Vitamin E lowers SBP but not DBP, mean arterial pressure
Vitamin E supplementation does not appear to contribute to blood pressure (BP) improvement, with results of a recent systematic review and meta-analysis showing decreases only in systolic (S)BP but no favourable effect on diastolic (D)BP and mean arterial pressure (MAP).
The investigators searched PubMed/Medline, Scopus and Google scholar up to March 2018 to identify studies that evaluated the effect of vitamin E supplementation on SBP, DBP and MAP. Weighted mean differences (WMD) and 95 percent CI were expressed as effect size.
Potential sources of heterogeneity were assessed by conducting a prespecified subgroup analysis. Meta-regression analyses were conducted to examine the relationship between BP-lowering effects of vitamin E and duration of follow-up and treatment dose.
A total of 18 trials comprising 839 participants were included in the meta-analysis. Compared to placebo, vitamin E supplementation significantly decreased SBP (WMD, –3.4 mm Hg; 95 percent CI, –6.7 to –0.11; p<0.001), with a high heterogeneity across the studies (I2, 94.0 percent; p<0.001). In addition, vitamin E supplementation showed no significant effects on DBP and MAP.
A review by Sozen and colleagues stated that vitamin E is “an important nutrient influencing key cellular and molecular mechanisms, as well as gene expression regulation centrally involved in the prevention of cardiovascular disease (CVD)”, which is one of the major causes of morbidity and mortality globally. [IUBMB Life 2019;71:507-515]
“In recent years, the physiological metabolites of vitamin E, including the liver derived (long- and short-chain) metabolites and phosphorylated (α-, γ-tocopheryl phosphate) forms, have also provided novel mechanistic insight into CVD regulation that expands beyond the vitamin E precursor. It is certain that this emerging insight into the molecular and cellular action of vitamin E will help to design further studies, either in animal models or clinical trials, on the reduction of risk for CVDs,” they said.