Saturday, April 26, 2014

True or False: Xanthan Will Reduce The Glycemic Index of Your Meals, Increase Satiety and Have an Overall Beneficial Effects on Your Metabolic Health (Glucose, Lipids, Waist, ...)

Can xanthan reduce the glycemic response to "sweet treats" like this?
Have you ever heard of xanthan? Yep that's E-number E415. What? If it has an E-Number it can't be good? Well, what about vitamin C, then? That's E-Number E300. Does this make it "bad" for you? If so, I'd suggest you skip today's SuppVersity article and avoid xanthan out of principle. Otherwise, I would like to offer you to join me for another "True or False" Session (find more of these | RSS-compatible browser or plugin for Chrome like SlickRSS needed) at the end of which we will know whether the statement "Xanthan Will Reduce Your Meals Glycemic Index, Increase Satiety and Have Overall Beneficial Effect on Your Metabolic Health" is true, or false.
You can find more True or False articles at the SuppVersity

Pasta "Al Dente" = Anti-Diabetic

Vinegar & Gums for Weight Loss

Teflon Pans Will Kill You!

Yohimbine Burns Stubborn Fat

You Can Wash Pesticides Away

High Volume Diet = Success
When it's added to juice (alongside with beta-glucans), xanthan will reduce the glucose response and thus help stabilize blood sugar levels (Paquin. 2012).

Figure 1: Mean (S.E.) changes of hunger, fullness, desire to eat, and prospective consumption after ingestion of 325 ml of a thin and thick shake. Ratings were provided on nine-point category scales. “*” indicates a significant difference in ratings for the two shakes (Mattes. 2001).
The stabilized blood sugar levels, in turn, will will eventually have beneficial effects on 24h satiety.

This goes, even though Julie Paquin and her colleagues did not detect an acute increase in their 2012 study on the effects of xanthan and β-glucan enriched juices on the glycemic response and satiety of healthy men. Previous studies suggest that the viscosity of a liquid meal, which is increased by the addition of xantham, may be an important determinant of the hunger response.

Mattes and Rothacker (2001), for example reported significantly greater and more prolonged reductions in hunger with thicker, but otherwise identical replacement shakes.

Marciani et al. (2001) even found that the viscosity of their high- vs. low-viscosity shakes with different macronutrient and energy content had a greater impact on the satiety than the fat, carbohydrate or energy content of the test meals.
Food Volume Matters!
SuppVersity Suggested Read: "True or False: High Volume + Nutrient + Low Energy Foods Keep You Lean. Bonus-Question: Will a High Volume Make Your Stomach Go Baggy & Mess Up Your Satiety Response?" | read more - Just in case you've already forgotten that I've covered the beneficial effects of a "high volume, high nutrient, low energy" diet and the corresponding increase in gastric volume in one of the last installments of the True or False Series | go trough previous installments.
The scientists from the University Hospital, Nottingham were also able to show a direct correspondence between the gastric volume of the viscous meal ad the satiety response. These observations support the dual hypothesis, i.e. that more viscous fibres exert their effect owing to distention in the gastric antrum and/or altered transport of nutrients to the small intestine, Caroline Hoad et al. put forward in their 2004 paper in the Journal of Nutrition (Hoad. 2004).

Table 1: Viscosity AUC values for solutions containing select dietary fibers during gastric digestion simulation
In view of the fact that a comparison of the total viscosity per gram of 12 different fiber types Dikeman et al. published in the Journal of Nutrition in April 2006 indicates that xanthan has by far the highest viscosity of all 12 tested types of dietary fiber (Dikeman. 2006), it appears to be certain that the polysaccharide, which is secreted by the bacterium Xanthomonas campestris, will exert significant beneficial effects on both the volume of a given liquid meal and the time it takes to pass through the digestive tract - and this will, as we have just learned, improve fullness and satiety, and decrease the energy intake of every dieter.
Why does glycemia even matter? Aside from the fact that extreme glucose excursions after a meal are partly responsible for the development of diabetes, avoiding them will (1) stabilize your energy levels and curb your cravings, (2) decrease inflammation and oxidative stress, (3) help you maintain healthy blood lipid and body fat levels, (4) reduce your cancer and heart disease risk, and so on. You see, if xanthan can help you stability your blood sugar levels, this alone would have a long string of beneficial health consequences.
At this point, I could probably cite the dirty dozen of studies that support the appetite suppressing effects of PGX®, a combination of xanthan, sodium alginate and glucomannan (e.g. Jenkins. 2010; Tao. 2010; Kacinik. 2011; Reichert. 2013).
Figure 2: Postprandial glycemia in healthy subjects after the consumption of various breakfast meals (Jenkins. 2008) similar beneficial effects in response to the addition of a 70% glucomannan and 30% xanthan blend to the buiscuits were observed in diabetic subjects, as well.
In view of the fact that we are interested in the individual effects of xanthan, and not in the promotion of an expensive, albeit scientifically proven fiber supplement where xanthan is only one (but probably one of the most important) ingredients, I will leave the PGX-related evidence behind and turn to "xanthan only" studies to substantiate my assertion that xanthan gum is a beneficial, albeit not necessary, addition to the dietary regimen of both, lean and overweight physical culturists.
Warning! Xanthan is safe for adults (Eastwood. 1987), but probably not safe for infants. This is at least what a report from the US Food and Drug Administration in the Journal of Pediatrics would suggest (Beal. 2012). According to the USDA, the potential for thickened feeds to increase risk of necrotizing enterocolitis (NEC), a leading cause of morbidity and mortality in neonates, has not been thoroughly assessed. Nevertheless, the occurrence of 202 cases of NEC in formula-fed (obviously) infants over 12 years should yet be reason enough to keep your xanthan stash far away from your newborn, irrespective of the fact that the case series Beal et al. present cannot prove an association between the xanthan-containing thickening agent SimplyThick and NEC.
Odutola Osilesi and colleagues from various US Universities and the USDA were among the first to propose and demonstrate the potential usefulness of xanthan gum in dietary management of diabetes mellitus (Osilesi. 1985). In the corresponding experimental trial, they supplied 9 drug-free diabetics with moderately elevated serum glucose and four nondiabetic controls controls with - you guessed it - muffins that contained 12g of xanthan gum.
Figure 3: Muffins w/ 12g xanthan/day have significant beneficial effects on glucose management in diabetics and beneficial, but non-significant effects on fasting and post-prandial blood sugar in healthy subjects (Osilesi. 1985)
The subjects were randomly assigned to to a "xanthan first" or "control first" group for 2x six weeks. Before the study and at the end of the xanthan and xanthan-free periods, the scientists analyzed the blood before and 2 h after an oral glucose load.

Figure 4: Effect of the guar (G), xanthan (X), locust bean gum (LBG), and 1: 1 mixtures of X and LBG (X/LBG) and X and Meyprodyn (X/Mey) on the movement of radiolabeled glucose in the mixture (concentrations in % | Edwards. 1987)
You can see the results of this undertaking in Figure 4. Basically, what the researchers found were...
  • significant reductions in fasting and postload serum glucose and reduced fasting levels of total plasma cholesterol in diabetic subjects, as well as
  • lower fasting and postload levels of gastrin and gastric inhibitory polypeptide (GIP) and fasting levels of total and VLDL triglyceride and cholesterol in VLDL and LDL fractions
Moreover, all subjects reported a sense of fullness after consuming xanthan muffins but no severe digestive symptoms. The latter will usually become more prevalent, when xanthan is mixed with other fibres like galactomannan in a (successful) effort to promote its anti-cholesterol effect (Yamamoto. 2000).

In view of the fact that mixing with (obviously) lower viscosity fibers will not necessarily increase the hypoglycemic (glucose improving) effects, of which Edwards et al. (1987) demonstrated that they depend almost exclusively on the viscosity of the chyme, it appears unwarranted to spend the extra bucks on galactomannan or other fibers... Unless you are battling high cholesterol levels and would like to see a similar beneficial effects on your blood lipids as the rodents in the Yamamoto study, of course.
Yes, xanthan will increase satiety and have beneficial effects on glucose metabolism. Whether it is a "necessary" addition to everyone's diet, on the other hand, is questionable. It's a supplement and supplements are, as their name implies "supplemental".

A single teaspoon will already make a protein shake really thick! And remem- ber: more xanthan = high viscosity = slow gastric passage, high satiety, but slow nutrient release
There are, moreover, also situations, where you may not even want to reduce the transit of a liquid meal through your digestive tract. After a workout, for example, xanthan should be used only people who go hypogylcemic in response to the whey (+sugar) induced insulin spike in response to their post-workout shake.

As part of a high protein snack, on the other hand it does really make sense to combine xanthan, whey and maybe some resistant starch (RS4) into a energy-laden power-"shake"... just be careful: If you use more than a teaspoon your "shake" will easily turn into a pudding and you can spoon-feed yourself a fluffy protein pudding ;-)
Reference:
  • Beal, Jennifer, et al. "Late onset necrotizing enterocolitis in infants following use of a xanthan gum-containing thickening agent." The Journal of pediatrics 161.2 (2012): 354-356.
  • Dikeman, Cheryl L., Michael R. Murphy, and George C. Fahey. "Dietary fibers affect viscosity of solutions and simulated human gastric and small intestinal digesta." The Journal of nutrition 136.4 (2006): 913-919. 
  • Edwards, C. A., et al. "Viscosity of food gums determined in vitro related to their hypoglycemic actions." The American journal of clinical nutrition 46.1 (1987): 72-77.
  • Eastwood, M. A., W. G. Brydon, and D. M. W. Anderson. "The dietary effects of xanthan gum in man." Food Additives & Contaminants 4.1 (1987): 17-26.
  • Hoad, Caroline L., et al. "In vivo imaging of intragastric gelation and its effect on satiety in humans." The Journal of nutrition 134.9 (2004): 2293-2300.
  • Jenkins, Alexandra L., et al. "Comparable postprandial glucose reductions with viscous fiber blend enriched biscuits in healthy subjects and patients with diabetes mellitus: acute randomized controlled clinical trial." Croatian medical journal 49.6 (2008): 772.
  • Jenkins, Alexandra L., et al. "Effect of adding the novel fiber, PGX®, to commonly consumed foods on glycemic response, glycemic index and GRIP: a simple and effective strategy for reducing post prandial blood glucose levels-a randomized, controlled trial." Nutrition journal 9.1 (2010): 58.
  • Kacinik, V., et al. "Effect of PGX, a novel functional fibre supplement, on subjective ratings of appetite in overweight and obese women consuming a 3-day structured, low-calorie diet." Nutrition & diabetes 1.12 (2011): e22.
  • Marciani, Luca, et al. "Effect of meal viscosity and nutrients on satiety, intragastric dilution, and emptying assessed by MRI." American Journal of Physiology-Gastrointestinal and Liver Physiology 280.6 (2001): G1227-G1233.
  • Mattes, Richard D., and Dana Rothacker. "Beverage viscosity is inversely related to postprandial hunger in humans." Physiology & Behavior 74.4 (2001): 551-557.
  • Osilesi, Odutola, et al. "Use of xanthan gum in dietary management of diabetes mellitus." The American journal of clinical nutrition 42.4 (1985): 597-603.
  • Paquin, Julie, et al. "Effects of juices enriched with xanthan and β-glucan on the glycemic response and satiety of healthy men." Applied Physiology, Nutrition, and Metabolism 38.4 (2012): 410-414.
  • Reichert, Ronald G., et al. "Meal replacements and fibre supplement as a strategy for weight loss. Proprietary PGX® meal replacement and PGX® fibre supplement in addition to a calorie-restricted diet to achieve weight loss in a clinical setting." Biotechnology and Genetic Engineering Reviews 29.2 (2013): 221-229. 
  • Tao, Wendy. "A clinical observational study on PGX® conducted at the Canadian Centre for Functional Medicine." Alternative Medicine Review (2010) 15.1: 68-75.
  • Yamamoto, Yukiko, et al. "Improved hypolipidemic effects of xanthan gum-galactomannan mixtures in rats." Bioscience, biotechnology, and biochemistry 64.10 (2000): 2165-2171.