This FOODplus seminar was held by Drs Natalie Luscombe-Marsh and Tanya Little, both post-doctoral researchers from the School of Medicine. Natalie and Tanya both have an interest in understanding how the gut senses different macronutrients, and the differential effect of different macromolecules from the diet on gut function and satiety. We learnt that fat has a more significant and prolonged appetite-suppressing effect than carbohydrate, and that this effect is also influenced by fat type; that is, properties of different fats, like chain length and degree of saturation, can alter how they affect gastrointestinal function and the release of gut peptides. Natalies work focused more on the gastrointestinal sensing of protein, and Natalie presented preliminary results from a trial that is currently underway which aims to better understand the impact of protein on gut function and satiety. There is no doubt that understanding more about how different foods and different food components influence satiety is important when we are trying to determine the potential health benefits of different foods. The methods that were presented by Natalie and Tanya have enormous potential for helping us to understand how the novel food products developed within FOODPlus might influence how long feelings of fullness are maintained after a meal and the release of gut peptides which are critical for the regulation of appetite.
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Food and Satiety - part 1
1. The Waite Research Institute
FOODplus Research Centre
Scientific Seminar Series 2010
#3a
Dr Tanya Little
Life Impact | The University of Adelaide
2. Dr Tanya Little
University of 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)
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 袖m * P < 0.05, LE-0.26 vs. control
LE-30 袖m
LE-170 袖m (Seimon et al., AJCN, 2009)
12. 40
Control
LE-0.26 袖m
LE-30 袖m
Score (mm)
20 LE-170 袖m
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)
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- ?
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)
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