The Influence of Increasing Lecithin Concentrations on Carotenoid Bioaccessibility and Cell Uptake

Abstract Objectives We sought to determine if lecithin would produce a dose-response effect, increasing carotenoid bioaccessibility and Caco-2 cell uptake. Methods A mixture of β-carotene, lycopene, lutein and zeaxanthin was digested with increasing concentrations of lecithin (0–10 mg lecithin/mL test meal) and ∼4% vegetable oil (n = 6 per condition). In vitro gastric, duodenal, and jejunal digestion was mimicked for 1 h each, and the micellar fraction isolated for analysis. Additionally, Caco-2 cells producing a monolayer reflecting a small intestinal phenotype were incubated with of the micellular fraction for 4 h, and cells harvested for extraction. The micellular fraction and cell were extracted with hexane and dichloromethane, and the organic phase dried under argon. Micellular carotenoids were quantitated using high performance liquid chromatography-diode-array detection (HPLC-DAD), while cellular carotenoids were quantitated using UHPLC-tandem mass spectrometry (UHPLC-MS/MS). One-way ANOVA followed by Tukey's post-hoc test was used to assess statistically significant differences between lecithin doses on carotenoid bioaccessibility and cellular uptake. Fractions of digesta were also visualized using confocal microscopy, to better elucidate the lecithin-micelle interaction. Results Lecithin significantly increased β-carotene and zeaxanthin bioaccessibility only when comparing the most extreme doses tested. No significant differences were observed for lycopene or lutein bioaccessibility. Likewise, lecithin did not produce a significant increase in the cell uptake in the range tested. Conclusions Overall, lecithin had minimal impact on carotenoid bioaccessibility, and Caco-2 cell uptake of carotenoids. Funding Sources This work was supported by a research grant from Nu Skin Enterprises, Inc.