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Food and Satiety - part 1
This document summarizes research by Dr. Tanya Little on the gastrointestinal (GI) sensing of dietary fat, highlighting the relationship between dietary fat intake, body weight, and oral sensitivity. It discusses the impact of free fatty acids (FFAs) on appetite and GI function, showing that variations in taste sensitivity to fat are linked to obesity and energy intake. The research emphasizes the need for further studies to explore the potential for improving GI responses in obese individuals through dietary interventions.
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Food and Satiety - part 1
- 1. The Waite ResearchInstitute FOODplus Research Centre Scientific Seminar Series – 2010 #3a Dr Tanya Little Life Impact | The University of Adelaide
- 2. Dr Tanya Little Universityof Adelaide Discipline of Medicine NHMRC Centre of Clinical Research Excellence (CCRE) in Nutritional Physiology, Interventions and Outcomes
- 3. Gastrointestinal (GI) sensing of dietary fat Which factors determine the GI responses to dietary fat? Oral detection of dietary fat Relationships between: ▪ dietary fat intake and body weight ▪ oral and GI sensitivity
- 4. There is a strong positive relationship between the intake of dietary fat with total energy intake and body weight (Golay and Bobbioni, Int J Obes Relat Metab Disord, 1997) Obese individuals have an increased preference for high-fat foods (Mela and Sacchetti, AJCN, 1991)
- 5. 5000 4000 * * 3000 2000 1000 0 Control Fat Glucose * P<0.01 vs. control and glucose (Chapman et al. , AJCN , 1999)
- 6. We examine downstream effects of fat sensing identified in cell line and animal studies. For example, changes in: GI motility plasma concentrations of GI peptides food intake Expression of fat sensing receptors in small intestinal biopsies
- 7. isolated pyloric proximal gastric pressure waves relaxation (IPPWs) pyloric tone small antral pressure intestinal waves fat duodenal pressure waves slowing of gastric emptying (Seimon et al., AJCN, 2010)
- 8. small inhibits energy intestinal fat intake CCK, PYY, GL P-1 ghrelin slows gastric emptying (Seimon et al., AJCN, 2010)
- 9. triacyl- monoacyl- glyceride glyceride ↓ Food intake ↓ food intake + lipase inhibition (Orlistat) FFAs ↑ CCK, GLP-1, ↑ CCK, GLP- PYY 1, PYY ↓ gastric ↓ ghrelin ↓ ghrelin emptying Pancreatic and pancreatic and gallbladder gallbladder secretion secretion
- 10. 9 CCK IPPWs 8 90 7 A 70 6 pmol/l 5 50 P 4 30 3 10 2 D 1 * -10 mmHg 0 Fat Fat+orlistat 0 15 30 45 60 75 90 105 120 Time (min) Energy intake 6400 * 5600 Fat 4800 Fat+Orlistat (kJ) 4000 * P<0.05 vs. Fat kJ 3200 2400 1600 800 0 (Feinle et al., Am J Physiol Gastrointest Liver Physiol, 2003)
- 11. IPPWs CCK 40 * 6 30 4 Number pmol/l 20 * 2 10 0 0 -15 0 30 60 90 120 0 30 60 90 120 Time (min) Time (min) Control LE-0.26 µm * P < 0.05, LE-0.26 vs. control LE-30 µm LE-170 µm (Seimon et al., AJCN, 2009)
- 12. 40 Control LE-0.26 µm LE-30 µm Score (mm) 20 LE-170 µm 0 * -20 0 30 60 90 120 Time (min) * P < 0.05, LE-0.26 vs. control (Seimon et al., AJCN, 2009)
- 13. 45 Effectiveness in slowing 35 gastric emptying 25 15 5 -5 0 2 4 6 8 10 12 14 16 18 Number of carbon atoms in chain (Hunt & Knox, J Physiol, 1968)
- 14. Pylorus Energy intake 120 # 6000 100 80 4000 Total * 60 No. 40 2000 20 0 0 Control C10 C12 Control C10 C12 # vs control: P < 0.05 * vs control/C10: P < 0.05 (Feltrin et al., Am J Physiol Regul Integr Comp Physiol, 2004)
- 15. CCK GLP-1 16 30 12 * 20 * pmol/l 8 # 10 4 0 0 0 15 30 45 60 75 90 0 15 30 45 60 75 90 Time (min) Time (min) Control * vs. control/C10: P < 0.05 # vs. control P < 0.01 C10 C12 (Feltrin et al., Am J Physiol Regul Integr Comp Physiol, 2004)
- 16. PYY Ghrelin 50 500 450 40 * 400 pmol/l 30 350 300 20 250 * 10 200 0 15 30 45 60 75 90 0 15 30 45 60 75 90 Time (min) Time (min) Control * vs. control/C10: P < 0.05 C10 C12 (Feltrin et al., Peptides, 2006)
- 17. vagotomy CCK1 receptor antagonist CCK ↓ Gastric ↓ Food Intake emptying Small intestinal fat
- 18. 60 Medulla 60 Hypothalamus %BOLD from baseline %BOLD from baseline 50 50 40 40 30 30 20 20 10 10 0 0 Lipid + - + - Lipid + - + - Dex - - + + Dex - - + + (Lassman et al., Gastroenterology, 2010)
- 19. CCK Ghrelin 2100 ^ 270000 (pmol/l*180min) (pg/ml*180min) 1575 202500 * AUC AUC 1050 135000 525 * 67500 0 0 Saline LCFA LCFA Saline LCFA LCFA + Dex + Dex PYY 32000 * (pg/ml*180min) 24000 AUC 16000 8000 0 ^ P<0.05 ,LCFA+DEX vs. saline Saline LCFA LCFA * P<0.05, LCFA vs. saline + Dex (Degen et al. Am J Physiol Regul Integr Comp Physiol, 2007)
- 20. 10000 ^ Energy intake (kcal) 8000 * 6000 4000 2000 0 Saline C18 C18+Lox Treatment (Matzinger et al., Gut, 2000)
- 21. CD36 GPR120, GPR119, GPR40 free fatty acid (>C12) Gut peptides (CCK/GLP-1) apo A-IV/chylomicron Gut peptide receptors (e.g. CCK/GLP-1) lumen OA OEA ? PPAR-ɑ ? intestinal L-cell enterocyte intestinal I-cell vagal afferent vagal afferent (from Richard Young)
- 22. CD36 GPR119 mRNA copy number mRNA copy number 1.0 R2 = 0.59 0.0003 R2 = 0.34 0.8 P = 0.02 P = NS 0.0002 0.6 0.4 0.0001 0.2 0.0 0.0000 20 25 30 35 40 20 25 30 35 40 BMI (kg/m2) BMI (kg/m2) (Little et al., unpublished observations)
- 23. FFAs are required for GI and appetite responses to fat Only FFAs with a chain length ≥12 are effective FFAs effects on GI function and energy intake are dependent on the CCK1 receptor Expression of FA sensing receptors in the human SI may be related to BMI
- 24. Recent evidence of a sixth “taste” modality responsive to oral free fatty acids (Chale-Rush et al., Chem Senses, 2007 et al.; Chale-Rush et al., AJP , 2007) FA taste mechanisms analogous to those involved in intestinal fat sensing, e.g. CD36, GPR119, GPR120 Animal studies have revealed a relationship between oral sensing of dietary fat with fat preference (Pittman et al., Chem Senses, 2008; Gilbertson et al., Ann NY Acad Sci, 1998)
- 25. Energy intake Fat intake 10000 40 * 8000 * 30 6000 kJ % 20 4000 2000 10 0 0 Hyper Hypo Hyper Hypo Taste sensitivity Taste sensitivity N = 54 (12 hyper sensitive, 42 hyposensitive Mean BMI: 22.8 (0.8), range 16.8 – 29, kg/m2 * P < 0.05 vs. hypersensitive (Stewart et al., Br J Nutr, 2010)
- 26. Fat taste threshold Energy intake Fat intake 12 14000 120 * * Concentration C18:1 (mM) * * 10 12000 100 10000 8 80 Weight (g) 8000 kJ 6 60 g 6000 4 40 4000 2 2000 20 0 0 0 Lean Obese Lean Obese Lean Obese Lean Obese (Seimon et al., unpublished observations)
- 27. Sensory detection threshold IPPWs Detection threshold (mmol/L) Total no. IPPWs/90 min 15 80 R = -0.615 P = 0.00 60 10 40 5 20 R = 0.669 P = 0.002 0 0 20 25 30 35 40 20 25 30 35 40 BMI (kg/m2) BMI (kg/m2) N = 19 (10 lean, 9 obese) (Seimon et al., unpublished observations)
- 28. Oral detection Habitual fat threshold intake IPPWs R = -0.515 R = -0.532 P = 0.029 P = 0.028 CCK R = -0.430 R = -0.538 P = 0.075 P = 0.015 PYY R = -0.478, P = 0.045 (Seimon et al., unpublished observations)
- 29. Individuals are able to sense or “taste” FFAs in the oral cavity There is large inter-individual variation in taste thresholds for oleic acid Individuals with lower sensitivity to oral fat have : increased BMI increased energy and fat intakes impaired GI responses to intestinal fat infusion
- 30. FFAs have potent effects on GI function, which favour suppression of energy intake Oral fat sensing appears important in mediating dietary fat intake Individuals who are less sensitive to oral FFAs have higher habitual fat, and energy, intakes and BMI Individuals with decreased oral sensitivity to FFAs also appear to have impaired GI sensitivity
- 31. Need to determine: whether the GI responses to fat can be restored in obese individuals, e.g. by energy restriction relationships between intestinal expression of fat sensing receptors with body weight, and acute and chronic nutrient exposure
- 32. Assoc Prof Christine Feinle-Bisset Radhika Seimon Dr Richard Young Assoc Prof Chris Rayner Lena Brandlhuber Deakin University Jessica Stewart Dr Russell Keast