Morten Georg Jensen

Dietary fibres in the regulation of appetite and food intake. Importance of viscosity.

Dietary fibres have many functions in the diet, one of which may be to promote control of energy intake and reduce the risk of developing obesity. This is linked to the unique physico-chemical properties of dietary fibres which aid early signalling of satiation and prolonged or enhanced sensation of satiety. Particularly the ability of some dietary fibres to increase viscosity of intestinal contents offers numerous opportunities to affect appetite regulation. Few papers on the satiating effect of dietary fibres include information on the physico-chemical characteristics of the dietary fibres being tested, including molecular weight and viscosity. For viscosity to serve as a proxy for soluble dietary fibres it is essential to have an understanding of individual dietary fibre viscosity characteristics. The goal of this paper is to provide a brief overview on the role of dietary fibres in appetite regulation highlighting the importance of viscosity.

Whole Grain Compared with Refined Wheat Decreases the Percentage of Body Fat Following a 12-Week, Energy-Restricted Dietary Intervention in Postmenopausal Women

Observational studies show inverse associations between intake of whole grain and adiposity and cardiovascular risk; however, only a few dietary intervention trials have investigated the effect of whole-grain consumption on health outcomes. We studied the effect of replacing refined wheat (RW) with whole-grain wheat (WW) for 12 wk on body weight and composition after a 2-wk run-in period of consumption of RW-containing food intake. In this open-label randomized trial, 79 overweight or obese postmenopausal women were randomized to an energy-restricted diet (deficit of ~1250 kJ/d) with RW or WW foods providing 2 MJ/d. Body weight and composition, blood pressure, and concentration of circulating risk markers were measured at wk 0, 6, and 12. Fecal output and energy excretion were assessed during run-in and wk 12. Plasma alkylresorcinol analysis indicated good compliance with the intervention diets. Body weight decreased significantly from baseline in both the RW (-2.7 ± 1.9 kg) and WW (-3.6 ± 3.2 kg) groups, but the decreases did not differ between the groups (P = 0.11). The reduction in body fat percentage was greater in the WW group (-3.0%) than in the RW group (-2.1%) (P = 0.04). Serum total and LDL cholesterol increased by ~5% (P < 0.01) in the RW group but did not change in the WW group; hence, the changes differed between the groups (P = 0.02). In conclusion, consumption of whole-grain products resulted in a greater reduction in the percentage fat mass, whereas body weight changes did not differ between the RW and WW groups. Serum total and LDL cholesterol, two important risk factors of cardiovascular disease, increased with RW but not WW consumption, which may suggest a cardioprotective role for whole grain.

Wholegrain vs. refined wheat bread and pasta. effect on postprandial glycemia, appetite, and subsequent ad libitum energy intake in young healthy adults.

Wholegrain foods have received much attention in recent years, and have been proposed to play a role in energy regulation through lowering of postprandial glycemia and appetite. This randomized crossover single meal study in 16 young adults was conducted to test the effect of iso-caloric meals based on wholemeal wheat breads and pasta in comparison to similar refined wheat products on postprandial glycemia, appetite and ad libitum energy intake (EI). Test meals (50 g carbohydrates; 2MJ) consisted of refined wheat bread (RWB), wholegrain wheat bread (WWB), refined wheat pasta (RWP) and wholegrain wheat pasta (WWP) and were served after an overnight fast. Appetite ratings and blood glucose were assessed for 180 min after which an ad libitum lunch meal was served and EI measured. The 180 min glucose responses were similar for wholemeal and refined products, but pasta meals gave significantly lower glucose responses. Only RWP had a lower glycemic index compared to RWB. WWB, but not WWP, resulted in increased satiety and reduced hunger compared to RWB. Ad libitum EI did not differ. In conclusion, the results show that wholemeal breads increased satiety measures compared to their refined counterparts; however no significant effect on subsequent EI was observed.

Flaxseed dietary fibers lower cholesterol and increase fecal fat excretion, but magnitude of effect depend on food type

BackgroundDietary fibers have been proposed to play a role in cardiovascular risk as well as body weight management. Flaxseeds are a good source of dietary fibers, and a large proportion of these are water-soluble viscous fibers.MethodHere, we examine the effect of flaxseed dietary fibers in different food matrices on blood lipids and fecal excretion of fat and energy in a double-blind randomized crossover study with 17 subjects. Three different 7-d diets were tested: a low-fiber control diet (Control), a diet with flaxseed fiber drink (3/day) (Flax drink), and a diet with flaxseed fiber bread (3/day) (Flax bread). Total fat and energy excretion was measured in feces, blood samples were collected before and after each period, and appetite sensation registered 3 times daily before main meals.ResultsCompared to control, Flax drink lowered fasting total-cholesterol and LDL-cholesterol by 12 and 15%, respectively, (p < 0.01), whereas Flax bread only produced a reduction of 7 and 9%, respectively (p < 0.05). Fecal fat and energy excretion increased by 50 and 23% with Flax drink consumption compared to control (p < 0.05), but only fecal fat excretion was increased with Flax bread compared to control (p < 0.05).ConclusionBoth Flax drink and Flax bread resulted in decreased plasma total and LDL-cholesterol and increased fat excretion, but the food matrix and/or processing may be of importance. Viscous flaxseed dietary fibers may be a useful tool for lowering blood cholesterol and potentially play a role in energy balance.Trial RegistrationClinicalTrials.gov: NCT00953004

Effect of alginate supplementation on weight loss in obese subjects completing a 12-wk energy-restricted diet: a randomized controlled trial

BACKGROUND Acute studies with alginate-based preloads suggested that these strong gelling fibers may induce increased feelings of satiety and reduce energy intakes. However, the long-term efficacy and safety of alginate supplementation on body weight regulation are lacking. OBJECTIVE The primary aim of the study was to investigate the effects in subjects of alginate supplementation in conjunction with energy restriction (-300 kcal/d) on loss of body weight and fat and, second, on metabolic risk markers in comparison with in a placebo group. DESIGN In a parallel, double-blind, placebo-controlled study, we randomly assigned 96 obese subjects to either an energy-restricted diet plus a placebo preload supplement or an energy-restricted diet plus an alginate-based preload supplement (15 g fiber). The preload was administered as a beverage 3 times/d before main meals for a period of 12 wk. RESULTS No differences in loss of body weight and fat between groups were shown in the intension-to-treat (ITT) analysis (P > 0.1). However, in the completer analysis (n = 80), we showed a greater weight loss with alginate (6.78 ± 3.67 kg) than with the placebo (5.04 ± 3.40 kg) (P = 0.03), which was mainly attributed to a reduction in the percentage of body fat (P = 0.03). In the ITT analysis, a larger decrease in systolic and diastolic blood pressure was shown in the placebo group than in the alginate group (P < 0.05). Plasma concentrations of glucose, insulin, C-reactive protein, and ghrelin, HOMA-IR, and lipid metabolism did not differ between treatment groups in the ITT analysis (P > 0.1). CONCLUSION These results suggest that alginate supplementation as an adjunct to energy restriction may improve weight loss in obese subjects who complete a 12-wk dietary intervention.

Probing Interactions between beta-Glucan and Bile Salts at Atomic Detail by H-1-C-13 NMR Assays

Polysaccharides are prospective hosts for the delivery and sequestration of bioactive guest molecules. Polysaccharides of dietary fiber, specifically cereal (1 → 3)(1 → 4)-β-glucans, play a role in lowering the blood plasma cholesterol level in humans. Direct host-guest interactions between β-glucans and conjugated bile salts are among the possible molecular mechanisms explaining the hypocholesterolemic effects of β-glucans. The present study shows that (1)H-(13)C NMR assays on a time scale of minutes detect minute signal changes in both bile salts and β-glucans, thus indicating dynamic interactions between bile salts and β-glucans. Experiments are consistent with stronger interactions at pH 5.3 than at pH 6.5 in this in vitro assay. The changes in bile salt and β-glucan signals suggest a stabilization of bile salt micelles and concomitant conformational changes in β-glucans.

Direct study of fluorescently-labelled barley β-glucan fate in an in vitro human colon digestion model

β-Glucans from cereals are β(1-3)(1-4)-mixed linkage linear homopolysaccharides of D-glucopyranosyl residues, recently recognised as functional components of foods with benefits in maintaining the health of the digestive tract not least through a prebiotic effect. Here we describe the development of methodology to facilitate the study of β-glucans as prebiotics. Relatively short β-glucan fragments (DP 6-50) were produced by partial hydrolysis of β-glucan fibres with Lichenase then functionalised at their reducing end with a tetramethylrhodamine dye. Their enzymatic break down by human colon microbiota in an in vitro fermentation model was examined. Digestion products were isolated by virtue of their fluorescence labels, identified and characterised using capillary electrophoresis and mass spectrometry. Complete digestion of the labelled substrates was indicated, as fluorescently labelled glucose was obtained as the final product. Furthermore, a pathway of enzymatic breakdown was proposed on the basis of a time course experiment; initial fast hydrolysis with an endo-1,3(4)-β-glucanase was followed by slow degradation with an exo-1,4-β-glucanase and finally slow action of an exo-1,3-β-glucanase.

Fate of ethanol during cooking of liquid foods prepared with alcoholic beverages: Theory and experimental studies

To obtain an understanding of the ethanol loss during cooking of liquid foods containing alcoholic beverages, ethanol concentration was measured as a function of time and remaining volume in meat stocks prepared with wine and beer. A mathematical model describing the decline in volatile compounds during heating of simple liquid foods was derived. The experimental results and the model show that concentration of ethanol at any given time is determined by the initial concentration and a power law function of the remaining volume fraction. The power law function is found to be independent of factors like pot dimensions and temperature. When using a lid to cover the pot during cooking, the model was still valid but the ethanol concentrations decreased more steeply, corresponding to a higher exponent. The results provide a theoretical and empirical guideline for predicting the ethanol concentration in cooked liquid foods.

Metabolic effects of propionic acid-enriched breads.

Publisher Summary Oral supplementation with sodium propionate in humans enhances satiety and reduces the postprandial glycemic and insulinemic responses. These metabolic effects suggest a potential therapeutic role for sodium propionate in the treatment of diseases related to insulin resistance. Bread products with added sodium propionate could be of particular interest in the coming years due to their capacity to optimize dietary treatments/ interventions in insulin-related metabolic diseases by provoking low glycemic response, thereby producing fewer fluctuations in blood glucose concentrations. This chapter discusses the metabolic effects of propionate-enriched breads and highlights some promising research avenues. Propionic acid is a naturally occurring carboxylic acid with chemical formula CH3CH2COOH. In its pure state, propionic acid is a colorless, corrosive liquid with a sharp, somewhat unpleasant, odor. Propionic acid and its salts are widely used in industry and especially in the food industry as antifungal agents. The majority of evidence in animals indicates a role for propionate in decreasing feed intake. Human studies have shown a beneficial effect of sodium propionate-enriched bread products on postprandial glucose and insulin responses as well as on satiety. The lowered glycemic response to ingestion of bread with added sodium propionate appears to be related to a lowered gastric emptying rate. The use of propionate offers a new avenue to innovate in the production of low glycemic index breads.