Vitamin E tocotrienol supplementation improves lipid profiles in chronic hemodialysis patients

Abstract

Purpose: Chronic hemodialysis patients experience accelerated atherosclerosis contributed to by dyslipidemia, inflammation, and an impaired antioxidant system. Vitamin E tocotrienols possess anti-inflammatory and antioxidant properties. However, the impact of dietary intervention with Vitamin E tocotrienols is unknown in this population.

Patients and methods: A randomized, double-blind, placebo-controlled, parallel trial was conducted in 81 patients undergoing chronic hemodialysis. Subjects were provided daily with capsules containing either vitamin E tocotrienol-rich fraction (TRF) (180 mg tocotrienols, 40 mg tocopherols) or placebo (0.48 mg tocotrienols, 0.88 mg tocopherols). Endpoints included measurements of inflammatory markers (C-reactive protein and interleukin 6), oxidative status (total antioxidant power and malondialdehyde), lipid profiles (plasma total cholesterol, triacylglycerols, and high-density lipoprotein cholesterol), as well as cholesteryl-ester transfer protein activity and apolipoprotein A1.

Results: TRF supplementation did not impact any nutritional, inflammatory, or oxidative status biomarkers over time when compared with the baseline within the group (one-way repeated measures analysis of variance) or when compared with the placebo group at a particular time point (independent t-test). However, the TRF supplemented group showed improvement in lipid profiles after 12 and 16 weeks of intervention when compared with placebo at the respective time points. Normalized plasma triacylglycerols (cf baseline) in the TRF group were reduced by 33 mg/dL (P=0.032) and 36 mg/dL (P=0.072) after 12 and 16 weeks of intervention but no significant improvement was seen in the placebo group. Similarly, normalized plasma high-density lipoprotein cholesterol was higher (P<0.05) in the TRF group as compared with placebo at both week 12 and week 16. The changes in the TRF group at week 12 and week 16 were associated with higher plasma apolipoprotein A1 concentration (P<0.02) and lower cholesteryl-ester transfer protein activity (P<0.001).

Conclusion: TRF supplementation improved lipid profiles in this study of maintenance hemodialysis patients. A multi-centered trial is warranted to confirm these observations.

Keywords: end-stage renal disease; hemodialysis; lipid profiles; nutrition intervention; tocotrienol-rich fraction; vitamin.

Figure 1

Mean changes in plasma TAG normalized to baseline. Notes: Values are presented as mean ± standard error of the mean. TAG data were normalized using baseline values. *Significant difference (P<0.05) compared with placebo at each time point based on independent t-test. At week 16, there was a marginal difference between TRF and placebo groups (P=0.072). Abbreviations: TAG, triacylglycerols; TRF, tocotrienol-rich fraction.

Figure 2

Mean changes in plasma HDLC normalized to baseline. Notes: Values are presented as mean ± standard error of the mean. HDLC data were normalized using baseline values. *Significant difference (P<0.05) compared with placebo at each time point based on independent t-test. Abbreviations: HDLC, high-density lipoprotein cholesterol; TRF, tocotrienol-rich fraction.

Figure 3

Comparison of ApoA1 (A) and CETP activity (B) during week 12 and week 16. Notes: Data are presented as mean ± standard error of the mean. *Significant difference (P<0.05) compared with placebo at each time point, tested by independent t-test. Figure (A) shows plasma ApoA1 concentration during week 12 and week 16 in both groups as measured by ELISA method. Figure (B) shows CETP activity during week 12 and week 16 in both groups as measured in the plasma using fluorometric assay kit. Abbreviations: ApoA1, apolipoprotein A1; CETP, cholesteryl ester transfer protein; ELISA, enzyme-linked immunoabsorbent assay; TRF, tocotrienol-rich fraction.

Figure 4

Pearson’s correlation coefficient in lipid parameters during week 12 and week 16. Notes: (A and B) Correlation between ApoA1 (mg/mL plasma) and HDLC (mg/dL plasma) at week 12 and week 16, respectively. (C and D) Correlation between CETP activity (pmol/μL plasma/hour) and TAG (mg/dL plasma) at week 12 and week 16, respectively. Abbreviations: ApoA1, apolipoprotein A1; CETP, cholesteryl ester transfer protein; HDLC, high-density lipoprotein cholesterol; TAG, triacylglycerols; TRF, tocotrienol-rich fraction.