Plasma fat-soluble vitamin and carotenoid concentrations after plant sterol and plant stanol consumption: a meta-analysis of randomized controlled trials

PURPOSE: Plant sterols and stanols interfere with intestinal cholesterol absorption, and it has been questioned whether absorption and plasma concentrations of fat-soluble vitamins and carotenoids are also affected. We conducted a meta-analysis to assess the effects of plant sterol and stanol consumption on plasma fat-soluble vitamin and carotenoid concentrations. METHODS: Forty-one randomized controlled trials involving 3306 subjects were included. Weighted absolute and relative changes of non-standardized and total cholesterol (TC)-standardized values (expressed as summary estimates and 95 % CIs) were calculated for three fat-soluble vitamins (α- and γ-tocopherol, retinol and vitamin D) and six carotenoids (β-carotene, α-carotene, lycopene, lutein, zeaxanthin and β-cryptoxanthin) using a random effects model. Heterogeneity was assessed using predefined subject and treatment characteristics. RESULTS: Average plant sterol or stanol intake was 2.5 g/d. Relative non-standardized and TC-standardized concentrations of β-carotene decreased by, respectively, −16.3 % (95 % CI −18.3; −14.3) and −10.1 % (−12.3; −8.0), α-carotene by −14.4 % (−17.5; 11.3) and −7.8 % (−11.3; −4.3), and lycopene by −12.3 % (−14.6; −10.1) and −6.3 % (−8.6; −4.0). Lutein concentrations decreased by −7.4 % (−10.1; −4.8), while TC-standardized concentrations were not changed. For zeaxanthin, these values were −12.9 % (−18.9; −6.8) and −7.7 % (−13.8; −1.7) and for β-cryptoxanthin −10.6 % (−14.3; −6.9) and −4.8 % (−8.7; −0.9). Non-standardized α-tocopherol concentrations decreased by −7.1 % (−8.0; −6.2) and γ-tocopherol by −6.9 % (−9.8; −3.9), while TC-standardized tocopherol concentrations were not changed. Non-standardized retinol and vitamin D concentrations were not affected. Results were not affected by baseline concentrations, dose, duration and type of plant sterols/stanols, except for significant effects of duration (≤4 vs. >4 weeks) on TC-standardized lutein concentrations (1.0 vs. −5.6 %) and type of plant sterol/stanol on TC-standardized β-carotene concentrations (−8.9 vs. −14.2 %). CONCLUSIONS: Plant sterol and stanol intake lowers TC-standardized hydrocarbon carotenoid concentrations, differently affects TC-standardized oxygenated carotenoid concentrations, but does not affect TC-standardized tocopherol concentrations or absolute retinol and vitamin D concentrations. Observed concentrations remained within normal ranges. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00394-016-1289-7) contains supplementary material, which is available to authorized users.