title: Energy intake and appetite are related to antral area in healthy young and older subjects. Effects of age on concentrations of plasma cholecystokinin, glucagon-like peptide 1, and peptide YY and their relation to appetite and pyloric motility. Weekly subcutaneous pegylated recombinant native human leptin (PEG-OB) administration in obese men. Effect of exogenous cholecystokinin (CCK)-8 on food intake and plasma CCK, leptin, and insulin concentrations in older and young adults: evidence for increased CCK activity as a cause of the anorexia of aging. Dose-Dependent Effects of Randomized Intraduodenal Whey-Protein Loads on Glucose, Gut Hormone, and Amino Acid Concentrations in Healthy Older and Younger Men Relation between food intake and visual analogue scale ratings of appetite and other sensations in healthy older and young subjects
abstract: BACKGROUND Gastric distension reduces food intake , and antral , rather than proximal , gastric distension may be the dominant mechanism in the induction of appetite-related sensations . Healthy aging is associated with reduced appetite . OBJECTIVE We examined the effects of different energy preloads on appetite , plasma cholecystokinin , antral area , and subsequent energy intake in healthy older and young subjects . DESIGN On 3 separate days , 12 young and 12 older subjects consumed 400 mL of a drink containing either 0 kcal ( water ) , 250 kcal , or 750 kcal 70 min before a buffet-style meal . RESULTS Hunger was less in the older than in the young subjects ( P < 0.001 ) . Both nutrient preloads reduced hunger and increased fullness more than did water ( P < 0.02 ) , and older subjects were more full than were the young ( P < 0.05 ) . Antral area was greater after the nutrient preloads than after water ( P = 0.001 ) and greater in the older than in the young subjects ( P = 0.005 ) . In both groups , food intake was suppressed in an energy-dependent manner ( P = 0.008 ) . Plasma cholecystokinin was greater in the older than in the young subjects ( P = 0.003 ) . Immediately before the meal , hunger ( r = -0.59 ) and energy intake ( r = -0.90 ) were inversely related and fullness ( r = 0.66 ) was directly related to antral area ( all : P < 0.001 ) . Antral area , but not plasma cholecystokinin , was a predictor of subsequent energy intake . CONCLUSION In healthy young and older subjects , the suppression of subsequent energy intake by a liquid preload is nutrient dependent and comparable , and both satiation and satiety are related to antral area and ( presumably ) antral distension BACKGROUND Aging is associated with a decrease in appetite and a slowing of gastric emptying . The gastrointestinal hormones cholecystokinin ( CCK ) , glucagon-like peptide 1 ( GLP-1 ) , and peptide YY ( PYY ) may mediate these changes . OBJECTIVE We investigated whether aging influenced the secretion of CCK , GLP-1 , and PYY and their effects on appetite and pyloric motility . DESIGN Eight healthy older ( 65 - 80 y ) and 7 younger ( 20 - 34 y ) men received isoenergetic ( 12.1 kJ/min ) intraduodenal infusions of lipid and glucose for 120 min on separate days . Plasma CCK , GLP-1 , and PYY concentrations were measured . RESULTS Plasma CCK concentrations were higher in older than in younger subjects ( P = 0.004 ) as a result of higher baseline values ( 4.7+/-0.2 compared with 3.2+/-0.2 pmol/L ; P < 0.0001 ) and a greater rise during lipid infusion ( increase from baseline : 7.1+/-0.5 compared with 5.3+/-0.6 pmol/L ; P = 0.048 ) . Plasma GLP-1 and PYY concentrations were not significantly different between groups . The decrease in hunger during intraduodenal lipid infusion was inversely related to the increase in CCK , GLP-1 , and PYY in younger but not older subjects . During intraduodenal lipid infusion , the increase in isolated pyloric pressure wave ( IPPW ) frequency was positively related to GLP-1 and PYY and the increase in IPPW amplitude was positively related to CCK in older but not younger subjects , whereas the increase in IPPW amplitude and pyloric tone was negatively related to GLP-1 and PYY in younger subjects . CONCLUSIONS Human aging is associated with increased CCK concentrations , which may contribute to the slowing of gastric emptying , mediated by increased pyloric motility . The role of increased plasma CCK concentrations in mediating the age-related decrease in appetite remains to be established To assess the biological activity and tolerability of pegylated recombinant native human leptin ( PEG-OB ) , 30 obese men ( mean body mass index , 33.9 kg/m2 ) were r and omized to a double-blind treatment with weekly sc injections of 20 mg PEG-OB or placebo for 12 weeks , in addition to a hypocaloric diet ( deficit , 2 MJ/day ) . Body composition , energy expenditure , and metabolic parameters were measured before and after treatment . PEG-OB was generally well tolerated based on adverse event reports , lab values , and vital signs . Weekly sc PEG-OB led to sustained serum concentrations of PEG-OB and leptin throughout treatment . No significant differences in the delta or percent weight loss , percent body fat , sleeping metabolic rate , or respiratory quotient were observed between the PEG-OB and placebo groups . Percent change in serum triglycerides from baseline was significantly correlated with body weight loss in the PEG-OB group , but not in the placebo group . Although larger reductions in serum triglycerides were observed in the PEG-OB group compared with the placebo group , these differences were not statistically significant . We concluded that weekly injection of PEG-OB leads to sustained serum concentration of PEG-OB and leptin throughout the 12-week treatment period and is generally well tolerated . The trends observed in serum triglycerides suggest that a weekly 20-mg sc treatment with PEG-OB may have biological effects in obese men Healthy aging is associated with reductions in appetite and food intake -- the so-called anorexia of aging , which may predispose to protein-energy malnutrition . One possible cause of the anorexia of aging is an increased satiating effect of cholecystokinin ( CCK ) . To investigate the impact of aging on the satiating effects of CCK , 12 young and 12 older healthy subjects received 25-min iv infusions of saline ( control ) and CCK-8 , 1 ng/kg per min or 3 ng/k per min , on 3 separate days before a test meal . Older subjects ate less than young subjects , and food intake was suppressed 21.6 % by CCK-8 , compared with the control day ( P < 0.05 ) . The suppression of energy intake by CCK-8 in older subjects was twice that in young subjects ( 32 + /- 6 % vs. 16 + /- 6 % SEM , P < 0.05 ) and was related to plasma CCK-8 concentrations , which were higher at baseline ( P < 0.05 ) and increased more during CCK-8 infusions in older than young subjects ( P < 0.01 ) . The extent of suppression of food intake per given rise in plasma CCK-8 concentrations did not differ between the two age groups ( P = 0.35 ) . Endogenous CCK concentrations were higher at baseline in older subjects ( P < 0.001 ) and decreased during the CCK-8 but not control infusions ( P < 0.01 ) , suggesting that CCK suppresses its own release . Plasma leptin concentrations were not affected by CCK infusion , whereas postpr and ial insulin concentrations were lowered and the peak postpr and ial glucose concentration was delayed but not affected by CCK-8 infusion . Because older people retain their sensitivity to the satiating effects of exogenous CCK and plasma endogenous CCK concentrations are higher in older people , increased CCK activity may contribute to the anorexia of aging Protein-rich supplements are used widely for the prevention and management of malnutrition in older people . We have reported that healthy older , compared to younger , adults have less suppression of energy intake by whey-protein — effects on appetite-related hormones are unknown . The objective was to determine the effects of intraduodenally administered whey-protein on glucose , gut hormone , and amino acid concentrations , and their relation to subsequent ad libitum energy intake at a buffet meal , in healthy older and younger men .  Hydrolyzed whey-protein ( 30 kcal , 90 kcal , and 180 kcal ) and a saline control ( ~0 kcal ) were infused intraduodenally for 60 min in 10 younger ( 19–29 years , 73 ± 2 kg , 22 ± 1 kg/m2 ) and 10 older ( 68–81 years , 79 ± 2 kg , 26 ± 1 kg/m2 ) healthy men in a r and omized , double-blind fashion . Plasma insulin , glucagon , gastric inhibitory peptide ( GIP ) , glucagon-like peptide-1 ( GLP-1 ) , peptide tyrosine-tyrosine ( PYY ) , and amino acid concentrations , but not blood glucose , increased , while ghrelin decreased during the whey-protein infusions . Plasma GIP concentrations were greater in older than younger men . Energy intake correlated positively with plasma ghrelin and negatively with insulin , glucagon , GIP , GLP-1 , PYY , and amino acids concentrations ( p < 0.05 ) . In conclusion , intraduodenal whey-protein infusions result ed in increased GIP and comparable ghrelin , insulin , glucagon , GIP , GLP-1 , PYY , and amino acid responses in healthy older and younger men , which correlated to subsequent energy intake Objective : Visual analogue scales are widely used in appetite research , yet the validity of these scales to evaluate appetite and mood has not been assessed in older subjects . The aim of this study was to determine the relations between food intake and visual analogue scale ( VAS ) ratings of appetite and nonappetite sensations in healthy older and young subjects . Design : Retrospective combined analysis of four single-blind , r and omised , controlled appetite studies . Setting : All studies were conducted in the University of Adelaide , Department of Medicine , Adelaide , Australia . Subjects : A total of 45 healthy young men ( n=24 ) and women ( n=21 ) aged 18–35 y and 45 healthy older men ( n=24 ) and women ( n=21 ) aged 65–85 y were recruited by advertisement . Interventions : Oral , intraduodenal or intravenous administration of treatments which suppressed food intake were compared to control . Up to 90 min after treatment , a test meal was offered and subjects ate freely for between 30 and 60 min . Perceptions were assessed by 100-mm visual analogue scales administered at regular intervals . Results : Food intake at the test meal was positively related to perceptions of hunger , drowsiness , and calmness at both baseline and premeal ( r>0.16 , P<0.05 ) , and inversely related to premeal ratings of fullness ( r > 0.2 , P<0.05 ) in both older and young subjects . Food intake was related to VAS ratings at least as strongly , if not more so , in older as in young subjects . Conclusions : These observations ( i ) confirm that food intake is related to perceptions of hunger and fullness as assessed by VAS in healthy older and young subjects , and ( ii ) suggest that sensations , not obviously associated with appetite , including ‘ drowsiness ’ and ‘ calmness ’ , are also associated with food intake
target: Higher circulating concentrations of insulin , leptin , cholecystokinin and peptide-YY accord with reduced appetite and energy intakes in healthy older adults .
  Interventions to reduce circulating levels of these hormones may be beneficial for combatting the anorexia of ageing
background: Ageing is associated with reduced appetite and energy intakes .
  However , the mechanisms underlying this phenomenon are not fully understood .
  This systematic review and meta- analysis quantified differences in circulating concentrations of appetite-related hormones between healthy older and younger adults .