Effects of dietary fats on the bioaccessibility and bioavailability of carotenoids: a systematic review and meta-analysis of in vitro studies and randomized controlled trials.

Abstract

Dietary fats are one of the well-known stimulators of carotenoid absorption, but the effects of the quantity and the type of dietary fats on carotenoid absorption have not yet been studied systematically. This review aimed to analyze data from both in vitro studies and randomized controlled trials (RCTs) to examine the effects of dietary fats on the bioaccessibility and bioavailability of carotenoids. A systematic search of 5 databases (Scopus, PubMed, Embase, CINAHL and the Cochrane Library) was conducted. In vitro studies and RCTs were selected according to the PICOS criteria and were reviewed independently by 2 investigators. Key study characteristics from the eligible in vitro studies and RCTs were extracted independently by 2 investigators using a standardized table. A total of 27 in vitro studies and 12 RCTs were included. The meta-regression of in vitro studies showed that the bioaccessibility of carotenoids, except for lycopene, was positively associated with the concentration of dietary fats. The meta-analysis of RCTs showed that the bioavailability of carotenoids was enhanced when a higher quantity of dietary fats was co-consumed. Moreover, fats rich in unsaturated fatty acids resulted in greater improvement in carotenoid bioavailability (SMD 0.90; 95%CI, 0.69-1.11) as compared with fats rich in saturated fatty acids (SMD 0.27; 95%CI, 0.08-0.47). Co-consuming dietary fats, particularly those rich in unsaturated fatty acids, with carotenoid-rich foods can improve the absorption of carotenoids. PROSPERO registration number CRD42020188539.