No significant differences in absorption between tablet and softgel capsule forms of folic acid

The bioavailability of folic acid does not significantly differ between delivery in standard tablet or softgel capsule forms, according to research published in this month's Journal of the Academy of Nutrition and Dietetics.  Folic Acid helps support a women's pregnancy and development of a healthy newborn.

"This research provides important information to health professionals who treat women of childbearing age. Because half of all pregnancies are unplanned intake of folic acid should be part of the daily routine for many women and this research helps to reduce barriers for its intake through supplements," said Louis I. Ndife, DVM, Ph.D., Director of Medical and Scientific Affairs at Pharmavite LLC. The folic acid tablets and prenatal multivitamins with DHA softgels used in the study were manufactured by Pharmavite LLC., makers of Nature Made® vitamins.

Absorption of Folic Acid from a Softgel Capsule Compared to a Standard Tablet

This randomized crossover study evaluated the bioavailability of folic acid from a multivitamin softgel capsule vs. a folic acid tablet in 16 premenopausal women (18-45 yr of age).  Participants were randomly assigned to receive a single dose of ~1000 mcg folic acid in two tablets or ~1000 mcg folic acid in a multivitamin softgel capsule, and then crossed over to receive the other study product ~one week later. Blood samples were collected pre-dose (0 hr) and 1, 2, 3, 4, 6 and 8 hr post-dose for serum folate analysis. The study results showed apparent bioavailability of folic acid was similar for the folic acid tablets and a multivitamin softgel capsule.

There were no significant differences between folic acid tablets and multivitamin/mineral softgel capsules for serum folate net incremental areas under the curve (niAUC 0-8 hr), total areas under the curve (AUC 0-8 hr) or maximum concentrations (C max).  There was an apparent delay in absorption of folic acid from the softgel capsule compared with the tablets, but this difference is likely clinically insignificant in the context of long-term nutrition.

The study concluded that serum folate AUC 0-8 hr and C max were similar for a multivitamin/mineral supplement with folic acid in a softgel capsule when compared to a similar formulation in tablet form, although the timing of absorption appeared to differ, with the peak folate concentration occurring later after capsule ingestion.  In the context of long-term nutrition, this difference in rate of absorption will likely be of little consequence.

Importance of Folic Acid

An estimated 3,000 pregnancies each year in the United States are affected by neural tube defects (NTDs), which are serious birth defects of the spine (spina bifida) and brain (anencephaly). However, consumption of the B vitamin folic acid prior to conception can reduce the occurrence of NTDs by up to 70%.

Because of this, both the U.S. Public Health Service and Institute of Medicine issued recommendations that all women capable of becoming pregnant consume 400 mcg of folic acid daily. Additionally, the Food and Drug Administration mandated fortification of cereal grain products with folic acid to increase women's daily intake.

While this fortification of the U.S. food supply resulted in a 26% reduction in NTDs, many women still do not receive adequate levels of folic acid from their diets. This has been particularly pronounced in the past decade, as many women of childbearing age follow low-carbohydrate weight loss diets, which limit many of the fortified foods. Therefore, increasing the use of vitamins containing folic acid remains an integral component of NTD prevention.