A psyllium fiber-enriched meal strongly attenuates postprandial gastrointestinal peptide release in healthy young adults

Effect of psyllium husk powder on the gelation behavior, microstructure, and intermolecular interactions in myofibrillar protein gels from Andrias davidianus

The interaction between proteins and soluble dietary fibers plays a vital role in the development of animal-derived foods. Herein, the effects of different contents (0-3.0%) of round-bracted psyllium husk powder (PHP) on the gelation behavior, microstructure, and intermolecular interactions of Andrias davidianus myofibrillar protein (MP) were investigated. Rheological and chemical forces suggested that PHP (1.5%-2.0%) enhanced the functional properties of MP at low ionic strength, thereby increasing the viscoelasticity of mixed gels. SDS-PAGE revealed that PHP reinforced the cross-linking and aggregation of protein molecules. Circular dichroism spectroscopy, low-field nuclear magnetic resonance, and scanning electron microscopy demonstrated that PHP induced the transformation of α-helix (decreased by 14.85%) to an ordered β-sheet structure (increased by 81.58%), which was more favorable for the formation of dense network structure and improved (10.53%) the water retention of MP gels. This study provided new insights for PHP to effectively meliorate the heat-induced gelling properties of MP.

Nutritional strategies to attenuate postprandial glycemic response

Maintaining good glycemic control to prevent complications is crucial in people with type 2 diabetes and in people with prediabetes and in the general population. Different strategies to improve glycemic control involve the prescription of blood glucose-lowering drugs and the modulation of physical activity and diet. Interestingly, lifestyle intervention may be more effective in lowering hyperglycemia than pharmaceutical intervention. Regulation of postprandial glycemia is complex, but specific nutritional strategies can be applied to attenuate postprandial hyperglycemia. These strategies include reducing total carbohydrate intake, consuming carbohydrates with a lower glycemic index, the addition of or substitution by sweeteners and fibers, using food compounds which delay or inhibit gastric emptying or carbohydrate digestion, and using food compounds which inhibit intestinal glucose absorption. Nevertheless, it must be noted that every individual may respond differently to certain nutritional interventions. Therefore, a personalized approach is of importance to choose the optimal nutritional strategy to improve postprandial glycemia for each individual, but this requires a better understanding of the mechanisms explaining the differential responses between individuals.

Beneficial Effects of Psyllium on the Prevention and Treatment of Cardiometabolic Diseases

Cardiometabolic diseases are reaching epidemic proportions worldwide. Nevertheless, current therapeutic strategies are insufficient; thus, studying novel complementary and alternative medicines remains of the upmost importance. Psyllium has been used for...

Investigation of different dietary-fibre-ingredients for the design of a fibre enriched bread formulation low in FODMAPs based on wheat starch and vital gluten

Consumption of fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) often induces symptoms of irritable bowel syndrome (IBS). Since FODMAPs and dietary fibre (DF) share certain characteristics, IBS-patients have a limited intake of DF. Therefore, enrichment of a low FODMAP model bread (based on 84% wheat starch and 16% vital gluten) with various fibres (bamboo, cellulose, psyllium, guar gum) in two different concentrations (3 g/100 g and 6 g/100 g) was investigated. Physico-chemical properties of doughs and breads were analysed (fermentation quality, gluten development, specific volume and hardness), as well as the release of reducing sugars during in vitro digestion. High performance anion exchange chromatography with coupled pulsed amperometric detection (HPAEC-PAD) was used to determine the FODMAP levels (contents of mannitol, sorbitol, fructose in excess of glucose, fructans and α-galactooligosaccharides) of both dough and bread. Prototypes were compared with wheat flour-based breads (bakers’ flour with and without wheat bran addition) to assess the performance of these prototypes. Prototypes showed a decreased quality compared to a baker’s flour control, however, a quality comparable to commercial wheat bran breads was found. This in combination with a lower release of reducing sugars during in vitro digestion underline the potential of fibre enriched breads as part of a healthier and more palateable low FODMAP diet. Furthermore, this study highlights the importance of the type (viscous and insoluble) and the concentration of fibres used. Application of psyllium in a concentration of 3 g/100 g showed the most beneficial impact on both physical (specific volume, hardness after 0 h and 24 h) and nutritional aspects of bread.

Psyllium husk intake and risk of type 2 diabetes: an evidence-based scientific and regulatory review of a qualified health claim conducted by the US Food and Drug Administration

The US Food and Drug Administration (FDA) received a petition from a company requesting that FDA issue an authorized health claim for the relationship between psyllium husk and a reduced risk of type 2 diabetes. After an initial assessment of the available scientific evidence, FDA determined that significant scientific agreement was lacking for this substance-disease relationship, whereupon the company agreed to have its petition reviewed as a qualified health claim. This article describes the process FDA used in conducting an evidence-based review of the science underpinning the proposed claim and addresses certain safety issues associated with psyllium husk that FDA considered in its review of the petition. Of the 6 studies from which scientific conclusions could be drawn, as identified through FDA's review, psyllium husk significantly improved plasma glucose levels and insulin sensitivity in only 1 study. Therefore, FDA's enforcement discretion letter for this qualified health claim stated: "Psyllium husk may reduce the risk of type 2 diabetes, although the FDA has concluded that there is very little scientific evidence for this claim."

Acute postprandial effect of yacon syrup ingestion on appetite: A double blind randomized crossover clinical trial

Yacon syrup is a rich source of fructooligosaccharides (FOS); however, its diet supplementation effect on subjective sensation and appetite biomarkers in human is still unknown. This study aimed to evaluate the acute postprandial effect of yacon syrup ingestion on appetite. The double-blind crossover clinical trial was carried out with 40 adult women: 20 eutrophic and 20 obese grade I. On each day, the first blood collection was performed after a 12-h fast. Then, the volunteers ingested either intervention A (breakfast + 40 g of placebo) or intervention B (breakfast + 40 g of yacon syrup, containing 14 g of FOS). New aliquots of blood were collected at 45, 60, 90, 120, and 180 min. Appetite was assessed by estimating ghrelin and glucagon-like peptide-1 (GLP-1) levels and by assessing subjective appetite sensation. Analysis was performed using two-way ANOVA, followed by Bonferroni's multiple comparison test. No effect of yacon syrup was observed on postprandial ghrelin and GLP-1 levels at all times evaluated. Similar observations were made after stratifying the analysis by BMI (body mass index) (eutrophic and obese). The effect of yacon syrup on postprandial subjective sensations of hunger, satiety, fullness, and desire to eat was not evident in the total group of women evaluated and even after BMI stratification. We concluded that yacon syrup had no effect on postprandial ghrelin and GLP-1 levels and on the subjective appetite sensation in young adult women.

Increasing oat β-glucan viscosity in a breakfast meal slows gastric emptying and reduces glycemic and insulinemic responses but has no effect on appetite, food intake, or plasma ghrelin and PYY responses in healthy humans: a randomized, placebo-controlled, crossover trial

BACKGROUND

The viscosity of oat β-glucan (OBG) determines its effect on serum cholesterol and glycemic responses, but whether OBG viscosity affects gastric emptying, appetite, and ad libitum food intake is unknown.

OBJECTIVES

We aimed to determine the effect of altering the amount or molecular weight (MW) and, hence, viscosity of OBG in a breakfast meal on the primary endpoint of food intake at a subsequent meal.

METHODS

Overnight-fasted males (n = 16) and nonpregnant females (n = 12) without diabetes, aged 18-60 y, with BMI 20.0-30.0 kg/m² who were unrestrained eaters participated in a double-blind, randomized, crossover study at a contract research organization. Participants consumed, in random order, breakfast meals equivalent in weight, energy, and macronutrients consisting of white-bread, butter, jam, and 2% milk plus hot cereal [Cream of Rice (CR), or instant-oatmeal plus either 3 g oat-bran (2gOBG), 10 g oat-bran (4gOBG), or 10 g oat-bran plus β-glucanase (4gloMW) to reduce OBG MW and viscosity compared with 4gOBG]. Gastric emptying, subjective appetite, and glucose, insulin, ghrelin, and peptide tyrosine tyrosine (PYY) responses were assessed for 3 h and then subjects were offered an ad libitum lunch (water and pizza).

RESULTS

Pizza intakes (n = 28) after CR, 2gOBG, 4gOBG, and 4gloMW (mean ± SEM: 887 ± 64, 831 ± 61, 834 ± 78, and 847 ± 68 kcal, respectively) were similar (nonsignificant). Compared with CR, 4gOBG significantly reduced glucose (78 ± 10 compared with 135 ± 15 mmol × min/L) and insulin (14.0 ± 1.6 compared with 26.8 ± 3.5 nmol × min/L) incremental area-under-the-curve and delayed gastric-emptying half-time (geometric mean: 285; 95% CI: 184, 442, compared with geometric mean: 105; 95% CI: 95, 117 min), effects not seen after 4gloMW. Subjective appetite, PYY, and ghrelin responses after 2gOBG, 4gOBG, and 4gloMW were similar to those after CR.

CONCLUSIONS

The results demonstrate that OBG viscosity determines its effect on postprandial glucose, insulin, and gastric emptying. However, we were unable to demonstrate a significant effect of OBG on appetite or food intake, regardless of its viscosity.This trial was registered at clinicaltrials.gov as NCT03490851.

Gastrointestinal and metabolic effects of noodles-based konjac glucomannan in rats

This study was conducted to investigate the hypothesis that the beneficial metabolic effects of dietary fiber, konjac glucomannan (KGM), related with in vivo digestion might be altered if the complicated food matrix was taken into consideration. A diet of precooked noodles (PN), as widely produced and consumed in Asia, was used to simulate an actual food context. Assays were conducted with male Wistar rats (n = 80); the rats were divided into five groups and fed with either PN (control), PN supplemented with medium-dose KGM (MK), precooked low-dose KGM-supplemented noodles (LKD), precooked medium-dose KGM-supplemented noodles (MKD) or precooked high-dose KGM supplemented noodles (HKD). The time-dependent changes in blood glucose and the sensitivity to insulin after intragastric administration were determined to evaluate the postprandial glycemic response. The activity of intestinal Na+-K+-ATPase and the levels of gut hormones including motilin, cholecystokin, GLP-1, and orexin were also determined to provide insights into the function of gastrointestinal motion and after-meal hormonal feedback in each group. The noodles-based KGM showed much more efficacy in sustaining glucose homeostasis compared with KGM supplemented in a diet of noodles, indicating there might be potential long-term health outcomes of satiety and energy balance using noodles-based KGM. The postprandial glycemia was largely moderated by LKD and MKD. Despite the significant reduction in the production of glucose, MKD caused insensitivity to insulin-blood glucose regulation and a rapid gut negative feedback following a severe blood glucose fluctuation. In conclusion, the health-promoting benefits of KGM supplements on glycemic response highly depend on the type of matrix and the dose of KGM.

Effect of Fibre-Enriched Orange Juice on Postprandial Glycaemic Response and Satiety in Healthy Individuals: An Acute, Randomised, Placebo-Controlled, Double-Blind, Crossover Study

Background: Consumption of fibre-enriched orange juice may be an appropriate way to supplement daily fibre intake and achieve beneficial effects on metabolic health. The present study aimed to assess the short-term effects of fibre-enriched orange juice on postprandial metabolism and satiety in a healthy adult population. Methods: In this double-blind, randomised, placebo-controlled, crossover study 10 healthy subjects underwent two one-day trials in which they consumed an orange juice beverage containing 1.4 g/100 mL of citrus fibre (29.3% soluble and 41.9% insoluble) or a placebo (regular orange juice without added fibre). Postprandial glucose, insulin, gut hormones (GLP1, GIP and ghrelin), leptin and qualitative appetite/satiety assessment were measured every 15 or 30 min over the 120 min test period. Results: The fibre-enriched orange juice decreased postprandial serum glucose and circulating insulin levels at 15 min compared with the placebo. In addition, after intake of the fibre-enriched juice, a significant effect on qualitative feelings of satiety and fullness was observed at 15 and 120 min, and was accompanied by a significant decrease in GLP1 response at 15 min. No significant changes were observed in leptin, GIP and ghrelin after juice intake. Conclusions: In healthy individuals, a single acute consumption of fibre-enriched orange juice has short-term beneficial effects on postprandial glycaemia, circulating insulin levels and satiety through GLP1 secretion.

Effect of Meal Acceptability on Postprandial Appetite Scores and Hormones of Male Participants with Varied Adiposity

OBJECTIVE

This study portrays the effect of hedonic manipulation (high acceptability [HA] vs. low acceptability [LA]) on postprandial hormones and appetite scores in healthy males.

METHODS

Thirty participants (15 with normal weight and 15 with obesity) were recruited for a randomized, crossover design. They were randomly assigned to the HA or LA (with acesulfame-K) custard. Blood samples were drawn before the meals and for 4 hours after the meals and were analyzed for glucose, insulin, ghrelin, and glucagonlike peptide 1 (GLP-1). Appetite scores and subsequent energy intake were recorded.

RESULTS

Postprandial glucose, insulin, and ghrelin were different according to adiposity, whereas meal acceptability did not correspond to any significant difference in postprandial glucose, insulin, ghrelin, and GLP-1 concentrations. Appetite scores showed lower hunger, higher satiety, and fullness after the HA meal without a significant difference between the meals. Subsequent energy intake, expressed as a percentage of the resting energy expenditure, was higher in participants with obesity but did not reflect postprandial hormones and appetite scores; there was no significant difference between meals.

CONCLUSIONS

Hedonic properties and palatability do not affect gut hormones, mainly ghrelin and GLP-1. Moreover, their postprandial concentrations were not paralleled by similar changes in appetite scores, and both were not found to affect subsequent intake.

How Satiating Are the 'Satiety' Peptides: A Problem of Pharmacology versus Physiology in the Development of Novel Foods for Regulation of Food Intake

Developing novel foods to suppress energy intake and promote negative energy balance and weight loss has been a long-term but commonly unsuccessful challenge. Targeting regulation of appetite is of interest to public health researchers and industry in the quest to develop ‘functional’ foods, but poor understanding of the underpinning mechanisms regulating food intake has hampered progress. The gastrointestinal (GI) or ‘satiety’ peptides including cholecystokinin (CCK), glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) secreted following a meal, have long been purported as predictive biomarkers of appetite response, including food intake. Whilst peptide infusion drives a clear change in hunger/fullness and eating behaviour, inducing GI-peptide secretion through diet may not, possibly due to modest effects of single meals on peptide levels. We conducted a review of 70 dietary preload (DIET) and peptide infusion (INFUSION) studies in lean healthy adults that reported outcomes of CCK, GLP-1 and PYY. DIET studies were acute preload interventions. INFUSION studies showed that minimum increase required to suppress ad libitum energy intake for CCK, GLP-1 and PYY was 3.6-, 4.0- and 3.1-fold, respectively, achieved through DIET in only 29%, 0% and 8% of interventions. Whether circulating ‘thresholds’ of peptide concentration likely required for behavioural change can be achieved through diet is questionable. As yet, no individual or group of peptides can be measured in blood to reliably predict feelings of hunger and food intake. Developing foods that successfully target enhanced secretion of GI-origin ‘satiety’ peptides for weight loss remains a significant challenge.

The effects of psyllium supplementation on body weight, body mass index and waist circumference in adults: A systematic review and dose-response meta-analysis of randomized controlled trials

Background: Previous studies reported inconsistent findings regarding the effects of psyllium supplementation on obesity measures. This systematic review and meta-analysis was performed to summarize data from available randomized clinical trials (RCTs) on the effect of psyllium supplementation on body weight, body mass index (BMI), and waist circumference (WC) in adults.Methods: PubMed, SCOPUS, Cochrane Library, and Google Scholar were searched to identify relevant articles up to August 2018. The effect sizes were presented as weighted mean difference (WMD) and 95% confidence intervals (CI) by using random effects model. To detect dose-response relationships, we used fractional polynomial modeling.Results: A total of 22 RCTs were included. Meta-analysis did not find any significant effect of psyllium supplementation on body weight (MD: -0.28 kg, 95% CI: -0.78, 0.21, p = 0.268), BMI (MD: -0.19 kg/m², 95% CI: -0.55, 0.15, p = 0.27) and WC (MD: -1.2 cm, 95% CI: -2.6, 0.2, p = 0.09). Subgroup analysis showed that psyllium dosage, kind of psyllium administration, duration of trial, study design, sample size, and gender were potential sources of heterogeneity. Moreover, there was nonlinear association between duration of psyllium consumption, BMI and WC.Conclusion: Psyllium supplementation does not reduce body weight, BMI, and WC significantly.

Dietary survey in Japanese patients with type 2 diabetes and the influence of dietary carbohydrate on glycated hemoglobin: The Sleep and Food Registry in Kanagawa study

AIMS/INTRODUCTION

The present study investigated the relationship between the macronutrient energy ratio, dietary carbohydrate and glycated hemoglobin levels in Japanese patients with type 2 diabetes, to generate a potential optimal dietary intake of macronutrients for such patients.

MATERIALS AND METHODS

In total, 3,032 patients participating in the Sleep and Food Registry in Kanagawa study were evaluated. Their diets were assessed for macronutrient content through a brief self-administered dietary history questionnaire. Relevant biochemical assays were carried out.

RESULTS

The mean energy intake (±standard deviation) was 1,711 ± 645 kcal/day. The proportion of energy supplied by protein, fat and carbohydrate were 16.3, 26.8 and 52.3%, respectively. Total fiber intake was 12.6 ± 5.7 g/day. The high glycated hemoglobin (HbA1c) group (HbA1c >8%) had significantly lower protein and higher carbohydrate intake than the low HbA1c group (HbA1c <6.5%). Higher HbA1c levels were positively correlated with unfavorable metabolic factors, including elevated body mass index and excess carbohydrate intake, and negatively correlated with age, protein intake and fiber intake. Multiple regression analysis showed a significant association between HbA1c and carbohydrate intake after adjusting for sex, age and body mass index (0.104, P < 0.0001). Additionally, patients within the uppermost tertile for the percentage of total energy intake from carbohydrate (>60%) were most likely to have high HbA1c levels. HbA1c was significantly correlated with carbohydrate (%E) in all age groups and in patients taking one or two antidiabetic drugs.

CONCLUSIONS

The dietary carbohydrate:energy ratio has a positive correlation with HbA1c, suggesting that avoiding excessive carbohydrate intake (>60%) might help foster glycemic control.

Dietary Fiber Intake and Type 2 Diabetes Mellitus: An Umbrella Review of Meta-analyses

Objective

The purpose of this study was to review previously published meta-analyses on the effectiveness of dietary fiber on type 2 diabetes.

Methods

An umbrella review of all published meta-analyses was performed. A PubMed search from January 1, 1980, to April 30, 2017, was conducted using the following search strategy: (fiber OR glucan OR psyllium) AND (meta-analysis OR systematic review). Only English-language publications that provided quantitative statistical analysis on type 2 diabetes, fasting blood glucose concentrations, or glycosylated hemoglobin were retrieved.

Results

Sixteen meta-analyses were retrieved for inclusion in this umbrella review. In the meta-analyses comparing highest versus lowest dietary fiber intake, there was a statistically significant reduction in the relative risk (RR) of type 2 diabetes (RR = 0.81-0.85), with the greatest benefit coming from cereal fibers (RR = 0.67-0.87). However, statistically significant heterogeneity was observed in all of these meta-analyses. In the meta-analyses of supplementation studies using β-glucan or psyllium fibers on type 2 diabetic participants, statistically significant reductions were identified in both fasting blood glucose concentrations and glycosylated hemoglobin percentages.

Conclusion

This review suggests that those consuming the highest amounts of dietary fiber, especially cereal fiber, may benefit from a reduction in the incidence of developing type 2 diabetes. There also appears to be a small reduction in fasting blood glucose concentration, as well as a small reduction in glycosylated hemoglobin percentage for individuals with type 2 diabetes who add β-glucan or psyllium to their daily dietary intake.

Gastrointestinal Transit Time, Glucose Homeostasis and Metabolic Health: Modulation by Dietary Fibers

Gastrointestinal transit time may be an important determinant of glucose homeostasis and metabolic health through effects on nutrient absorption and microbial composition, among other mechanisms. Modulation of gastrointestinal transit may be one of the mechanisms underlying the beneficial health effects of dietary fibers. These effects include improved glucose homeostasis and a reduced risk of developing metabolic diseases such as obesity and type 2 diabetes mellitus. In this review, we first discuss the regulation of gastric emptying rate, small intestinal transit and colonic transit as well as their relation to glucose homeostasis and metabolic health. Subsequently, we briefly address the reported health effects of different dietary fibers and discuss to what extent the fiber-induced health benefits may be mediated through modulation of gastrointestinal transit.

The Effect of Soluble Fiber Supplementation on Metabolic Syndrome Profile among Newly Diagnosed Type 2 Diabetes Patients

Diets with high fiber content improve most metabolic syndrome (MetS) profile in non-diabetic individuals, but there is scarce information about the role of fiber intake in patients with the MetS and diabetes. The objective of this study is to determine whether soluble fiber supplementation improve MetS profile for 8 weeks of intervention in newly diagnosed type 2 diabetes (T2D) adult patients. After one week of dietary stabilization phase, 36 newly diagnosed T2D patients were stratified to different strata according to sex, age, fasting blood sugar (FBS), and waist circumference (WC). Then they were randomly allocated into 2 groups. The psyllium group (n = 18) received 10.5 g of psyllium daily for 8 weeks. The control group (n = 18) maintained their regular diet for 8 weeks. Soluble fiber supplementation showed significant reduction in the majority of MetS profile; FBS (43.55 mg/dL, p < 0.001), triglyceride (37.89 mg/dL, p < 0.001), total cholesterol (20.32 mg/dL, p < 0.001), systolic blood pressure (7.50 mmHg, p < 0.001), diastolic blood pressure (2.78 mmHg, p = 0.013), and WC (2.54 cm, p < 0.001) in the intervention group compared with the control group after 8 weeks of intervention. The high-density lipoprotein cholesterol was reduced in both groups, but this reduction was insignificant. The improvement in the MetS profile was enhanced by combining psyllium to the normal diet. Consumption of foods containing moderate amounts of these fibers may improve MetS profile in newly diagnosed T2D patients. This study was registered in Current Controlled Trials (PHRC/HC/28/15).

Increased Protein Consumption during the Day from an Energy-Restricted Diet Augments Satiety but Does Not Reduce Daily Fat or Carbohydrate Intake on a Free-Living Test Day in Overweight Women

Background: Higher-protein (HP) energy-restriction diets improve weight management to a greater extent than normal-protein (NP) versions. Potential mechanisms of action with regard to assessment of eating behaviors across the day have not been widely examined during energy restriction.Objectives: The objectives of this study were to test whether the consumption of an HP energy-restriction diet reduces carbohydrate and fat intakes through improvements in daily appetite, satiety, and food cravings compared with NP versions and to test whether protein type within the NP diets alters protein-related satiety.Methods: Seventeen overweight women [mean ± SEM age: 36 ± 1 y; body mass index (kg/m2): 28.4 ± 0.1] completed a randomized, controlled-feeding crossover study. Participants were provided with the following ∼1250-kcal/d energy-restricted (-750-kcal/d deficit) diets, each for 6 d: HP [124 g protein/d; 60% from beef and 40% from plant sources (HP-BEEF)] or NP (48 g protein/d) that was protein-type matched (NP-BEEF) or unmatched [100% from plant-based sources (NP-PLANT)]. On day 6 of each diet period, participants completed a 12-h testing day containing repetitive appetite, satiety, and food-craving questionnaires. On day 7, the participants were asked to consume their protein requirement within each respective diet but were provided with a surplus of carbohydrate- and fat-rich foods to consume, ad libitum, at each eating occasion across the day. All outcomes reported were primary study outcomes.Results: The HP-BEEF diet reduced daily hunger by 16%, desire to eat by 15%, prospective food consumption by 14%, and fast-food cravings by 15% but increased daily fullness by 25% compared with the NP-BEEF and NP-PLANT diets (all P < 0.05). However, consuming more protein throughout the day did not reduce the energy consumed ad libitum from the fat- and carbohydrate-rich foods (HP-BEEF: 2000 ± 180 kcal/d; NP-BEEF: 2120 ± 190 kcal/d; NP-PLANT: 2070 ± 180 kcal/d). None of the outcomes differed between the NP-BEEF and NP-PLANT treatments.Conclusions: Although appetite control, satiety, and food cravings improved after an HP energy-restriction diet, increased protein consumption did not reduce carbohydrate and fat intakes throughout the free-living test day in overweight healthy women exposed to highly palatable foods. This trial was registered at clinicaltrials.gov as NCT02614729.

Postprandial PYY increase by resistant starch supplementation is independent of net portal appearance of short-chain fatty acids in pigs

Increased dietary fiber (DF) fermentation and short-chain fatty acid (SCFA) production may stimulate peptide tyrosine-tyrosine (PYY) secretion. In this study, the effects of hindgut SCFA production on postprandial PYY plasma levels were assessed using different experimental diets in a porto-arterial catheterized pig model. The pigs were fed experimental diets varying in source and levels of DF for one week in 3×3 Latin square designs. The DF sources were whole-wheat grain, wheat aleurone, rye aleurone-rich flour, rye flakes, and resistant starch. Postprandial blood samples were collected from the catheters and analyzed for PYY levels and net portal appearance (NPA) of PYY was correlated to NPA of SCFA. No significant effects of diets on NPA of PYY were observed (P > 0.05), however, resistant starch supplementation increased postprandial NPA of PYY levels by 37 to 54% compared with rye-based and Western-style control diets (P = 0.19). This increase was caused by higher mesenteric artery and portal vein PYY plasma levels (P < 0.001) and was independent of SCFA absorption (P > 0.05). The PYY levels were higher in response to the second daily meal compared with the first daily meal (P < 0.001), but similar among diets (P > 0.10). In conclusion, the increased postprandial PYY responses in pigs fed with different levels and sources of DF are not caused by an increased SCFA absorption and suggest that other mechanisms such as neural reflexes and possibly an increased flow of digesta in the small intestine may be involved. The content of DF and SCFA production did not affect PYY levels.

Addition of Rye Bran and Pea Fiber to Pork Meatballs Enhances Subjective Satiety in Healthy Men, but Does Not Change Glycemic or Hormonal Responses: A Randomized Crossover Meal Test Study

Background: The development of high-protein, fiber-rich foods targeting appetite control could be an efficient tool in obesity prevention.Objectives: We investigated whether ad libitum energy intake (EI), appetite, and metabolic markers in a meal context were affected by 1) fiber addition (rye bran and pea fiber) to pork meatballs, 2) the food matrix of the fiber (fiber meatballs compared with fiber bread), or 3) the protein source (animal compared with vegetable protein patties).Methods: In a crossover design, 40 healthy men [mean ± SD: body mass index (BMI; in kg/m2), 22.2 ± 1.9; age, 23.3 ± 2.9 y] consumed 4 test meals: a low-fiber meal consisting of pork meatballs plus wheat bread (LF meal); pork meatballs plus fiber bread; fiber meatballs plus wheat bread, and vegetable patties with a natural fiber content plus wheat bread (∼3000 kJ; protein ∼18% of energy, carbohydrate ∼50% of energy, fat ∼30% of energy; 13 g fiber in the fiber meals). Ad libitum EI after 4 h was the primary endpoint. Moreover, appetite sensations and postprandial responses of glucose, insulin, glucagon-like peptide-1, peptide YY 3-36, and plasma amino acids were measured.Results: Ad libitum EI did not differ significantly between the meals. Satiety and fullness increased 11% and 13%, respectively, and hunger and prospective intake decreased 17% and 15%, respectively, after the meal of fiber meatballs plus wheat bread compared with the LF meal (P < 0.01). Hormonal and metabolic responses did not differ between the meals. In general, plasma amino acid concentrations were higher after the fiber-rich meals than after the LF meal.Conclusions: Meals based on meatballs and bread with differences in the fiber content, food matrix of fiber, and protein source had similar effects on ad libitum EI in healthy men. However, fiber addition to pork meatballs favorably affected appetite sensations but without changes in hormonal and metabolic responses. Moreover, animal- and vegetable-protein-based, fiber-matched meals had similar effects on appetite regulation. This trial was registered at clinicaltrials.gov as NCT02521805.

Influence of Plantago ovata husk (dietary fiber) on the bioavailability and other pharmacokinetic parameters of metformin in diabetic rabbits

Background

Metformin is an oral hypoglycemic agent frequently used in patients with type 2 diabetes. In this study, we have investigated the influence of the dietary fiber Plantago ovata husk on the pharmacokinetics of this drug when included in the diet, as well as when administered at the same time as metformin.

Methods

Six groups of 6 rabbits were used. Groups 1 to 3 were fed with standard chow and groups 4 to 6 with chow supplemented with fiber (3.5 mg/kg/day). Groups 1 and 4 received metformin intravenously (30 mg/kg). Groups 2 and 5 received metfomin orally (30 mg/kg), and number 3 and 6 were treated orally with metformin (30 mg/kg) and fiber (300 mg/kg).

Results

The changes caused by the inclusion of fiber in the feeding were more important in groups that received oral metformin. In this way, metformin oral bioavailability showed an increase of 34.42% when rabbits were fed with supplemented chow.

Conclusions

Plantago ovata husk increased the amount of absorbed metformin when included in the diet (significant increase in AUC), and delayed its absorption when administered at the same time (significant increase in t_max).

Effects of Higher Dietary Protein and Fiber Intakes at Breakfast on Postprandial Glucose, Insulin, and 24-h Interstitial Glucose in Overweight Adults

Dietary protein and fiber independently influence insulin-mediated glucose control. However, potential additive effects are not well-known. Men and women (n = 20; age: 26 ± 5 years; body mass index: 26.1 ± 0.2 kg/m²; mean ± standard deviation) consumed normal protein and fiber (NPNF; NP = 12.5 g, NF = 2 g), normal protein and high fiber (NPHF; NP = 12.5 g, HF = 8 g), high protein and normal fiber (HPNF; HP = 25 g, NF = 2 g), or high protein and fiber (HPHF; HP = 25 g, HF = 8 g) breakfast treatments during four 2-week interventions in a randomized crossover fashion. On the last day of each intervention, meal tolerance tests were completed to assess postprandial (every 60 min for 240 min) serum glucose and insulin concentrations. Continuous glucose monitoring was used to measure 24-h interstitial glucose during five days of the second week of each intervention. Repeated-measures ANOVA was applied for data analyses. The HPHF treatment did not affect postprandial glucose and insulin responses or 24-h glucose total area under the curve (AUC). Higher fiber intake reduced 240-min insulin AUC. Doubling the amount of protein from 12.5 g to 25 g/meal and quadrupling fiber from 2 to 8 g/meal at breakfast was not an effective strategy for modulating insulin-mediated glucose responses in these young, overweight adults.

Orange Pomace Improves Postprandial Glycemic Responses: An Acute, Randomized, Placebo-Controlled, Double-Blind, Crossover Trial in Overweight Men

Orange pomace (OP), a fiber-rich byproduct of juice production, has the potential for being formulated into a variety of food products. We hypothesized that OP would diminish postprandial glycemic responses to a high carbohydrate/fat breakfast and lunch. We conducted an acute, randomized, placebo-controlled, double blind, crossover trial with 34 overweight men who consumed either a 255 g placebo (PLA), a low (35% OP (LOP)), or a high (77% (HOP)) dose OP beverage with breakfast. Blood was collected at 0, 10, 20, 30, and 45 min and at 1, 1.5, 2, 3, 4, 5, 5.5, 6, 6.5, 7, and 8 h. Lunch was consumed after the 5.5-h blood draw. OP delayed the time (T_max1) to the maximum concentration (C_max1) of serum glucose during the 2-h period post breakfast by ≥36% from 33 (PLA) to 45 (HOP) and 47 (LOP) min (p = 0.055 and 0.013, respectively). OP decreased post-breakfast insulin C_max1 by ≥10% and LOP delayed the T_max1 by 14 min, compared to PLA at 46 min (p ≤ 0.05). HOP reduced the first 2-h insulin area under concentration time curve (AUC) by 23% compared to PLA. Thus, OP diminishes postprandial glycemic responses to a high carbohydrate/fat breakfast and the second meal in overweight men.

Effect on Insulin, Glucose and Lipids in Overweight/Obese Australian Adults of 12 Months Consumption of Two Different Fibre Supplements in a Randomised Trial

Higher fibre intakes are associated with risk reduction for chronic diseases. This study investigated the effects of supplementation with PolyGlycopleX^® (PGX), a complexed polysaccharide, on insulin, glucose and lipids in overweight and obese individuals. In this double-blind 12 months study, participants were randomised into three groups: control (rice flour); PGX or psyllium (PSY). Participants followed their usual lifestyle and diet but consumed 5 g of their supplement before meals. Insulin was significantly lower in the PGX and PSY groups compared to control at 3 and 6 months and in the PSY group compared to control at 12 months. Serum glucose was significantly lower in the PGX group at 3 months compared to control. Total cholesterol was significantly lower in the PGX and PSY groups compared to control at 3 and 6 months. High density lipoprotein (HDL) cholesterol was significantly increased in the PGX group compared to control at 12 months. low density lipoprotein (LDL) cholesterol was significantly lower in the PGX group at 3 and 6 months compared to control and in the PSY group at 3 months compared to control. A simple strategy of fibre supplementation may offer an effective solution to glucose, insulin and lipid management without the need for other nutrient modification.

Effect on body weight and composition in overweight/obese Australian adults over 12 months consumption of two different types of fibre supplementation in a randomized trial

BACKGROUND/OBJECTIVES

Higher fibre intakes are associated with risk reduction for chronic diseases. However, many people find difficulty in consuming sufficient fibre through their diet. Supplements may be an effective alternative. We aimed to investigate the effects of PolyGlycopleX® (PGX®), a proprietary polysaccharide complex and a proprietary Psyllium product (PgxSyl™) (PSY) on diet, body weight and composition in overweight and obese individuals.

SUBJECTS/METHODS

This was a double-blind 52 weeks study with 159 people randomized to 3 groups: control (rice flour); PGX (PGX) and proprietary psyllium (PSY). Participants did not change any of their usual habits or diet except they consumed 5 g of supplement taken with a total of 500 ml of water 5-10 min before meals.

RESULTS

Weight was significantly lower in the PGX group compared to control at 3 (-1.6 kg [0.57, 2.67, p = 0.003]), 6 (-2.6 kg [1.01, 4.13, p = 0.001]) and 12 months (-2.6 kg [0.59, 4.64, p = 0.012]) and in the PSY group compared to control group at 3 (-1.1 kg [0.07, 2.12, p = 0.037]) and 6 months (-2.4 kg [0.95, 3.93, p = 0.002]). This was a difference of - 2.8% for the PGX group and - 1.5% for the PSY group compared to control after 12 months supplementation. Body Fat was significantly lower in PGX compared to control at 6 (-1.8 kg [0.63, 2.95, p = 0.003]) and 12 months (-1.9 kg [0.43, 3.36, p = 0.012]) and in PSY compared to control at 6 (-1.9 kg [0.84, 3.04, p = 0.001]) and 12 months (-1.4 kg [0.08, 2.71, p = 0.038]).

CONCLUSIONS

PGX was better than PSY at maintaining dietary changes and weight loss over the 12 month intervention period, with no change to exercise. A simple strategy of PGX supplementation may offer an effective solution to long-term weight-loss and then management without the need for other nutrient modification.

TRIAL REGISTRATION

ANZCTR: ACTRN12611000415909. Registered 20 April 2011.

Soluble fibers from psyllium improve glycemic response and body weight among diabetes type 2 patients (randomized control trial)

BACKGROUND

Water-soluble dietary fibers intake may help control blood glucose and body weight.

OBJECTIVE

The objective of the study was to determine whether soluble fiber supplementation from psyllium improves glycemic control indicators and body weight in type 2 diabetic patients.

METHOD

Forty type 2 diabetes patients, non-smoker, aged >35 years were stratified to different strata according to sex, age, body mass index (BMI) and fasting blood sugar level (FBS) and randomly assigned into two groups; The intervention group which consists of 20 participants was on soluble fiber (10.5 g daily), and the control group which consist of 20 participants continued on their regular diet for eight weeks duration.

RESULTS

After 8 weeks of intervention, soluble fiber supplementation showed significant reduction in the intervention group in BMI (p < 0.001) when compared with the control group. Moreover, water soluble fiber supplementation proven to improve FBS (163 to 119 mg/dl), HbA1c (8.5 to 7.5 %), insulin level (27.9 to 19.7 μIU/mL), C-peptide (5.8 to 3.8 ng/ml), HOMA.IR (11.3 to 5.8) and HOMA-β % (103 to 141 %).

CONCLUSION

The reduction in glycemic response was enhanced by combining soluble fiber to the normal diet. Consumption of foods containing moderate amounts of these fibers may improve glucose metabolism and lipid profile in type 2 diabetes patients.

TRIAL REGISTRATION

Current Controlled Trials PHRC/HC/28/15 .

Comparative Study on the Effect of Plantago psyllium and Ocimum basilicum Seeds on Anthropometric Measures in Nonalcoholic Fatty Liver Patients

Background:

Due to the attribution of fatty liver with some chronic diseases such as obesity, finding a way to control obesity can be useful for the management of fatty liver. This study was performed to assess the effects of Plantago psyllium (PP) and Ocimum basilicum (OB) on anthropometric measurements in people with hepatic steatosis.

Methods:

All patients with nonalcoholic fatty liver disease (NAFLD) were enrolled in this four-arm parallel, randomized, and single blind trial. They randomly assigned into four groups receiving (1) OB 10 g/day; (2) PP 10 g/day; (3) mix of OB and PP 10 g/day; and (4) control group without placebo for 12 weeks. Anthropometric measurements were assessed during study baseline and after 12 weeks intervention. The data were analyzed using paired sample t-test for within group and analysis of covariance for between groups.

Results:

In within group analysis, weight and body mass index show a significant reduction after 12 weeks intervention. In addition, soft lean mass and lean body mass were decreased in PP and mixed of PP and OB groups significantly; another group (OB) shows the same result for mass body fat. Although in intervention groups, we see considerable reduction, between group changes did not demonstrate the same consequences.

Conclusions:

The results of this study showed that administration of OB, PP, or mix of them for 12 weeks does not affect any of the anthropometric measures in NAFLD.

Orange pomace fibre increases a composite scoring of subjective ratings of hunger and fullness in healthy adults

Dietary fibre has been shown to increase subjective satiating ratings. However data from human trials has produced mixed results, possibly due to different types of fibre which have diverse physicochemical properties and gastrointestinal transit behaviour. The aim of study 1 was to investigate whether orange juice (OJ) with 5.5 g of added orange pomace fibre (OPF) was as satiating as whole orange (WO, chopped and blended to a puree/liquid) compared with OJ. Study 2 was to evaluate the dose-dependent satiating effect of OPF delivered in an orange-flavoured beverage. Both studies were randomized, controlled, double blind, cross over in design with 4 intervention arms in study 1 including OJ, OPF, WO, and water, and 3 arms in study 2: orange-flavoured beverage with low (2.5 g) and high (5.5 g) dose of OPF (LD-OPF and HD-OPF), and orange-flavoured beverage without fibre (Control). Volunteers were asked to response to 8 questions relating to hunger, fullness, desire to eat, thirst and discomfort by visual analogue scale (VAS) for each question. Differences were detected in least squares mean estimates of composite satiety scores and each individual question with statistical modelling to adjust for differences in baseline scores. Addition of 5.5 g OPF either to OJ or to orange-flavoured beverage significantly increased the composite satiety scores compared with OJ (P < 0.0001) or Control (P < 0.0001), and the effect was comparative to WO. LD-OPF showed some satiating effect (less desire to eat) compared with Control (P = 0.038), though less effective than HD-OPF (P = 0.043). In conclusion, the addition of OPF to OJ was as effective at increasing satiety as WO consumption compared with OJ; and there was a trend of dose-dependent effect of OPF on satiety compared with the control.

High Protein Pasta is Not More Satiating than High Fiber Pasta at a Lunch Meal, Nor Does it Decrease Mid-Afternoon Snacking in Healthy Men and Women

This study compared satiety after high protein pasta (16 g protein, 6 g fiber), high fiber pasta (11 g protein, 8 g fiber) or control pasta (11 g protein, 6 g fiber) in a randomized, placebo-controlled, double-blind crossover trial. Participants were 36 healthy and men and women from the University of Minnesota campus. Fasted men and women ate calorie controlled, but macronutrient different pastas at 12:00 pm along with 500 mL of water. The primary outcome was satiety assessed by Visual Analogue Scales at 0, 15, 30, 45, 60, 90, 120, and 180 min daily after consuming the pastas. Secondary outcomes were calories consumed at an ad libitum snack at 3:00 pm, calories from food intake, gastrointestinal tolerance, and palatability. No differences were found among the pasta treatments for satiety, snacking, or gastrointestinal tolerance. Men ate significantly more calories for the rest of the (P = 0.007) after the high protein pasta versus the high fiber pasta (1701 ± 154 compared with 1083 ± 154) with control pasta being intermediate to the other treatments. No significant differences were found for gastrointestinal tolerance, but the palatability ratings showed the high protein pasta was less tasty (P = 0.03) and less pleasant (P = 0.01) than the other 2 pastas. Satisfaction was positively associated with pleasantness and negatively associated with aftertaste. Our results do not support the idea that high protein or high fiber pasta produces a greater satiety response compared to pasta with lower amounts of either nutrient. It is likely that since pasta is already a very satiating food, the subjects were unable to differentiate between the 3 conditions.

Evaluating the Intervention-Based Evidence Surrounding the Causal Role of Breakfast on Markers of Weight Management, with Specific Focus on Breakfast Composition and Size

Nutritional strategies are vitally needed to aid in the management of obesity. Cross-sectional and epidemiologic studies consistently demonstrate that breakfast consumption is strongly associated with a healthy body weight. However, the intervention-based long-term evidence supporting a causal role of breakfast consumption is quite limited and appears to be influenced by several key dietary factors, such as dietary protein, fiber, and energy content. This article provides a comprehensive review of the intervention-based literature that examines the effects of breakfast consumption on markers of weight management and daily food intake. In addition, specific focus on the composition and size (i.e., energy content) of the breakfast meal is included. Overall, there is limited evidence supporting (or refuting) the daily consumption of breakfast for body weight management and daily food intake. In terms of whether the type of breakfast influences these outcomes, there is accumulating evidence supporting the consumption of increased dietary protein and fiber content at breakfast, as well as the consumption of more energy during the morning hours. However, the majority of the studies that manipulated breakfast composition and content did not control for habitual breakfast behaviors, nor did these studies include a breakfast-skipping control arm. Thus, it is unclear whether the addition of these types of breakfast plays a causal role in weight management. Future research, including large randomized controlled trials of longer-term (i.e., ≥6 mo) duration with a focus on key dietary factors, is critical to begin to assess whether breakfast recommendations are appropriate for the prevention and/or treatment of obesity.

Breakfast Protein Source Does Not Influence Postprandial Appetite Response and Food Intake in Normal Weight and Overweight Young Women

Breakfasts higher in protein lead to a greater reduction in hunger compared to breakfasts higher in carbohydrate. However, few studies have examined the impact of higher protein breakfasts with differing protein sources. Our objective was to determine if protein source (animal protein (AP) versus plant protein (PP)) influences postprandial metabolic response in participants consuming a high protein breakfast (~30% energy from protein). Normal weight (NW; n = 12) and overweight women (OW; n = 8) aging 18–36 were recruited to participate. Participants completed two visits in a randomized, cross-over design with one week between visits. Subjects had 15 minutes to consume each breakfast. Blood glucose and appetite were assessed at baseline, 15, 30, 45, 60, and 120 minutes postprandial. Participants kept a 24-hour dietary record for the duration of each test day. No difference was found between NW and OW participants or breakfasts for postprandial appetite responses. AP had a significantly lower glucose response at 30 minutes compared with PP (−11.6%; 127 ± 4 versus 112 ± 4 mg/dL; P < 0.05) and a slower return to baseline. There was no difference in daily energy intake between breakfasts. These data suggest that protein source may influence postprandial glucose response without significantly impacting appetite response in breakfast consumers.

Non-cereal ingredients for the attenuation of glycaemic response to bread: a review of the clinical evidence

Enrichment of bread with non-cereal ingredients could favourably influence postprandial glucose response to bread.

Psyllium fiber improves glycemic control proportional to loss of glycemic control: a meta-analysis of data in euglycemic subjects, patients at risk of type 2 diabetes mellitus, and patients being treated for type 2 diabetes mellitus

BACKGROUND

A number of health benefits are associated with intake of soluble, viscous, gel-forming fibers, including reduced serum cholesterol and the attenuation of postprandial glucose excursions.

OBJECTIVE

We assess the effects of psyllium, which is a soluble, gel-forming, nonfermented fiber supplement, on glycemic control in patients who were being treated for type 2 diabetes mellitus (T2DM) and in patients who were at risk of developing T2DM.

DESIGN

A comprehensive search was performed of available published literature (Scopus scientific database) and clinical records stored by Procter & Gamble with the use of key search terms to identify clinical studies that assessed the glycemic effects of psyllium in nondiabetic, pre-T2DM, and T2DM patients.

RESULTS

We identified 35 randomized, controlled, clinical studies that spanned 3 decades and 3 continents. These data were assessed in 8 meta-analyses. In patients with T2DM, multiweek studies (psyllium dosed before meals) showed significant improvement in both the fasting blood glucose (FBG) concentration (-37.0 mg/dL; P < 0.001) and glycated hemoglobin (HbA1c) [-0.97% (-10.6 mmol/mol); P = 0.048]. Glycemic effects were proportional to baseline FBG; no significant glucose lowering was observed in euglycemic subjects, a modest improvement was observed in subjects with pre-T2DM, and the greatest improvement was observed in subjects who were being treated for T2DM.

CONCLUSIONS

These data indicate that psyllium would be an effective addition to a lifestyle-intervention program. The degree of psyllium's glycemic benefit was commensurate with the loss of glycemic control. Because the greatest effect was seen in patients who were being treated for T2DM, additional studies are needed to determine how best to incorporate psyllium into existing prevention and treatment algorithms with concomitant hypoglycemic medications.

Effect of an isocaloric diet containing fiber-enriched flour on anthropometric and biochemical parameters in healthy non-obese non-diabetic subjects

We studied the effect of soluble fiber-enriched products on anthropometric and biochemical variables in 30 healthy non-obese, non-diabetic subjects. This was a randomized, controlled crossover, single-blind, dietary intervention study performed for 8 weeks. Subjects received an isocaloric diet with fiber-enriched products for the first 4 weeks and with regular flour products for the following 4 weeks, or vice versa. Weight, height, measures of fat distribution (waist, hip circumference), glucose, insulin and triglycerides were measured at baseline, after 4 and 8 weeks of intervention. BMI and insulin sensitivity indices were calculated. Weight and BMI decreased in the first period of isocaloric diet in both groups, regardless of the type of flour consumed (weight p<0.01, p<0.001 respectively; BMI p = 0.01, p<0.001 respectively). At the end of the 8 weeks, weight and BMI further decreased in the group consuming the fiber-enriched diet (p<0.01). Insulin resistance, estimated with the Homeostasis Model Assessment index and the Lipid Accumulation Product index, improved in all subjects after the fiber-enriched flour diet (p = 0.03, p = 0.02, respectively). In conclusion, an isocaloric diet supplemented with fiber-enriched products may improve measures of fatness and insulin sensitivity in healthy non-obese non-diabetic subjects. We might hypothesize a similar effect also in subjects with metabolic abnormalities.

Positive impact of a functional ingredient on hunger and satiety after ingestion of two meals with different characteristics

The ingestion of unavailable carbohydrates - functional ingredients - has presented an inverse relationship with the risk for chronic non-communicable diseases. The objective of this work was to evaluate the effects of addition of inulin to two ready-to-eat frozen meals on the release of gastrointestinal hormones and other parameters related to hunger and satiety. Prototypes of two different kinds of frozen meals were elaborated by the food industry: control meal (C1 and C2); and test meals, added inulin (T1 and T2). Three sequential clinical assays were performed with healthy volunteers: 1) evaluation of glycemic response (n=16); 2) evaluation of gastrointestinal hormones related to satiety (n=15); and 3) evaluation of satiety (by Visual Analogue Scale - VAS and energy intake) (n=52). The meals showed low glycemic index and glycemic load, and T1 showed a decreased glycemic response peak compared to C1. The addition of inulin (~8g) to the test meals (lunch) provided significant satiety, resulting in an decrease in energy intake of 419 (group 1) and 586kJ (group 2) in the two subsequent meals (after 180min and 360min) and a decrease in hunger and increase in satiety at 120 and 180min when comparing with control meals. A positive post-prandial variation was observed in the plasmatic levels of ghrelin and insulin in relation to the control meal (hormones related to hunger in high levels), after the intake of both two test meals. Inulin is an ingredient that presents several positive characteristics for the elaboration of products that stimulate healthy eating habits. These effects are currently being evaluated in medium-term trials.

The role of protein in weight loss and maintenance

Over the past 20 y, higher-protein diets have been touted as a successful strategy to prevent or treat obesity through improvements in body weight management. These improvements are thought to be due, in part, to modulations in energy metabolism, appetite, and energy intake. Recent evidence also supports higher-protein diets for improvements in cardiometabolic risk factors. This article provides an overview of the literature that explores the mechanisms of action after acute protein consumption and the clinical health outcomes after consumption of long-term, higher-protein diets. Several meta-analyses of shorter-term, tightly controlled feeding studies showed greater weight loss, fat mass loss, and preservation of lean mass after higher-protein energy-restriction diets than after lower-protein energy-restriction diets. Reductions in triglycerides, blood pressure, and waist circumference were also reported. In addition, a review of the acute feeding trials confirms a modest satiety effect, including greater perceived fullness and elevated satiety hormones after higher-protein meals but does not support an effect on energy intake at the next eating occasion. Although shorter-term, tightly controlled feeding studies consistently identified benefits with increased protein consumption, longer-term studies produced limited and conflicting findings; nevertheless, a recent meta-analysis showed persistent benefits of a higher-protein weight-loss diet on body weight and fat mass. Dietary compliance appears to be the primary contributor to the discrepant findings because improvements in weight management were detected in those who adhered to the prescribed higher-protein regimen, whereas those who did not adhere to the diet had no marked improvements. Collectively, these data suggest that higher-protein diets that contain between 1.2 and 1.6 g protein · kg^-1 · d^-1 and potentially include meal-specific protein quantities of at least ∼25-30 g protein/meal provide improvements in appetite, body weight management, cardiometabolic risk factors, or all of these health outcomes; however, further strategies to increase dietary compliance with long-term dietary interventions are warranted.

Consuming Beef vs. Soy Protein Has Little Effect on Appetite, Satiety, and Food Intake in Healthy Adults

BACKGROUND

Although protein-rich plant foods have recently been touted as an equivalent to animal products, limited data exist regarding the effects of animal vs. plant proteins on appetite, satiety, and subsequent food intake.

OBJECTIVE

The objective was to determine whether a high-protein beef lunch alters the appetitive, hormonal, and neural signals controlling food intake regulation vs. a macronutrient and fiber-matched (MF) or serving size-matched (SS) soy lunch in healthy adults.

METHODS

A randomized, double-blind, crossover design study was completed in 21 adults (aged 23 ± 1 y; body mass index: 23.8 ± 0.6 kg/m²; mean ± SEM) to compare 400-kcal MF and SS lunches varying in protein quality. The MF lunches contained 24-g beef protein or 24-g soy protein, whereas the SS lunches contained 1 serving of beef (24-g protein/1-g fiber) or soy (14-g protein/5-g fiber). Pre- and postlunch appetite questionnaires and blood sampling were completed over an 8-h period until dinner was voluntarily requested. In addition, pre- and postlunch functional MRI brain scans were completed to assess neural activation in response to food stimuli.

RESULTS

On average, dinner was requested at ∼250 ± 20 min postlunch with no differences between beef vs. soy within the MF and SS conditions. Furthermore, no differences in hunger, fullness, peptide YY, or glucagon-like peptide-1 responses were observed after the beef vs. soy lunches within the MF and SS conditions. The SS beef meal led to reductions in anterior cingulate activation (-22 ± 6%) vs. soy (+7 ± 9%; P < 0.01) and greater reductions in insular activation (-30 ± 6%) vs. SS soy (-7 ± 10%; P < 0.01). The participants consumed ∼945 ± 78 kcal after the MF meals and 910 ± 74 kcal after the SS meals with no differences between beef vs. soy.

CONCLUSIONS

When comparing 2 high-quality protein sources, such as beef and soy, the type of protein consumed within a mixed meal elicited very little effect on appetite, satiety, and food intake in healthy adults.