Flaxseed dietary fiber supplements for suppression of appetite and food intake

January 1, 2012 Human Health and Nutrition Data 0 Comments

Flaxseed dietary fiber supplements for suppression of appetite and food intake

Year: 2012
Authors: Ibrugger, S. Kristensen, M. Mikkelsen, M.S. Astrup, A.
Publication Name: Appetite
Publication Details: doi:10.1016/j.appet.2011.12.024


We conducted two single-blinded randomized crossover acute studies with 24 and 20 subjects, respectively, to compare (I) Control vs. Flax drink; and (II) Flax drink vs. Flax tablets. The subjects were exposed to one of the treatments after an overnight fast, and rated appetite sensation for 120 min using visual analog scales (VAS). Hereafter they consumed an ad libitum early lunch to assess energy intake. The treatments were iso-caloric and iso-volumeric: Control: 300 mL drink; Flax drink: Control drink with addition flax fiber extract (2.5 g of soluble fibers); and Flax tablet: Control drink with flax fiber tablets (2.5 g of soluble fibers). Flax drink increased sensation of satiety and fullness compared to Control and a significant decrease in subsequent energy intake was observed after the Flax drink compared to Control (2937 vs. 3214 kJ). Appetite ratings were similar for Flax tablets and Flax drink as they did not differ by more than 1 to 4%. Subsequent energy intake was similar after the two treatments (3370 vs. 3379 kJ). A small dose of flaxseed fiber significantly suppresses appetite and energy intake. Furthermore, flaxseed fibers administered as drinks or tablets produce similar responses. (Authors abstract)
The dietary fibre from flax (mucilage) incorporated into breads induced increased sensation of satiety postprandially in young healthy males as well as suppression of ghrelin. In this study, flaxseed fibers consumed as a drink reduce appetite and food intake compared to a non-fiber Control drink was tested.  Secondly, whether flaxseed fibers given as tablets would have similar effects on appetite and food intake as when given as a drink was also assessed. The results of the present study demonstrate that consumption of a small dose of flaxseed fibers increase perceived satiety and reduce energy intake at a subsequent ad libitum meal in comparison to Control. Furthermore, the suppression of appetite appears equally effective whether the flaxseed fibers are administered as a beverage or as tablets. In a number of studies it has been observed that consumption of viscous fibers enhances sensation of satiety suggesting viscosity as an independent determinant for satiety. The flaxseed fiber extract contained 2.5 g of water-soluble dietary fibers that form highly viscous solutions upon hydration. Rheological measurements showed that viscosity was high at serving temperature as well as at a physiological temperature of 37 degrees C, thus it is likely that viscosity of the gastric chyme increased considerably. The fact that we observed a comparable appetite reduction with the flaxseed fiber tablets allows us to assume that the tablets were well dissolved and hydrated in the stomach giving rise to an enhanced gastric chyme viscosity. It has been suggested that the viscous texture in the mouth may induce early fullness. In the present study, a relation between palatability and satiety is indicated by the observation that in study II for Flax drink ad libitum energy intake was greater than in study I, concomitantly with higher palatability ratings. Further, in study II, despite higher palatability ratings for Flax tablet than Flax drink, ad libitum intake did not differ between the treatments. Thus, it is rather unlikely that in the present study palatability played a notable role in enhancing satiety and gastric and hormonal mechanisms seem more plausible.  In the present study the flaxseed fibers were consumed with a beverage of relatively low energy-content (575 kJ, 34 g sucrose), which suggests that gastric signals were primarily responsible for the increased satiety sensations. Therefore, it is likely that besides gastric signals also intestinal mechanisms were involved.  Viscous fibers are known to attenuate postprandial blood glucose and insulin responses.  The texture of viscous beverages is often perceived as unpalatable, which makes them rather unsuitable for commercial use. In the present study this becomes apparent in the higher palatability ratings of the Control drink compared to the flaxseed drink. Flaxseed fiber tablets may be an attractive alternative, as they appear to be as effective as a viscous beverage, but more convenient. In conclusion, the ingestion of the flaxseed fiber, both as a powder and tablets, increased satiety and decreased energy intake at a subsequent meal. Flaxseed fiber may be applicable to control appetite. The administration as tablets may constitute a more palatable and convenient alternative to viscous beverages. (Editors comments)

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