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Put the "A" to the "D": Very High Dietary Vitamin A (Retinol, not Beta Carotene!) Content Ameliorates Visceral Adiposity and Improves Insulin Sensitivity in Obesity Prone Rats

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What's the first letter in the alphabet? "D"? Well if you look at current research on vitamins, you would think so. Vitamin D is everywhere, vitamin A - if anything - its toxic antagonist. You, as a faithful student of the SuppVersity know better anyway: balance is where the magic lies; and thus you probably won't be surprised that not vitamin D, but vitamin A supplementation improves insulin sensitivity and ameliorates weight gain in a group of obesity prone rats on their favorite fattening stock-diet ( Jeyakumar. 2011 ). Image 1: Molecular structure of all-trans retinol In the Journal of Diabetes, Obesity and Metabolism , Jeyakumar et al. published the results of an early 3-months intervention with a vitamin A-enriched diet (129mg vitamin A/kg diet) on visceral obesity and insulin sensitivity in 50days old obesity prone (WNIN/ob strain) rats: Compared to stock diet-fed obese rats, vitamin A-enriched diet ...
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Exercise OR Calorie Restriction? Is This a Valid Question? Differential Epigenetics of Exercise and Calorie Restriction Suggest Otherwise.

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It is beyond me, why the war between proponents of exercise based and calorie reduction based approaches to weight loss are still raging. As a faithful "student" of the SuppVersity, you know that I have always been recommending a combination of both for improved body composition, well-being and general health and was pretty angry, when Gary Taubes claimed in the course of Dr. Oz's ridiculous dissertation on the dangers of low carb diets, that exercise would only stimulate hunger and would thus fail to produce a beneficial effect on weight loss and related health problems (cf. video 1, below). A group of researchers ( Karrie. 2011 ) from the Department of Nutritional Sciences at the University of Texas have now conducted a research study that may well shed some light onto what exactly (in this case this means on a epigenetic level) happens in the course of calorie restriction and/or exercise induced weight loss... Video 1: Gary Taubes on Dr. Oz' show talking...
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There Are Two Sides to Each Coin: Vitamin D Increases Insulin Sensitivity in Obese, Yet Decreases it in Lean Mice

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I am probably repeating myself, but I cannot emphasize enough that a common fallacy of medical research is the focus on pathologies. A recent example with respect to the "omnipotency" (that's what the Internet news could make you believe) of vitamin D comes from researchers at George Town University ( GU. Press Release ). The scientists were able to replicate the results of previous studies, where high dose vitamin D supplementation had "significantly reduced development of estrogen receptor-positive (ER+) breast cancer", but for estrogen receptor-negative (ER-) breast cancer they found either no effect (lean mice) or even an increased rate of cancerous growth in the group of obese mice. What's yet even more interesting that a similar contradiction was evident with respect to vitamin D's widely perpetuated beneficial effects on insulin resistance. In the pathologic model of the obese mice, vitamin D @ 15-25k IU per day was in fact able to ameliorat...
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Ironclad Liver Hampers Insulin Sensitivity: Association Between Hepatic Iron Load and Insulin Resistance Discovered

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"Insulin resistance", "insulin sensitivity", etc. Type in these key words and find 4.000.000 +1 results on Google. I want to focus on the +1 here and briefly report the results of a study ( Haap. 2011 ) coming from the University of Thübingen, Germany. Via magnetic resonance gradient echo imaging technique Michael Haap and his colleges assessed the iron load in the livers of of  113 healthy nondiabetic subjects [69 females, 44 males; age 47 ± 1 yr; body mass index (BMI) = 28.9 ± 0.5 kg/m2], who were "at increased risk for type 2 diabetes" . Various statistical analysis of their data revealed that: [Hepatic iron levels] adjusted for age negatively associated with serum ferritin levels (P < 0.0001) and positively associated with IS [insulin resistance] (P = 0.009). In addition, T2* values [indicator of hepatic iron load] associated with LF [liver fat] (P = 0.008) but not with BMI (P = 0.6). In a multivariate model, IS adjusted for gender, age, and BM...
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Acquittal: Anti-Oxidants do not Blunt the Beneficial Effect of Endurance Training on Insulin Sensitivity!

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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 ...
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Want to Stay Lean on a High-Fat Diet? Consume Whey Protein Everyday.

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Listeners of Carl Lenore's Super Human Radio already know: Dr. Paul Arciero of Skidmore College is going to publish a study the results of which confirm that obese individuals can lose weight and improve markers of metabolic health by just adding a 20g shake of whey protein 3x a day. While you still have to wait for the detailed results of this study to be published, another group of scientists ( Shertzer. 2011 ) derived similar results from a study on mice. Despite being on a high fat diet, mice who received 100mg of whey protein isolate (WPI) per liter of their drinking water (WPI group) ... had lower rates of body weight gain and percent body fat and greater lean body mass , although energy consumption was unchanged . These results were consistent with WPI mice having higher basal metabolic rates , respiratory quotients , and hepatic mitochondrial respiration . [...] Livers from WPI mice...
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L-Arginine Biscuits Exhibit Ameliorated Insulin Response. A Viable Alternative for People with Metabolic Syndrome!?

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"L-Arginine ameliorates insulin resistance and has beneficial effects on blood pressure", "Fat people love cookies and tend to develop insulin resistance!" - if these two thoughts get together in the head of an Italian scientists, a new product is born: the L-Arginine Biscuit! In a recent study Emanuela Setola ( Setola. 2011 ) investigated the effect of a biscuit with 6.6g arginine on selected metabolic parameters of 7 healthy subjects. The results are encouraging: A significant increase of nitric oxide (NOx) and cGMP levels were significantly increased with Biscuit +L-ARG 6.6 g and Powdered L-ARG as compared to Biscuit. AUC NOx and cGMP were significantly increased (p<0.04vs Biscuit). Percentage incremental increase of post-ischemic blood flow significantly increased with Biscuit +L-ARG 6.6 g and Powdered L-ARG, suggesting a functional effect of L-ARG added to the food preparation. Further, at 240 minute mean arterial blood pressure and peripheral v...
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Vitamin D & Insulin: A Question of Race?

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Could it be that vitamin D intake is more important for people with an African American (AA) background than for their European American (EA) neighbors? This is exactly, what a study that was recently published in Nutrition&Metabolism ( Alvarez. 2010 ) seems to suggest. In 115 African American (AA) and 137 European American (EA) healthy, premenopausal women the scientists  determined with 4-day food records and assessed the individual insulin sensitivity indexes (SI), as well as the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) values. The results are quite unequivocal: Vitamin D intake was positively associated with SI (standardized β = 0.18, P = 0.05) and inversely associated with HOMA-IR (standardized β = -0.26, P = 0.007) in AA, and the relationships were independent of age, total body fat, energy intake, and % kcal from fat. Vitamin D intake was not significantly associated with indices of insulin sensitivity/resistance in EA (standardized β = 0.03, P =...
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Cardio on Empty Improves Insulin Sensitivity

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Doing your cardio sessions on an empty stomach (mostly first thing in the morning) may be debatable, if you are already lean and eat a clean and healthy calorie-restriced diet. If you gorge yourself of fatty high-energy foods, on the other hand, you may be happy to hear that K. Van Proeyen et al. ( Proeyen. 2010 ) found " fasted training is more potent than fed training to facilitate adaptations in muscle and to improve whole-body glucose tolerance and insulin sensitivity during hyper-caloric fat-rich diet ". The scientists had a group of healthy male volunteers (18-25y) consume a hyper-caloric (~+30% kcal/day) fat-rich (50% of kcal) diet for 6 weeks. Part of the subjects performed endurance exercise training (4d/week) in the fasted state (F; n=10), whilst the others ingested carbohydrates before and during the training sessions (CHO; n=10). With regard to the effects of this interve...
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Want to Relieve Insulin Resistance? Eat your Blueberries!

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Scientists from the Center for the Study of Botanicals and Metabolic Syndrome at the Pennington Biomedical Research Center of the Louisiana State University have found that bioactives in blueberries improve Insulin Sensitivity in Obese, Insulin-Resistant Men and Women . The researchers measured inflammatory biomarkers and adiposity of 32 obese, nondiabetic, and insulin-resistant men and women and found that after 6 weeks of supplementation with either a smoothie containing 22.5 g blueberry bioactives (blueberry group, n = 15) or a smoothie of equal nutritional value without added blueberry bioactives (placebo group, n = 17) twice daily, The mean change in insulin sensitivity improved more in the blueberry group (1.7 ± 0.5 mg·kg FFM–1·min–1) than in the placebo group (0.4 ± 0.4 mg·kg FFM–1·min–1) (P = 0.04). Insulin sensitivity was enhanced in the blueberry group at the end of the study without significant changes in adiposity , energy intake, and inflammatory biomarkers. Being e...
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