Unbalanced serum leptin and ghrelin dynamics prolong postprandial satiety and inhibit hunger in healthy elderly: another reason for the "anorexia of aging"

Anorexia of ageing is associated with elevated fasted and lower post-prandial ghrelin, independent of ghrelin O-acyltransferase

The role of ghrelin metabolism in anorexia of ageing is unclear. The aim of this study was to determine acyl-ghrelin, total ghrelin, and ghrelin O-acyltransferase concentrations when fasted and in responses to feeding in older adults exhibiting anorexia of ageing. Twenty-five older adults (OA; 15f, 74 ± 7 years, 24.5 kg·m-2) and twelve younger adults (YA; 6f, 21 ± 2 years, 24.4 kg·m-2) provided a fasted measure of subjective appetite and fasted blood sample (0 min) before consuming a standardised porridge breakfast meal (450 kcal). Appetite was measured every 30 min for 240 min and blood was sampled at 30, 60, 90, 120, 180 and 240 min while participants rested. At 240 min, an ad libitum pasta-based lunch meal was consumed. Older adults were identified as those with healthy appetite (HA-OA) or low appetite (LA-OA), based on habitual energy intake, self-report appetite, BMI, and ad libitum lunch intake. YA ate more at lunch (1108 ± 235 kcal) than HA-OA (653 ± 133 kcal, p = 0.007) and LA-OA (369 ± 168 kcal; p < 0.001). LA-OA, but not HA-OA, had higher fasted concentrations of acyl- and total ghrelin than YA (acyl-ghrelin: 621 ± 307 pg·mL-1 vs. 353 ± 166 pg·mL-1, p = 0.047; total ghrelin: 1333 ± 702 pg·mL-1 vs. 636 ± 251 pg·mL-1, p = 0.006). Acyl-ghrelin (60 min and 90 min) and total ghrelin (90 min) were suppressed to a greater extent for LA-OA than for YA (p < 0.05). No differences were observed in subjective appetite, acyl-to-total ghrelin ratio, or plasma GOAT content (p > 0.1). Higher fasting ghrelin and an augmented ghrelin response to feeding in LA-OA, but not HA-OA, suggests that alterations to ghrelin metabolism are not functions of ageing per se and may be independent causal mechanisms of anorexia of ageing.

Endogenous Ghrelin Levels and Perception of Hunger: A Systematic Review and Meta-Analysis

BACKGROUND

Ghrelin is an orexigenic hormone primarily released by the stomach and has 2 isoforms: acylated ghrelin (AG) and de-acylated ghrelin (DAG), that appear to have different functions in humans.

OBJECTIVES

To perform a systematic review and meta-analysis of the association between plasma concentrations of total ghrelin (TG), AG, and DAG and perceptions of hunger in healthy adults.

METHODS

The following criteria were used for inclusion: 1) sample contained adults ≥18 y of age, 2) body mass index [BMI kg/m2] was ≥18.5, 3) ghrelin was sampled through blood, 4) subjective hunger was measured on a validated scale, 5) study reported a Pearson product correlation of ghrelin or had relevant figure(s) for data extraction, 6) participants were healthy with no overt disease, 7) protocols contained no physical activity or weight loss medication that suppressed appetite, 8) interventions were conducted without environmental manipulations. Moderators assessed were age, BMI, percentage of body fat (%BF), macronutrient content of test meals, energy intake (kcals), sex, and ghrelin isoform (AG, DAG, or TG).

RESULTS

The analysis included 47 studies (110 trials, n = 1799, age: 31.4 ± 12.0 y, BMI: 26.0 ± 4.75 kg/m2) and measured AG (n = 47 trials), DAG (n = 12 trials), and TG (n = 51 trials). The overall model indicated that ghrelin concentrations and perceptions of hunger were moderately correlated (r = 0.43, P < 0.001), and ghrelin isoform significantly moderated this relationship (AG: r = 0.60, P < 0.001; TG: r = 0.215, P = 0.01; DAG: r = 0.53, P = 0.695). Other significant moderators included age (b = -0.02, P = 0.01), BMI (b = -0.03, P = 0.05), %BF (b = -0.03, P = 0.05), energy intake (b = 0.0003, P = 0.04), and percentage of carbohydrates of test meals (b = 0.008, P = 0.05).

CONCLUSIONS

Ghrelin is associated with perceptions of hunger in humans, and this relationship is strengthened when AG is isolated; thus, AG may have a large impact on hunger signals in various populations. Future research should attempt to understand the role of DAG in hunger sensations.

Relationship Between Appetite-Related Peptides and Frailty in Older Adults

BACKGROUND

Frailty, is a geriatric syndrome that reduces the resistance to stress situations caused by activities of daily living and increases morbidity and mortality. We hypothesized that a decrease in orexigenic peptides or an increase in anorexigenic peptides might be associated with frailty. We aimed to investigate the relationship between frailty and six appetite-related peptides: ghrelin, neuropeptide Y (NPY), agouti-related peptide (AgRP), cocaine-amphetamine-associated peptide (CART), peptide YY, and alpha MSH (α-MSH).

METHODS

This cross-sectional study was conducted on 85 older adults who visited the outpatient clinic. All patients underwent comprehensive geriatric assessment. Frailty status was assessed using the Fried frailty index. Plasma levels of six appetite-related peptides were studied.

RESULTS

The mean age was 73.7 ± 5.4 years, 27 (31.8%) of the patients were male, and 32 of the patients (37.6%) were frail. While plasma levels of ghrelin, NPY and AgRP were significantly lower in frail patients, CART and α-MSH levels were higher compared to non-frail patients (p < .05 for all). Peptide YY was found to be higher in the frail group, however, the difference did not reach statistical significance (p = .052). In multivariate logistic regression analysis, the ghrelin, AgRP, CART, and α-MSH levels were independent predictors of frailty. Moreover, a weak correlation was found between all peptides(except NPY) and handgrip strength and Lawton-Brody score.

CONCLUSION

Ghrelin, AgRP, CART, and α-MSH levels were found to be independent predictors of frailty. Our results suggest that appetite-related peptides might be playing roles in the pathogenesis of frailty. Further larger prospective studies are needed to test this hypothesis.

Anorexia of Aging: Metabolic Changes and Biomarker Discovery

The age-associated decrease in appetite and food intake is referred to as "anorexia of aging". Older adults with anorexia show changes in the quantity/quality of energy supplied to the organism which eventually may cause a mismatch between ingested calories and physiological energy demands. Therefore, a state of malnutrition and impaired metabolism may ensue which renders older people more vulnerable to stressors and more prone to incur negative health outcomes. These latter cover a wide range of conditions including sarcopenia, low engagement in physical activity, and more severe consequences such as disability, loss of independence, hospitalization, nursing home placement, and mortality. Malnutrition has been recognized by the European Society of Clinical Nutrition (ESPEN) among the chief risk factors for the development of frailty. Frailty refers to a state of increased vulnerability to stressors stemming from reduced physiologic reserve, and according to ESPEN, is also nutrition-based. Alike frailty, anorexia is highly prevalent among older adults, and its multifactorial nature includes metabolic changes that develop in older age and possibly underly the condition. Circulating factors, including hormones (eg, cholecystokinin, ghrelin, leptin, and inflammatory and microbial mediators of gut dysbiosis), have been proposed as biomarkers for this condition to support early identification and develop personalized nutritional interventions. Additional studies are needed to untangle the interrelationship between gut microbiota and appetite regulation in older adults operating through brain-gut crosstalk. Furthermore, the contribution of the genetic background to appetite regulation and specific nutritional needs warrants investigation. Here, we provide an overview on anorexia of aging in the context of age-related metabolic changes. A special focus is placed on candidate biomarkers that may be used to assist in the early identification of anorexia of aging and in the development of personalized nutritional counseling.

Fasting and postprandial ghrelin changes in older and younger volunteers

BACKGROUND

Little evidence is available on how both forms of ghrelin change during the aging process. Most of the earlier studies measured only total ghrelin levels and mainly in the fasting state. This study aimed to assess periprandial changes of acylated and deacylated ghrelin (AG, DAG) in volunteers aged ≥65 and <65 years and to establish an association between both forms of ghrelin and nutritional status in older volunteers.

METHODS

Venous blood for serum AG and DAG assays were collected in sixty volunteers after an overnight fast and two hours after the consumption of a standard 300 kcal-mixed meal. In those aged 65 years or more nutritional status was assessed.

RESULTS

Levels of DAG and AG were lower in older compared to younger volunteers in the fasting state as well as postprandial. DAG levels after a meal decreased in older, but not in younger subjects. However, significantly higher levels of postprandial AG were found in subjects with a risk of malnutrition and those with reduced appetite in comparison to well-nourished ones. Interestingly, elderly subjects with the lowest insulin and BMI had the lowest fasting AG levels and subjects with too high BMI and hyperinsulinemia presented also the highest fasting AG levels.

CONCLUSIONS

In older subjects, levels of both forms of ghrelin were lower and differential postprandial AG and DAG responses were observed when compared to younger subjects.

Involvement of Ghrelin Dynamics in Stress-Induced Eating Disorder: Effects of Sex and Aging

Stress, a factor that affects appetite in our daily lives, enhances or suppresses appetite and changes palatability. However, so far, the mechanisms underlying the link between stress and eating have not been fully elucidated. Among the peripherally produced appetite-related peptides, ghrelin is the only orexigenic peptide, and abnormalities in the dynamics and reactivity of this peptide are involved in appetite abnormalities in various diseases and psychological states. This review presents an overview of the research results of studies evaluating the effects of various stresses on appetite. The first half of this review describes the relationship between appetite and stress, and the second half describes the relationship between the appetite-promoting peptide ghrelin and stress. The effects of sex differences and aging under stress on appetite are also described.

Endocrinological and Nutritional Implications of Anorexia of Aging

Poor appetite—known as anorexia—is a common condition in aging and is associated with poor outcomes, including reduced survival and impaired quality of life. The anorexia of aging is mainly the result of several complex endocrinological, metabolic, and nutritional changes occurring with later age. The modulation of different peptides and hormones has been identified as an important determinant for the development of low appetite; in particular, an altered imbalance of plasma ghrelin, leptin, and cholecystokinin and increased inflammatory markers are implicated in its pathophysiology, and robust evidence of their involvement in anorexia of aging has been produced in the clinical setting. More recently, researchers identified that the gut microbiome composition significantly varies according to the appetite status. Other important clinical factors may worsen the symptoms of the anorexia in the elderly, in particular the potential concomitant presence of chronic catabolic comorbidities. Importantly, data indicate that anorexia is prevalent in frail older adults, negatively impacting body composition and specifically in altering muscle mass and function. For all these reasons, a prompt and early diagnosis of anorexia in the elderly is crucial to implement personalized metabolic and nutrition interventions to improve the outcomes and ameliorate quality of life.

Understanding the appetite modulation pathways: The role of the FFA1 and FFA4 receptors

Pharmaconutrition is an area of current interest, especially concerning the advances in the pharmacology of nutrient-sensing receptors, as have been accomplished in the last 20 years. The family of free fatty acid (FFA) receptors is composed of four members, sequentially named as FFA1 to FFA4, which are activated by the short to long-chain fatty acids. The affinity of the FFA1 and FFA4 receptors for the omega-3 polyunsaturated fatty acids prompted pre-clinical and clinical investigations regarding their involvement in metabolic diseases. The main studies have been focused on the receptors' expression analyses, the featuring of knockout mice, and the assessment of selective synthetic ligands. These clearly have indicated a relevant role for FFA1 and FFA4 in the peripheral and central circuits for the regulation of energetic metabolism. This review article aimed to discuss the relevance of the FFA1 and FFA4 receptors in appetite-related complications, mainly related to obesity, cancer cachexia, and anorexia in the elderly, emphasizing whether their pharmacological modulation might be useful for the management of these disorders.

Appetite Control across the Lifecourse: The Acute Impact of Breakfast Drink Quantity and Protein Content. The Full4Health Project

Understanding the mechanisms of hunger, satiety and how nutrients affect appetite control is important for successful weight management across the lifecourse. The primary aim of this study was to describe acute appetite control across the lifecourse, comparing age groups (children, adolescents, adults, elderly), weight categories, genders and European sites (Scotland and Greece). Participants (n = 391) consumed four test drinks, varying in composition (15% (normal protein, NP) and 30% (high protein, HP) of energy from protein) and quantity (based on 100% basal metabolic rate (BMR) and 140% BMR), on four separate days in a double-blind randomized controlled study. Ad libitum energy intake (EI), subjective appetite and biomarkers of appetite and metabolism (adults and elderly only) were measured. The adults' appetite was significantly greater than that of the elderly across all drink types (p < 0.004) and in response to drink quantities (p < 0.001). There were no significant differences in EI between age groups, weight categories, genders or sites. Concentrations of glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) were significantly greater in the elderly than the adults (p < 0.001). Ghrelin and fasting leptin concentrations differed significantly between weight categories, genders and sites (p < 0.05), while GLP-1 and PYY concentrations differed significantly between genders only (p < 0.05). Compared to NP drinks, HP drinks significantly increased postprandial GLP-1 and PYY (p < 0.001). Advanced age was concomitant with reduced appetite and elevated anorectic hormone release, which may contribute to the development of malnutrition. In addition, appetite hormone concentrations differed between weight categories, genders and geographical locations.

Effect of White Potatoes on Subjective Appetite, Food Intake, and Glycemic Response in Healthy Older Adults

The objective of this study was to determine the effect of white potato cooking methods on subjective appetite, short-term food intake (FI), and glycemic response in healthy older adults. Using a within-subject, repeated-measures design, 20 participants (age: 70.4 ± 0.6 y) completed, in random order, five treatment conditions: three potato treatments (baked potatoes, mashed potatoes, and French fries), an isocaloric control treatment (white bread), or a fasting condition (meal skipping). Subjective appetite and glycemic response were measured for 120 min using visual analogue scales and capillary blood samples, respectively. Lunch FI was measured with an ad libitum pizza meal at 120 min. Change from baseline subjective appetite (p < 0.001) and lunch FI (p < 0.001) were lower after all test treatments compared with meal skipping (p < 0.001), but did not differ among test treatments. Cumulative FI (test treatment + lunch FI) did not differ among treatment conditions. Blood glucose concentrations were higher after all test treatments compared with meal skipping (p < 0.001), but were not different from each other. In healthy older adults, white potatoes suppressed subjective appetite and lunch FI compared with meal skipping, suggesting white potatoes do not bypass regulatory control mechanisms of FI.

Emotional eating in patients attending a specialist obesity treatment service

OBJECTIVE

The prevalence of emotional eating (EE) has increased in the general population over past decades. There is limited information on how common EE is among people seeking obesity treatment. We aimed to estimate the proportion of people with EE, and strength of associations between a predefined set of factors and EE in people referred for obesity treatment.

METHODS

Cross-sectional study recruiting 387 adults from a hospital obesity service. "Emotional eating" was defined as Emotional Eating Scale (EES) score ≥25. Strength of associations were estimated by boot-strapped quantile regression analysis. Results are presented as quantile difference (QD) of EES scores at the 25th, 50th or 75th quantile, and 95% confidence intervals (95%CI).

RESULTS

The study population consisted of 71% women, with a median age of 52 years (interquartile range [IQR]: 42, 61), and a median body mass index of 42 kg/m² (IQR: 37, 49). 187 participants were managed with lifestyle modification alone, 103 with the addition of obesity pharmacotherapy, 79 with bariatric surgery, and 18 with both bariatric surgery and medications. EE was reported by an estimated 58% (95%CI: 53, 63) of participants. Factors with the largest and most consistent magnitude of association with EES differences include age, sex, use of glucagon-like peptide-1 (GLP-1) agonists, history of sleeve gastrectomy and recent bariatric surgery.

CONCLUSION

Emotional eating affected more than half of people referred for obesity treatment. Age, sex, use of GLP-1 agonists, history of sleeve gastrectomy and recent bariatric surgery had the strongest associations with EE. These findings allow hypothesis generation about the underlying physiological mechanisms behind emotional eating for investigation in future research.

Breaking the vicious circle of diet, malnutrition and oral health for the independent elderly

Aging impairs senses, mastication, oral status and function, causing nutritional needs and diet insufficiencies. The present needs of independent older adults suggest that health research and oral health care should shift from reductionist disease management to integral and personal treatment plans, including lifestyle, psychological, nutritional and oral health coaching approaches. Dentists and other medical professionals that work in the field of gerodontology should be educated on the macro and micronutrient needs of the elderly and incorporate certain nutritional plans early in the life of their patients with their approval and cooperation, in order to postpone tooth loss and masticatory impairment. Old recipes such as the Mediterranean diet should be kept as a base for all the elderly and be enriched in a customized interpersonal way from the dentist as well as the medical professional according to the specific needs of one's oral and general health status. In this nonsystematic review paper, the basic aspects of the vicious cycle of nutrition and oral health status are discussed and suggestions of major nutrients' influence and needs for independent elders are reported. Based on the scientific data collected, suggestions are made for the food industry for better quality and dosage of foods for this category of individuals. Such strategies can be a whole new area of interest for the food industry in order to obtain better quality of food packaging for the independent OA with accepted texture, odor, colors, macronutrients and micronutrients' consistency and in specific portions.

The effect of oral essential amino acids on incretin hormone production in youth and ageing

BACKGROUND

The effect of substantive doses of essential amino acids (EAA) on incretin and insulin production, and the impact of age upon this effect, is ill-defined.

METHODS

A 15-g oral EAA drink was administered to young (N = 8; 26 ± 4.4 years) and older (N = 8; 69 ± 3.8 years) healthy volunteers. Another group of younger volunteers (N = 9; 21 ± 1.9 years) was given IV infusions to achieve equivalent plasma amino acids (AA) profiles. Plasma AA, insulin, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) were quantified over 2 hours.

RESULTS

In younger recruits, EAA-induced rapid insulinaemia and aminoacidaemia with total amino acids(AA), EAA and branched chain amino acids (BCAA) matched between oral and IV groups. Insulin peaked at 39 ± 29 pmol L-1 at 30 minutes following oral feeding compared to 22 ± 9 pmol L-1 at 60 minutes following IV feeding (P: NS). EAA peaked at 3395 μmol L-1 at 45 minutes during IV infusion compared to 2892 μmol L-1 following oral intake (Feeding effect: P < 0.0001. Oral vs IV feeding: P: NS). There was an 11% greater increase in insulin levels in the 120 minutes duration of the study in response to oral EAA as opposed to IV EAA. GIP increased following oral EAA (452 pmol L-1 vs 232 pmol L-1, P < 0.05). Age did not impact insulin or incretins production.

CONCLUSION

Postprandial rises in EAA levels lead to rapid insulinaemia which is higher with oral compared with IV EAA, that is attributed more to GIP and unaffected by age. This finding supports EAA, on their own or as part of high-protein meal, as nutritive therapeutics in impaired glycaemia and ageing.

Gastrointestinal Sensing of Meal-Related Signals in Humans, and Dysregulations in Eating-Related Disorders

The upper gastrointestinal (GI) tract plays a critical role in sensing the arrival of a meal, including its volume as well as nutrient and non-nutrient contents. The presence of the meal in the stomach generates a mechanical distension signal, and, as gastric emptying progresses, nutrients increasingly interact with receptors on enteroendocrine cells, triggering the release of gut hormones, with lipid and protein being particularly potent. Collectively, these signals are transmitted to the brain to regulate appetite and energy intake, or in a feedback loop relayed back to the upper GI tract to further adjust GI functions, including gastric emptying. The research in this area to date has provided important insights into how sensing of intraluminal meal-related stimuli acutely regulates appetite and energy intake in humans. However, disturbances in the detection of these stimuli have been described in a number of eating-related disorders. This paper will review the GI sensing of meal-related stimuli and the relationship with appetite and energy intake, and examine changes in GI responses to luminal stimuli in obesity, functional dyspepsia and anorexia of ageing, as examples of eating-related disorders. A much better understanding of the mechanisms underlying these dysregulations is still required to assist in the development of effective management and treatment strategies in the future.

Dose-Dependent Effects of Randomized Intraduodenal Whey-Protein Loads on Glucose, Gut Hormone, and Amino Acid Concentrations in Healthy Older and Younger Men

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 randomized, 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 resulted 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.

Effect of Age on Blood Glucose and Plasma Insulin, Glucagon, Ghrelin, CCK, GIP, and GLP-1 Responses to Whey Protein Ingestion

Protein-rich supplements are used widely to prevent and manage undernutrition in older people. We have previously shown that healthy older, compared to younger, adults have less suppression of energy intake by whey protein-although the effects of age on appetite-related gut hormones are largely unknown. The aim of this study was to determine and compare the acute effects of whey protein loads on blood glucose and plasma gut hormone concentrations in older and younger adults. Sixteen healthy older (eight men, eight women; mean ± SEM: age: 72 ± 1 years; body mass index: 25 ± 1 kg/m²) and 16 younger (eight men, eight women; 24 ± 1 years; 23 ± 0.4 kg/m²) adults were studied on three occasions in which they ingested 30 g (120 kcal) or 70 g (280 kcal) whey protein, or a flavored-water control drink (~2 kcal). At regular intervals over 180 min, blood glucose and plasma insulin, glucagon, ghrelin, cholecystokinin (CCK), gastric inhibitory peptide (GIP), and glucagon-like peptide-1 (GLP-1) concentrations were measured. Plasma ghrelin was dose-dependently suppressed and insulin, glucagon, CCK, GIP, and GLP-1 concentrations were dose-dependently increased by the whey protein ingestion, while blood glucose concentrations were comparable during all study days. The stimulation of plasma CCK and GIP concentrations was greater in older than younger adults. In conclusion, orally ingested whey protein resulted in load-dependent gut hormone responses, which were greater for plasma CCK and GIP in older compared to younger adults.

Acute fiber supplementation with inulin-type fructans curbs appetite sensations: a randomized, double-blind, placebo-controlled study

Background: Research points to a benefit of inulin fiber on appetite and weight regulation but results remain mixed. Objectives: To test the impact of 16 g/d of Inulin-type fructans (ITFs) on appetite and food intake in acute settings.

Design: Forty college age females received either a fiber drink with 16 g of ITFs in 330 ml water or placebo. On the 8^th day of the study, appetite sensations were assessed using visual analogue scale (VAS) along with food intake. Repeated-measures ANOVA were performed comparing VAS ratings during test day. Energy consumption was compared using paired t-tests. Significance was determined at p<0.05.

Results: On the 8^th day, the fiber group reported lower ratings for hunger, desire to eat, and prospective food consumption with significantly higher ratings for satisfaction and fullness. Subsequently, the fiber group consumed 21% less kcal from food at lunch (453 ± 47 kcal) compared to controls (571 ± 39 kcal) (p<0.05).

Conclusions: Consuming 16 g/d of ITFs in the morning for 7 days, and after an overnight fast, curbed appetite sensations and helped reduce food intake during lunch meal. These findings highlight the potential of using ITFs in weight management. Future studies should explore ITFs long term benefits.

Anorexia of Aging: Risk Factors, Consequences, and Potential Treatments

Older people frequently fail to ingest adequate amount of food to meet their essential energy and nutrient requirements. Anorexia of aging, defined by decrease in appetite and/or food intake in old age, is a major contributing factor to under-nutrition and adverse health outcomes in the geriatric population. This disorder is indeed highly prevalent and is recognized as an independent predictor of morbidity and mortality in different clinical settings. Even though anorexia is not an unavoidable consequence of aging, advancing age often promotes its development through various mechanisms. Age-related changes in life-style, disease conditions, as well as social and environmental factors have the potential to directly affect dietary behaviors and nutritional status. In spite of their importance, problems related to food intake and, more generally, nutritional status are seldom attended to in clinical practice. While this may be the result of an “ageist” approach, it should be acknowledged that simple interventions, such as oral nutritional supplementation or modified diets, could meaningfully improve the health status and quality of life of older persons.

Ageing Is Associated with Decreases in Appetite and Energy Intake--A Meta-Analysis in Healthy Adults

It is not well recognized that in the elderly weight loss is more common than weight gain. The aim of this analysis was to determine the effect of ageing on appetite (hunger/fullness) and energy intake, after overnight fasting and in a postprandial state, by meta-analyses of trials that included at least two age groups (>18 years). We hypothesized that appetite and energy intake would be less in healthy older compared with younger adults. Following a PubMed-database systematic search up to 30 June 2015, 59 studies were included in the random-effects-model meta-analyses. Energy intake was 16%-20% lower in older (n = 3574/~70 years/~71 kg/~25 kg/m²) than younger (n = 4111/~26 years/~69 kg/~23 kg/m²) adults (standardized mean difference: -0.77 (95% confidence interval -0.90 to -0.64)). Hunger was 25% (after overnight fasting; weighted mean difference (WMD): -17 (-22 to -13) mm) to 39% (in a postprandial state; WMD: -14 (-19 to -9) mm) lower, and fullness 37% (after overnight fasting; WMD: 6 mm (95% CI: 1 to 11 mm)) greater in older than younger adults. In conclusion, appetite and energy intake are less in healthy older than younger adults, suggesting that ageing per se affects food intake.

The emergence of sedentary behaviour physiology and its effects on the cardiometabolic profile in young and older adults

It has recently emerged that sedentary behaviour is independent of a lack of physical activity as individuals can be sufficiently active, based on the recommended physical activity guidelines, but also spend the majority of their waking hours engaging in sedentary behaviour. Individuals who follow this pattern of physical activity and sedentary behaviour are known as 'active couch potatoes'. Sedentary behaviour has been found to have detrimental effects on cardiometabolic markers associated with cardiovascular disease. Since the positive effects of moderate-to-vigorous intensity physical activity do not necessarily negate the deleterious effects of sedentary behaviour on cardiometabolic markers, it is postulated that engaging in light physical activity is an intervention that will successfully reduce levels of sedentary behaviour and may hence improve health markers of quality of life. We propose that such lifestyle changes may be particularly relevant to older populations as these engage in sedentary behaviour for the majority of their waking hours, thereby adding to the negative aging effect on cardiometabolic markers.

Mechanisms of the anorexia of aging-a review

Many, even healthy, older people fail to adequately regulate food intake and experience loss of weight. Aging-associated changes in the regulation of appetite and the lack of hunger have been termed as the anorexia of aging. The etiology of the anorexia of aging is multi-factorial and includes a combination of physiological changes associated with aging (decline in smell and taste, reduced central and peripheral drive to eat, delayed gastric emptying), pathological conditions (depression, dementia, somatic diseases, medications and iatrogenic interventions, oral-health status), and social factors (poverty, loneliness). However, exact mechanisms of the anorexia of aging remain to be elucidated. Many neurobiological mechanisms may be secondary to age-related changes in body composition and not associated with anorexia per se. Therefore, further studies on pathophysiological mechanisms of the anorexia of aging should employ accurate measurement of body fat and lean mass. The anorexia of aging is associated with protein-energy malnutrition, sarcopenia, frailty, functional deterioration, morbidity, and mortality. Since this symptom can lead to dramatic consequences, early identification and effective interventions are needed. One of the most important goals in the geriatric care is to optimize nutritional status of the elderly.

A New Strategy Using Rikkunshito to Treat Anorexia and Gastrointestinal Dysfunction

Because the clinical condition of gastrointestinal dysfunction, including functional dyspepsia, involves tangled combinations of pathologies, there are some cases of insufficient curative efficacy. Thus, traditional herbal medicines (Kampo medicines) uniquely developed in Japan are thought to contribute to medical treatment for upper gastrointestinal symptoms. Rikkunshito is a Kampo medicine often used to treat dyspeptic symptoms. Over the past few years, several studies have investigated the efficacy of rikkunshito for dysmotility, for example, upper abdominal complaints, in animals and humans. Rikkunshito ameliorated the decrease in gastric motility and anorexia in cisplatin-treated rats, stress-loaded mice, and selective serotonin reuptake inhibitor-treated rats by enhancing plasma ghrelin levels via serotonin2B/2C receptor antagonism. In addition, rikkunshito ameliorated the decrease in food intake in aged mice and stress-loaded decreased gastric motility via enhanced ghrelin receptor signaling. Several clinical studies revealed that rikkunshito was effective in ameliorating upper gastrointestinal symptoms, including dyspepsia, epigastric pain, and postprandial fullness. In this review, we discuss these studies and propose additional evidence-based research that may promote the clinical use of Kampo medicines, particularly rikkunshito, for treating anorexia and gastrointestinal dysfunction.

Loneliness predicts postprandial ghrelin and hunger in women

Loneliness is strongly linked to poor health. Recent research suggests that appetite dysregulation provides one potential pathway through which loneliness and other forms of social disconnection influence health. Obesity may alter the link between loneliness and appetite-relevant hormones, one unexplored possibility. We examined the relationships between loneliness and both postmeal ghrelin and hunger, and tested whether these links differed for people with a higher versus lower body mass index (BMI; kg/m(2)). During this double-blind randomized crossover study, women (N=42) ate a high saturated fat meal at the beginning of one full-day visit and a high oleic sunflower oil meal at the beginning of the other. Loneliness was assessed once with a commonly used loneliness questionnaire. Ghrelin was sampled before the meal and postmeal at 2 and 7h. Self-reported hunger was measured before the meal, immediately postmeal, and then 2, 4, and 7h later. Lonelier women had larger postprandial ghrelin and hunger increases compared with less lonely women, but only among participants with a lower BMI. Loneliness and postprandial ghrelin and hunger were unrelated among participants with a higher BMI. These effects were consistent across both meals. These data suggest that ghrelin, an important appetite-regulation hormone, and hunger may link loneliness to weight gain and its corresponding negative health effects among non-obese people.

Novel insights on nutrient management of sarcopenia in elderly

Sarcopenia is defined as a syndrome characterized by progressive and generalized loss of muscle mass and strength. The more rationale approach to delay the progression of sarcopenia is based on the combination of proper nutrition, possibly associated with the use of dietary supplements and a regular exercise program. We performed a narrative literature review to evaluate the till-now evidence regarding (1) the metabolic and nutritional correlates of sarcopenia; (2) the optimum diet therapy for the treatment of these abnormalities. This review included 67 eligible studies. In addition to the well recognized link between adequate intake of proteins/amino acids and sarcopenia, the recent literature underlines that in sarcopenic elderly subjects there is an unbalance in vitamin D synthesis and in omega-6/omega-3 PUFA ratio. Given the detrimental effect of these metabolic abnormalities, a change in the lifestyle must be the cornerstone in the treatment of sarcopenia. The optimum diet therapy for the sarcopenia treatment must aim at achieving specific metabolic goals, which must be reached through accession of the elderly to specific personalized dietary program aimed at achieving and/or maintaining muscle mass; increasing their intake of fish (4 times/week) or taking omega-3 PUFA supplements; taking vitamin D supplementation, if there are low serum levels.

Hyperghrelinemia in Prader-Willi syndrome begins in early infancy long before the onset of hyperphagia

Circulating total ghrelin levels are elevated in older children and adults with Prader-Willi syndrome (PWS). However, the presence or absence of hyperghrelinemia in young children with PWS remains controversial. We hypothesized that a more robust way to analyze appetite-regulating hormones in PWS would be by nutritional phases rather than age alone. Our objectives were to compare total serum ghrelin levels in children with PWS by nutritional phase as well as to compare total ghrelin levels in PWS (5 weeks to 21 years of age) to normal weight controls and individuals with early-onset morbid obesity (EMO) without PWS. Fasting serum total ghrelin levels were measured in 60 subjects with PWS, 39 subjects with EMO of unknown etiology, and in 95 normal non-obese sibling controls of PWS or EMO subjects (SibC) in this 12 year longitudinal study. Within PWS, total ghrelin levels were significantly (P < 0.001) higher in earlier nutritional phases: phase 1a (7,906  ±  5,887); 1b (5,057 ± 2,624); 2a (2,905 ± 1,521); 2b (2,615 ± 1,370) and 3 (2,423 ± 1,350). Young infants with PWS also had significantly (P = 0.009) higher total ghrelin levels than did the sibling controls. Nutritional phase is an important independent prognostic factor of total ghrelin levels in individuals with PWS. Circulating ghrelin levels are elevated in young children with PWS long before the onset of hyperphagia, especially during the early phase of poor appetite and feeding. Therefore, it seems unlikely that high ghrelin levels are directly responsible for the switch to the hyperphagic nutritional phases in PWS.

Anorexia of aging and gut hormones

We are expected to live longer than if we had been born 100 years ago however, the additional years are not necessarily spent in good health or free from disability. Body composition changes dramatically over the course of life. There is a gradual increase in body weight throughout adult life until the age of about 60-65 years. In contrast, body weight appears to decrease with age after the age of 65-75 years, even in those demonstrating a previous healthy body weight. This age related decrease in body weight, often called unintentional weight loss or involuntary weight loss can be a significant problem for the elderly. This has been shown to be related to decline in appetite and food intake is common amongst the elderly and is often referred to the anorexia of aging. Underlying mechanisms regulate energy homeostasis and appetite may change as people age. In this review, peripheral factors regulating appetite have been summarized in regards to their age-dependent changes and role in the etiology of anorexia of aging. Understanding the alterations in the mechanisms regulating appetite and food intake in conjunction with aging may help inform strategies that promote healthy aging and promote health and wellbeing in the elderly years, with the end goal to add life to the years and not just years to our lives.

Effects of age, gender and chronic obstructive pulmonary disease on taste acuity

PRIMARY OBJECTIVE

Multifactoral interactions of age, gender and medical conditions were investigated because of lack of definitive results in previous studies.

METHODS

Absolute detection and recognition were determined thresholds using a three-alternative forced-choice test by younger men (n=50) and women (n=48); and by older men (n=43) and women (n=46) for each of the four basic tastes (sweet, sour, bitter, salty). Data from 46 elderly men with chronic obstructive pulmonary disease (COPD) were included.

RESULTS

Age was consistently associated with elevated recognition thresholds for each of the four tastants for men only. Gender differences were seen for absolute sweet thresholds and for sour, bitter, and sweet recognition thresholds for older participants. Men with COPD had the highest levels for absolute and recognition thresholds for each tastant.

CONCLUSIONS

Gender plays a role in taste perception. COPD diminishes taste.

Pathophysiology of the anorexia of aging

PURPOSE OF REVIEW

Anorexia represents a major problem for older persons leading to weight loss, sarcopenia, functional decline, and mortality. There is increasing information on the pathophysiological mechanisms that lead to anorexia.

RECENT FINDINGS

Increasing evidence has shown the importance of gastrointestinal hormones (ghrelin, cholecystokinin, and glucagon-like peptide) and adipokines in producing the anorexia of aging. Numerous neurotransmitters have been shown to be involved in this aging anorexia, but evidence in humans is lacking.

SUMMARY

The early recognition of anorexia of aging is important to allow intervention and prevent functional deterioration in older persons. Screening tests for anorexia have been developed. New approaches to managing anorexia are being tested.

Age effect on myocellular remodeling: response to exercise and nutrition in humans

Aging is associated with decline in muscle mass and muscle functions. Muscle strength declines disproportionate to the decline in muscle mass indicating that muscle quality or protein quality also declines with age. Human studies have shown a progressive decline in muscle protein synthesis including proteins in the contractile apparatus and mitochondria with age. However, the decline in muscle protein synthesis is disproportionate to the decline in muscle mass that occurs with age prompting to hypothesize that muscle protein degradation also declines with age. A decline in mitochondrial capacity to synthesize ATP is likely a limiting factor of both synthesis and degradation, which are ATP dependent processes. In support of the above hypothesis, several studies have shown a decline in whole body protein turnover (synthesis and degradation). The timely and efficient degradation of irreversibly damaged or modified proteins is critical to maintain the quality of protein. It is proposed that a failure to degrade the damaged proteins and replacing them with newly synthesized proteins contribute to age related decline in muscle mass and quality of muscle proteins. The underlying molecular mechanism of these age related changes in human muscle needs further investigation.

Hormonal appetite control is altered by shift work: a preliminary study

Shift work has been associated with a higher propensity for developing nutritional problems and obesity. However, the possible changes in leptin and ghrelin (2 hormones that contribute importantly to the central regulation of food intake) concentrations in this population are poorly described. The objective of the study was to evaluate the daily concentrations of leptin, nonacylated ghrelin, and acylated ghrelin and the appetite ratings in men working different shift schedules. Daily concentrations of nonacylated ghrelin, acylated ghrelin, and leptin and appetite were measured in 3 groups of subjects: workers on fixed night shifts (n = 9), fixed early morning shifts (n = 6), and fixed day shifts (n = 7). Appetite was evaluated by a validated questionnaire. Blood samples were collected every 4 hours over the course of 24 hours for a total of 6 samples. When comparing the 3 groups, leptin concentrations at 8:00 am and 4:00 pm for those workers on the day shift were significantly lower than for those on the early morning shift; and concentrations at noon for those workers on the day shift were significantly lower than for those on the night shift. Nonacylated and acylated ghrelin concentrations were significantly lower for those workers on the early morning shift than for those on the day shift. In general, appetite was the lowest in those working the early morning shift. Shift workers on the early morning shift have lower appetites and concentrations of leptin and nonacylated and acylated ghrelin than the workers on other shifts. Further studies are required to better understand the detailed needs of these individuals.

Gastrointestinal issues in the older female patient

As the body ages, it undergoes a multitude of changes. Some of these changes are visible, whereas others are not and may be elicited during the patient encounter. Some gastrointestinal issues may be more common in the elderly population and possibly in older women. These issues range from motility disorders, such as fecal incontinence and constipation, to changes in neuropeptide function and its effect on the anorexia of aging. This article comprehensively reviews gastrointestinal issues that commonly afflict the elderly female population.

The quantity of meal fat influences the profile of postprandial hormones as well as hunger sensation in healthy elderly people

BACKGROUND

In healthy elderly people, reduced appetite and the consequent decrease in food intake has been defined as the "anorexia of aging"; this condition may lead to malnutrition. The aim of this study was to investigate how different compositions of macronutrients affect satiety and hunger signals as well as subjective sensations after meals in healthy elderly subjects.

METHODS

Experimental controlled study. Ambulatory healthy community-dwelling subjects evaluation in a single center on 12 elderly subjects, (75.2+/-2 years old) and 12 younger controls (28.2+/-2 years old). Using a visual analogical scale, hunger was evaluated under fasting conditions and at 30-minute intervals for up to 4 hours after two 800-kcal meals, where 20% and 40% of the calories were derived from fat. Serum samples were collected at -30, 60, 120, and 240 minutes to determine the concentrations of GLP-1, acylated and desacylated ghrelin, triglycerides, glucose, and insulin.

RESULTS

Serum concentrations of GLP-1 were higher after the 40% fat meal than after the 20% fat meal (P < .01) in the elderly but not in the younger subjects. Acylated to desacylated ratio was lower after the 40% fat meal (P < .05) in the elderly. Only in the older group were triglycerides higher (P < .05), whereas hunger was significantly lower (P < .05) after the 40% fat meal.

CONCLUSION

In healthy elderly people relatively large amounts of fat increase the satiety signal from GLP-1 and lower the acylated to desacylated ratio of ghrelin, consequently decreasing hunger. This condition may lead to a reduction in calorie intake.

Impaired postprandial response of active ghrelin and prolonged suppression of hunger sensation in the elderly

BACKGROUND

The role of the orexigenic hormone ghrelin is of major interest in the altered appetite regulation of the elderly.

METHODS

Basal and postprandial levels of active and total ghrelin were measured in 15 younger (mean age 35.4 years) and 19 older (80.7 years) participants following a carbohydrate-rich test meal.

RESULTS

Our results showed that older participants felt postprandially less hungry and more full. Although basal levels were not significantly different, active and total ghrelin levels declined postprandially only in the younger study participants. Highly significant differences between the two age groups were shown for the changes of the area under the curve for active ghrelin (p = .024).

CONCLUSIONS

Our study demonstrates for the first time that differences in hunger and satiety sensations in relation to age are paralleled by a substantially different response of acylated and total ghrelin, that is, the absence of a postprandial decline in ghrelin levels.

Satiety and the anorexia of ageing

The 'anorexia of aging' refers to reduced appetite and energy intakes observed in some older adults. Satiation (the process that leads to the termination of eating, which may be accompanied by a feeling of satisfaction) and satiety (the feeling of fullness that persists after eating, potentially suppressing further energy intake until hunger returns) are important factors in the control of appetite and energy intake, and there is evidence that some aspects of satiation and satiety are altered in older adults. Factors affected include gastric emptying, which could affect satiation, and levels of gut hormones which could affect satiety. Sensory specific satiety also appears to be reduced in older subjects. This might be important in the anorexia of aging and dietary strategies could be used to reduce satiety and encourage an increased energy intake. However, many other factors may affect the anorexia of aging and it is important to understand these in order to help those at risk of malnutrition.

Effect of age and frailty on ghrelin and cholecystokinin responses to a meal test

BACKGROUND

Ghrelin and cholecystokinin (CCK) are among the peripheral signals that regulate hunger and satiety.

OBJECTIVE

The objective was to assess whether ghrelin and CCK responses to a standard nutritional load are related to age and frailty.

DESIGN

Ghrelin, CCK, insulin, glucose, and 4-h visual analog hunger scale curves after a standard nutritional load test (380 kcal) were described and compared between 3 groups: old (>75 y) and frail persons (group A), old (>75 y) but nonfrail persons (group B), and young (25-65 y) adults (group C).

RESULTS

Frail persons showed no postprandial ghrelin suppression, and old subjects, frail and nonfrail, showed no significant postprandial ghrelin recovery compared with young adults. Frailty was also associated with lower fasting ghrelin concentrations. No differences in fasting CCK were observed between young and old persons; however, postprandial CCK concentrations were enhanced in young persons, whereas no frailty effect on the CCK curve was observed in the old subjects. No correlations between mean ghrelin and hunger values over time were found, but strong negative correlations were shown between CCK and hunger (group A: r(s) = -0.88, P = 0.009; group B: r(s) = -0.86, P = 0.014; group C: r(s) = -0.71, P = 0.071) and insulin and hunger (group A: r(s) = -0.901, P = 0.006; group B: r(s) = -0.964, P < 0.001; group C: r(s) = -0.929, P = 0.003).

CONCLUSIONS

Advanced age determines a poorer ghrelin postprandial recuperation phase, a reduced CCK postprandial response, and an exaggerated postprandial insulin release. A loss of ghrelin prandial rhythm is present in old frail persons. The impaired response of these hunger regulatory hormones with age might contribute to the mechanisms of anorexia associated with aging.

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.

Possible entrainment of ghrelin to habitual meal patterns in humans

Ghrelin is reportedly a meal-initiation signal based on observations that concentrations increase before meals coincident with rising hunger. However, evidence that ghrelin peaks vary with feeding schedules suggests that it rises in anticipation of an expected meal, rather than eliciting feeding. To explore the entrainment of ghrelin profiles, this study investigated the association between varying habitual meal patterns and plasma ghrelin concentrations. Lean and obese adults following either a short intermeal interval (SII) pattern, with 2.5-3.5 h between their habitual breakfast and lunch times, or a long intermeal interval (LII) pattern, with 5.5-6.5 h between these eating occasions, participated. Food intake and appetite were recorded for 2 baseline days. On the subsequent test day, blood samples were collected over 8 h while participants ate a breakfast and lunch matched to their customary meals and pattern. Appetite ratings were obtained and ghrelin, insulin, glucose, and leptin concentrations were measured. Peak ghrelin concentrations differed significantly by group and occurred prior to each group's respective lunch time. Ghrelin concentrations directly correlated with subjective hunger. This association was stronger when hunger preceded ghrelin, a pattern inconsistent with ghrelin causing the hunger rise. Ghrelin concentrations were inversely correlated with insulin, and peak insulin concentrations preceded nadir ghrelin concentrations postprandially. Ghrelin concentrations periprandially, and over the entire test session, did not differ by meal group, likely because of similar intakes between groups. These data demonstrate that the timing of ghrelin peaks is related to habitual meal patterns and may rise in anticipation of eating rather than eliciting feeding.

Immunosupportive therapies in aging

The primary role of the immune system is to protect the organism against pathogens, but age-associated alterations to immunity increase the susceptibility of the elderly to infectious disease. The exact nature of these changes is still controversial, but the use of screening procedures, such as the SENIEUR protocol to exclude underlying illness, helped to better characterize the changes actually related to physiological aging rather than pathology. It is generally agreed that the most marked changes occur in the cellular immune response reflecting profound alterations in T cells. Much of this is due to thymic involution as well as changes in the proportions of T cell subpopulations resulting from antigen exposure, and altered T cell activation pathways. However, a body of data indicates that innate immune responses, including the critical bridge between innate and adaptive immunity, and antigen presenting capacity are not completely resistant to senescence processes. The consequences of all these alterations are an increased incidence of infections, as well as possibly cancers, autoimmune disorders, and chronic inflammatory diseases. The leading question is what, if anything, can we do to prevent these deleterious changes without dangerously dysregulating the precarious balance of productive immunity versus immunopathology? There are many potential new therapeutic means now available to modulate immunosenescence and many others are expected to be available shortly. One main problem in applying these experimental therapies is ethical: there is a common feeling that as ageing is not a disease; the elderly are not sick and therefore do not require adventurous therapies with unpredictable side-effects in mostly frail individuals. Animal models are not helpful in this context. In this chapter we will first briefly review what we think we know about human immunosenescence and its consequences for the health status of elderly individuals. We will then discuss possible interventions that might one day become applicable in an appropriate ethical environment.

Lack of an acute effect of ghrelin on markers of bone turnover in healthy controls and post-gastrectomy subjects

BACKGROUND

Ghrelin is a gut-brain peptide that powerfully stimulates appetite and growth hormone secretion and is also known to directly regulate osteoblast cell function in vitro and in animal models. Little is known about the effects of ghrelin on bone turnover in humans. As the stomach is the main site of ghrelin synthesis, gastrectomy patients are deficient in ghrelin; they are also prone to osteopenia and osteomalacia.

HYPOTHESIS

Ghrelin may play a role in bone regulation in humans; ghrelin deficiency following gastrectomy is associated with the disrupted regulation of bone turnover seen in these subjects.

SUBJECTS AND METHODS

In a randomised, double-blind, placebo-controlled study 8 healthy controls and 8 post-gastrectomy subjects were infused with intravenous ghrelin (5 pmol/kg/min) or saline over 240 min on different days. Subjects were given a fixed energy meal during the infusion. Ghrelin, GH, type-1 collagen beta C-telopeptide (betaCTX), a marker of bone resorption, and procollagen type-1 amino-terminal propeptide (P1NP), a marker of bone formation, were measured.

RESULTS

Fasting ghrelin was significantly lower in the gastrectomy group during the saline infusion (226.1+/-62.0 vs. 762+/-71.1 ng/l p<0.001). Growth hormone was significantly higher at 90 min after the ghrelin infusion, compared to saline in both healthy controls (61.1+/-8.8 vs. 1.4+/-0.6 mIU/l p<0.001) and gastrectomy subjects (61.1+/-11.8 vs. 0.9+/-0.2 mIU/l p<0.001) confirming the ghrelin was bioactive. Gastrectomy subjects were significantly older and had significantly higher plasma betaCTX than healthy controls at all time points (ANOVA p=0.009). After adjustment for age and BMI ghrelin was found to be a significant predictor of baseline plasma betaCTX and was inversely correlated with baseline plasma betaCTX (beta=-0.54 p=0.03 R2=26%). However, there was no significant effect of the ghrelin infusion on plasma betaCTX or P1NP in either subject group.

CONCLUSIONS

Ghrelin infusion has no acute effect on markers of bone turnover in healthy controls and post-gastrectomy subjects, but is inversely correlated with bone resorption.

Is overweight/obesity associated with short sleep duration in older women?

BACKGROUND AND AIM

No study to date has documented the association between short sleep duration and the risk for obesity in older people. Therefore, the aim of this study was to examine cross-sectional associations between short sleep duration and variations in body fat indices in older women.

METHODS

Anthropometric and body composition measurements, resting energy expenditure, daily energy expenditure, daily energy intake, plasma lipid-lipoprotein profile, and self-reported sleep duration were determined in a sample of 90 women of 50 years and above.

RESULTS

The odds ratios for overweight/obesity were comparable in subjects reporting <7 hours and >or=7 hours of sleep per day, with or without adjustment for age, daily energy expenditure and daily energy intake. The results did not permit to observe any significant difference between the two sleeper groups for all the variables investigated. The correlations between sleep duration and adiposity indices were also non significant.

CONCLUSIONS

Short sleep duration does not predict an increased risk of being overweight/obese in older women. This observation, together with our previously reported results in younger subjects, suggests that the sleep-body fat relationship progressively becomes less detectable with increasing in age.

Sleep and metabolic control: waking to a problem?

1. The aim of the present review is to outline: (i) the association between sleep and metabolism; (ii) how sleep duration influences the development of disease; and (iii) how sex differences, ageing and obesity may potentially influence the relationship between sleep, metabolic control and subsequent disease. 2. Sleep is associated with a number of endocrine changes, including a change in insulin action in healthy young individuals. Sleep duration shows a prospective U-shaped relationship with all-cause mortality, cardiovascular disease and Type 2 diabetes. 3. Chronic sleep restriction is becoming more common. Experimental sleep restriction impedes daytime glucose control and increases appetite. 4. The sex hormones oestrogen and testosterone influence sleep duration and quality and may account for sex differences in the prevalence of sleep-related disorders. 5. Ageing is associated with a decreased sleep duration, decreased muscle mass and impaired insulin action. 6. Obesity impairs insulin action and is associated with the incidence and severity of obstructive sleep apnoea. 7. Sleep plays an integral role in metabolic control. Consequently, insufficient sleep may represent a modifiable risk factor for the development of Type 2 diabetes. The challenge ahead is to identify how sex differences, ageing and obesity could potentially influence the relationship between sleep and metabolism.