Non-Fat Fermented Milk Enhanced the Bioavailability of Fat-Soluble Vitamins in Humans: A Crossover Study

Deficiencies of essential fat-soluble vitamins have been identified in several conditions. Previously we reported the co-ingestion of non-fat fermented milk and vegetables enhanced absorption of carotenoids. Both carotenoids and fat-soluble vitamins have similar absorption mechanisms. Therefore, we hypothesized that the absorption of fat-soluble vitamins may be enhanced when co-ingested with non-fat fermented milk. Twenty healthy male participants were included in this two-group, two-phase crossover study. Participants co-ingested 50 g of a fat-soluble vitamin solution with either 75 g of water or 75 g of non-fat fermented milk before switching after a 2-wk washout. The fat-soluble vitamins were mixed in 50 g of water with 830 μg vitamin A (as retinol), 230 μg of vitamin D (as cholecalciferol), 100.8 mg of vitamin E, and 16.8 mg of vitamin K (as menaquinone-7). Blood samples were collected before and 2, 4, 6, and 8 h after test food consumption and the concentrations of fat-soluble vitamins in the triacylglycerol-rich lipoprotein (TRL) and total plasma fractions were determined. The incremental area under the curve for retinyl palmitate, cholecalciferol, and menaquinone-7 concentrations in the total plasma fraction, and α-tocopherol and γ-tocopherol concentrations in the TRL fraction of plasma were significantly higher for the group of the co-ingestion of fat-soluble vitamins and non-fat fermented milk, compared with the co-ingestion of fat-soluble vitamins and water. Our findings suggest a new nutritional means by which fat-soluble vitamin bioavailability can be enhanced via co-ingestion with non-fat fermented milk. This approach could improve nutritional deficiencies of global health concern.