Production of asymmetric oxidative metabolites of [13C]-β-carotene during digestion in the gastrointestinal lumen of healthy men. Issue 4 (22nd August 2018)

• Record Type: Journal Article
• Authors: Kopec, Rachel E; Caris-Veyrat, Catherine; Nowicki, Marion; Gleize, Beatrice; Carail, Michel; Borel, Patrick
• Is Part Of: American journal of clinical nutrition. Volume 108:Issue 4(2018)
• Page Start: 803
• Page End: 813
• Publication Date: 2018-08-22
• Subjects: [¹³C]-β-carotene -- metabolism -- asymmetric metabolites -- digestion -- stomach -- duodenum -- gastrointestinal lumen; Diet therapy -- Periodicals; Nutrition -- Periodicals; Dietetics -- Periodicals; 613.205
• DOI: 10.1093/ajcn/nqy183
• Languages: English
• ISSNs: 0002-9165

Abstract

Abstract: Background: Asymmetric β-apo-carotenoids (nonvitamin A–active metabolites) of provitamin A carotenoids have been observed in humans, but no study has investigated their formation during digestion. Objective: The aim of this study was to follow the formation and absorption of asymmetric β-apo-carotenoids during digestion. Design: Healthy men were intragastrically and intraduodenally intubated, and randomly assigned to consume a lipid-rich control meal ( n = 3) or a lipid-rich test meal containing 20 mg [ 13 C-10]-β-carotene ( n = 7). Digesta samples were collected over 5 h, and blood collected over 7 h. The triglyceride-rich lipoprotein (TRL) fractions of plasma were also isolated. Lipophilic extracts of digesta, plasma, and TRL were analyzed via a high-performance liquid chromatography-tandem mass spectrometry method developed to identify [ 13 C]-labeled β-apo-carotenals/carotenone, [ 13 C]-β-apo-carotenols, and [ 13 C]-β-apo-carotenoic acids. Results: Relative to [ 13 C]-β-carotene, [ 13 C]-β-apo-carotenal levels remained ∼3 orders of magnitude lower throughout digestion (no [ 13 C]-β-apo-carotenols, or [ 13 C]-β-apo-carotenoic acids were observed). A mixed model determined relative influence of digesta type and time on digesta metabolite level. Increasing time significantly increased the model levels of digesta [ 13 C]-β-apo-10′, 12′, 14′, 15-carotenal and [ 13 C]-β-apo-13-carotenone ( P < 0.05) and trended toward decreased [ 13 C]-β-apo-8′-carotenal ( P = 0.0876). Gastric digesta were associated with a significantly higher level of [ 13 C]-β-apo-8′-carotenal ( P = 0.0289), and lower levels of [ 13 C]-β-apo-12′, 14′, 15-carotenal ( P < 0.05), relative to duodenal digesta. Anticipated retinoids, but no asymmetric [ 13 C]-β-apo-carotenals, [ 13 C]-β-apo-carotenols, or [ 13 C]-β-apo-carotenoic acids, were observed in the blood or TRL samples. Conclusions: β-Carotene appears to be robust to digestion, with minor amounts of β-apo-carotenals/carotenone formed. Absence of asymmetric [ 13 C]-β-apo-carotenals in plasma and TRL suggests lack of absorption, levels below the limit of detection, lack of stability, or further conversion during the digestive process to as-yet unidentified products. Lack of asymmetric [ 13 C]-β-apo-carotenals in plasma also suggests a lack of postprandial intestinal BCO2 activity in healthy humans. This trial was registered at clinicaltrials.gov as NCT03492593.