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.