerns that high levels of vitamin A (found naturally in cod liver oil, though at moderate levels), might cause birth defects (1). Since then, no further recommendations were made on supplementing vitamin D and now a resurgence of rickets is being seen (1).
The importance of vitamin D during pregnancy is also supported by the increased number of vitamin D receptors on pregnancy-specific tissues, such as the placenta (5). Also there is a correlation between low maternal levels of vitamin D and an increased prevalence of pre-eclampsia* and miscarriage (1).
The current research found that 90% of white pregnant women living in the South of England had vitamin D (25(OH)D) concentrations below the recommended level (<50nmol/l; approximately 403,000 women) during the winter and spring months; 28% were seriously deficient (<25nmol/l; over 150,000 women); and no one reached 75 nmol/l, which is currently considered the optimal level (1). Because of the high prevalence of vitamin D deficiency, the recommendation of supplementation with 400 IU/day of vitamin D for pregnant women in the United Kingdom was proposed (1).
In conclusion, vitamin D deficiency is reaching record levels in Western societies. This is causing a major concern in pregnant women and increasing the risk of children born with rickets. New guidelines in the United Kingdom recommend supplementation of 400 IU/day (1). Further research needs to be done to establish potential benefits of higher levels of maternal vitamin D intakes (1).
* Pre-eclampsia-a serious condition that may occur in late pregnancy involving rise in blood pressure, weight gain, headache, and other problems
Source: Hyppönen, Elina, and Barbara J. Boucher. “Avoidance of vitamin D deficiency in pregnancy in the United Kingdom: the case for a unified approach in National policy.” British Journal of Nutrition 104.03 (2010): 309-314.
© The Authors 2010
Posted August 5, 2010.
References:
- Hypponen E, Boucher B. Avoidance of vitamin D deficiency in pregnancy in the United Kingdom: the case for a unified approach in National policy. British Journal of Nutrition, July 2010.
- Prentice A. Vitamin D deficiency: a global perspective. Nutr Rev 10 Suppl. 2, 66, S153-164.
- Holick MF (2006) Resurrection of vitamin D deficiency and rickets. J Clin Invest 116, 2062-2072.
- Dietary Supplement Fact Sheet: Vitamin D (NIH). See the National Institute of Health website.
- Evans KN, et al. Vitamin D and placental-decidual function. J Soc Gynecol Investig 2004. 11:263-271.
