MLN9708 Jensen and his co authors studied

Jensen and his co-authors [31] studied the effects on postprandial satiety feelings, MLN9708 intake, and gastric emptying rate, of two different volumes of an alginate-based preload in normal-weight subjects (see Table 1). Twenty individuals were randomly assigned to receive a 3% preload concentration of either low volume (9.9g alginate in 330mL) or high volume (15.0g alginate in 500mL) alginate-based beverage, or an iso-volume placebo drink. The preloads were consumed 30min before a fixed breakfast and again before an ad libitum lunch. The ingestion of low volume-alginate preload induced a significant decrease (8.0%) in energy intake compared to the placebo drink at the following lunch meal, while differences in satiety feelings were not observed. The high volume-alginate induced a non-significant reduction in energy consumption by only 5.5% although a significant increase in satiety feelings, reduced hunger and the feeling of prospective food consumption was reported [31]. These findings suggest that alginate consumption can affect satiety feelings and energy intake. In a pilot study, Jensen et al. [32] investigated in obese participants the effects on body weight loss and gastrointestinal tolerance of consuming low viscous alginate fiber-based preloads of 3% concentration (500mL volume) three times a day as an adjuvant to a calorie-restricted diet (see Table 1). The intake of the alginate preloads was moderately acceptable to the majority of subjects but did not produce additional body weight loss beyond calorie restriction in comparison to the control group. These findings do not suggest that alginate supplementation can enhance the weight loss following a hypo-caloric diet [32]. Jensen et al. [33] repeated the study using a larger sample (see Table 1) and investigated the effects of alginate supplementation in conjunction with energy restriction (−300kcal/day) on loss of body weight and on several metabolic risk markers. In conjunction with an energy-restricted diet either an alginate-based preload supplement (15g fiber) or a placebo preload supplement were administered. The preload drinks were given 3 times a day before main meals for 12 weeks. At completion of trial, a greater weight loss was observed with alginate than with placebo. This was mainly attributed to a reduction in the percentage of body fat. Differences in plasma concentrations of glucose, insulin, C-reactive protein, ghrelin, HOMA-IR, and lipid metabolism were not found [33]. These results suggest that alginate administration as an adjunct to energy restriction may improve weight loss due to alterations in body fat mass in obese subjects who complete a 12-week dietary alginate intervention as an adjuvant to a calorie-controlled diet. The positive effects of alginate supplementation on weight management reported previously have been challenged by findings of Odunsi et al. [34]. These authors analyzed the effects of a 10-day treatment with alginate or placebo on gastric functions, satiation, appetite and gut hormones associated with satiety in overweight or obese adults without psychiatric co-morbidity or binge eating disorder (see Table 1). In all participants, gastric emptying, fasting and postprandial gastric volumes, postprandial satiation, calorie intake at a free choice meal and gut hormones (ghrelin, CCK, GLP-1, PYY) were measured after 1 week of alginate (3 capsules versus placebo per day, ingested 30min before the main meal). Six capsules were ingested with 30min before the gastric emptying and the gastric volume and satiation tests on days 8–10. Group effects of treatment were not found in regard to gastric emptying or volumes, gut hormones, satiation, total and macronutrient calorie intake at a free choice meal. No differences were observed between obese and overweight participants [34]. Alginate treatment over 10 days did not appear to affect gastric motor functions, satiation, appetite or gut hormones. However, other authors [35] urge caution in extrapolating results from the specific commercially available product used by Odunsi et al. [34] to alginates in general since both chemical structure and concentration of the specific alginate source material can have effects on the gel strength [36,37].