Anti-oxidant supplementation potentially blunts the insulin-sensitizing effects of weight-trianing

1. Properly Time Your Antioxidant Intake

When I first got interested in weight lifting and bodybuilding I read stories about professional bodybuilders and their tackle boxes full of supplements and vitamins. Most notably, Skip La Cour would keep one in the trunk of his car. When he left the gym he'd open his trunk and go through a post-workout ritual of pill popping, including vitamins E and C.

With a physique like Skip's, it would be hard to question his methods, but what if his post-workout E and C supplementation was actually hindering potential results and decreasing his insulin sensitivity?

Ludicrous right? Well, keep reading.

It's common knowledge that one of the benefits of training is that it increases insulin sensitivity. Recently a group of German exercise physiologists set out to examine how supplementing with vitamin C (1000mg) and vitamin E (400 IU) affected the post-workout boost in insulin sensitivity.

In this study, 40 young men exercised five days a week (50 minute sessions including cycling and circuit training) for four weeks. The addition of vitamin C and E supplementation in that group completely eliminated the beneficial insulin-sensitizing effects of exercise!

With further investigation it seems that the post-workout increase in reactive oxygen species (ROS) — which is blunted by C and E supplementation — is a necessary phenomenon for increasing insulin sensitivity. The argument for the temporal benefit of ROS post-workout is strengthened by the fact that long term antioxidant supplementation has been shown to increase insulin sensitivity.(1, 2)

Okay, so what do you do with this info? While it's what some would consider "fringe" nutritional science and the standard, "more studies need to be done in this area to further explore our findings" was added by the authors, I say run with it.

If you're looking for an extra potential edge, then I'd avoid antioxidant supplements and high antioxidant foods around and directly after your workouts. This will allow for the natural post-exercise rise in ROS and improvement in insulin sensitivity.