The Role of Protein in Weight Management: A Biochemist s Perspective

Transcription

1 The Role of Protein in Weight Management: A Biochemist s Perspective Elaine S. Krul, PhD Global Nutrition Solae LLC, St. Louis, MO American Meat Science Association Reciprocal Meat Conference, June 18, 2012

2 Weight Management is More than Weight Loss Body Mass Index (BMI) BMI = body wt (kg) m 2 = body wt (lb) x 703 in 2 Weight Status < 18.5 Underweight Normal Overweight >30 Obese 2

3 Weight Management is More than Weight Loss Hazardous Waist

4 Maintaining Muscle Mass is Important for Healthy Ageing 4

5 High Protein Meals Important in Weight Management Higher thermogeniccost (higher energy cost to metabolize amino acids) Increased fat oxidation Attenuate glycemic response & insulin release Higher satiety (fullness) levels than low protein meal Threshold effect to increase muscle protein synthesis (~20 g) 5

6 Isoenergetic Substitution of Carbohydrate with Either Pork or Soy Protein Increases 24 hr Energy Expenditure Acute Feeding Crossover Study N=12 (all male) Fasted overnight prior to starting test diet period Test diets for 4 days; 0900h Day h Day 5 spent in whole-body calorimeter %Energy Carb Pork Soy Fat Carbohydrate Protein MikkelsenPB et al. (2000) AJCN 72:

7 Protein Oxidation Lower after Meat vssoy Meal but No Difference in Energy Expenditure, Carbohydrate or Fat Oxidation between Meat, Dairy & Soy Acute Feeding Crossover Study N=12 (9 men, 3 females) Fasted overnight prior to entering whole-room calorimeter for 8 h Test meals 40%En Carb, 30%En Fat & 30%En Prot (variable) 7 Tan S-Y et al. (2010) ObesFacts 3:

8 High Protein Meals Important in Weight Management Higher thermogeniccost (higher energy cost to metabolize amino acids) Increased fat oxidation Attenuate glycemic response & insulin release Higher satiety (fullness) levels than low protein meal Threshold effect to increase muscle protein synthesis (~20 g) 8

9 Glycemic Index, Insulin Secretion and Weight Management Plasma Glucose Area Under the Curve food 1 hour 2 hours High glycemic response Low glycemic response Induces higher insulin secretion Functions of Insulin (anabolic): Tissue absorption of glucose, fatty acids and amino acids Breaking downglucose, fatty acids and amino acids;glycogen into glucose; fat into fatty acids and glycerol; and proteins into amino acids Buildingglycogen from glucose;fats (triglycerides) from glycerol and fatty acids; and proteins from amino acids 9

10 Protein & Fat Modify Glycemic & Insulinemic Responses to a Mashed Potato-Based Meal * p<0.05 vsmp 10 Acute Feeding Crossover Study; N=11 (3 M, 9 F) Standardized evening meal prior to fasting overnight prior to receiving one of 6 different test meals Test meals provided in randomized order 1 week apart Available carbohydrate 50 g in MP, MP+oil, MP+CB and 54 g in MP+S, MP+oil, CB, S & MP+oil,CB, S &RB MP, mashed potatoes; oil, rapeseed oil; CB, chicken breast; S, salad; RB, rye bread HatonenKA et al. (2011) Br J Nutr106:

11 Adding Soy Protein and Soy Fiber Reduces the Glycemic Index of Foods Product Glycemic Index Low GI 55 Medium GI High GI Protein (g) Fiber Rice Crisp Bar 97 2 < 1 Soy Protein Crisp Bar <1 (g) Soy Protein & Fiber Crisp Bar Soy protein & soy fiber independently reduce the glycemic index of foods Hughes, Solae unpublished data

12 High Protein Meals Important in Weight Management Higher thermogeniccost (higher energy cost to metabolize amino acids) Increased fat oxidation Attenuate glycemic response & insulin release Higher satiety (fullness) levels than low protein meal Threshold effect to increase muscle protein synthesis (~20 g) 12

13 No Difference in Satiety between Meat, Dairy & Soy Meals Based on Visual Analogue Scale Acute Feeding Crossover Study N=12 (9 men, 3 females) Fasted overnight prior to entering whole-room calorimeter for 8 h Test meals 40%En Carb, 30%En Fat & 30%En Prot (variable) VAS measured over 8 h 13 Tan S-Y et al. (2010) Obes Facts 3:

14 Cholescystokinin(CCK) and Satiety Gallbladder contraction Satiety signal to NTS in brain CCK Slows gastric emptying Pancreatic enzyme secretion

15 Glucagon-Like Peptide-1 (GLP-1) and Satiety Punjabi M et al (2011) Physiol Behav105:

16 EnteroendocrineCell-based Screen for CCK & GLP-1 Release STC-1 murine enteroendocrine cell line Peptides / hydrolysates* BSA & media controls Soy hydrolysate(lot 4730) positive control Intestinal Villus Acceptable assay variability for multi-step process (samples, cells, ELISA) CCK: Intra-assay %CV ~4-9% GLP-1: Intra-assay %CV ~9-14% GLP-1 (2 hrs) and CCK (4 hrs) measured in cell media by ELISA Evaluate cell viability via MTT reagent * Peptides/hydrolysates soluble in Dulbecco s PBS

17 In Vitro Digestion Protocol Conducted on peptides to confirm that bioactivity of proteins or hydrolysatesare retained after passage through the gut 1. Proteins are digested with pepsin to mimic stomach digestion 2. Proteins are then digested with pancreatin (mix of pancreatic enzymes) to mimic digestion in upper small intestine 3. Enzymes are heat inactivated & digests are centrifuged & sterile filtered to remove insoluble peptides

18 Summary of CCK & GLP-1 Screening Studies Proteins from different sources showed a differential ability to induce CCK or GLP-1 release from the STC-1 cells (after simulated digestion) CCK:Soy > Beef > Egg Albumin ~ Plasma Protein ~ Dairy Whey Protein > Caseinate ~ Beef Gelatin GLP-1:Soy > Dairy Whey Protein > Beef Protein ~ Egg Albumin > Plasma Protein > Beef Gelatin ~ Caseinate 18

19 Use of Different Food Grade Enzymes Generate Hydrolysates with Unique Peptide Profiles Opportunity for obtaining unique protein functionality and bioactivity Degree of hydrolysis Food Grade Enzyme A HIGHER LOWER 19 Protein Molecule A Food Grade Enzyme B B Enzyme Cleavage Site Protein Hydrolysatecontaining Peptide fragments

20 Identification of hydrolysateswith enhanced ability to stimulate CCK & GLP-1 release from STC-1 cells: Summary of Screening Data CCK GLP-1 (% Control) GLP-1 CCK (% Control) Diverse hydrolysateswith unique peptides were generated; approximately 20 hydrolysates have the highest CCK & GLP-1 inducing ability

21 Summary of CCK & GLP-1 Screening Studies Proteins from different sources showed a differential ability to induce CCK or GLP-1 release from the STC-1 cells (after simulated digestion) CCK:Soy > Beef > Egg Albumin ~ Plasma Protein ~ Dairy Whey Protein > Caseinate ~ Beef Gelatin GLP-1:Soy > Dairy Whey Protein > Beef Protein ~ Egg Albumin > Plasma Protein > Beef Gelatin ~ Caseinate Hydrolysis of soy protein by food enzymes further increases the satiety hormone inducing activity of soy protein & this activity is not lost, but further increased by simulated gastrointestinal digestion 21

22 Next Steps We need to test the hypothesis that the proteins with increased CCK and GLP-1 inducing activity do show an enhanced satiating activity in humans in a clinical study Determine what other factors may contribute to inducing satiety that may be additive or synergistic to the satiating effect of protein per se 22

23 Longer chewing time is associated with increased satiety Changes in Hunger CassadyBA et al (2009) AJCN 89: Sakata T et al (2003) ExpBiolMed (Maywood) 228:

24 High Protein Meals Important in Weight Management Higher thermogeniccost (higher energy cost to metabolize amino acids) Increased fat oxidation Attenuate glycemic response & insulin release Higher satiety (fullness) levels than low protein meal Threshold effect to increase muscle protein synthesis (~20 g) 24

25 High Quality Protein from Various Sources Promotes Muscle Protein Synthesis *p < 0.01 vscasein # p < 0.05 vssoy Tang JE et al (2009) J ApplPhysiol107: Healthy men (3 parallel groups; n=6 per group) Exercised one leg (leg press and leg extension) (Ex) and rested the other (Rest) Each protein (22g) was consumed as a single drink immediately following exercise Vastuslateralismuscle at 180 min post drink consumption Measure mixed muscle FSR-rate of tracer incorporation into muscle

26 Ingestion of 20 g High Quality Protein is Sufficient to Maximally Stimulate Muscle Protein Synthesis Healthy men (age 22 ±2 yr; N=6) Randomized crossover design; visits >1 week apart Overnight fast Bout of resistance exercise followed by catheterization fro blood draws Immediately consumed 400 ml beverage containing 0,5,10,20 or 40 g egg protein Vastuslateralismuscle at 1 and 4 hr post drink consumption Moore DR et al (2009) AJCN 89: Measure mixed muscle FSR-rate of tracer incorporation into muscle 26

27 D5-Phe Free Amino Acids Gln Muscle Protein Synthesis Leu Insulin IGF-1 PI-3 Kinase Mechanotransduction signals Exercise Blood Extracellular MPS Gln Free Amino Acid Pool un-incorporated Protein incorporated MPB? 4EBP1 PKB mtor DO NOT DISTRIBUTE p70s6k? eif4g Intracellular Muscle protein synthesis FSR = Fractional Synthetic Rate FSR=(E b X100)/(E a X t)

28 Beef Protein Promotes Muscle Protein Synthesis in Young & Elderly Subjects With or Without Resistance Exercise 28 Symons TB et al (2011) J Health NutrAging 15: Young men (age 29 ±3yr; N=7) & Older men (age 67 ±2yr; N=7) Overnight fast 90% Lean Beef meal (90g 1200 hr Resistance exercise at 1300 hr Vastuslateralismuscle at 0900, 1200 and 1700 hr Measure mixed muscle FSR-rate of tracer incorporation into muscle

29 The Rationale for Consuming Protein Blends in Sports Nutrition Complete Protein Adds Lean Body Mass High in Glutamine & Arginine Digestion Rate High in Branched- Chain Amino Acids Attacks Anti- Free Oxidant Radicals Capacity Soy Protein Intermediate Whey Protein Fast Casein Combination Slow Prolonged

30 Human Clinical Study to Assess the Effect of a Protein Blend vs Whey Protein on Muscle FSR Whey Protein Soy-Dairy Blend Soy-Dairy Blend 25% Whey 50% Caseinate 25% Soy Protein Young Healthy subjects (n=10/group), normal to overweight Single intake of Blend or Whey protein one hour after exercise; Protein normalized to kg lean mass (avg 22 grams PRO)-all subjects received leucine threshold ( 2g) FSR was measured to determine muscle protein synthesis

31 Muscle Protein Synthesis Prolonged after Blend vs Whey Protein Consumption Whey protein alone and whey:caseinate:soyprotein blend stimulated muscle protein synthesis and this was significantly higher after 3 hours compared to baseline for both beverages consumed after exercise Only the whey:caseinate:soyblend showed significantly higher muscle protein synthesis over basal levels 5 hours after beverage consumption; consuming the whey protein beverage alone failed to show significantly increased muscle protein synthesis after 5 hours Paul T. Reidy 1 et al., presented at Experimental Biology, San Diego, April 2012

32 The Hearty Griller A high quality protein blend with reduced fat Combination 80% lean beef and soy textured protein (SuproMax ) 37% by weight hydrated soy protein Reduction in fat and cholesterol vs. 80% beef burger No compromise in nutritional protein quality Final product has 16% more protein by weight

33 80% Lean Beef with 0.6% Salt Hearty Griller 27% Fewer Calories 44% Less Fat 47% Less Sat. Fat 44% Less Cholesterol 16% More Protein Providing animal protein with a more health friendly label!

34 Hearty Griller Product Acceptance (mean scores) Dislike Extremely 90% Lean All Beef 5.9 Hearty Griller % Lean All Beef Overall Liking 9 1 Appearance 9 1 Flavor 9 b a a a 1 Texture 9 b No Difference 1 Juiciness 9 b a a Like Extremely

35 Summary High quality proteins promote muscle protein synthesis with or without resistance exercise when consumed at levels of 20 g or more per eating event Blends of different proteins consumed at a meal may offer additional advantages to promote muscle protein synthesis over an extended period of time Blends of soy protein with animal derived proteins can offer a cost effective way to reduce the fat and cholesterol content while maintaining an acceptable high quality protein product needed for muscle protein synthesis 35

36 Overall Summary Consuming high protein diets promotes energy expenditure and fat oxidation compared to low protein diets thereby contributing to reduced overall energy intake and less weight gain High protein meals reduce the glycemic index for a given amount of carbohydrate; this reduces the hyper secretion of insulin and prevents insulin mediated fat deposition Different proteins induce satiety hormone release in cell-based assays to varying degrees; partial enzyme hydrolysis of soy protein appears to enhance CCK & GLP-1 release 36 High quality proteins promote muscle protein synthesis & protein blends may have additional benefits by stimulating muscle protein synthesis for longer periods & offers ways to increase the relative protein to lipid content of product offerings

37 Acknowledgements Global Nutrition Nutrition Discovery Nancy McGraw Nida Napawan Dustie Butteiger Global Nutrition Applied Nutrition Mark Cope Ratna Mukherjea Applications Sensory Science & Meat Science Elizabeth Reim Colleen Conley Ingredient Science & Technology Barry Tulk

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