Effect of Fat and Fasting on Post-Prandial Relative Bioavailability of Vitamin E

Abstract Objectives We hypothesized that meal fat co-administered with fat-soluble α-tocopherol (vitamin E) facilitates vitamin E absorption and increases relative bioavailability in the immediate post-prandial phase, when compared with non-fat meals. We tested this hypothesis using deuterated oral α-tocopherol co-administered with breakfast containing meal fat (40% group) and without meal fat (0% group) in hospitalized healthy women. We also evaluated the role of subsequent meals in modulating the vitamin E relative bioavailability by fasting patients for 12 h following a breakfast meal with 0% fat (0% fat-fasting group). We compared area under the curve (AUC) for oral d3-α-tocopherols %enrichment at 0–4 h, 0–12 h and 0–24 h. Methods Custom-synthesized deuterated d3-α-tocopherol was co-administered with breakfast meal with and without fat, with subsequent serial sampling. Enrolled subjects were healthy women hospitalized for 5–6 days at the NIH Clinical Research Center. Results The AUC0–4 h for 40% fat group was more than twice 0% fat group (6.4 ± 1.8 vs 2.3 ± 0.7). This difference was erased following ingestion of meals containing 30% fat at 4 h and 8 h post-dosing, with AUC0–12 h for 40% and 0% fat groups (96.8 ± 10.2 vs 107.4 ± 8.) and AUC0–24 h (254 ± 16.3 vs 301.8 ± 19.7). To evaluate the effect of fasting, we compared 0% fat group with 0% fat-fast groups. At 4 h and 8 h post-dosing, the 0% fat group received meals with 30% fat, while 0% fat-fast group remained in fasting state. We therefore predicted and found significantly higher AUC0–12 h in the 0% fat group compared with the 0% fat-fast (107.4 ± 8.1 vs 41.1 ± 5.2 P < 0.001). Following meal consumption by 0% fat-fast group 12 h post-dosing, AUC0–24 h between 0% fat and 0% fat-fast groups narrowed but remained significantly different (301.8 ± 19.7 vs 207.4 ± 10.6, P < 0.002) respectively. Conclusions Findings demonstrate the effect of meal fat in facilitating vitamin E absorption in the immediate post-prandial state, resulting in increased relative bioavailability. Conversely, fasting decreases vitamin E relative bioavailability. Funding Sources NIDDK Intramural Program.