Fermentable fiber and the gut-brain-axes: The key to lifelong leanness?
If this is not your first visit to the SuppVersity, you will certainly be aware that the idea of a magic pill (or fiber) that will allow you to eat whatever, whenever and in whichever amounts without having to cope with the metabolic consequences is illusive. When the addition of 10% inulin (or beta glucan) to the diets of 36 male C57BL/6 mice had an "anti-obesogenic" effect, this does not mean that the poor critters who were kept on a hypercaloric high fat (41.8%) diet for 8 weeks did not get obese. What it does mean, though, is that the addition of 10% fermentable (=being food for certain gut bacteria) fiber in the form of
- inulin from Synergy(TM)*, a fructan based preparation containing both long and short chain
- beta-glucan from Glucagel(TM)* a highly rich (,80%) barley derived b-glucan preparation
"[...] increases in both Bifidobacteria and Lactobacillius and a significant increase in short chain fatty acids (SCFA) [went hand in hand with] increase in neuronal activation within the arcuate nucleus (ARC) of animals that received In [inulin] supplementation" (Anastasovska. 2012)do not (and this is a result of the researchers very latest experiments) simply blunt the rodents appetite. If that was the case, the rodents that received the beta glucan supplemented chow and consumed 12% less energy should have had the most favorable body composition. A cursory glance at figure 1 will yet tell you that this was not the case, though.
Inulin beats beta glucan when it comes to body fat reduction / repression
If we take a closer look a the differential effects of inulin and beta glucan, there yet only one figure that really sticks out and that's the accumulation of fat within the musculature of the animals. The "beautiful marbling" people are looking for in their steaks, however, usually is a harbinger of impeding or even existing skeletal muscle insulin resistance. A muscle fat content above the high fat control (it's certainly a weakness that we don't have a "real" control group on standard rodent chow, here) as Arora et al. observed it in the tissue samples of the beta glucan group, does thus tell you something about its potential usefulness, or rather uselessness of this specific type of fermentable fiber.
|Figure 2: Effects of the different types of fermentable fiber on cecal microflora groups (figures are in scientific notation, this means "1E+6" equals 1mio, "1E+9" would be 1 billion etc.; data based on Arora. 2012)|
Inulin or beta glucan? This is not a question...
While the latter, i.e. inulin, which has by the way been found to directly suppress lipogenesis in a 2011 study by Belgian scientists in a similar HFD rodent model (Dewulf. 2011), appears to be promising for everyone, regardless of whether he or she is poisoning him- or herself with the standard American diet (which is, with its high fat and high carbohydrate content de facto an identical twin of the so-called "high fat diet" in rodent studies), the ingestion of larger amounts of the former, i.e. beta glucan, does at least appear questionable.
Whether having 10% of your diet in form of inulin, or to make this more conceivable, having 1 tablespoon of plain inulin for every 9 tablespoons of whatever else you eat is either feasible or reasonable, is a whole different story (to put that into perspective: The average inulin intake of Westerners is 1-10g per day (van Loo. 1995). Even 10g would yet only be enough if you ate only 100g of food within 24h!)... and I must forewarn you, if you go by the fecal volume of the mice in the Arora study, it is possible that you will spend >3x more time on the toilette than usual ;-)
- Arora T, Loo RL, Anastasovska J, Gibson GR, Tuohy KM, Sharma RK, Swann JR, Deaville ER, Sleeth ML, Thomas EL, Holmes E, Bell JD, Frost G. Differential effects of two fermentable carbohydrates on central appetite regulation and body composition. PLoS One. 2012;7(8):e43263.
- Anastasovska J, Arora T, Sanchez Canon GJ, Parkinson JR, Touhy K, Gibson GR, Nadkarni NA, So PW, Goldstone AP, Thomas EL, Hankir MK, Van Loo J, Modi N, Bell JD, Frost G. Fermentable carbohydrate alters hypothalamic neuronal activity and protects against the obesogenic environment. Obesity (Silver Spring). 2012 May;20(5):1016-23.
- Astegiano M, Pellicano R, Terzi E, Simondi D, Rizzetto M. Treatment of irritable bowel syndrome. A case control experience. Minerva Gastroenterol Dietol. 2006 Dec;52(4):359-63.
- Bassaganya-Riera J, DiGuardo M, Viladomiu M, de Horna A, Sanchez S, Einerhand AW, Sanders L, Hontecillas R. Soluble fibers and resistant starch ameliorate disease activity in interleukin-10-deficient mice with inflammatory bowel disease. J Nutr. 2011 Jul;141(7):1318-25.
- Dewulf EM, Cani PD, Neyrinck AM, Possemiers S, Van Holle A, Muccioli GG, Deldicque L, Bindels LB, Pachikian BD, Sohet FM, Mignolet E, Francaux M, Larondelle Y, Delzenne NM. Inulin-type fructans with prebiotic properties counteract GPR43 overexpression and PPARγ-related adipogenesis in the white adipose tissue of high-fat diet-fed mice. J Nutr Biochem. 2011 Aug;22(8):712-22.
- van Loo J, Coussement P, de Leenheer L, Hoebregs H, Smits G. On the presence of inulin and oligofructose as natural ingredients in the western diet. Crit Rev Food Sci Nutr. 1995 Nov;35(6):525-52.
- Zenhom M, Hyder A, de Vrese M, Heller KJ, Roeder T, Schrezenmeir J. Prebiotic oligosaccharides reduce proinflammatory cytokines in intestinal Caco-2 cells via activation of PPARγ and peptidoglycan recognition protein 3. J Nutr. 2011 May;141(5):971-7.