Processing of vegetable-borne carotenoids in the human stomach and duodenum

Carotenoids are thought to diminish the incidence of certain degenerative diseases, but the mechanisms involved in their intestinal absorption are poorly understood. Our aim was to obtain basic data on the fate of carotenoids in the human stomach and duodenum. Ten healthy men were intragastrically fed three liquid test meals differing only in the vegetable added 3 wk apart and in a random order. They contained 40 g sunflower oil and mashed vegetables as the sole source of carotenoids. Tomato puree provided 10 mg lycopene as the main carotenoid, chopped spinach (10 mg lutein), and carrot puree (10 mg β-carotene). Samples of stomach and duodenal contents and blood samples were collected at regular time intervals after meal intake. all-trans and ciscarotenoids were assayed in stomach and duodenal contents, in the fat and aqueous phases of those contents, and in chylomicrons. Thecis-trans β-carotene and lycopene ratios did not significantly vary in the stomach during digestion. Carotenoids were recovered in t...