Gerald Harvey Anderson

Beta Glucan: Health Benefits in Obesity and Metabolic Syndrome

Despite the lack of international agreement regarding the definition and classification of fiber, there is established evidence on the role of dietary fibers in obesity and metabolic syndrome. Beta glucan (β-glucan) is a soluble fiber readily available from oat and barley grains that has been gaining interest due to its multiple functional and bioactive properties. Its beneficial role in insulin resistance, dyslipidemia, hypertension, and obesity is being continuously documented. The fermentability of β-glucans and their ability to form highly viscous solutions in the human gut may constitute the basis of their health benefits. Consequently, the applicability of β-glucan as a food ingredient is being widely considered with the dual purposes of increasing the fiber content of food products and enhancing their health properties. Therefore, this paper explores the role of β-glucans in the prevention and treatment of characteristics of the metabolic syndrome, their underlying mechanisms of action, and their potential in food applications.

Regular consumption of pulses for 8 weeks reduces metabolic syndrome risk factors in overweight and obese adults

Pulses are low in energy density, supporting their inclusion in the diet for the management of risk factors of the metabolic syndrome (MetSyn). The aim of the present study was to describe the effects of frequent consumption (five cups/week over 8 weeks) of pulses (yellow peas, chickpeas, navy beans and lentils), compared with counselling to reduce energy intake by 2093 kJ/d (500 kcal/d), on risk factors of the MetSyn in two groups (nineteen and twenty-one subjects, respectively) of overweight or obese (mean BMI 32·8 kg/m2) adults. Body weight, waist circumference, blood pressure, fasting blood parameters and 24 h food intakes were measured at weeks 1, 4 and 8. Blood glucose, insulin, C-peptide, glucagon-like peptide-1 (GLP-1) and ghrelin were measured after a 75 g oral glucose load at weeks 1 and 8. At week 8, both groups reported reductions in energy intake, waist circumference, systolic blood pressure, glycosylated Hb (HbA1c) and glucose AUC and homeostasis model of insulin resistance (HOMA-IR) following the glucose load (P < 0·05). However, HDL, fasting C-peptide and insulin AUC responses were dependent on diet (P < 0·05). HDL and C-peptide increased by 4·5 and 12·3 %, respectively, in the pulse group, but decreased by 0·8 and 7·6 %, respectively, in the energy-restricted group. Insulin AUC decreased in both females and males on the energy-restricted diet by 24·2 and 4·8 %, respectively, but on the pulse diet it decreased by 13·9 % in females and increased by 27·3 % in males (P < 0·05). In conclusion, frequent consumption of pulses in an ad libitum diet reduced risk factors of the MetSyn and these effects were equivalent, and in some instances stronger, than counselling for dietary energy reduction.

Regulation of Protein Intake by Plasma Amino Acids

Since the first statement of the aminostatic theory of food-intake regulation by Mellinkoff (1957), the role of dietary and plasma amino acids in the regulation of food intake has been examined in many studies (Harper et al,1970; Harper, 1976). Generally, animals decrease their food intake when fed diets in which the protein content is very low, very high, or deficient in an indispensable amino acid, or in which the protein pattern is grossly distorted from the amino acid requirements of the animal. This food-intake depression has been attributed to changes in free amino acids in body fluids, which give rise to signals monitored in the central nervous system (CNS) (Rogers and Leung, 1973). Even though it has been shown that specific brain regions are involved in the feeding response to the amino acid content of the diet, the functional separation of a protein-intake regulatory mechanism from the energy-intake regulatory mechanism has only recently been investigated. The demonstration that protein and energy intake are regulated independently was achieved through the use of a self-selection feeding model (Booth, 1974; Musten et al, 1974; Ashley and Anderson, 1975a, 1977a). This model has also permitted the identification of specific relationships between plasma amino acid patterns and food selection (Ashley and Anderson, 1975b; Anderson and Ashley, 1976). The same plasma amino acid patterns have been shown to affect brain neurotransmitter metabolism and behavior (Fernstrom, 1976). Consequently, a mechanism whereby plasma amino acids give rise to signals that are important determinants of both protein and energy intake can be proposed.

Food Intake and Satiety Following a Serving of Pulses in Young Men: Effect of Processing, Recipe, and Pulse Variety

Background: Diets containing beans have been associated with a lower risk of obesity and overweight in several dietary surveys. These results suggest a benefit might be derived from beans and other pulses, possibly due to improved satiety or satiation and therefore lowering energy intake. Such a hypothesis has not been tested. Objectives: To investigate the effect of processing, recipe, and pulse variety on short-term food intake (FI), subjective appetite, and glycemic response after pulse consumption in healthy young men. Design: Three experiments were conducted. In a randomized repeated-measures design, young men aged 18–35 years with a body mass index of 20–25 kg/m2 were fed the test treatments. In experiment 1 (n  =  14), navy beans canned in Canada or in the United Kingdom were compared with homemade navy beans and 300 ml of glucose drink, each containing 50 g of available carbohydrate. In experiment 2 (n  =  14), canned navy beans in tomato sauce, maple style, with pork and molasses, and homemade navy beans with pork and molasses were compared with white bread, each containing 50 g of available carbohydrate. In experiment 3 (n  =  15), 4 equicaloric (300-kcal) treatments of pulses were compared with both a white bread and water control. Blood glucose and subjective appetite were measured from immediately before consumption of the treatment to 120 minutes later when FI from a pizza meal was measured. Results: All caloric treatments decreased subjective appetite. In no experiment did any pulse treatment lower FI at 120 minutes compared with white bread or result in lower cumulative FI (sum of calories from treatment and pizza meal) compared with either 50 g of available carbohydrate as a glucose drink (experiment 1) or from white bread (experiment 2) or compared with equal food energy from white bread (experiment 3). Glycemic response to navy beans was affected by recipe, but not processing, and as with the other pulses, it was lower than with white bread. An inverse relationship was observed between glycemic response and both subjective appetite and FI at 120 minutes in experiment 3 (r  =  −0.4, p  =  0.001) but not in experiments 1 (r  =  0.1, p  =  0.62) and 2 (r  =  0.2, p  =  0.10). Conclusion: The short-term effect of pulse consumption on subjective appetite and FI at a meal 120 minutes later and in cumulative food intake was determined primarily by energy content and was little influenced by composition, processing, recipe, or variety. Thus, the epidemiological associations between frequent pulse consumption and lower risk of obesity and overweight are not explained by short-term effect of pulses on satiety and FI.

Milk proteins in the regulation of body weight, satiety, food intake and glycemia.

Consumption of dairy products and their milk proteins increase satiety and reduce food intake and blood glucose response when consumed alone or with carbohydrate. Dairy proteins are of interest because proteins are more satiating than either carbohydrate or fat, and they regulate food intake and metabolic functions by the combined actions of the intact protein, encrypted peptides and amino acids on gastrointestinal and central pathways. As shown in this review, milk proteins have physiologic functions that contribute to the maintenance of a healthy body weight and control of factors associated with the metabolic syndrome through their effects on mechanisms regulating food intake and blood glucose. More recent reports show that these benefits can be achieved within the range of usual consumption of dairy. In addition, recent research points to an intrinsic value of small amounts of milk protein or dairy consumed shortly before a meal to reduce the glycemic response to carbohydrate and that this is not at the cost of increased demand for insulin.

The acute effect of commercially available pulse powders on postprandial glycaemic response in healthy young men.

Whole pulses (beans, peas, chickpeas and lentils) elicit low postprandial blood glucose (BG) responses in adults; however, their consumption in North America is low. One potential strategy to increase the dietary intake of pulses is the utilisation of commercial pulse powders in food products; however, it is unclear whether they retain the biological benefits observed with whole pulses. Therefore, the present study examined the effects of commercially prepared pulse powders on BG response before and after a subsequent meal in healthy young men. Overall, three randomised, within-subject experiments were conducted. In each experiment, participants received whole, puréed and powdered pulses (navy beans in Expt 1; lentils in Expt 2; chickpeas in Expt 3) and whole-wheat flour as the control. All treatments were controlled for available carbohydrate content. A fixed-energy pizza meal (50·2 kJ/kg body weight) was provided at 120 min. BG concentration was measured before (0-120 min) and after (140-200 min) the pizza meal. BG concentration peaked at 30 min in all experiments, and pulse forms did not predict their effect on BG response. Compared with the whole-wheat flour control, navy bean treatments lowered peak BG concentrations (Expt 1, P< 0.05), but not the mean BG concentration over 120 min. The mean BG concentration was lower for all lentil (Expt 2, P= 0.008) and chickpea (Expt 3, P= 0.002) treatments over 120 min. Processing pulses to powdered form does not eliminate the benefits of whole pulses on BG response, lending support to the use of pulse powders as value-added food ingredients to moderate postprandial glycaemic response.

The Role of Alginates in Regulation of Food Intake and Glycemia: A Gastroenterological Perspective

Regulation of food intake through modulation of gastrointestinal responses to ingested foods is an ever-growing component of the therapeutic approaches targeting the obesity epidemic. Alginates, viscous and gel-forming soluble fibers isolated from the cell wall of brown seaweeds and some bacteria, are recently receiving considerable attention because of their potential role in satiation, satiety, and food intake regulation in the short term. Enhancement of gastric distension, delay of gastric emptying, and attenuation of postprandial glucose responses may constitute the basis of their physiological benefits. Offering physical, chemical, sensorial, and physiological advantages over other viscous and gel-forming fibers, alginates constitute promising functional food ingredients for the food industry. Therefore, the current review explores the role of alginates in food intake and glycemic regulation, their underlying modes of action and their potential in food applications.

Effect of sodium alginate addition to chocolate milk on glycemia, insulin, appetite and food intake in healthy adult men.

Background/Objectives:Sodium alginate reduces appetite and glycemia, when consumed in water- and sugar-based drinks. But, its effects when added to other commonly consumed beverages have not been reported. Because chocolate milk (CM) is criticized for raising blood glucose more than unflavored milk, the aim of our study was to investigate the effect of adding a strong-gelling sodium alginate to CM on glycemia, insulinemia, appetite and food intake.Subjects/Methods:In a randomized crossover design, 24 men (22.9±0.4 years; 22.5±0.3 kg/m2) were provided with isovolumetric (325 ml) treatments of CM, 1.25% alginate CM, 2.5% alginate CM or 2.5% alginate solution. Sodium alginate had a ratio of 0.78:1 of mannuronic acid (M) to guluronic acid (G) residues, and was block distributed. Treatments were standardized for lactose, sucrose and calcium content, and provided 120 min before an ad libitum pizza meal during which food intake was measured. Appetite and blood glucose and insulin were measured at baseline and at intervals pre- and post-meal.Results:Addition of 2.5% alginate to CM reduced peak glucose concentrations, at 30 min, by an average of 6% and 13% compared with 1.25% alginate CM (95% confidence intervals (CIs): 0.02–1.08; P=0.037) and CM alone (95% CIs: 0.49–1.55; P=0.000) respectively. Insulin peaks at 30 min were lower by 46% after 2.5% alginate CM relative to CM (95% CIs: 3.49–31.78; P=0.009). Pre-meal appetite was attenuated dose dependently by alginate addition to CM; CM with 2.5% alginate reduced mean appetite by an average of 134% compared with CM alone (95% CIs: 8.87–18.98; P=0.000). However, total caloric intake at the pizza meal did not differ among treatments.Conclusions:The addition of a strong-gelling sodium alginate to CM decreases pre-meal glycemia, insulinemia and appetite, but not caloric intake at a meal 2 h later, in healthy adult men.

Application of dairy-derived ingredients in food intake and metabolic regulation

This chapter discusses the role of milk and dairy products, and their ingredients in obesity and the regulation of food intake and components of metabolic syndrome. In addition to protein (whey and casein), fat (saturated, mono- and poly-unsaturated fatty acids) and carbohydrate (lactose), milk contains biologically active substances such as immunoglobulins, enzymes, antimicrobial peptides, oligosaccharides, hormones, cytokines and growth factors. Each of these may affect food intake and metabolic regulation through a large number of physiologic mechanisms. Thus, their actions may explain the positive health associations between more frequent dairy consumption, a healthier body weight, and decreased risk of developing the metabolic syndrome.