Research article
Relative bioavailability of iron and folic acid from a new powdered supplement compared to a traditional tablet in pregnant women
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* Corresponding author: Stanley Zlotkin stanley.zlotkin@sickkids.ca
1 Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada
2 Department of Paediatrics and the Department of Public Health Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada
3 Program in Child Health and Evaluative Sciences, Research Institute, Hospital for Sick Children, Toronto, Canada
4 Physiology and Experimental Medicine, and the Department of Clinical Dietetics, Hospital for Sick Children, Toronto, Canada
BMC Pregnancy and Childbirth 2009, 9:33 doi:10.1186/1471-2393-9-33
Published: 27 July 2009Abstract
Background
Deficiencies of iron and folic acid during pregnancy can lead to adverse outcomes for the fetus, thus supplements are recommended. Adherence to current tablet-based supplements is documented to be poor. Recently a powdered form of micronutrients has been developed which may decrease side-effects and thus improve adherence. However, before testing the efficacy of the supplement as an alternate choice for supplementation during pregnancy, the bioavailability of the iron needs to be determined. Our objective was to measure the relative bioavailability of iron and folic acid from a powdered supplement that can be sprinkled on semi-solid foods or beverages versus a traditional tablet supplement in pregnant women.
Methods
Eighteen healthy pregnant women (24 – 32 weeks gestation) were randomized to receive the supplements in a crossover design. Following ingestion of each supplement, the changes (over baseline) in serum iron and folate over 8 hours were determined. The powdered supplement contained 30 mg of iron as micronized dispersible ferric pyrophosphate with an emulsifier coating and 600 μg folic acid; the tablet contained 27 mg iron from ferrous fumarate and 1000 μg folic acid.
Results
Overall absorption of iron from the powdered supplement was significantly lower than the tablet (p = 0.003). There was no difference in the overall absorption of folic acid between supplements. Based on the differences in the area under the curve and doses, the relative bioavailability of iron from powdered supplement was lower than from the tablet (0.22).
Conclusion
The unexpected lower bioavailability of iron from the powdered supplement is contrary to previously published reports. However, since pills and capsules are known to be poorly accepted by some women during pregnancy, it is reasonable to continue to explore alternative micronutrient delivery systems and forms of iron for this purpose.
Trial Registration
ClinicalTrials.gov NCT00789490