Monday, July 27, 2015

Nutrition Research Update: Stem Cell Treatment For Type II Diabetes, Probiotics and Weight Loss Reviewed (Twice) and D-Xylose Sweet Poison for Superfluous Body Fat

With the right diet and lifestyle, stem cell treatments, probiotic supplements or xylose-laden "functional foods" wouldn't be necessary in the first place.
You're probably used to it, but I am in the mood for bragging: The SuppVersity is where you'll read about the latest nutrition, exercise and supplement related studies first. In research updates like the one today, I am trying to provide a little more information than in the SV Facebook News, though, where I usually stick only to the main results of studies that have just been published or at least accepted for publication.

In today's installment of what I often call the "Short News", I will discuss three papers that are going to be published in one of the next issues of the peer-reviewed scientific journal Nutrition News.

Studies dealing with a pre-clinical, but promising stem cell therapy for diabetics, the verdict on probiotic supplements (including my evaluation of the scientists' verdict ;-) for weight loss and an update on the effects of the xylitol precursor d-xylose and its effect on mammalian fat cells in vivo.
Read older short news and true or false article at www.suppversity.com:

Pasta "Al Dente" = Anti-Diabetic

Vinegar & Gums for Weight Loss

Teflon Pans Will Kill You!

Yohimbine Burns Stubborn Fat

You Can Wash Pesticides Away

Milk = Poisonous Hormone Cocktail
  • Stem Cells as Diabetes Treatment (Xing. 2015) - In software development you'd probably call the latest study from the Cangzhou City Central Hospital an "early alpha version" of an intriguing new way of treating type II diabetes.

    In their latest rodent study, Baoheng Xing et al. build on previous experiments in which pancreatic progenitors derived from human embryonic stem cells were shown to be able to effectively treat diabetes in mice (Kroon. 2008). In their study, however, Xing et al. went one step further and developed a system for treating diabetes using human embryonic stem cell–derived pancreatic endoderm in a mouse model of gestational diabetes mellitus.
    Figure 1: Glucose (a), insulin (b) and body weight (c) levels of wild type (wt) and treated (db/+PE) vs. untreated (db/+) pregnant mice before and during gestation, as well as Kaplan-Meier survival curves of litters show significant improvement right into the normal range in response to treatment (Xing. 2015)
    To this ends, the researchers had human embryonic stem cells differentiate in vitro into pancreatic endoderm, which were then transplanted into db/+ mice suffering from gestational diabetes mellitus.

    As the data in Figure 1 goes to show you, the transplant, of which the researchers expect that it could be used in humans, too, greatly improved the glucose metabolism and reproductive outcome of the treated female rats compared with the control groups. With their results Xing et al. do thus contribute to the growing evidence that diabetes may (sooner or later) be a "curable" disease when we are eventually mastering the use of differentiated human embryonic stem cells for treating general and gestational diabetes mellitus patients.
  • Probiotics and weight loss - reviewed (Park. 2015): What's the verdict? You will remember that I am still skeptical with respect to the real world benefits of the new en-vogue supplements that contain billions of life or dead bacteria and promise benefits from increased gut health to... you guessed it, the most marketable of all benefits: weight loss!

    A recent systematic review by scientists from the Hoseo University and the Keimyung University in Korea presents the first attempt to summarize and critically evaluate the evidence from clinical trials that have tested the effectiveness of probiotics or foods containing probiotics as a treatment for weight loss. Literature searches of electronic databases such as PubMed, Cochrane Library, and EMBASE were conducted. Methodological quality was assessed using body weight and body mass index (BMI). Initial searches yielded 368 articles. Of these, only 9 met the selection criteria. Because of insufficient data, only 4 of the studies were randomized controlled trials (RCTs) that compared the therapeutic efficacy of probiotics with placebo.

    As my skepticism would have made me believe, the meta-analysis of these data showed no significant effect of probiotics on body weight and BMI (body weight, n = 196; mean difference, −1.77; 95% confidence interval, −4.84 to 1.29; P = .26; BMI, n = 154; mean difference, 0.77; 95% confidence interval, −0.24 to 1.78; P = .14).
    Figure 3: It's not like there were no benefits. You just have to look at the right parameters to see them. Studies like Kadooka et al. show that the effects on BMI are small compared to those on metabolically more relevant markers like total fat mass, waist circumference and visceral fat (Kadooka. 2015).
    That does not mean that there are no benefits at all, though. I reviewed the few studies that measured not just body weight and BMI, but also the subjects' body fat levels. This is an important difference, because a focus on BMI ignores potentially health relevant changes in body composition. Changes as they were observed by Kadooka et al. (2013; see Figure 3), for example, who found a significant time x group differences for visceral fat, fat percentage, fat mass, and waist circumference with much less pronounced effects on BMI (too low to influence the result of a systematic review significantly) in their 12-week study. In this context, it is also worth mentioning that Sanchez et al. (2014) observed a significant beneficial effect in obese women (but not man) for whom the consumption of 1.6 × 10^8 colony-forming units of LPR/capsule with oligofructose and inulin made it significantly easier to maintain their body weight after a weight loss intervention. Another benefit that must not be ignored.
A lot of choline and potassium, but also a significant amount of fiber, this simple meal has everything US and other inhabitants of the Westernized fast food world don't get enough of - so why even bother w/ supplements if your diet can have it all? | more
Scrape the probiotics grab the prebiotics: Unlike for probiotics, the evidence for the weight management benefits of various prebiotics (fiber that feeds the bacteria in your gut) is more promising. One has to be careful wrt to making overgeneralized statements based on evidence that has been generated with specific types of fiber, even though probiotic fiber has more to offer than just a weight loss effect: Improvements in blood pressure, blood glucose management and blood lipids are only three additional items on the "benefits of increased fiber intake"-list. Moreover, fiber is one of the nutrients for which westerners are at the highest risk of not getting enough in their fast food diets (learn more) if you want so supplement, "supplement" high fiber foods.
  • Overall, I still feel obliged to repeat what I wrote in my recent article on the effects of sweeteners on the microbiome: We still have to learn very much about the effects of probiotics in general and individual types of gut bacteria, in particular, before we can actually give good strain-specific supplement recommendations. It's after all possible that the same strains that work in the obese subjects of studies like Kadooka (2015) won't work or even do the opposite in lean individuals.
  • D-Xylose Exerts Epigenetic Anti-Obesity Effects and Stops Fat Cell Growth (Lim. 2015) - Yes, this is not the first study to show that the provision of D-Xylitol or, as in the case of a 2011 study by Amo,et al., its cousin and "artificial sweetener" xylitol can reduce the weight gain due to obesogenic diets. What makes it interesting, though, is that it involved two different, relatively low dosages of D-xylitol as they could easily be added to our own food chain.
    Figure 4: While the effects on body weight and fat gain were significant, the differences (expressed relative to the rodents on regular chow) are still significant, so even if you replace 5-10% of the sugar in your junkfood diet with the low calorie sweetener (2.4kcal/g), you will get fat. If anything it may completely prevent the increase in liver fat - albeit only if the dosage is high enough and the effects are identical in humans (data from Lim. 2015)
    With only 5% and 10% of the sucrose content of the high fat chow of the rodents in Lim et al.'s latest study being replaced by D-Xylose, the scientists observed
    • significant reductions in weight and more importantly fat gain
    • significant reductions in hepatic steatosis (NAFLD),
    • a reduction of the genes that are responsible for the storage of fat to normal (5%) and sub-normal (10% D-Xylose) levels, and
    • significant reductions in total cholesterol and low-density lipoprotein cholesterol, low-/high-density lipoprotein, and the important total cholesterol/high-density lipoprotein ratio.
    In view of the fact that replacing just a relatively small amount of sucrose in our diet with D-Xylose (and probably xylitol) can ameliorate the weight and adipose tissue gain, normalize blood glucose levels and blood lipid profiles and lower the lipid accumulation in the liver by "regulating expression of lipogenesis- and β-oxidation–related genes" (Lim. 2015), it is probably actually warranted to speculate, just like Lim et al., about a "possible application of d-xylose as a dietary supplement for the prevention of obesity-related metabolic disorders" (Lim. 2015) - even though clinical human trials are still warranted.
My recent article on "Getting Your Macros Straight" may help you improve your diet | learn more 
Bottom line: In spite of the fact that new developments like those discussed above are both exciting and promising, an active lifestyle and a largely unprocessed whole-foods high(er) protein lowe(er -/ compared to the current) carbohydrate diet that derives the lion's share of its fats from low(er) omega-6 foods, olive and other high MUFA oils, alone, would be enough to maintain healthy blood sugar and lipid, as well as body fat levels for most of us.

I mean, if you don't get fat in the first place, you don't have to take probiotic supplements or use stem cell therapy to handle or undo the damage you've done... right? | Comment!
References:
  • Amo, Kikuko, et al. "Effects of xylitol on metabolic parameters and visceral fat accumulation." Journal of clinical biochemistry and nutrition 49.1 (2011): 1.
  • Kadooka, Yukio, et al. "Effect of Lactobacillus gasseri SBT2055 in fermented milk on abdominal adiposity in adults in a randomised controlled trial." British Journal of Nutrition 110.09 (2013): 1696-1703.
  • Kroon, Evert, et al. "Pancreatic endoderm derived from human embryonic stem cells generates glucose-responsive insulin-secreting cells in vivo." Nature biotechnology 26.4 (2008): 443-452.
  • Lim, Eunjin, et al. "d-Xylose suppresses adipogenesis and regulates lipid metabolism genes in high-fat diet–induced obese mice." Nutrition Research (2015).
  • Park, Sunmin, and Ji-Hyun Bae. "Probiotics for Weight Loss: A Systematic Review and Meta-Analysis." Nutrition Research (2015).
  • Sanchez, Marina, et al. "Effect of Lactobacillus rhamnosus CGMCC1. 3724 supplementation on weight loss and maintenance in obese men and women." Br J Nutr 111.8 (2014): 1507-19.
  • Xing, Baoheng, et al. "Human embryonic stem cell-derived pancreatic endoderm alleviates diabetic pathology and improves reproductive outcome in C57BL/KsJ-Lepdb/+ gestational diabetes mellitus mice." Nutrition Research (2015).