Plasma responses in human subjects after ingestions of multiple doses of natural alpha-cryptoxanthin: a pilot study.

Xanthophylls have attracted a lot of interest since their health benefits were documented. Unfortunately, studying their intestinal absorption is often affected by high baseline levels present in the fasting plasma. As alpha-cryptoxanthin is rarely found in the traditional European diet, its concentration in human plasma is extremely low. A pilot human intervention study was designed using alpha-cryptoxanthin for the first time as a marker xanthophyll in a minimally formulated cellulose-based supplement. Alpha-cryptoxanthin was administered in gelatin soft-gel capsules in multiple doses of 156 microg/d to three male volunteers (age 27.3 (SD 4.7) years; BMI 21.6 (SD 0.3) kg/m(2)) for 16 d after a 2-week carotenoid depletion period. Fasting blood samples were taken before the intervention and after 3, 6, 9, 13 and 16 d. Plasma HPLC analyses allowed for determination of the concentration; liquid chromatography-MS in the single ion monitoring mode was used to confirm peak assignment. The concentrations of alpha-cryptoxanthin increased significantly after only 3 d of supplementation. The concentration-time plots showed a characteristic shape with a first maximum after day 6, a decline until day 9 and a gradual second rise until the end of the study. Standardisation of plasma alpha-cryptoxanthin concentrations to triacylglycerol or total cholesterol did not influence the characteristics. The maximum concentrations reached at the end of the intervention period ranged from 0.077 to 0.160 micromol/l. These results suggest a high intestinal absorption and an enrichment of alpha-cryptoxanthin in the plasma even from a minimally formulated cellulose-based supplement.