13C β‐Carotene stability during digestion in healthy humans

Non‐provitamin A metabolites of β‐carotene may be produced after the consumption of β‐carotene, but to date, no study has investigated their formation during digestion. Nine healthy men were recruited in total, with seven men consuming a liquid test meal containing 20 mg of 13 C β‐Carotene, and two men consuming a control meal. Gastric and duodenal samples were taken postprandially over 5 hours using a nasoduodenal tube, while plasma samples, from which the triglyceride‐rich lipoprotein (TRL) fraction containing chylomicrons was isolated, were taken over 7 hours. An LC‐MS/MS method was developed to identify and quantitate 13 C β‐apo‐carotenals, 13 C β‐apo‐carotenols, and 13 C β‐apo‐carotenoic acids in gastric and duodenal digesta, plasma, and TRL samples using mixtures of standards. Gastric and duodenal digesta 13 C β‐apo‐carotenal concentrations (including 13 C retinal) increased over 5 hours relative to 13 C β‐carotene, with the exception of 13 C β‐apo‐8′‐carotenal which peaked at 2 hours. 13 C β‐apo‐carotenols and 13 C β‐apo‐carotenoic acids were not observed in the digesta samples. 13 C retinyl esters and 13 C β‐carotene were observed in the whole plasma and in the TRL fraction, and 13 C retinol was observed in whole plasma. However, no non‐vitamin A 13 C β‐apo‐carotenals, 13 C β‐apo‐carotenols, or 13 C β‐apo‐carotenoic acids were observed in the plasma or TRL samples. Taken together, our data suggests that the conditions of digestion favor β‐apo‐carotenal formation. However, it is not clear if these β‐apo‐carotenals are absorbed at levels too low for our limit of detection, or whether they are not absorbed at all. The biological effect(s) of these compounds in the digestive tract remains to be elucidated. Support or Funding Information This work was supported by a grant from the PACA (Provence‐Alpes‐Côte d'Azur) region. Rachel Kopec received support from the European Union, in the framework of the Marie‐Curie FP7 COFUND People Programme, through the award of an AgreenSkills fellowship (under grant agreement n° 267196), as well as the Foundation Olga Triballat.