alpha-Tocopherol bioavailability is lower in adults with metabolic syndrome regardless of dairy fat co-ingestion: a randomized, double-blind, crossover trial

作者：Mah Eunice; Sapper Teryn N; Chitchumroonchokchai Churee****; Failla Mark L; Schill Kevin E; Clinton Steven K; Bobe Gerd; Traber Maret G; Bruno Richard S^*

来源：American Journal of Clinical Nutrition, 2015, 102(5): 1070-1080.

DOI：10.3945/ajcn.115.118570

• alpha-tocopherol
• bioavailability
• metabolic syndrome
• nonalcoholic steatohepatitis
• pharmacokinetics

Background: Increasing dietary fat intake is expected to improve alpha-tocopherol bioavailability, which could be beneficial for improving alpha-tocopherol status, especially in cohorts at high cardiometabolic risk who fail to meet dietary alpha-tocopherol requirements.
Objective: Our objective was to assess dose-dependent effects of dairy fat and metabolic syndrome (MetS) health status on alpha-tocopherol pharmacokinetics in plasma and lipoproteins.
Design: A randomized, crossover, double-blind study was conducted in healthy and MetS adults (n = 10/group) who ingested encapsulated hexadeuterium-labeled (d(6))-RRR-alpha-tocopherol (15 mg) with 240 mL nonfat (0.2 g fat), reduced-fat (4.8 g fat), or whole (7.9 g fat) milk before blood collection at regular intervals for 72 h.
Results: Compared with healthy participants, those with MetS had lower (P < 0.05) baseline plasma alpha-tocopherol (mu mol/mmol lipid) and greater oxidized low-density lipoprotein (LDL), interleukin (IL)-6, IL-IL-10, and C-reactive protein. Regardless of health status, d(6)-alpha-tocopherol bioavailability was unaffected by increasing amounts of dairy fat provided by milk beverages, but MetS participants had lower estimated d(6)-alpha-tocopherol absorption (+/- SEM) than did healthy participants (26.1% +/- 1.0% compared with 29.5% +/- 1.1%). They also had lower plasma d(6)-alpha-tocopherol AUC from 0 to 72 h, as well as maximal concentrations (C-max: 2.04 +/- 0.14 compared with 2.73 +/- 0.18 mu mol/L) and slower rates of plasma disappearance but similar times to C-max. MetS participants had lower d(6)-alpha-tocopherol AUC from t = 0-12 h (AUC(0-t) (final)) 1 in lipoprotein fractions [chylomicron, very-low-density lipoprotein (VLDL), LDL, high-density lipoprotein]. Percentages of d(6)-alpha-tocopherol AUC(0-t) (final) in both the chylomicron (r = -0.46 to -0.52) and VLDL (r = -0.49 to -0.68) fractions were inversely correlated with oxidized LDL, IL-10, IL-6, and C-reactive protein.
Conclusions: At dietary intakes equivalent to the Recommended Dietary Allowance, alpha-tocopherol bioavailability is unaffected by dairy fat quantity but is lower in MetS adults, potentially because of greater inflammation and oxidative stress that limits small intestinal alpha-tocopherol absorption and/or impairs hepatic alpha-tocopherol trafficking. These findings support higher dietary alpha-tocopherol requirements for MetS adults.

• 出版日期2015-11