Acquittal: Anti-Oxidants do not Blunt the Beneficial Effect of Endurance Training on Insulin Sensitivity!

Regular visitors of the SuppVersity will remember that there has been and still is a controversy about whether or not athletes and average gymrats benefit from antioxidants or whether this may even blunt training induced adaptation effects. Other than a 2009 study by Ristow et al. (Ristow. 2009), a more recent investigation into the effects of antioxidant supplementation (Yfanti. 2011), coming from my northern neighbors from Denmark, did not find any negative effects of antioxidants on the exercise induced rise in insulin sensitivity.

In the study 21 young, healthy men, who received 500 mg vitamin C and 400 IU vitamin E (α-tocopherol) daily, completed a 5-days-a-week supervised intense endurance-training (interval training on Tuesday & Thursday; steady-state cardio on Wednesday & Friday). Insulin response, maximal oxygen consumption (VO_2max), maximal power output (P_max) and body composition (fat mass, fat-free mass) were measured and "muscle biopsies were obtained for determination of the concentration and activity of proteins regulating glucose metabolism". The scientists summarize their results as follows:

Although plasma levels of vitamin C (P < 0.05) and α-tocopherol (P < 0.05) increased markedly in the AO group, insulin-stimulated glucose uptake increased similarly in both the AO (17.2%, P < 0.05) and the PL (18.9%, P < 0.05) group in response to training. VO_2max and P_max also increased similarly in both groups (time effect: P < 0.0001 for both) as well as protein content of GLUT4, hexokinase 2 and total Akt (time effect: P ≤ 0.05 for all).

I don't know if you consider this "good" or "bad" news, but in any case, I suspect you will want to know what happened to the participants body composition (at least I would want). Well, the scientists say, there were no significant pre-post changes and from a statistic point of view, this is unquestionably right. I find it interesting, nevertheless that the average decline in fat mass was somewhat larger in the placebo (-21%)  vs. the anti-oxidant group (-8%); the intra-group differences are however so large that, with the given count of subjects, this is hardly meaningful.

Resveratrol Increases Lipolysis and Reduces Lipogenesis in Mature Adipocytes

If you are (as I hope) an avid reader and daily visitor of the SuppVersity, you probably remember Friday's news on the "Side Effects of Polyphenol Supplementation". I just hope you did not throw away all your supplements immediately, because eventually the question of side effects is always relative. If, for example, you are a sumo competitor and in dire need of gaining mass, no matter what. It would be an unwelcome side-effect of resveratrol supplementation not to gain or even to lose body fat...

A report (Baile. 2011), recently published in the Annals of the New York Academy of Sciences does now confirm, what supplement companies have been promising all along: the right dose of supplemental resveratrol will limit fat gain and improve lipolysis in a mouse model:

Treatment of mice with resveratrol alone was shown to improve resistance to weight gain caused by a high-fat diet. Moreover, dietary supplementation of aged ovariectomized rats with a combination of resveratrol and vitamin D, quercetin, and genistein not only decreased weight gain but also inhibited bone loss.

The human equivalent dose to that used in the cited study would be about 35mg/kg (= 2.800mg for a 80kg human being), which, unfortunately, is much more than your average resveratrol product contains. So, what does this tell you? Either you spend a fortune for minor improvements in your resistance to an unhealthy diet OR you just consume a healthy diet in the first place - I bet you will end up leaner and healthier using the second option.

Another Good Reason to Take Creatine: Creatine Helps with Exercise Induced Arterial Stiffness

If there is one supplement out there on the fitness market that is really worth each cent you spend on it, it is probably creatine monohydrate.

In a recent study, scientists from the Florida State University (Sanchez-Gonzalez. 2011) report on the positive effects, of creatine supplementation (creatine monohydrate @ 2x5g /day for 3 weeks) on arterial stiffness and hemodynamics in 16 healthy male subjects:

Compared with the Pl group, the Cr group had attenuated (P\0.05) increases in SBP [systolic blood pressure] at PE5 [5 minutes post exercise] (Pl 14.0 ± 2.5, Cr 5.6 ± 2.3 mmHg), HR [heart rate] at both P5 (Pl 28 ± 4 vs. Cr 16 ± 2 beats/min) and PE15 (Pl 21 ± 3, Cr 11 ± 2 beats/min) and rate pressure product at P5 (Pl 45.8 ± 6.4, Cr 24.8 ± 2.2) and P15 (Pl 34.2 ± 5.0, Cr 15.9 ± 6.0). Compared with the Pl group, the Cr group had suppressed
increases in baPWV [brachial-ankle pulse wave velocity] at PE5 (Pl 1.5 ± 0.4, Cr-0.1 ± 0.4 m/s) and PE15 (Pl 1.1 ± 0.2, Cr -0.3 ± 0.3 m/s) and returned SBP to pre-exercise values at PE15 (Pl 10.6 ± 2.8, Cr 2.1 ± 2.6 mmHg). PWV in the exercised leg decreased at PE5 in both groups.

Overall, this indicates that creatine supplementation reduces cardiac stress from strength training. It would have been interesting, though, to see a more realistic setting for the study - with the single-leg extension exercise in an isokinetic dynamometer used in this you probably don't induce much cardiac stress, anyway. Sometimes, I am asking myself if any of those researchers have ever been to the gym to take a look at the intensity levels at which many ambitious gymrats work out...