Dalia El Khoury
, Glenview

PhD Physiology Physiopathology


  • Dalia El Khoury · Goff HD · Anderson GH
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    ABSTRACT: Abstract 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.
    No preview · Article · Aug 2015 · Critical Reviews in Food Science and Nutrition
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    ABSTRACT: The objective of this study was to describe the interaction of beverage and food intake with meal advancement in healthy adults. In a randomized controlled study, 29 men and women consumed to satiation, over 20min, a pizza meal with one of the five beverages including water, 1% milk, orange juice, regular cola and diet cola. Mealtime food and fluid intake were measured, within each of three 7-min phases of the meal. A progressive decline occurred from phase 1 to 3 in fluid intake and food intake, averaging 59mL and 268kcal (P<0.0001) respectively; however, the relative intake of fluid to food (mL/kcal) increased (P<0.0001). Beverage type was not a factor. All beverages resulted in similar fluid volume intake compared to water. However, caloric beverages led to higher mealtime total energy intake compared to water (P<0.001) and diet cola (P<0.0001). Baseline thirst correlated positively with both fluid (r=0.28; P<0.001) and food (r=0.16; P<0.05) intakes at the meal, whereas baseline appetite associated positively only with mealtime food intake (r=0.23; P<0.01). In conclusion, mealtime fluid and food intakes interact, unaffected by beverage characteristics, to increase the ratio of fluid to food intake with meal progression. Copyright © 2015. Published by Elsevier Inc.
    No preview · Article · Feb 2015 · Physiology & Behavior
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    ABSTRACT: Milk reduces post-meal glycemia when consumed either before or within an ad libitum meal. The objective of this study was to compare the effect of each of the macronutrient components and their combination with whole milk on postprandial glycemia, glucoregulatory and gastrointestinal hormones and gastric emptying in healthy young men. In a randomized, crossover study, 12 males consumed beverages (500 mL) of whole milk (3.25% M.F.) (control), a simulated milk beverage based on milk macronutrients, complete milk protein (16 g), lactose (24 g), or milk fat (16 g). Whole and simulated milk were similar in lowering postprandial glycemia and slowing gastric emptying while increasing insulin, C-peptide, PYY and CCK, but simulated milk resulted in higher (41%) GLP-1 and lower (43%) ghrelin areas under the curve (AUC) than whole milk (P = 0.01 and P = 0.04, respectively). Whole and simulated milk lowered glucose (P = 0.0005) more than predicted by the sum of AUCs for their components. Adjusted for energy content, milks produced lower glucose and hormone responses than predicted from the sum of their components. The effect of protein/kcal on the AUCs was higher than fat/kcal for insulin, C-peptide, insulin secretion rate, GLP-1, CCK, and paracetamol (P < 0.0001), but similar to lactose except for CCK and paracetamol, which were lower. The response in PYY and ghrelin was similar per unit of energy for each macronutrient. In conclusion, milk lowers postprandial glycemia by both insulin and insulin-independent mechanisms arising from interactions among its macronutrient components and energy content.
    No preview · Article · Nov 2014 · The Journal of Nutritional Biochemistry
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    ABSTRACT: Background: The acute relationship between substrate oxidation as measured by respiratory exchange ratio (RER) and food intake (FI) has not been defined. Objective: To determine acute relationships between RER, modified by exercise and a glucose load, and FI and net energy balance (NEB) in physically active normal-weight boys and men. Methods: In a crossover design, 15 boys (9-12y) and 15 men (20-30y) were randomly assigned to four conditions: 1) water and rest, 2) glucose-drink and rest, 3) water and exercise and 4) glucose-drink and exercise. Indirect calorimetry was used to determine RER, energy expenditure (EE), and carbohydrate and fat oxidation. Subjective appetite and blood glucose were also measured. Results: RER was higher after glucose (0.91±0.01) compared with water (0.87±0.01) (p<0.0001), and after exercise (0.91±0.01) compared with rest (0.88±0.01) (p=0.0043) in men (0.91±0.01) compared with boys (0.88±0.01) (p=0.0002). FI (kcal/m2) did not differ between boys and men. Glucose (582±24 kcal/m2) reduced FI compared with water (689±25 kcal/m2) (p<0.0001), and further decreased FI when combined with exercise (554±34 kcal/m2) (p=0.0303). NEB was reduced with exercise (573±25 kcal/m2) compared with the sedentary condition (686±24 kcal/m2) (p < 0.0001), but was higher after the glucose drink (654±27 kcal/m2) compared with water (605±25 kcal/m2) (p=0.0267). No correlations were found between RER and FI or NEB in boys and men, except in the control condition of resting with water. Conclusions: In conclusion, the short-term modification of substrate oxidation by glucose and/or exercise in normal weight and active boys and men did not affect FI and NEB.
    Full-text · Article · Oct 2014 · Applied Physiology Nutrition and Metabolism

  • No preview · Conference Paper · Apr 2014
  • D El Khoury · H D Goff · S Berengut · R Kubant · G H Anderson
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    ABSTRACT: 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/m(2)) 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.
    No preview · Article · Mar 2014 · European journal of clinical nutrition
  • Dalia El Khoury · G Harvey Anderson
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    ABSTRACT: Purpose of review: There is growing interest in defining the dietary approaches for the management of lipid disorders. This review focuses on dietary proteins. Recent findings: Increasing protein intake was coupled with improved lipid profiles in humans and animals. However, most studies increased the protein content by reducing that of fat or carbohydrate or both, making unclear the role of protein alone. Mechanisms of action differ with the sources of proteins, because of amino acid composition and bioactive peptides encrypted in their sequences. Soy protein was investigated the most, and many studies show that its consumption reduces blood cholesterol. The role of other constituents including isoflavones is debated. Short-term studies are consistent in showing lipid-lowering properties of whey proteins, attributed to their relative high content in branched chain amino acids. A limited number of studies, the majority being on animals, have shown hypocholesterolemic activities of fish proteins. Summary: Dietary proteins regulate lipid metabolism in a manner dependent on their quantity and composition. There is a general consensus that proteins slow lipid absorption and synthesis, and promote lipid excretion. The benefits of dietary proteins remain to be confirmed in individuals with lipid abnormalities, for formulation of optimal dietary alternatives for the management of lipid disturbances.
    No preview · Article · Apr 2013 · Current opinion in lipidology
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    ABSTRACT: Background & aims: We aimed to compare the effects of protein to carbohydrate ratio and physical form in dairy on glucose homeostasis and food intake. Methods: In a crossover design, 20 healthy males consumed 250 g of one of five treatments, plain yogurt, plain yogurt with honey, strawberry yogurt, skim milk or orange juice, as mid-morning snacks. Food intake was assessed 120 min later. Blood glucose, serum insulin and subjective satiety were measured pre- and post-meal. Results: Pre-meal glucose responses were attenuated in a dose-dependent manner to the increasing protein and decreasing sugars in dairy. Protein to carbohydrate ratio correlated negatively with pre-meal glucose due to improved efficacy of insulin action rather than to increased insulin concentrations. Compared with a carbohydrate beverage (orange juice), cumulative blood glucose was lower after dairy snacks but the effect was not explained by their protein to carbohydrate ratio or physical form. Skim milk, with the lowest protein to carbohydrate ratio among dairy products, attenuated both pre-meal and post-meal glucose compared to orange juice without inducing higher insulin levels. There was no effect of treatments on appetite and food intake. Conclusions: While pre-meal glycemia was attenuated dose-dependently to increased protein to carbohydrate ratio in dairy snacks, the contribution of dairy products to post-meal glucose control and to satiety and food intake was independent of their protein to carbohydrate ratio and physical form in healthy men. This trial was registered at clinicaltrials.gov as NCT01673321.
    No preview · Article · Mar 2013 · Clinical nutrition (Edinburgh, Scotland)
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    ABSTRACT: The objective was to compare the effects of ad libitum consumption of commonly consumed meal-time beverages on energy and fluid intakes and post-meal average subjective appetite and blood glucose in healthy adults. In a randomized controlled design, 29 males and females consumed to satiation an ad libitum pizza meal with one of five beverages in unlimited amount including water (0kcal), 1% milk (44kcal/100ml), regular cola (44kcal/100ml), orange juice (44kcal/100ml) and diet cola (0kcal). Food and fluid intakes were measured at the meal. Average subjective appetite and blood glucose were measured before and for 2h after the meal. Although energy intake from pizza was similar among all beverage treatments, the amount of fluid consumed (g) varied among the beverages with intake of orange juice higher than regular and diet cola, but not different from water or milk. Meal-time ingestion of caloric beverages, milk, orange juice and regular cola, led to higher total meal-time energy intakes compared to either water or diet cola. Post-meal blood glucose area under the curve (AUC) was lower after milk than after meals with water, orange juice and regular cola and post-meal average subjective appetite AUC was lower after milk than after meals with water. Meal intakes of nutrients including protein, calcium, phosphorus, zinc, vitamins B12, A and D were higher at the meal with milk compared to the other beverages. Thus, caloric beverages consumed ad libitum during a meal add to total meal-time energy intake, but 1% milk favors a lower post-meal blood glucose and average subjective appetite score and adds to nutrient intake.
    No preview · Article · Feb 2013 · Appetite
  • El Khoury Dalia

    No preview · Article · Jan 2013
  • Dalia El Khoury

    No preview · Chapter · Jan 2013
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    ABSTRACT: The objective was to compare the effects of pre-meal consumption of familiar beverages on appetite, food intake, and glycemic response in healthy young adults. Two short-term experiments compared the effect of consumption at 30 (experiment 1) or 120min (experiment 2) before a pizza meal of isovolumetric amounts (500mL) of water (0kcal), soy beverage (200kcal), 2% milk (260kcal), 1% chocolate milk (340kcal), orange juice (229kcal) and cow's milk-based infant formula (368kcal) on food intake and subjective appetite and blood glucose before and after a meal. Pre-meal ingestion of chocolate milk and infant formula reduced food intake compared to water at 30min, however, beverage type did not affect food intake at 2h. Pre-meal blood glucose was higher after chocolate milk than other caloric beverages from 0 to 30min (experiment 1), and after chocolate milk and orange juice from 0 to 120min (experiment 2). Only milk reduced post-meal blood glucose in both experiments, suggesting that its effects were independent of meal-time energy intake. Combined pre- and post-meal blood glucose was lower after milk compared to chocolate milk and orange juice, but did not differ from other beverages. Thus, beverage calorie content and inter-meal intervals are primary determinants of food intake in the short-term, but macronutrient composition, especially protein content and composition, may play the greater role in glycemic control.
    No preview · Article · Sep 2012 · Appetite
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    D El Khoury · S Antoine-Jonville
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    ABSTRACT: The use of nutritional supplements among exercisers in gyms has been never investigated in the Middle East. The aim of the current study was to assess the prevalence intake of nutritional supplements and the potential influencing factors among people exercising in gyms in Beirut city. In this cross-sectional study, 512 exercisers, aged between 20 and 50 years, were randomly selected from gyms. The intake of nutritional supplements was reported among 36.3% (95% confidence interval 32.2-40.5) of participants, with a weak presence of medical supervision. Patterns of supplement use differed by gender and age. Men and younger exercisers were found to focus on supplements associated with performance enhancement and muscle building, while women and older exercisers were more concerned with health-promoting products such as vitamins, minerals, and herbal supplements. An appropriate dissemination of accurate and scientifically sound information regarding the benefits and side effects of nutritional supplements is highly recommended in the sports environment in Beirut city.
    Full-text · Article · Feb 2012 · Journal of nutrition and metabolism
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    D El Khoury · C Cuda · B.L. Luhovyy · G.H. Anderson
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    ABSTRACT: 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.
    Full-text · Article · Jan 2012 · Journal of nutrition and metabolism
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    ABSTRACT: Dietary proteins elicit a wide range of nutritional and biological functions. Beyond their nutritional role as the source of amino acids for protein synthesis, they are instrumental in the regulation of food intake, glucose and lipid metabolism, blood pressure, bone metabolism and immune function. The interaction of dietary proteins and their products of digestion with the regulatory functions of the gastrointestinal (GI) tract plays a dominant role in determining the physiological properties of proteins. The site of interaction is widespread, from the oral cavity to the colon. The characteristics of proteins that influence their interaction with the GI tract in a source-dependent manner include their physico-chemical properties, their amino acid composition and sequence, their bioactive peptides, their digestion kinetics and also the non-protein bioactive components conjugated with them. Within the GI tract, these products affect several regulatory functions by interacting with receptors releasing hormones, affecting stomach emptying and GI transport and absorption, transmitting neural signals to the brain, and modifying the microflora. This review discusses the interaction of dietary proteins during digestion and absorption with the physiological and metabolic functions of the GI tract, and illustrates the importance of this interaction in the regulation of amino acid, glucose, lipid metabolism, and food intake.
    Full-text · Article · May 2011 · Nutrients
  • D. El Khoury · S. Maïga · N. Hwalla · A. Kalopissis · M. Chabert

    No preview · Article · Mar 2011 · Diabetes & Metabolism
  • Dalia El Khoury · Rola El-Rassi · Sami Azar · Nahla Hwalla
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    ABSTRACT: This study was conducted to investigate whether a higher proportion of protein or fat is more favorable for optimal ghrelin and peptide YY (PYY) release in subjects consuming low carbohydrate meals. Eight normal weight men received, on three separate occasions, high protein low fat (HPLF) (40% protein, 25% fat), low protein high fat (LPHF) (10% protein, 55% fat) or medium protein medium fat (MPMF) (25% protein, 40% fat) meals, with equal low carbohydrates content in all three meals (35% of energy). Postprandial blood samples were collected before and 15, 30, 60, 120, 180 and 240 min following the ingestion of each meal. Plasma acylated ghrelin and PYY(3-36) as well as serum insulin, glucose and triglycerides were measured. Comparing meals and considering each time point separately, a trend for a statistically significant difference in acylated ghrelin was observed between HPLF and LPHF meals and a statistically significant change of PYY from baseline was noted between HPLF and LPHF meals as compared to the MPMF meal at certain time points. When data were pooled together, a statistically significant difference in acylated ghrelin change from baseline was observed between HPLF and LPHF meals, while both HPLF and LPHF meals resulted in a significantly higher PYY(3-36) release in comparison to MPMF meal. AUC data analysis for PYY(3-36) revealed significantly higher values following HPLF in comparison to MPMF meal. Correlation analysis revealed a significant negative correlation between acylated ghrelin and insulin only with the HPLF meal. Postprandial glucose and triglyceride levels were not significantly different between the three meals. In subjects consuming low carbohydrate meals, higher concentrations of proteins to fat seem to have more favorable effects on postprandial appetite hormones.
    No preview · Article · Dec 2010 · European Journal of Nutrition
  • Dalia El Khoury · Nahla Hwalla
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    ABSTRACT: The aim of this study was to investigate the appetite hormones and metabolic responses of hyperinsulinemic subjects to high-protein (HP) meals as compared to high-carbohydrate (HC) and high-fat (HF) meals. Fifteen hyperinsulinemic normoglycemic men received, on 3 separate occasions, HP, HC, or HF meals in a randomized crossover design. Blood samples were collected before and after the ingestion of each meal. Postprandially, acylated ghrelin, PYY(3-36), insulin, glucose, and triglycerides were measured. While the HC meal induced an acutely greater postprandial ghrelin decrease below baseline, the HP meal maintained this decline significantly more than the HF meal at 240 min. Postprandial PYY(3-36) responses did not significantly vary with time and meal composition. Postprandial insulin and glucose peaks were significantly lower following the HP and HF meals in comparison to the HC meal, whereas triglyceride responses were significantly higher following the HF meal. Significant correlations, negative between acylated ghrelin and insulin and positive between PYY(3-36) and insulin, were observed. In hyperinsulinemic normoglycemic men, HP meals ensure a longer-lasting suppression of circulating ghrelin levels and result in more favorable metabolic responses, characterized by a lower surge of postprandial insulin and glucose and a reduced postprandial triglyceride response, as compared to both HC and HF meals.
    No preview · Article · Aug 2010 · Annals of Nutrition and Metabolism
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    ABSTRACT: The metabolic syndrome (MS) is a cluster of heterogeneous abnormalities conferring increased risk of cardiovascular diseases. Few postprandial studies have been conducted in MS individuals. We aimed to study MS subjects with the same abnormalities: abdominal obesity, hypertriglyceridemia and low plasma HDL. We assessed postprandial variations of metabolic parameters related to obesity, dyslipidemia and glucose homeostasis. In this randomized, double-blind, cross-over study, male MS and control subjects consumed, at separate occasions, a high carbohydrate (HC), high fat (HF) or high protein (HP) breakfast meal providing 30% of each subject's resting energy expenditure. Appetite hormones peptide YY and ghrelin did not differ between-subject groups. Interleukin-6 was two-fold higher in MS compared with control subjects, consistently with an inflammatory state. Hypertriglyceridemia of MS subjects was aggravated postprandially with the HF and HP meals and was lowest after the HC meal, arguing against increased hepatic VLDL production. HDL-cholesterol of MS subjects remained low postprandially, whereas apolipoprotein (apo) A-II was higher than in control subjects. Unexpectedly, postprandial insulin and glucose responses were higher in MS compared with control subjects, with the HP meal inducing the greater effects. The sustained postprandial hypertriglyceridemia of MS subjects after all meals suggests defective catabolism of triglyceride-rich lipoproteins. The greater postprandial increases in plasma insulin and glucose in MS relatively to control subjects indicate decreased insulin sensitivity, not revealed in the fasted state.
    No preview · Article · May 2010 · Atherosclerosis

  • No preview · Article · Jun 2009 · Atherosclerosis Supplements

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