Food label education does not reduce sodium intake in people with type 2 diabetes mellitus. A randomised controlled trial.

BACKGROUND: Sodium intake is high in people with type 2 diabetes (T2DM). The aim of this study was to investigate whether urinary sodium excretion can be reduced by educating people with T2DM to read food labels and choose low sodium products. METHOD: In a 3 month randomised controlled trial, 78 men (n=49) and women (n=29) with T2DM were recruited from a Diabetes Centre at a University teaching hospital. The intervention group was educated in a single session to use the nutrition information panel on food labels to choose products which complied with the Food Standards Australia New Zealand (FSANZ) guideline of <120 mg sodium/100 g food. The control group continued on their usual diet. The primary outcome measure was 24h urinary sodium excretion which was performed at baseline and 3 months. Data was analysed using repeated measures analysis of variance, independent samples t-test and Pearson's correlations. RESULTS: At 3 months mean urinary sodium excretion was unchanged in the intervention (174±13 mmol/24 h and 175±13 mmol/24 h) and control group (167±15mmol/24h and 161±13 mmol/24 h), and there was no between group difference (p>0.05). CONCLUSION: Sodium excretion was not reduced following the label reading education provided to this group of people with T2DM.

Orlistat accentuates the fat-induced fall in blood pressure in older adults.

Postprandial hypotension may be influenced by the digestion of fat. The aim of the present study was to evaluate the hypothesis that products of fat digestion mediate the hypotensive response to fat. In part A of the study, nine healthy older subjects were studied on three separate occasions in randomised order. Blood pressure, heart rate (HR), plasma TAG and gastric emptying were measured following the ingestion of equivolaemic drinks: (1) 300 ml of high-fat drink (88 % fat); (2) fat drink mixed with 120 mg orlistat (lipase inhibitor); (3) water (control). In part B of the study, ten healthy older subjects were studied on two separate occasions. Blood pressure, HR, plasma TAG and superior mesenteric artery flow were measured during 90 min intraduodenal infusions of 10 % intralipid (2·7 ml/min), with and without 120 mg orlistat. Oral fat ingestion was associated with decreases in systolic and diastolic blood pressures (both P = 0·0001) that were greater when orlistat was co-administered (both P < 0·05), and an increase in HR (P = 0·0001) that was inhibited by orlistat co-administration (P < 0·03). Gastric emptying was slowed by oral fat digestion, and orlistat administration inhibited this slowing (P < 0·04). Intraduodenal fat infusion was not associated with changes in blood pressure but increased HR (P < 0·0001), an effect attenuated by orlistat (P < 0·05). In conclusion, orlistat potentiates the hypotensive response to oral fat in older adults, possibly as a result of faster gastric emptying of fat. The results do not support a role for fat digestion in lowering blood pressure.

The effect of testosterone and a nutritional supplement on hospital admissions in under-nourished, older people.

BACKGROUND: Weight loss and under-nutrition are relatively common in older people, and are associated with poor outcomes including increased rates of hospital admissions and death. In a pilot study of 49 undernourished older, community dwelling people we found that daily treatment for one year with a combination of testosterone tablets and a nutritional supplement produced a significant reduction in hospitalizations. We propose a larger, multicentre study to explore and hopefully confirm this exciting, potentially important finding (NHMRC project grant number 627178). METHODS/DESIGN: One year randomized control trial where subjects are allocated to either oral testosterone undecanoate and high calorie oral nutritional supplement or placebo medication and low calorie oral nutritional supplementation. 200 older community-dwelling, undernourished people [Mini Nutritional Assessment score <24 and either: a) low body weight (body mass index, in kg/m(2): <22) or b) recent weight loss (>7.5% over 3 months)]. Hospital admissions, quality-adjusted life years, functional status, nutritional health, muscle strength, body composition and other variables will be assessed. DISCUSSION: The pilot study showed that combined treatment with an oral testosterone and a supplement drink was well tolerated and safe, and reduced the number of people hospitalised and duration of hospital admissions in undernourished, community dwelling older people. This is an exciting finding, as it identifies a treatment which may be of substantial benefit to many older people in our community. We now propose to conduct a multi-centre study to test these findings in a substantially larger subject group, and to determine the cost effectiveness of this treatment. TRIAL REGISTRATION: Australian Clinical Trial Registry: ACTRN 12610000356066.

Effects of nutritional supplementation on the appetite and energy intake responses to IV cholecystokinin in older adults.

Human aging is associated with a reduction in appetite and food intake. Increased activity of the satiety hormone, cholecystokinin (CCK), may be partly responsible. This study aimed to determine whether an increase in fat and energy intake modifies the suppressive effects of CCK-8 on appetite and energy intake. Fourteen healthy older adults completed three separate dietary periods, a 14-day and a 7-day normal diet (ND; 8272 ± 480 kJ/day; 35% fat), and a 14-day high-fat diet (HFD; 11,642 ± 414 kJ/day; 43% fat), in randomised order. Immediately following each diet, subjects received, in single-blinded fashion, a 30-min intravenous infusion of either CCK-8 (1.5 ng/kg/min) (ND-CCK, HFD-CCK) or 0.9% saline (ND-SAL), the latter following only ND. Plasma CCK concentrations, appetite responses and energy intake at a buffet meal were determined. Energy intake at the buffet meal was higher on the ND-SAL study day (3349 ± 224 kJ), when compared with either ND-CCK (3023 ± 317 kJ) or HFD-CCK (2905 ± 316 kJ). The suppression of energy intake by CCK-8 infusion did not differ between the two diets. We conclude that suppression of energy intake by exogenous CCK-8 does not appear to be attenuated by incorporation of supplemental high-energy, high-fat drinks in the diet of healthy older adults.

Carbohydrate and fat digestion is necessary for maximal suppression of total plasma ghrelin in healthy adults.

It is uncertain whether the postprandial suppression of ghrelin is dependent on digestion and absorption of nutrients or whether the presence of nutrients in the small intestine is sufficient. Twenty-four healthy young adults with a mean age of 23 ± 0.6 years were examined on 3 separate days after an overnight fast. Twelve subjects participated in Part A, and the other 12 subjects in Part B. In Part A, subjects consumed, in random order, one of three study drinks: 300 mL water; 300 mL high-fat drink, with and without, 120 mg orlistat. In Part B, subjects received, in random order, one of three drinks: 300 mL water; 300 mL sucrose, with and without, 100mg acarbose. In both parts gastric emptying as measured by 2-D ultrasound. In Part A, plasma ghrelin concentrations decreased following ingestion of the high-fat drink, but did not change with the high-fat-orlistat drink or water. In Part B, the suppression of plasma ghrelin following the sucrose drink, was attenuated by acarbose. Orlistat accelerated gastric emptying of the high-fat drink, while acarbose delayed gastric emptying of the sucrose drink. In conclusion, fat and carbohydrate digestion is required for maximal suppression of ghrelin secretion.

Hyperbaric oxygen but not hyperbaric air increases insulin sensitivity in men with type 2 diabetes mellitus.

INTRODUCTION: We have previously shown that hyperbaric oxygen treatment (HBOT) increased insulin sensitivity in men who were obese or overweight, both with and without type 2 diabetes. The aim of this study was to test whether this insulin-sensitising effect is seen in hyperbaric air (HA). METHODS: Men with type 2 diabetes who were obese or overweight were randomised to two groups: HBOT (n = 13) or HA (n = 11). A hyperinsulinaemic euglycaemic glucose clamp (80 mU·m-2·min-1) was performed at baseline and during hyperbaric intervention. Both groups were compressed to 203 kPa (two atmospheres absolute) for 90 minutes followed by a linear 30-minute decompression. The HBOT group breathed oxygen via a hood while the HA group breathed chamber air. Insulin sensitivity was assessed from the glucose infusion rate (GIR) during the last 30 minutes in the hyperbaric chamber (SS1) and the first 30 minutes after exit (SS2). Data were analysed for within-group effect by paired student t-test and between-group effect by one-way ANOVA. RESULTS: HBOT increased GIR by a mean 26% at SS1 (P = 0.04) and 23% at SS2 (P = 0.018). There was no significant change in GIR during or after HA. A between-group effect was evident for the change in GIR at SS1 in HBOT vs HA (P = 0.036). CONCLUSIONS: The pathway by which insulin sensitivity is increased in men with type 2 diabetes requires the high oxygen partial pressures of HBOT and should be further investigated. Insulin sensitivity was not changed in hyperbaric air.

Fasting ghrelin is related to skeletal muscle mass in healthy adults.

BACKGROUND/OBJECTIVES: The determinants of plasma ghrelin concentrations including the effects of aging, gender, and body composition, are unclear. Appetite and energy intake decrease with advancing age, and there is a corresponding decline in total body lean tissue, and an increase in fat mass. METHODS: We measured fasting plasma ghrelin and insulin concentrations in 52 healthy subjects aged 22-82 years, and assessed body composition by dual energy X-ray absorptiometry. Energy intake was estimated from diet diaries. RESULTS: Fasting ghrelin concentrations were not significantly correlated with age and energy intake (R = 0.07, P = 0.62; and R = -0.14, P = 0.34 respectively) on univariate regression analysis, and ghrelin concentrations were higher in females than males (2886.8 +/- 182.1 pg/ml vs 2082.5 +/- 121.2 pg/ml; P = 0.001). Ghrelin was inversely related to body mass index (R = -0.328, P = 0.018), fat-free body mass (R = -0.428, P = 0.002), and total skeletal muscle mass (R = -0.439, P = 0.001), but not related to body fat mass (R = 0.177, P = 0.208). On multiple regression analysis, total skeletal muscle mass (corrected for height) was the only significant negative predictor (P < 0.0001) of fasting ghrelin concentrations. CONCLUSIONS: In conclusion, in healthy adults, plasma ghrelin concentrations are not significantly influenced by age or energy intake per se, but relate to skeletal muscle mass.

Effects of intraduodenal glucose, fat, and protein on blood pressure, heart rate, and splanchnic blood flow in healthy older subjects.

BACKGROUND: Postprandial hypotension frequently occurs in the elderly. The hypotensive response to a meal is triggered by the interaction of nutrients with the small intestine; information relating to the effects of different macronutrients on blood pressure (BP) is limited and inconsistent. OBJECTIVE: The objective of the study was to determine the effects of intraduodenal glucose, fat, and protein on BP, heart rate (HR), and superior mesenteric artery (SMA) blood flow in healthy older subjects. DESIGN: Eight subjects received intraduodenal glucose (64 g), fat (10% oil emulsion), protein (72 g whey), or saline (0.9%) at a rate of 2.7 mL/min for 90 min, followed by intraduodenal saline for 30 min. BP, HR, and SMA blood flow were measured. RESULTS: The falls in systolic BP during infusions of glucose, fat, and protein did not differ significantly (P=0.97); however, the fall occurred significantly earlier during the glucose infusion; (18+/-3.0 min) than during the fat (46+/-11.0 min; P=0.02) and protein 33+/-7 min; P=0.04) infusions. The increases in HR during glucose, fat, and protein infusions (P<0.0001 for all) did not differ significantly. SMA blood flow increased significantly after all infusions (P<0.001 for all), but the increase was significantly (P<0.05) lower after protein than after the other infusions. CONCLUSIONS: Intraduodenal glucose, fat, and protein decrease systolic BP in healthy older subjects, but the onset of the hypotensive response is earlier after glucose, and the effect of protein on SMA blood flow is less than that of the other nutrients.

Vitamin D, glucose, insulin, and insulin sensitivity.

This review examines available evidence of links between abnormalities of glucose and insulin metabolism and vitamin D deficiency. Possible mechanisms of action of vitamin D include stimulation of insulin secretion and effects on insulin sensitivity. Sun exposure usually implies greater outdoor physical activity, which in itself may have beneficial effects on insulin sensitivity, unrelated to serum 25-hydroxyvitamin D concentrations. The observed associations in humans among vitamin D, insulin, and glucose metabolism have not yet been confirmed by intervention studies and, hence, a causal association has not been established. Clinical trials are needed to determine whether vitamin D treatment of vitamin D-deficient individuals is able to prevent or treat diabetes mellitus.

Glucose tolerance and vitamin D: effects of treating vitamin D deficiency.

OBJECTIVE: We investigated the effects of vitamin D treatment on plasma glucose, serum insulin, and insulin sensitivity in vitamin D-deficient individuals without diabetes mellitus. METHODS: Thirty-three adults with vitamin D insufficiency (serum 25-hydroxyvitamin D concentration < or = 50 nmol/L) and without diabetes (12 with impaired glucose tolerance) were given two oral doses of 100 000 IU of cholecalciferol, 2 wk apart. Before the first dose and 2 wk after the second dose, a 75-g oral glucose tolerance test was performed. Plasma glucose, serum insulin, 25-hydroxyvitamin D, and parathyroid hormone concentrations were measured and insulin sensitivity was calculated from the oral glucose tolerance test. RESULTS: Mean serum 25-hydroxyvitamin D increased from 39.9 +/- 1.5 (SEM) to 90.3 +/- 4.3 nmol/L (P < 0.0001) and mean serum parathyroid hormone decreased from 6.7 +/- 1.2 to 4.5 +/- 0.6 pmol/L (P = 0.055). There was no change in blood glucose mean of 0-120 min (6.1 +/- 0.3 before versus 6.2 +/- 0.3 mmol/L, P = 0.63) or insulin mean of 0-120 min (47.8 +/- 5.35 versus 48.9 +/- 5.22 mU/L, P = 0.67) concentrations, and no change in insulin sensitivity (Avignon's insulin sensitivity index [SiM], P = 0.97; insulin sensitivity index at 0 and 120 min [ISI(0,120)], P = 0.74; Quantitative Insulin Sensitivity Check Index [QUICKI], P = 0.88; homeostasis model assessment [HOMA], P = 0.99) after vitamin D treatment. Results did not differ between subjects, with and without, impaired glucose tolerance. CONCLUSION: In adults without diabetes, correction of vitamin D deficiency is not associated with any effect on blood glucose or insulin concentrations or insulin sensitivity as assessed during an oral glucose tolerance test. These observations do not support an association between glucose/insulin homeostasis and vitamin D, at least in the short term.

Dopa-testotoxicosis: disruptive hypersexuality in hypogonadal men with prolactinomas treated with dopamine agonists.

Dopamine agonists are the first line of therapy for prolactinomas, with high rates of biochemical control and tumour shrinkage. Toxicity is considered to be low and manageable by switching of agents and dose reduction. Dopamine agonist-induced impulse control disorders are well described in the neurology setting, but further data are required regarding this toxicity in prolactinoma patients. We performed a multicenter retrospective cohort study of eight men with prolactinomas and associated central hypogonadism. The eight men had no prior history of psychiatric disease, but each developed disruptive hypersexuality whilst on dopamine agonist therapy at various doses. Cabergoline, bromocriptine and quinagolide were all implicated. Hypersexuality had manifold consequences, including relationship discord, financial loss, reduced work performance, and illicit activity. We hypothesise that this phenomenon is due to synergy between reward pathway stimulation by dopamine agonists, together with rapid restoration of the eugonadal state after prolonged hypogonadism. We refer here to this distinct drug toxicity as 'dopa-testotoxicosis'. Given the profound impact in these patients and their families, cessation of dopamine agonists should be considered in men who develop hypersexuality, and pituitary surgery may be required to facilitate this. Awareness of this distinct impulse control disorder should enable further research into the prevalence, natural history and management of dopa-testotoxicosis. The condition is likely under-reported due to the highly personal nature of the symptoms and we suggest a simple written questionnaire to screen for hypersexuality and other behavioural symptoms within the first six months of dopamine agonist treatment.

Effect of oral testosterone undecanoate on visuospatial cognition, mood and quality of life in elderly men with low-normal gonadal status.

OBJECTIVES: The effects of supplemental testosterone on cognition, mood and wellbeing in ageing men are unclear. This study aimed to assess the effect of 12-months of oral testosterone supplementation on cognitive function, mood and quality of life in elderly men with low-normal gonadal status, not specifically selected for cognitive or mood defects. METHODS: A standard oral dose (80 mg twice daily) of testosterone undecanoate (TU) or placebo was administered for one year to 76 healthy men 60 years or older. All men had a free testosterone index (FTI) of 0.3-0.5, which represents a value below the normal lower limit for young men (19-30 years), but remains within the overall normal male range. A neuropsychological assessment including the trail making test (part B), visuospatial (VSP) block design test, mini mental state exam (MMSE), Geriatric Depression Scale (GDS), a 5-point Likert and a 10-point visual analogue quality of life (QoL) scale, along with serum hormone measurements were obtained at baseline, 6, and 12 months. RESULTS: Although calculated bioavailable testosterone (cBT) and FTI were higher, and muscle mass increased after 12 months, there was no difference in scores on the trail making or VSP block tests, the MMSE, GDS or either of the QoL scales between the testosterone and placebo group. There was no relationship between baseline cBT or FTI and treatment effect for any of the outcome measures. CONCLUSIONS: 12-month supplementation with oral TU does not affect scores on visuospatial tests or mood and quality of life scales in older men with low-normal gonadal status.

Recruiting older people at nutritional risk for clinical trials: what have we learned?

BACKGROUND: The difficulty of recruiting older people to clinical trials is well described, but there is limited information about effective ways to screen and recruit older people into trials, and the reasons for their reluctance to enrol. This paper examines recruitment efforts for a community-based health intervention study that targeted older adults. METHODS: One year randomized control trial. Undernourished men and women, aged ≥ 65 years and living independently in the community were recruited in three Australian states. Participants were allocated to either oral testosterone undecanoate and high calorie oral nutritional supplement or placebo medication and low calorie oral nutritional supplementation. Hospital admissions, functional status, nutritional health, muscle strength, and other variables were assessed. RESULTS: 4023 potential participants were identified and 767 were screened by a variety of methods: hospital note screening, referrals from geriatric health services, advertising and media segments/appearances. 53 participants (7% of total screened) were recruited. The majority of potentially eligible participants declined participation in the trial after reading the information sheet. Media was the more successful method of recruiting, whereas contacting people identified by screening a large number of hospital records was not successful in recruiting any participants. CONCLUSION: Recruitment of frail and older participants is difficult and multiple strategies are required to facilitate participation. TRIAL REGISTRATION: Australian Clinical Trial Registry: ACTRN 12610000356066 date registered 4/5/2010.

Appetite, food intake, and plasma concentrations of cholecystokinin, ghrelin, and other gastrointestinal hormones in undernourished older women and well-nourished young and older women.

Aging is associated with a reduction in appetite and food intake, predisposing to protein-energy malnutrition. The causes of this "anorexia of aging" are largely unknown. To investigate possible contributions of enhanced satiating effects of cholecystokinin (CCK) and reduced stimulation of food intake by ghrelin, eight undernourished older women [age, 80.4 +/- 2.6 yr; body mass index (BMI), 16.9 +/- 0.57 kg/m(2)], eight well-nourished older women (age, 77 +/- 0.9 yr; BMI, 23.7 +/- 0.8 kg/m(2)), and eight well-nourished young women (age, 22 +/- 1.3 yr; BMI, 20.5 +/- 0.4 kg/m(2)), in randomized order, ate on 1 d a 280-kCal preload and on the other no preload, 90 min before an ad libitum meal. At baseline the undernourished, but not the well-nourished, older subjects were less hungry (P < 0.05) than young subjects. Before and after the preload, plasma CCK levels were higher (P < 0.05) in the older than young subjects, with no difference between the older groups. Plasma ghrelin concentrations were higher in the undernourished than both well-nourished groups and decreased similarly after the preload in all groups. The preload suppressed food intake in the well-nourished older and young subjects (P < 0.05), but was without effect in the undernourished old. These observations suggest that reduced basal hunger, rather than increased meal-induced satiety, contributes to the anorexia of aging and that changes in CCK and ghrelin are unlikely to be responsible.

Food intake and ageing--the role of the gut.

Healthy ageing is associated with decreased appetite and energy intake and this is generally associated with weight loss after about 70 years of age. The mechanisms responsible for this 'physiological' anorexia are not well understood, but it may predispose to the development of protein-energy malnutrition in older people, which is associated with increased morbidity and mortality. Many sensory and social factors, including olfactory changes and economic status, contribute to under-nutrition in older people; however, normal ageing is associated with a number of significant changes in gastrointestinal function. The control of appetite is complex but it is clear that gastrointestinal signals are important in the regulation of appetite and food intake. This review examines the role of small intestinal hormones and gastrointestinal motor function in the observed changes to appetite and food intake in older people.

Oral testosterone supplementation increases muscle and decreases fat mass in healthy elderly males with low-normal gonadal status.

BACKGROUND: Loss of muscle mass (sarcopenia) leads to frailty in older men. The decline in testosterone over the life span may contribute to this muscle loss. We studied the ability of oral testosterone to prevent muscle loss in older men over a 12-month period. METHODS: A standard dose (80 mg twice daily) of testosterone undecanoate or placebo was administered for 1 year to 76 healthy men aged 60 years or older. All men had a free testosterone index of 0.3-0.5, which represents a value below the normal lower limit for young men (19-30 years), but remains within the overall normal male range. Measurements of body composition, muscle strength, hormones, and safety parameters were obtained at 0, 6, and 12 months. RESULTS: Lean body mass increased (p =.0001) and fat mass decreased (p =.02) in the testosterone as compared with the placebo-treated group. There were no significant effects on muscle strength. There was a significant increase in hematocrit (0.02%) in the testosterone-treated group (p =.03). Plasma triglycerides, total cholesterol, and low-density lipoprotein cholesterol levels were similar in both groups, but there was a decrease in high-density lipoprotein cholesterol (-0.1 mmol/L) at 12 months in the testosterone group as compared to the placebo group (p = 0.026). There were no differences in prostate-specific antigen or systolic or diastolic blood pressure between the groups. CONCLUSION: Oral testosterone administration to older relatively hypogonadal men results in an increase in muscle mass and a decrease in body fat.

Plasma glucagon-like peptide-1 (GLP-1) responses to duodenal fat and glucose infusions in lean and obese men.

It has been suggested that obesity is associated with a reduced glucagon-like peptide-1 (GLP-1) response to oral carbohydrate, but not fat. The latter may, however, be attributable to changes in gastric emptying. We have assessed plasma GLP-1 levels in response to these infusions in lean and obese subjects. Seven healthy lean (body mass index (BMI), 19.1-24.6 kg/m(2)) and seven obese (BMI, 31.3-40.8 kg/m(2)) young men received an intraduodenal infusion of glucose and fat for 120 min (2.86 kcal/min) on two separate days. Blood samples for plasma GLP-1 were obtained at baseline and every 20 min during the infusion. Plasma GLP-1 increased during infusion of glucose and fat (P = 0.001), but there were no differences between lean and obese subjects, nor the two nutrients. We conclude that GLP-1 secretion in response to duodenal infusion of glucose and fat is not altered in obese subjects.

Performance of nutritional screening tools in predicting poor six-month outcome in hospitalised older patients.

Malnutrition is a major problem in hospitalised older people. Many nutrition screening tools are available for malnutrition identification, however little is known about their prognostic ability. This prospective, observational study investigated the prognostic value of three nutritional screening tools in a Geriatric Evaluation and Management Unit: the Geriatric Nutritional Risk Index (GNRI), the Mini Nutritional Assessment (MNA) and the Mini Nutritional Assessment short form (MNA-SF), incorporating either body mass index or calf circumference. Poor six- month outcome was defined as new admission to higher level residential care or mortality at six months post-discharge. Predictive ability of poor outcome was assessed by logistic regression models, adjusting for age, gender, cognition and co-morbidity. Predictive accuracy was determined by area under Receiver Operator Characteristic curves, sensitivity, specificity, predictive values and Youden Index. One hundred and seventy-two consecutive patients with a mean (SD) age=85.2 (6.4) years were included in the study. Malnutrition was identified in 31% of patients using the MNA and was associated with a higher risk of poor six-month outcome when identified by the MNA (OR, 95% CI=3.29, 1.17-9.23) and the GNRI (OR, 95% CI=2.84, 1.31-6.19), but not by the MNA-SF. All screening tools lacked discriminative power for outcome prediction. The MNA and GNRI were useful clinical predictors of poor six-month outcome, although their accuracy of prediction was low. Nutritional screening remains a priority in the routine assessment of hospitalised older people.

Body weight, anorexia, and undernutrition in older people.

Ideal body weight for maximum life expectancy increases with advancing age. Older people, however, tend to weigh less than younger adults, and old age is also associated with a tendency to lose weight. Weight loss in older people is associated with adverse outcomes, particularly if unintentional, and initial body weight is low. When older people lose weight, more of the tissue lost is lean tissue (mainly skeletal muscle) than in younger people. When excessive, the loss of lean muscle tissue results in sarcopenia, which is associated with poor health outcomes. Unintentional weight loss in older people may be a result of protein-energy malnutrition, cachexia, the physiological anorexia of aging, or a combination of these. The physiological anorexia of aging is a decrease in appetite and energy intake that occurs even in healthy people and is possibly caused by changes in the digestive tract, gastrointestinal hormone concentrations and activity, neurotransmitters, and cytokines. A greater understanding of this decrease in appetite and energy intake during aging, and the responsible mechanisms, may aid the search for ways to treat undernutrition and weight loss in older people.