Vitamins C and E adversely affect muscle mitochondria response to
exercise, and can cause post workout pain, and muscle fatigue.
Several studies have shown that vitamins C and E impair glucose
regulation (NEJM JW Psychiatry Jun 8 2009) and raise risk for
Alzheimer disease (NEJM JW Psychiatry Apr 23 2012). Here is another
study to relate to our patients who believe that these antioxidant
vitamins “can’t hurt.”
In a double-blind study partially funded by supplement manufacturers,
54 individuals (28 women; mean age, 24) were randomized to receive
placebo or vitamin C (1000 mg/day) plus vitamin E (DL-alpha-tocopherol
acetate, 235 mg/day) while they participated in an 11-week endurance
training program. The two groups did not differ in change in
performance over time (VO2max, submaximal running, and a shuttle run
test). However, only the placebo group showed improvement at 11 weeks
in mitochondrial markers (obtained via muscle biopsy). Only the
placebo group had significantly improved fat oxidation and reduced
heart rates at submaximal workloads.
Paulsen G et al. J Physiol 2014 Feb 3.