Can supplementation with vitamin E improve exercise recovery? Original paper

In this meta-analysis of randomized controlled trials, supplemental vitamin E did not improve recovery from exercise-induced muscle damage, soreness, and strength and had no effects on blood markers of inflammation and oxidative stress after an acute physical exercise session.

The effects of supplemental vitamin E, a fat-soluble antioxidant, on the recovery from exercise-induced muscle damage, muscle soreness, and muscle strength and on blood markers of inflammation and oxidative stress.

A total of 298 adults (average age of 22; 83% men, 17% women) without apparent health conditions.

The participants consisted of athletes (28%) as well as active (16%) and untrained (56%) adults.

A systematic review and meta-analysis of 5 crossover studies and 15 randomized controlled trials was conducted. Vitamin E was taken orally as doses ranging from 89 to 1,490 IU for a period of 1 to 84 days before the exercise session, thus exceeding the daily recommended dose (22 IU) but not the daily tolerable upper intake level (1,500 IU).^[1] Most studies (70%) performed an aerobic exercise protocol.

The outcomes were assessed immediately or up to 94 hours after the exercise session and included muscle soreness, muscle strength, and blood markers of DNA damage, protein oxidation, lipid peroxidation, inflammation, and muscle damage. To assess the inflammatory response, blood levels of cortisol and C-reactive protein (CRP) as well as interleukins 6, 8, and 10 were determined. To assess muscle damage, blood levels of creatine kinase and lactate dehydrogenase were measured. Muscle soreness and muscle strength were investigated through isometric peak torque and maximal voluntary contraction.

Supplemental vitamin E had no effects on the recovery from an acute physical exercise session.

The majority of the outcomes had a low heterogeneity, meaning that the included studies were mostly consistent in their outcomes. Only the outcomes for muscle soreness, oxidative protein degradation, and the inflammatory marker interleukin 6 showed considerable heterogeneity.

The majority of the included studies had a low risk of bias (61%), with only few studies showing some concerns (26%) or a high risk of bias (13%). The evidence quality ranged from very low to moderate.

Because vitamin E is a potent antioxidant, it was hypothesized that supplementation with exogenous vitamin E could protect against excessive free radical production during and after exercise, thus decreasing muscle damage and improving recovery from intense exercise. Although previous studies have shown that vitamin E supplementation attenuated lipid peroxidation and protein damage,^[2][3] this meta-analysis found no benefits in adults without health conditions who were recovering from an acute physical exercise session. As such, the current body of evidence does not suggest that supplemental vitamin E might be an effective strategy for adults seeking to improve their recovery from exercise.