Vanadium for Type II Diabetes!? Beneficial Effect of Trace Element on Blood Glucose Management in Rat Model.

Some of you may remember that vanadium has once been hailed as nutrient repartitioner (it has been shown to increase glucose uptake into muscle tissue via GLUT4-receptors) in the fitness & bodybuilding community. After reports on possible toxicity issues, which were - at least in parts - based on reports of people who dosed according to the common "more helps more" mentality of our society, vanadium supplements, stand-alone or larger doses as part of micronutrient blends, have disappeared from the market. Science, on the other hand has not given up on this promising, yet non-benign "medication".

A recent study (Kurt. 2011) published in the journal Biometals underlines that the effects of vanadium, which was named after the Scandinavian goddess of beauty and fertility, Vanadis, do in fact border on those of a pharmaceutical drug. After treating rats with streptozotocin and thus inducing a metabolic profile that is generally considered an appropriate model for human type II diabetes, the researchers from the Department of Chemistry, at the University of Istanbul, supplemented the chow of their animals (control & STZ-induced type II diabetic rats) with 100mg vanadyl sulfate per kg of body weight. For an 80kg male human this would amount to a massive dose of 1.200mg vanadium sulfate per day, the consumption of which is not advisable until definitive human data on short- and especially long-term consequences are available.

Figure 1: Blood glucose levels (mg/dl) of rats at different time-points
(data adapted from Kurt. 2011)

Regardless of the results of future studies on the effects & safety of vanadium on humans, the study results (as shown in figure 1) clearly indicate that vanadium is able to counter, maybe even reverse, the negative effects streptozotocin has on blood glucose and insulin management in rats.

Its also noteworthy that, according to the scientists, the administration of vanadium also reversed the pro-oxidative effects of streptozotocin-induced diabetes. I am yet not sure if this conclusion Kurt et al. base on a reduction of anti-oxidant activity in the tissue of the diabetic rats is valid. After all, the latter could also be a direct consequence of potential toxic effects of the trace mineral. Until further human data will be available, I would thus strongly advice against taking high dose vanadium supplements, even if you have type II diabetes.

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.