An underfeeding study in healthy men and women provides further evidence of impaired regulation of energy expenditure in old age

Is dieting a risk for higher weight gain in normal-weight individual? A systematic review and meta-analysis

While there is an increasing prevalence of dieting in the overall population, weight loss (WL) practices could be a risk factor for weight gain (WG) in normal-weight (NW) individuals. The aim of the present work was to systematically review all the studies implicating diet restriction and body weight (BW) evolution in NW people. The literature search was registered in PROSPERO (CRD42021281442) and was performed in three databases from April 2021 to June 2022 for articles involving healthy NW adults. From a total of 1487 records initially identified, eighteen were selected in the systematic review. Of the eight dieting interventional studies, only one found a higher BW after weight recovery, but 75 % of them highlighted metabolic adaptations in response to WL favouring weight regain and persisting during/after BW recovery. Eight of the ten observational studies showed a relationship between dieting and major later WG, while the meta-analysis of observational studies results indicated that 'dieters' have a higher BW than 'non-dieters'. However, considering the high methodological heterogeneity and the publication bias of the studies, this result should be taken with caution. Moreover, the term 'diet' was poorly described, and we observed a large heterogeneity of the methods used to assess dieting status. Present results suggest that dieting could be a major risk factor for WG in the long term in NW individuals. There is, however, a real need for prospective randomised controlled studies, specifically assessing the relationship between WL induced by diet and subsequent weight in this population.

Clinical Impact of Nutritional Status and Energy Balance in Elderly Hospitalized Patients

OBJECTIVES

This study aimed 1) to assess the nutritional status of patients hospitalized in a geriatric ward using the recent Global Leadership Initiative on Malnutrition (GLIM) criteria, 2) to determine the balance between the energy intake (EI) with an enriched diet and the energy requirement (ER) using indirect calorimetry, and 3) to assess whether undernutrition is associated with 1-year outcome.

DESIGN

This is a prospective cross-sectional study.

SETTING

This study was performed in a geriatric unit.

PARTICIPANTS

Patients of this geriatric unit were eligible for the study if they agreed to participate and if they did not meet the exclusion criteria (presence of malignant tumour, uncontrolled heart or renal failure, thyroidal disease, uncontrolled sepsis, oedema of the lower limbs, wearing of a pacemaker, biological thyroid dysfunction and inability to perform walking tests).

MEASUREMENTS

Rest energy expenditure (REE) was measured by indirect calorimetry within the week of hospitalization. Total energy expenditure (TEE) was obtained by multiplying REE by a physical activity level coefficient and energy expenditure that was related to thermogenesis (i.e., 10% of the total amount of energy ingested over 24 h) was added. Food intake was measured over a 3-day period. Undernutrition was defined using MNA and the criteria of the GLIM leadership. Clinical outcomes included 1-year institutionalisation and mortality.

RESULTS

Seventy-nine patients (84.9 ± 5.3 years) were included. A total of 21 (26.6 %) patients were found undernourished. REE was 1088 ± 181kcal/day (17.8 ± 2.9 kcal/kg/day) and TEE was 1556 ± 258 kcal/day (25.4 ± 4.2 kcal/kg/day). Weight-adjusted REE and TEE were higher in undernourished patients compared to those well-nourished (19.8 ± 3.1 vs. 17.1 ± 2.6 kcal/day and 28.4±4.5 vs. 24.4±3.7 kcal/day) (p<0.05). The lower was the Body Mass Index (BMI), the higher was the energy needs (p<0.01). EI was significantly greater than energy requirements (difference requirements - intake with enriched diet = -354 ± 491 kcal/day; p<0.0001). This difference did not depend on BMI (p=0.82), appendicular skeletal mass index (ASMI) (p=0.63), or the presence of undernutrition (p=0.33). At 1-year follow-up, 15 (19%) patients died and 20 (25.6%) were institutionalized. On multivariable analysis, male gender (OR=5.63; p=0.015) and undernutrition (OR=7.29; p=0.0043) emerged as independently associated with death. On multivariable analysis, only ASMI (OR 0.59 (0.35-0.99), p=0.044) and activities of daily living (ADL) (OR 1.14 (1.00-1.30), p=0.043) were significantly associated with institutionalization.

CONCLUSIONS

Undernutrition as assessed by the GLIM criteria remains common in elderly patients hospitalized in a geriatric unit and is associated with increased 1-year mortality but not with institutionalization. Energy requirements are higher in undernourished patients and in patients with a low BMI. Enriched energy intakes could sufficiently cover the energy needs of this population.

Long-Term Weight Loss With Metformin or Lifestyle Intervention in the Diabetes Prevention Program Outcomes Study

BACKGROUND

Identifying reliable predictors of long-term weight loss (LTWL) could lead to improved weight management.

OBJECTIVE

To identify some predictors of LTWL.

DESIGN

The DPP (Diabetes Prevention Program) was a randomized controlled trial that compared weight loss with metformin, intensive lifestyle intervention (ILS), or placebo. Its Outcomes Study (DPPOS) observed patients after the masked treatment phase ended. (ClinicalTrials.gov: NCT00004992 and NCT00038727).

SETTING

27 DPP and DPPOS clinics.

PARTICIPANTS

Of the 3234 randomly assigned participants, 1066 lost at least 5% of baseline weight in the first year and were followed for 15 years.

MEASUREMENTS

Treatment assignment, personal characteristics, and weight.

RESULTS

After 1 year, 289 (28.5%) participants in the metformin group, 640 (62.6%) in the ILS group, and 137 (13.4%) in the placebo group had lost at least 5% of their weight. After the masked treatment phase ended, the mean weight loss relative to baseline that was maintained between years 6 and 15 was 6.2% (95% CI, 5.2% to 7.2%) in the metformin group, 3.7% (CI, 3.1% to 4.4%) in the ILS group, and 2.8% (CI, 1.3% to 4.4%) in the placebo group. Independent predictors of LTWL included greater weight loss in the first year in all groups, older age and continued metformin use in the metformin group, older age and absence of either diabetes or a family history of diabetes in the ILS group, and higher fasting plasma glucose levels at baseline in the placebo group.

LIMITATION

Post hoc analysis; examination of nonrandomized subsets of randomized groups after year 1.

CONCLUSION

Among persons with weight loss of at least 5% after 1 year, those originally randomly assigned to metformin had the greatest loss during years 6 to 15. Older age and the amount of weight initially lost were the most consistent predictors of LTWL maintenance.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Prevalence of malnutrition and associated factors among community-dwelling older persons in Sri Lanka: a cross-sectional study

BACKGROUND

Malnutrition in older persons is a public health concern. This study aimed to estimate the prevalence of malnutrition and its associated factors among community-dwelling older persons in Sri Lanka.

METHODS

A cross-sectional study was conducted in the Kandy district, Sri Lanka. The nutritional status of older persons was assessed using the Mini Nutritional Assessment -Short Form (MNA-SF). A standardised questionnaire was used to record factors associated with malnutrition: demographic characteristics, financial characteristics, food and appetite, lifestyle, psychological characteristics, physical characteristics, disease and care, oral health, and social factors. Complex sample multinomial logistic regression analysis was performed.

RESULTS

Among the 999 participants included in the study, 748 (69.3%) were females and 251 (25.1%) were males. The mean age was 70.80 years (95% CI: 70.13, 71.47). The prevalence of malnutrition, risk of malnutrition and well-nutrition was 12.5%, 52.4% and 35.1% respectively. In the multivariate model, hypertension (adjusted OR = 1.71; 95% CI: 1.02, 2.89), alcohol consumption (aOR = 4.06; 95% CI: 1.17, 14.07), and increased age (aOR = 1.06; 95% CI: 1.01, 1.11) were positively associated with malnutrition. An increased number of people living with the older person (aOR: 0.91; 95% CI: 0.85, 0.97) was a protective factor among those at risk for malnutrition.

CONCLUSION

Both the prevalence of malnutrition and risk of malnutrition were commonly observed among community-dwelling older persons in Sri Lanka. The associated factors identified in this study might help public health professionals to implement necessary interventions that improve the nutritional status of this population.

Excess ω-6 fatty acids influx in aging drives metabolic dysregulation, electrocardiographic alterations, and low-grade chronic inflammation

Maintaining a balance of ω-6 and ω-3 fatty acids is essential for cardiac health. Current ω-6 and ω-3 fatty acids in the American diet have shifted from the ideal ratio of 2:1 to almost 20:1; while there is a body of evidence that suggests the negative impact of such a shift in younger organisms, the underlying age-related metabolic signaling in response to the excess influx of ω-6 fatty acids is incompletely understood. In the present study, young (6 mo old) and aging (≥18 mo old) mice were fed for 2 mo with a ω-6-enriched diet. Excess intake of ω-6 enrichment decreased the total lean mass and increased nighttime carbohydrate utilization, with higher levels of cardiac cytokines indicating low-grade chronic inflammation. Dobutamine-induced stress tests displayed an increase in PR interval, a sign of an atrioventricular defect in ω-6-fed aging mice. Excess ω-6 fatty acid intake in aging mice showed decreased 12-lipoxygenase with a concomitant increase in 15-lipoxygenase levels, resulting in the generation of 15( S)-hydroxyeicosatetraenoic acid, whereas cyclooxygenase-1 and -2 generated prostaglandin E₂, leukotriene B_4, and thromboxane B₂. Furthermore, excessive ω-6 fatty acids led to dysregulated nuclear erythroid 2-related factor 2/antioxidant-responsive element in aging mice. Moreover, ω-6 fatty acid-mediated changes were profound in aging mice with respect to the eicosanoid profile while minimal changes were observed in the size and shape of cardiomyocytes. These findings provide compelling evidence that surplus consumption of ω-6 fatty acids, coupled with insufficient intake of ω-3 fatty acids, is linked to abnormal changes in ECG. These manifestations contribute to functional deficiencies and expansion of the inflammatory mediator milieu during later stages of aging. NEW & NOTEWORTHY Aging has a profound impact on the metabolism of fatty acids to maintain heart function. The excess influx of ω-6 fatty acids in aging perturbed electrocardiography with marked signs of inflammation and a dysregulated oxidative-redox balance. Thus, the quality and quantity of fatty acids determine the cardiac pathology and energy utilization in aging.

Context-dependent correlation between resting metabolic rate and daily energy expenditure in wild chipmunks

Several empirical studies have shown that variation in daily energy expenditure (DEE) and resting metabolic rate (RMR) is influenced by environmental and individual factors, but whether these shared influences are responsible for, or independent of, relationships between DEE and RMR remains unknown. The objectives of this study were to (i) simultaneously evaluate the effects of environmental and individual variables on DEE and RMR in free-ranging eastern chipmunks (Tamias striatus) and (ii) quantify the correlation between DEE and RMR before and after controlling for common sources of variation. We found that the influence of individual factors on DEE and RMR is most often shared, whereas the influence of environmental factors tends to be distinct. Both raw and mass-adjusted DEE and RMR were significantly correlated, but this correlation vanished after accounting for the shared effect of reproduction on both traits. However, within reproductive individuals, DEE and RMR remained positively correlated after accounting for all other significant covariates. The ratio of DEE to RMR was significantly higher during reproduction than at other times of the year and was negatively correlated with ambient temperature. DEE and RMR appear to be inherently correlated during reproduction, but this correlation does not persist during other, less energy-demanding periods of the annual cycle.

Rate of weight loss can be predicted by patient characteristics and intervention strategies

BACKGROUND

Although dietary weight-loss counseling usually employs a 500 to 1,000 kcal/day energy deficit to induce weight loss of 0.5 to 1 kg/week, this rate of weight loss is rarely achieved in research settings. Biological factors, such as changes in metabolic rate, are partly responsible, but would only account for a small deviation from expected weight loss. There must be other factors, behavioral or related to study design and implementation, that affect the rate of weight loss observed.

OBJECTIVE

To examine factors that influence the rate of weight loss obtained in clinical studies.

DESIGN

Thirty-five weight-loss studies published between 1995 and 2009 were identified that used dietary counseling to induce weight loss in healthy subjects. Studies were included if they had a duration of at least 6 weeks, used a strategy to counsel subjects to reduce free-living energy intakes, and reported weight-loss data based on a completers analysis. Variables that were associated with the rate of weight loss among age, sex (percent female subjects), initial body weight, frequency of dietary counseling, placebo use, exercise level, study length, and prescribed energy deficit were examined using linear regression analysis.

RESULTS

Study length was negatively related to the rate of weight loss (P<0.0001), whereas subject age (P<0.002), subject age squared (P=0.0073), initial body weight (P=0.0003), frequency of dietary counseling (P=0.0197), and prescribed energy deficit (P<0.0001) were positively related to the rate of weight loss observed in clinical studies.

CONCLUSIONS

These findings provide a tool for investigators and clinical dietitians to predict the rate of weight loss that can be expected within a population given the age, initial body weight, frequency of dietary counseling, and energy deficit prescription. These data from clinical studies suggest that the rate of weight loss is greater in older and heavier subjects and with higher contact frequency and caloric restriction.

Effects of branched amino acids supplementation in malnourished elderly with catabolic status

BACKGROUND

Among various nutrients branched amino acids (BCAAS) have been shown to be the most responsible for the stimulation of protein synthesis in various situations including catabolic states.

OBJECTIVES

We evaluated the effect of a small amount of proteins enriched with BCAAs (0.4 g/kg/day and 0.2 g/kg/day BCAAs) on body weight and composition; nitrogen balance, energy intake and inflammation after 2 weeks of supplementation in acute elderly with catabolic status.

DESIGN

Two weeks randomized controlled trial.

SETTING

Geriatric department of teaching hospital.

SUBJECTS

Thirty patients with malnutrition and inflammatory process (MNA < 24, albumin < 30 g/l and CRP > or = 20 mg/l) who agreed to participate in the study were consecutively included.

METHODS

Body composition was determined by labelled water dilution method; resting energy expenditure (REE) was determined by indirect calorimetry; energy intake was calculated for a 3 days period at D1 and D12. Nutritional and inflammatory proteins and cytokines (IL-6 and TNF) were measured at day 1 and 14.

RESULTS

No difference was observed at day 14 between supplemented (S) and control (C) group for weight (S: 58.0 +/- 11.8 kg and C: 60.0 +/- 15.9 kg); fat free mass (S: 40.7 +/- 8.3 kg and C: 40 +/- 8.2 kg); nitrogen balance (S: 1.34 +/- 2.21 g/day and C: 0.59 +/- 4.47 g/day); and energy intake (S: 20 +/- 3.6 kcal/day and C: 20.5 +/- 8.6 kcal/day). Energy intake was at similar level than REE and clearly less than energy requirement in C and S. A significant decrease was observed for orosomucoid and Prognostic Inflammatory and Nutritional Index (PINI) in S.

CONCLUSION

Our results do not confirm improvement of nutritional status with enriched BCAAs supplementation as suggested in the literature. Persistence of inflammatory condition may be an explanation despite an improvement of inflammatory status was observed in the supplemented group. Those results show clearly that energy requirements are not covered in acute hospitalized elderly people. The fact that not only energy intake but also REE are decreased brings a new insight on catabolic situations.

Effects of exercise and caloric restriction on insulin resistance and cardiometabolic risk factors in older obese adults--a randomized clinical trial

BACKGROUND

The prevalence of insulin resistance, metabolic syndrome, and cardiovascular disease is greatest in older obese patients, and effective evidence-based treatment strategies are lacking.

METHODS

A prospective controlled study was conducted on 24 older (65.5 +/- 5.0 years) obese (body mass index, 34.3 +/- 5.2 kg/m(2)) adults with clinically diagnosed metabolic syndrome. We examined the effect of exercise alone (EX) or exercise combined with moderate caloric restriction (-500 kcal, EX + CR) on metabolic and cardiovascular risk factors. Measures of insulin sensitivity assessed by euglycemic hyperinsulinemic clamp and by oral glucose tolerance test, lipid profiles, blood pressure, body composition, abdominal fat, and aerobic capacity were all obtained before and after the interventions.

RESULTS

Both groups experienced significant weight loss, but the reduction was greater in the EX + CR group than in the EX group (-6.8 +/- 2.7 kg vs -3.7 +/- 3.4 kg, respectively, p = .02). Both interventions improved insulin sensitivity (2.4 +/- 2.4 mg/kg FFM/min and 1.4 +/- 1.7 mg/kgFFM/min, respectively, p < .001) and indices of metabolic syndrome (systolic/diastolic blood pressure, waist circumference, glucose, and triglycerides; p < .05). High-density lipoprotein levels remained unchanged. Total abdominal, subcutaneous, and visceral fat; aerobic capacity; and total and low-density lipoprotein cholesterol were also improved. With the exception of weight loss and subcutaneous fat, there was no difference in the magnitude of improvement between the interventions.

CONCLUSION

These data suggest that exercise alone is an effective nonpharmacological treatment strategy for insulin resistance, metabolic syndrome, and cardiovascular disease risk factors in older obese adults.

Postprandial ghrelin suppression is exaggerated following major surgery; implications for nutritional recovery

Meeting patients' nutritional requirements and preventing malnutrition is a challenge following major surgical procedures. The role of ghrelin in nutritional recovery after non-gastrointestinal major surgery is unknown. We used coronary artery bypass grafting (CABG) as an example of anticipated good recovery post major surgery.

Seventeen patients undergoing CABG (mean ± SEM: 70.1 ± 2.2 yrs, BMI 29.1 ± 1.4 kg/m², 15 male) underwent fasting and postprandial (45 mins after standard test breakfast) blood sampling pre-operatively (day 0), post-operatively (day 6) and at follow-up (day 40). Changes in food intake, biochemical and anthropometric markers of nutritional status were recorded. A comparison was made to 17 matched healthy controls (70.6 ± 2.3 yrs, BMI 28.4 ± 1.3 kg/m²).

We observed significantly increased post-operative and follow-up fasting ghrelin concentrations compared with pre-operatively (pre-op. 402 ± 42 pmol/L vs post-op. 642 ± 97 pmol/L vs follow-up 603 ± 94 pmol/L) (ANOVA p < 0.05). Significantly exaggerated postprandial suppression of ghrelin was seen postoperatively and continued until follow-up (Δ pre-op. 10 ± 51 pmol/L vs Δ post-op. -152 ± 43 pmol/L vs Δ follow-up -159 ± 65 pmol/L, p < 0.05). This was associated with a 50% reduction in food intake {post-op. 4.5 ± 0.5 MJ/D (1076 ± 120 kcal/D) compared with estimated requirements 9.9 ± 0.5 MJ/D (2366 ± 120 kcal/D)}, leading to a 4% weight loss and a 5% reduction in muscle arm circumference loss over length of follow up.

Our data support the hypothesis that prolonged changes in fasting and postprandial plasma ghrelin concentrations are associated with impaired nutritional recovery after CABG. These findings reinforce the need to investigate ghrelin in other patients groups undergoing major surgery.

Dietary variety and its effect on food intake of elderly adults

BACKGROUND

Older people frequently have poor food intake. This present study investigated the effect of dietary variety on food intake in younger and older people.

METHODS

Eighteen young adults (mean age = 26 years) and 18 older adults (mean age = 70 years) consumed four consecutive courses of sandwiches on two occasions. In the plain treatment, each course of sandwiches was of the same type, while in the variety treatment four courses, each of a different type of sandwich, were served. Each time the participants were presented with a serving of sandwiches and asked to eat as much as they liked.

RESULTS

In the plain condition, the older adult group consumed more than their young counterparts. This situation was reversed for the variety condition when the young group ate more than the older adults. Interestingly, the older adult group ate more when a variety of sandwiches was presented. This may be contrary to what is predicted by the sensory-specific satiety model of eating behaviour.

CONCLUSIONS

This study suggests that presenting the older people with a varied meal may be a valid strategy to improve food intake in this group.

Pharmacological Treatment of Geriatric Cachexia: Evidence and Safety in Perspective

Anticachexic or antisarcopenic medications are prescribed worldwide for geriatric patients with poor appetite and associated weight loss. They represent a valuable treatment option for managing cachexia. However, the well-publicized adverse reports about these medications in acquired immunodeficiency syndrome (AIDS) and in the cancer population has led to some concern and much subsequent discussion over the safety of these medications being used in geriatric population. This review looks at the evidence in relation to the benefits and risks of these medications and discusses what we know about their use in the geriatric population.

Effect of increased dairy consumption on appetitive ratings and food intake

OBJECTIVE

The influence of dairy product consumption on food intake and appetitive sensations was explored in a cross-over design study with individuals who were habitually low (<1 serving/d) or high (>3 servings/d) dairy consumers.

RESEARCH METHODS AND PROCEDURES

Fifty-eight participants were required to eat one portion of dairy each day (low dairy) or three portions of dairy each day (high dairy) for 7 days. After a 7-day washout period, the opposite treatment condition was completed. Food intake and appetitive ratings were measured on each day of the treatment periods.

RESULTS

During the high-dairy period, participants consumed 209 kcal/d more than during the low dairy period (p < 0.05). There were no significant differences in subjective appetite ratings. Habitual dairy use did not influence either the appetitive or dietary findings.

DISCUSSION

These data indicate that increasing dairy consumption may lead to increased energy intake, which could potentially cause weight gain.

Enhanced energy expenditure and fat oxidation in humans with high BMI scores by the ingestion of novel and non-pungent capsaicin analogues (capsinoids)

The biochemical and physiological indices were monitored in 44 subjects after 4-week capsinoids (capsaicin analogues with low pungency) intake. The subjects were randomly assigned to 3 groups: CSNs3 (3 mg/kg of capsinoids), CSNs10 (10 mg/kg of capsinoids) and the control (placebo). Measurements were performed in the morning on overnight-fasted subjects. The oxygen consumption (VO(2)), resting energy expenditure (REE) and fat oxidation increased slightly compared to pre-administration values without any adverse effects, although the increase was not significant. The increase in fat oxidation was positively and significantly correlated with the body mass index (BMI). A meta-analysis was therefore conducted on a subgroup consisting of subjects with BMI >or= 25 (n=28). As a result, not only VO(2) increased significantly (p<0.05) in the CSNs10 group, but also REE in the CSNs10 group and fat oxidation in the CSNs3 and CSNs10 groups tended to increase (p<0.1). Consequently, a capsinoids intake would be able to enhance the energy expenditure and fat burning in humans, particularly those with high BMI.

Energy requirements in frail elderly people: A review of the literature

This review collates studies of healthy, sick, underweight (BMI < or = 21 kg/m2) and very elderly people (> or = 90 yr), in whom resting energy expenditure (REE) was measured using indirect calorimetry. We have observed the following: (1) REE, when adjusted for differences in both body weight and fat-free mass (FFM), is similar in healthy and in sick elderly people being 20 and 28 kcal/kg of FFM per day, respectively, (2) their nutritional status influences their energy requirements given that weight-adjusted REE increases in line with a decrease in BMI, (3) total energy expenditure is lower in sick elderly people given that their physical activity level, i.e. the ratio of total energy expenditure to REE, is reduced during disease averaging at 1.36, (4) energy intake (EI) being only 1.23 x REE is insufficient to cover energy requirements in sick elderly patients, whereas the EI of healthy elderly people appears sufficient to cover requirements, and finally, (5) gender ceases to be a determinant of REE in people aged 60 yr or over, with the Harris & Benedict equation capable of accurately predicting mean REE in this population, whether healthy or sick.

Malnutrition and ageing

This article aims to provide an overview of the problems that exist in relation to malnutrition and the elderly population. The changes that occur in body composition during ageing are described and how this may affect disease risk. The possible metabolic processes behind weight loss are discussed and the numerous factors that affect nutritional status in the older age group are described. Prevention of malnutrition in this group is important and so the roles of nutrition screening and assessment are examined.

Eating behavior and weight change in healthy postmenopausal women: results of a 4-year longitudinal study

BACKGROUND

The association of psychological eating behavior constructs with overweight and obesity during early adult life and middle age has been documented in several studies. However, the association of eating behavior with unexplained weight change in old age is relatively unexplored.

METHODS

Body weight, eating behavior (dietary restraint, disinhibition, and hunger as assessed by the Eating Inventory), reported dietary intake, and physical activity level were assessed at baseline in 36 nonobese postmenopausal women aged 61.3 +/- 3.1 years (mean +/- standard deviation). Measurements were repeated 4.4 +/- 0.9 years later, and changes in body weight were examined in relation to baseline and follow-up eating behavior scores, reported dietary intake, and physical activity level.

RESULTS

Participants had no major changes in health or lifestyle characteristics over the study interval. Weight change ranged from -7.5 to +5.8 kg (mean -0.3 +/- 3.5 kg), and there were no significant changes in reported dietary intake. Mean hunger score (calculated as the mean of baseline and follow-up hunger score) predicted weight change per year over the study period (bivariate r = 0.386, p =.020), even in statistical models adjusted for mean dietary intake variables (partial r = 0.658, p =.003). Restraint, disinhibition, and physical activity level did not predict weight change.

CONCLUSIONS

Reported hunger assessed by the Eating Inventory was associated with unintentional weight change in healthy postmenopausal women. The Eating Inventory questionnaire may provide a clinically useful tool for identifying older individuals at risk of undesirable weight change, and particularly unintentional weight loss, a factor strongly associated with increased morbidity and premature death in this population.

Nutrition and Aging: Changes in the Regulation of Energy Metabolism With Aging

Changes in energy regulation occur during normal aging and contribute to the common phenomenon of weight and fat losses late in life. This review synthesizes data on aging-related changes in energy intake and energy expenditure and on the regulation of energy intake and expenditure. The ability of older adults to accurately regulate energy intake is impaired, with a number of possible explanations including delayed rate of absorption of macronutrients secondary to reductions in taste and smell acuity and numerous hormonal and metabolic mediators of energy regulation that change with aging. There are also changes in patterns of dietary intake and a reduction in the variety of foods consumed in old age that are thought to further reduce energy intake. Additionally, all components of energy expenditure decrease with aging, in particular energy expenditure for physical activity and basal metabolic rate, and the ability of energy expenditure to increase or decrease to attenuate energy imbalance during overeating or undereating also decreases. Combined, these changes result in an increased susceptibility to energy imbalance (both positive and negative) in old age that is associated with deteriorations in health. Practical interventions for prevention of weight and fat fluctuations in old age are anticipated here based on emerging knowledge of the role of such factors as dietary variety, taste, and palatability in late-life energy regulation.

Effect of Aging on the Response of Ghrelin to Acute Weight Loss

OBJECTIVES

To determine whether the failure of the orexigenic hormone ghrelin to increase as it normally does with weight loss contributes to impaired weight recovery in older persons.

DESIGN

Prospective diet intervention study.

SETTING

University of Washington Medical Center from 2001 through 2005.

PARTICIPANTS

Twenty-one younger (18-35) and 18 older (> or =70) men and women.

INTERVENTION

Two weeks of a weight-maintaining diet were followed in sequence by 2 weeks of 30% calorie restriction, then 4 weeks of ad libitum food intake.

MEASUREMENTS

Twenty-four-hour plasma ghrelin levels, dual x-ray absorptiometry scan for body composition, resting energy expenditure, and calorie intakes were measured.

RESULTS

Both younger and older subjects lost weight with calorie restriction and failed to fully regain their baseline weight. The older adults trended toward increasing their calorie intake above their baseline level during the ad libitum period (111+/-66 kcal, P=.11), whereas the younger individuals did not (-236+/-95 kcal, P=.02). There was no statistically significant difference between the two cohorts in 24-hour ghrelin levels before or after calorie restriction. Ghrelin levels in the two cohorts increased equivalently after calorie restriction and decreased after ad libitum food consumption resumed.

CONCLUSION

Ghrelin levels in healthy older individuals respond appropriately in a compensatory manner to changes in body weight and calorie intake.

Spend less, live longer. The "thrifty aged" hypothesis

Evolutionary biology has rejected any argument in favour of planned ageing. In this article, the metabolic changes that follow in ageing have been analysed, and in accordance with that, an evolutionary explanation for the senescence program has been proposed. Ageing is characterised by a set of metabolic features all of them designed to reduce energy expenditure and to promote energy storage. Otherwise, the undoubted beneficial effect to fitness that means to live longer could generate a conflict between parents and offspring for energy resources. The solution to that conflict is an adult economical individual, a "thrifty aged". The way to obtain this cheaper individual is through the genetically induced physiological changes that finally lead the process. In conclusion, it is proposed that ageing is the condition, imposed by natural selection, that let organisms to outlast the obligatory reproductive time.

Basal metabolic rate and thyroid hormones of late-middle-aged and older human subjects: the ZENITH study

OBJECTIVE

This paper describes baseline data on basal metabolic rate (BMR), thyroid hormone levels and body composition of middle-aged and older people participating in the ZENITH project and the correlation of thyroid hormone levels with zinc status.

DESIGN

A multicentre prospective intervention study employing a randomised double blind design.

SETTING

Clermont-Ferrand, Theix (France), Coleraine (Northern Ireland), Grenoble (France), Rome (Italy).

INTERVENTIONS

BMR has been measured on a subsample of 70 middle-aged volunteers (35 men and 35 women recruited in Clermont-Ferrand, France, aged 55-70 y) and 108 older volunteers (56 men and 52 women recruited in Rome, Italy, aged 70-85 y). Thyroid hormone levels were evaluated in the entire group of ZENITH volunteers (n = 387). BMR was measured by indirect calorimetry. Fat-free mass (FFM) was derived by four skinfold thicknesses using Durnin and Womersley's equations. Concentrations of thyroid hormones (total T3 and T4) were measured using a competitive immunoassay with an enhanced chemiluminescence end point.

RESULTS

Italian older volunteers had a significantly lower FFM than middle-aged French volunteers (-7% P < 0.01). A negative correlation between BMR and age (men, r = -0.64; women, r = -0.62; both P < 0.0001) was observed: BMR was significantly (P < 0.000001) lower in Italian elderly volunteers (4.03+/-0.46 kJ/min and 3.29+/-0.42 kJ/min for men and women, respectively) than in middle-aged French volunteers (4.84+/-0.45 kJ/min and 3.87+/-0.38 kJ/min for men and women, respectively), even after adjustment for FFM (-12%). No correlation has been observed between BMR and thyroid hormones both in French and Italian subjects. Total T4 (TT4) concentrations were lowest in middle-aged population (-10%, P < 0.0001). A moderate negative correlation has been found with TT4 and red blood cell zinc (r = -0.12, P < 0.02, slope -0.026).

CONCLUSIONS

The results confirm an age-related decline in BMR not entirely explained by body composition or thyroid hormones differences.

Investigating heterogeneity in studies of resting energy expenditure in persons with HIV/AIDS: a meta-analysis

BACKGROUND

There is conflict in the literature about the extent of alterations of resting energy expenditure (REE) in persons with HIV.

OBJECTIVE

The study was conducted to ascertain the mean difference in REE (in kJ) per kilogram of fat-free mass (FFM; REE/FFM) between HIV-positive subjects and control subjects and to investigate heterogeneity in the literature.

DESIGN

A meta-analysis comparing classical and Bayesian methods was conducted. Heterogeneity was investigated by using subgroup analysis, metaregression, and a mixed indirect comparison.

RESULTS

Of 58 studies meeting the inclusion criteria, 32 included both HIV-positive and control groups; 24 of these 32 were included. Thirty-seven studies were used in the mixed indirect comparison, and 30 were used in the subgroup comparisons of the HIV-symptomatic, lipodystrophy, weight-losing, and weight-stable subgroups and the healthy (HIV-negative) control group. Mean REE/FFM was significantly higher in 732 HIV-positive subjects than in 340 control subjects [11.93 kJ/kg (95% CI: 8.44,15.43 kJ/kg) and 12.47 kJ/kg (95% CI: 8.19,16.57 kJ/kg), classical and Bayesian random effects, respectively]; the test for heterogeneity was significant (P < 0.001). Both the mixed indirect comparison and the subgroup analysis indicated that REE/FFM was highest in the symptomatic subgroup; however, the small number of studies investigating symptomatic subjects limited statistical comparisons. The presence of lipodystrophy, use of highly active antiretroviral therapy, subject age, and method of body-composition measurement could not explain the heterogeneity in the data with the use of metaregression.

CONCLUSIONS

REE/FFM (kJ/kg) is significantly higher in HIV-positive subjects than in healthy control subjects. Symptomatic HIV infection may contribute to the variations reported in the literature.

Obesity over the life course

Obesity in middle-aged humans is a risk factor for many age-related diseases and decreases life expectancy by about 7 years, which is roughly comparable to the combined effect of all cardiovascular disease and cancer on life span. The prevalence of obesity increases up until late middle age and decreases thereafter. Mechanisms that lead to increased obesity with age are not yet well understood, but current evidence implicates impairments in hypothalamic function, especially impairments in the ability of hypothalamic pro-opiomelanocortin neurons to sense nutritional signals. The rapid increase in the prevalence of obesity at all ages in the past decade suggests that, in the next two or three decades, diseases associated with obesity, especially diabetes, will begin to rise rapidly. Indeed, these trends suggest that for the first time in modern history, the life expectancy of people in developed societies will begin to decrease, unless the rapid increase in the prevalence of obesity can be reversed.

Energy requirements in the eighth decade of life

BACKGROUND

Knowledge of energy requirements among relatively healthy elderly is limited.

OBJECTIVES

The objectives of the study were to measure total energy expenditure (TEE)-derived energy requirements in a biracial population of older adults without limitations to daily life and to test these empirical measures against national and international recommendations.

DESIGN

TEE (measured by the doubly labeled water method), resting metabolic rate (RMR), activity-related energy expenditure (AEE), and body composition were measured in 288 persons aged 70-79 y selected from the Health, Aging, and Body Composition Study.

RESULTS

TEE was lower in women (approximately 530 kcal/d; P < 0.0001) than in men because of the women's lower RMR and AEE. Fat-free mass explained the sex difference in RMR, but body weight failed to account for the women's lower AEE (approximately 1 kcal x kg(-1) x d(-1); P = 0.007). Blacks had lower TEE than did whites (approximately 100 kcal/d, P = 0.03), and that was explained by blacks' lower RMR. Physical activity level (TEE/RMR) did not differ significantly between sexes and races (1.70 +/- 0.23). The World Health Organization (WHO) recommendations overestimated TEE by 10 +/- 15% (P < 0.0001) in women but not in men, and the dietary reference intakes (DRIs) were accurate to 0 +/- 14% (P = 0.1). Both WHO and DRI recommendations are based on an underestimated physical activity level, and WHO recommendations are based on overestimated RMR.

CONCLUSIONS

This study of well-functioning older adults confirms the racial difference in energy metabolism and supports the use of the 2002 DRIs. Because the DRIs and WHO recommendations underestimated PAL, new predictive equations of energy requirements are proposed.

Eating well: ageing gracefully!

The potential impact of dietary manipulation on the maintenance of physical and cognitive function between middle and old age has profound consequences for optimization of health, independence and well-being for the latter years. This review article considers four key areas: the role of diet and longevity; potential dietary measures to prevent sarcopenia; diet and cognitive function; and dietary interventions with regard to primary or secondary prevention of age-related chronic disorders. Caloric restriction has been shown to slow ageing and maintain health status in both primates and rats. The evidence has limited applicability to humans, since it is unlikely that 30% reduced diets could be maintained long-term. The causes of sarcopenia, which manifests as loss of strength, disability and reduced quality of life, are multifactorial. However, resistance with ageing to regulatory amino acids known to modulate translation and initiation, particularly leucine, raise possibilities with regard to dietary intervention. The pattern of protein intake appears to be important in whole-body protein retention in older adults. A body of evidence is emerging that associates various dietary factors with a reduction in cognitive decline with age, or a delay in the progression of Alzheimer's disease, particularly with regard to intake of vitamin E and C-containing foods, as well as fish intake. Epidemiological evidence demonstrates a role for dietary intervention in the primary prevention of chronic diseases, even in old age. However, the potentially harmful effects of micronutrient supplementation in the secondary prevention of coronary heart disease raise concern regarding appropriate dietary messages for the elderly. The role of the antioxidants, lycopene, lutein and zeaxanthin, in the prevention of cataracts and age-related macular degeneration support the almost universal dietary guideline 'eat more fruit and vegetables'. In future dietary guidelines for the elderly need to be evidence-based and take into account protective food patterns, rather than target specific foods.

Calculating energy requirements for men with HIV/AIDS in the era of highly active antiretroviral therapy

OBJECTIVES

1. To determine if resting energy expenditure (REE) adjusted for body composition is elevated in HIV-positive males when compared with healthy controls in the era of highly active antiretroviral therapy. 2. To examine the accuracy of prediction equations for estimating REE in people with HIV. 3. To determine if REE adjusting for body composition is significantly different between those HIV-positive subjects reporting lipodystrophy (LD) or weight loss (>or=5%) and those who are weight stable when compared to controls.

DESIGN

Cross-sectional study.

SETTING

Tertiary referral hospital HIV unit and an outpatient clinic specializing in HIV care.

SUBJECTS

HIV-positive males (n=70) and healthy male controls (n=16).

METHODS

REE was measured using indirect calorimetry. Body composition was assessed using bioelectrical impedance analysis.

RESULTS

1. REE when adjusted for fat-free mass and fat mass using the general linear model (analysis of covariance) was greater in HIV-positive subjects than controls (7258+/-810 kJ, n=70 vs 6615+/-695 kJ, n=16, P<0.05). 2. The Harris and Benedict, Schofield, Cunningham and the two equations previously published by Melchior and colleagues in HIV-positive subjects all gave an estimate of REE significantly different from the measured REE in the HIV-positive subjects, therefore a new prediction equation was developed. The inability of the published equations to predict REE in the different HIV-positive subgroups reflected the heterogeneity in body composition. 3. REE adjusted for fat-free and fat mass was significantly greater in the both the HIV patients who were weight stable and those with lipodystrophy compared with the healthy controls.

CONCLUSION

REE is significantly higher in HIV-positive males when compared with healthy controls. Body composition abnormalities common in HIV render the use of standard prediction equations for estimating REE invalid. When measuring REE in HIV-positive males adjustment steps should include fat-free and fat mass.