A randomized, crossover study to evaluate α-tocopherol bioavailability via a microemulsion gel or dry tablet delivery...

Vitamin E (α-tocopherol) is an essential micronutrient for human health and optimal physiological function. Inadequacy may be common due to a lack of bioavailability. The use of dietary lipids alongside other emulsification agents may elicit more robust serum concentrations of α-tocopherol via improved bioavailability. Therefore, the aim of the study was to examine oral bioavailability of two delivery methods of α-tocopherol, (1) a microemulsion gel formula composed of dietary lipids and other emulsification agents and (2) a dry solid tablet over 12 hours.

Twelve participants (age  =  37.3  ±  9.6 years; height  =  173.4  ±  11.8 cm; body mass  =  71.2  ±  10.0 kg) participated in a double-blind, randomized, crossover trial comparing two delivery methods both dosed at 288 mg of α-tocopherol. Serum α-tocopherol concentrations were assessed from blood donated by participants at pre-consumption, 2-, 4-, 8-, and 12-hour post-consumption. Study conditions were separated by a 7-day washout.

The microemulsion gel formula delivery demonstrated significantly greater area under the curve (p < 0.001) and serum concentration maximums (p  =  0.003) for serum α-tocopherol compared to the tablet delivery. No significant differences were detected between conditions for the time to reach concentration maximums (p  =  0.375).

We conclude that a mixture of dietary lipids and emulsification agents in the form of a microemulsion gel formula was able to significantly improve bioavailability of serum α-tocopherol compared to a tablet by yielding higher serum α-tocopherol maximum concentrations and area under the curve over a 12-hour study period despite dosage being matched.