Saturday, February 21, 2015

Polydextrose and Resistant Maltodextrin as Dieting Aids W/ GLP-1 Boosting & Appetite Reducing Effects: 7% Reduced Energy Intake per 10g/day of Polydextrose in Clinical Trials

Many of them look like powder sugar, but they are much more. Novel food ingredients like polydextrose or resistant maltodextrin may help us to slow the progression of obesity, but they won't solve the global obesity problems.
Whenever we are talking about resistant starches, we are not actually interested in the starches themselves, but rather in what happens after they are digested by the bacteria in our guts. The result of this process are short-chain fatty acids. These specific fatty acids interact with receptors in the digestive tract which in turn trigger the release of GLP-1, of which you as a SuppVersity reader have long known that it is of paramount importance for glucose and weight control (learn more).

Next to naturally occuring resistant starches in foods like cooled potatoes or green bananas and relative expensive high molecular weight designer starches, polydextrose and resistant maltodextrose constitute two promising food ingredients of which researchers believe that they may help us to keep the obesity epidemic at bay.
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Resistant maltodextrin (RMD) is a water-soluble, non-viscous and non-digestible saccharide. Like polydextrose, resistant maltodextrin has previously been reported to improve the glycaemic response (12,13) and postprandial TAG elevation (14), and also promotes mineral absorption (15). The mechanisms involved in the improvement of glucose tolerance, however, are poorly understood.

Accordingly, the goal of Tohru Hira et al.'s latest study was to examine whether these effects that have been observed in both human and rodent studies, previously, could be mediated by changes in plasma GLP-1 levels and GLP-1 production in the small and large intestines.
Figure 1: Glucose levels after glucose load (A), changes in glucose (B) and total GLP-1 and active GLP-1 levels (C, D) with different amounts of resistant maltodextrin or fructo-oligosaccharides in the diet of the rodents (Hira. 2015).
If you've read the introductory paragraph of this article, you will not be surprised to see that the data from the Hokkaido University in Japan shows that the ingestion of resistant maltodextrin lead to dose-dependent (more = better) increases in GLP-1 in the blood (Figure 1, C-D) and the intestine (not shown), as well as corresponding improvements in glucose control (Figure 1, A-B).
Do not make the fatal mistake to believe that increasing your resistant starch intake alone will help you lose weight. Unless the increases in GLP-1 make you eat less food, you will -just like the rodents in the study at hand- not lose a single pound of body fat. In addition, polydextrose and probably also resistant maltodextrin - like many of the sugar replacements - has the nasty side effect of giving you the run if you consume high doses in isolation (Flood. 2004). So, if you want to use them, use them wisely.
In that, it is particularly important that the benefits the healthy rodents derived from the ingestion of resistant maltodextrin was significantly more pronounced than the benefits of fructo-oligosaccharides which have likewise been hailed as potential obesity preventers (Arora. 2013).

Speaking of obesity preventers,...

you are probably already wondering about the other "obesity preventer" I mentioned in the headline: Polydextrose, a a glucose polymer that is completely soluble in water and is used asa food additive to give foods the texture of sucrose at 75% lower calories in over 60 countries.

The effects and potential benefits this agent which is usually labeled as "fiber" on the label of commercially produced foods have recently been reviewed by scientists from the St Luke’s Roosevelt Hospital Center in New York (Ibarra. 2015). As of now, we know from several individual studies that polydextrose has the ability to reduce energy intake, but until now, no one had systematically reviewed the disparate evidence on this topic.
Figure 2: Calculated slopes of the effects of adding polydextrose to the diets of men and women on their food intake at lunch (left) and over 24h (right) - individual study results are represented as dots (Ibarra. 2015).
With the study by Ibarra et al. (2015) this review is now available and it shows significant effects on food intake at lunch (Figure 2, left) and total 24h food intake (Figure 2, right). Only the food intake at dinner was not significantly influenced in the few hitherto existing amply controlled clinical human trials (not shown in Figure 2).

A closer look at the data in Figure 2 does also show that there was - just like it was the case for the GLP-1 response to resistant maltodextrin ingestion in the Hira study - a dose-dependent increase in satiety with the ingestion of only 25g of polydextrose per day being able to reduce the total 24h food intake by more than 12%! Based on linear regression analysis the Ibarra et al. calculated the average decrease in food intake over 24h to be 3.8% and 2.3% per 10 gram of polydextrose consumed in men and women respectively. Significantly more pronounced effects were observed in studies investigating the effects of polydextrose ingestion at breakfast on food intake during an ad-libitum lunch which was reduced 7% and 5.7% per 10g in men and women.
According to the first meta-analysis of the existing human clinical trials consuming 10g of polydextrose per day leads will significantly decrease the food intake. The data does yet also show: Women benefit to a lesser degree than men.
Bottom line: There is little doubt that the consumption of increased amounts of resistant starches and more specifically GLP-1 boosting and appetite reducing resistant maltodextrin and polydextrose may help you to lose / control the amount of body fat you are carrying.

It is unrealistic, however, to assume that adding 20g of either of the agents to your diet would be sufficient to trigger significant fat loss in the absence of other lifestyle changes. It is furthermore interesting to observe that - once more - women appear to benefit less from the appetite reducing effects of these agent and that despite the fact that the relative contribution of 20g of these agents to the total food intake of a woman is lower than it would be for a man who obviously consumes more food | Comment on Facebook!
References:
  • Arora, Tulika, Satvinder Singh, and Raj Kumar Sharma. "Probiotics: Interaction with gut microbiome and antiobesity potential." Nutrition 29.4 (2013): 591-596.
  • Flood, M. T., M. H. Auerbach, and S. A. S. Craig. "A review of the clinical toleration studies of polydextrose in food." Food and chemical toxicology 42.9 (2004): 1531-1542.
  • Hira, Tohru, et al. "Resistant maltodextrin promotes fasting glucagon-like peptide-1 secretion and production together with glucose tolerance in rats." British Journal of Nutrition (2015): 1-9.
  • Ibarra, Alvin, et al. "Effects of polydextrose on different levels of energy intake. A systematic review and meta-analysis." Appetite 87 (2015): 30-37.