Dietary nitrate does not modify blood pressure and cardiac output at rest and during exercise in older adults: a randomised cross-over study.

Dietary nitrate (NO3-) supplementation has been associated with improved vascular and metabolic health. We conducted a double-blind, cross-over, placebo-controlled RCT to investigate the effects of 7-d consumption of beetroot juice compared with placebo on (1) blood pressure (BP) measured in resting conditions and during exercise, (2) cardiac and peripheral vascular function and (3) biomarkers of inflammation, oxidative stress and endothelial integrity. Twenty non-smoking healthy participants aged 60-75 years and BMI 20.0-29.9 kg/m2 were recruited. Measurement was conducted before and after each 7-d intervention period. Consumption of NO3- had no effect on resting systolic and diastolic BP. NO3- consumption did not improve indexes of central and peripheral cardiac function responses during cardiopulmonary exercise testing. Dietary NO3- supplementation did not modify biomarkers of inflammation, oxidative stress and endothelial integrity. This study does not support the short-term benefits of dietary NO3- supplementation on physiological and biochemical markers of vascular health in older healthy adults.

Serum 25-hydroxyvitamin D concentration and its determinants in the very old: the Newcastle 85+ Study.

SUMMARY: Data on vitamin D status in very old adults are lacking. The aim of this study was to assess 25-hydroxyvitamin D [25(OH)D] concentrations and its predictors in 775 adults aged 85 years old living in North-East England. Low 25(OH)D was alarmingly high during winter/spring months, but its biological significance is unknown. INTRODUCTION: Despite recent concerns about the high prevalence of vitamin D deficiency in much of the British adult and paediatric population, there is a dearth of data on vitamin D status and its predictors in very old adults. The objective of the present study was to describe vitamin D status and its associated factors in a broadly representative sample of very old men and women aged 85 years living in the North East of England (55° N). METHODS: Serum concentrations of 25-hydroxyvitamin D [25(OH)D] were analysed in 775 participants in the baseline phase of the Newcastle 85+ cohort study. Season of blood sampling, dietary, health, lifestyle and anthropometric data were collected and included as potential predictors of vitamin D status in ordinal regression models. RESULTS: Median serum 25(OH)D concentrations were 27, 45, 43 and 33 nmol/L during spring, summer, autumn and winter, respectively. The prevalence of vitamin D deficiency according to North American Institute of Medicine guidelines [serum 25(OH)D <30 nmol/L] varied significantly with season with the highest prevalence observed in spring (51%) and the lowest prevalence observed in autumn (23%; P < 0.001). Reported median (inter-quartile range) dietary intakes of vitamin D were very low at 2.9 (1.2-3.3) µg/day. In multivariate ordinal regression models, non-users of either prescribed or non-prescribed vitamin D preparations and winter and spring blood sampling were associated with lower 25(OH)D concentrations. Dietary vitamin D intake, disability score and disease count were not independently associated with vitamin D status in the cohort. CONCLUSION: There is an alarming high prevalence of vitamin D deficiency (<30 nmol/L) in 85-year-olds living in North East England at all times of the year but particularly during winter and spring. Use of vitamin D containing preparations (both supplements and medications) appeared to be the strongest predictor of 25(OH)D concentrations in these very old adults.

Ageing modifies the effects of beetroot juice supplementation on 24-hour blood pressure variability: An individual participant meta-analysis.

OBJECTIVES: Abnormal circadian oscillations of blood pressure (BP) and nocturnal-diurnal BP differences (i.e., dipping) increase cardiovascular risk. Whether inorganic nitrate supplementation influences 24-hr BP variability is currently unknown. We studied the effects of high-nitrate beetroot juice supplementation on BP variability measured by 24-hr ambulatory BP monitoring (24-hr ABPM) in older subjects. METHODS: Data from four independent randomised clinical trials were collated. Eighty-five older participants (age range: 55-76 years) were included in the final database. Two trials had an open-label, parallel design and two trials had a cross-over, double-blind design. Participants were randomised to either beetroot juice or placebo. Changes in 24-hr ABPM (daily, diurnal, nocturnal), variability (weighted-SDs), night-dipping, morning surge for systolic and diastolic BP were measured. Meta-analysis was conducted to obtain pooled estimates of the effect size for each BP outcome. Sub-group analyses were conducted to evaluate the influence of age, BMI, gender, BP status and changes in nitrite concentrations on the effect size. RESULTS: The pooled effect of beetroot juice on all BP outcomes was not significant. Beetroot juice ingestion determined a significant decrease in nocturnal systolic BP variability in subjects aged less than 65 y (2.8 mmHg, -4.5 -1.0, p = 0.002) compared to the older group (≥ 65 y; 1.0 mmHg, -2.2 4.2, p = 0.54). A greater change in NO2(-) concentrations after beetroot supplementation was associated with significant differences for nocturnal mean (-3.4 mmHg, -0.6 -2.4, p = 0.02) and variability (-0.8 mmHg, -1.5 -0.06, p = 0.03) of systolic BP. CONCLUSIONS: The vascular responsiveness to inorganic nitrate may be modified by mechanisms of vascular ageing influencing the reducing capacity to convert inorganic nitrate into nitrite and tissue-specific responses to dietary nitrate supplementation.

Shifts in population dietary patterns and physical inactivity as determinants of global trends in the prevalence of diabetes: an ecological analysis.

BACKGROUND AND AIMS: The worldwide epidemiology of diabetes is rapidly changing as a result of the spreading of westernised nutritional and lifestyle habits. We conducted an ecological analysis to identify dietary, lifestyle and socio-economic factors associated with global diabetes prevalence. METHODS AND RESULTS: Country-specific estimates of diabetes prevalence were obtained. Data were then matched to year- and country-specific food and energy availability for consumption, and to year-specific information on obesity, physical inactivity, urbanisation, gross domestic product (GDP), and smoking. Data were obtained from publicly available databases compiled by the Food Agricultural Organisation (FAO), World Health Organisation (WHO) and World Bank. Cluster analysis was used to derive dietary patterns of global food consumption. The association with diabetes prevalence was evaluated. Stepwise multiple regression analysis was conducted to identify predictors associated with worldwide diabetes prevalence. 96 countries were eligible for inclusion in the analysis. The average diabetes prevalence was 7.0% and the highest rate was observed in the Middle-Eastern region (13.1%). The worldwide prevalence of obesity and physical inactivity was 15.1% and 36.1%, respectively. Diabetes prevalence was associated with age and physical inactivity prevalence in a fully adjusted multiple regression model. Three dietary patterns (agricultural, transitional and westernised) were identified by the cluster analysis. Diabetes prevalence showed a direct dose-response association with the degree of exposure to a westernised dietary pattern. CONCLUSIONS: The adoption of sedentary lifestyle and westernised dietary patterns appears to be closely linked to the global rise in diabetes prevalence.

Body composition, leg length and blood pressure in a rural Italian population: a test of the capacity-load model.

BACKGROUND AND AIMS: Whereas adult weight or body mass index (BMI) are directly associated with blood pressure (BP), birth weight is inversely associated with BP. The scenario for height is more complex, as both tall and short stature have been associated with higher BP. We used a theoretical model treating sitting height (SH) and tissue masses (fat mass, lean mass) as components of metabolic load, and leg length (LL) as a marker of homeostatic metabolic capacity. We predicted that decreased capacity and increased load would be independently associated with increased BP.. METHODS AND RESULTS: Anthropometry, body composition (bio-electrical impedance analysis) and BP were measured in 601 adults (228 male) aged 20-91 years from three hill villages in southern Italy. Multiple regression analysis was used to investigate associations of body composition and anthropometry with BP. Adjusting for age, systolic BP (SBP) was associated with lean mass in males, and with adiposity in females, whereas diastolic BP (DBP) was associated with fat mass in both sexes. Associations of LL and SH with BP were in opposite directions. LL was inversely associated with SBP and DBP in males, with a similar trend evident in females. SH was directly associated with SBP and DBP in females, and with DBP in males. CONCLUSIONS: Consistent with our theoretical model, metabolic load is associated with increased BP, though differently between the sexes, whereas metabolic capacity is independently associated with lower BP. Our findings suggest that early growth improves hemodynamic tolerance of high metabolic load in adulthood..

Accuracy of three novel predictive methods for measurements of fat mass in healthy older subjects.

UNLABELLED: This study evaluated the agreement of novel anthropometric equations and established indirect methods (skinfold thickness and bioimpedance analysis) with reference methods [dual X-ray absorptiometry (DXA) and air displacement plethysmography (ADP)] for fat mass assessment (FM) in older subjects. METHODS: Forty subjects (M/F = 15/25, age = 61-84 years, BMI = 18-37 kg/m(2)) were recruited. The agreement of the following predictive equations was evaluated: body adiposity index (BAI), BAI-Fels and Clínica Universidad de Navarra-body adiposity estimator (CUN-BAE). RESULTS: BAI estimates were comparable to DXA (Δ ± 2SD = 0.4 ± 6.0 kg, p > 0.05) but not to ADP (Δ ± 2SD = -2.8 ± 7.2 kg, p < 0.001); BAI-Fels estimates were comparable to DXA (Δ ± 2SD = 0.8 ± 5.5 kg, p > 0.05) but not to ADP (Δ ± 2SD = -4.0 ± 6.9 kg, p < 0.001). The difference between CUN-BAE and ADP was not significant (Δ ± 2SD = -0.4 ± 5.6 kg, p > 0.05), whereas it significantly overestimated DXA (Δ ± 2SD = 2.8 ± 5.4 kg, p < 0.001). ADP significantly overestimated FM compared to DXA (Δ ± 2SD = 3.2 ± 5.4 kg, p < 0.001) and the measurement bias was significantly correlated with BMI in men (p = 0.004). CONCLUSIONS: The accuracy of the three anthropometric indexes is dependent on the choice of the reference method. The variability of the FM estimates was large and these indexes cannot be recommended for the assessment of FM in older subjects.

Weight loss expectations and body dissatisfaction in young women attempting to lose weight.

BACKGROUND: Unrealistic weight loss expectations (WLEs) and greater body dissatisfaction may be associated with the poor long-term outcomes of dietary and lifestyle weight loss treatments. We evaluated the association between body size, WLEs and body dissatisfaction in young women attempting to lose weight. METHODS: Forty-four young healthy women [age range 18-35 years, body mass index (BMI) range 23-40 kg/m2] were recruited. Women were classified as obese (BMI ≥ 30.0 kg/m2) and non-obese (BMI <30.0 kg/m2). The Body Dissatisfaction scale of the Eating Disorder Inventory-2 and the Body Image Assessment for Obesity silhouette charts were used to assess body dissatisfaction. WLEs were categorised according to personal (ideal, happiness, satisfaction, weight history), lifestyle (fitness) and social (career, family acceptance, peer acceptance, mass media, social pressure) factors. Individual WLEs were compared with recommended clinical targets (5%, 10% and 20%) for weight loss. RESULTS: Body dissatisfaction was lower in non-obese subjects and was directly associated with BMI (P < 0.05). WLEs were directly associated with BMI and the obese group reported greater expectations. Five non-obese subjects (23%) desired to lose more than 20% of their body weight, whereas the proportion was significantly higher in the obese group (17 subjects; 74%). Subjects derived the greatest WLEs from mass media, whereas they perceived that family and friends were supportive of a lesser degree of weight loss. CONCLUSIONS: We observed a mismatch between clinical and personal expectations, and social pressure and interpersonal relationships appear to have a prominent role with respect to influencing the association.

Feasibility of two levels of protein intake in patients with colorectal cancer: findings from the Protein Recommendation to Increase Muscle (PRIMe) randomized controlled pilot trial.

BACKGROUND: Low muscle mass (MM) predicts unfavorable outcomes in cancer. Protein intake supports muscle health, but oncologic recommendations are not well characterized. The objectives of this study were to evaluate the feasibility of dietary change to attain 1.0 or 2.0 g/kg/day protein diets, and the preliminary potential to halt MM loss and functional decline in patients starting chemotherapy for stage II-IV colorectal cancer. PATIENTS AND METHODS: Patients were randomized to the diets and provided individualized counseling. Assessments at baseline, 6 weeks, and 12 weeks included weighed 3-day food records, appendicular lean soft tissue index (ALSTI) by dual-energy X-ray absorptiometry to estimate MM, and physical function by the Short Physical Performance Battery (SPPB) test. RESULTS: Fifty patients (mean ± standard deviation: age, 57 ± 11 years; body mass index, 27.3 ± 5.6 kg/m2; and protein intake, 1.1 ± 0.4 g/kg/day) were included at baseline. At week 12, protein intake reached 1.6 g/kg/day in the 2.0 g/kg/day group and 1.2 g/kg/day in the 1.0 g/kg/day group (P = 0.012), resulting in a group difference of 0.4 g/kg/day rather than 1.0 g/kg/day. Over one-half (59%) of patients in the 2.0 g/kg/day group maintained or gained MM compared with 44% of patients in the 1.0 g/kg/day group (P = 0.523). Percent change in ALSTI did not differ between groups [2.0 g/kg/day group (mean ± standard deviation): 0.5% ± 4.6%; 1.0 g/kg/day group: -0.4% ± 6.1%; P = 0.619]. No differences in physical function were observed between groups. However, actual protein intake and SPPB were positively associated (ß = 0.37; 95% confidence interval 0.08-0.67; P = 0.014). CONCLUSION: Individualized nutrition counselling positively impacted protein intake. However, 2.0 g/kg/day was not attainable using our approach in this population, and group contamination occurred. Increased protein intake suggested positive effects on MM and physical function, highlighting the potential for nutrition to attenuate MM loss in patients with cancer. Nonetheless, muscle anabolism to any degree is clinically significant and beneficial to patients. Larger trials should explore the statistical significance and clinical relevance of protein interventions.

The neuropathological profile of mild cognitive impairment (MCI): a systematic review.

Whether mild cognitive impairment (MCI) has a distinct neuropathological profile that reflects an intermediate state between no cognitive impairment and dementia is not clear. Identifying which biological events occur at the earliest stage of progressive disease and which are secondary to the neuropathological process is important for understating pathological pathways and for targeted disease prevention. Many studies have now reported on the neurobiology of this intermediate stage. In this systematic review, we synthesize current evidence on the neuropathological profile of MCI. A total of 162 studies were identified with varied definition of MCI, settings ranging from population to specialist clinics and a wide range of objectives. From these studies, it is clear that MCI is neuropathologically complex and cannot be understood within a single framework. Pathological changes identified include plaque and tangle formation, vascular pathologies, neurochemical deficits, cellular injury, inflammation, oxidative stress, mitochondrial changes, changes in genomic activity, synaptic dysfunction, disturbed protein metabolism and disrupted metabolic homeostasis. Determining which factors primarily drive neurodegeneration and dementia and which are secondary features of disease progression still requires further research. Standardization of the definition of MCI and reporting of pathology would greatly assist in building an integrated picture of the clinical and neuropathological profile of MCI.

Assessment of Dietary Intake in Three Cohorts of Advanced Age in Two Countries: Methodology Challenges.

OBJECTIVES: Dietary intake information is key to understanding nutrition-related outcomes. Intake changes with age and some older people are at increased risk of malnutrition. Application, difficulties, and advantages of the 24-hour multiple pass recall (24hr-MPR) dietary assessment method in three cohorts of advanced age in the United Kingdom (UK) and New Zealand (NZ) is described. PARTICIPANTS: The Newcastle 85+ study (UK) recruited a single year birth cohort of people aged 85 years during 2006-7. LiLACS NZ recruited a 10-year birth cohort of Maori (indigenous New Zealanders) aged 80-90 years and a single year birth cohort of non-Maori aged 85 years in 2010. MEASUREMENTS: Two 24hr-MPR were conducted on non-consecutive days by trained assessors. Pictorial resources and language were adapted for the New Zealand and Maori contexts. Detailed methods are described. RESULTS: In the Newcastle 85+ study, 805 (93%) participants consented to the 24-MPR, 95% of whom completed two 24hr-MPR; in LiLACS NZ, 218 (82%) consented and 203 (76%) Maori and 353 (90%) non-Maori completed two 24hr-MPR. Mean time to complete each 24hr-MPR was 22 minutes in the Newcastle 85+ study, and 45 minutes for Maori and 39 minutes for non-Maori in LiLACS NZ. Dietary assessment of participants residing in residential care and those requiring proxy respondents were successfully included in both studies. Most participants (83-94%) felt that data captured by the 24hr-MPR reflected their usual dietary intake. CONCLUSIONS: Dietary assessment using 24hr-MPR was successful in capturing detailed dietary data including information on portion size and time of eating for over 1300 octogenarians in the UK and New Zealand (Maori and non- Maori). The 24hr-MPR is an acceptable method of dietary assessment in this age group.

Post-challenge hyperglycaemia, nitric oxide production and endothelial dysfunction: the putative role of asymmetric dimethylarginine (ADMA).

The endothelium is a thin layer of cells at the internal surface of blood vessels in continuous contact with the circulating fluids. The endothelial cells represent the primary barrier for the transport of glucose from the vascular conduits into the interstitial space. Insulin and nitric oxide have an important role in the regulation of glucose transport and metabolism. Hyperglycaemia is the main criteria for the diagnosis of diabetes and is responsible for the micro- and macro-vascular pathology seen in diabetic patients. Recent evidence suggests that post-challenge hyperglycaemia is a better predictor of cardiovascular risk than fasting glucose. Acute glucose elevations have been associated with a reduced endothelial-dependent flow mediated dilation indicating a decrease in nitric oxide production. Post-prandial hyperglycaemic peaks have been directly associated with increased intima media thickness in type 2 diabetic patients indicative of an increased atherosclerotic risk. The increase in intra-cellular glucose concentrations in the endothelial cells induces a hyper-generation of reactive oxygen species via the activation of different pathways (polyol-sorbitol, hexosamine, advanced glycated end products, activation of PKC, asymmetric dimethylarginine (ADMA)). These mechanisms influence the expression of genes and release of signalling and structural molecules involved in several functions (inflammation, angiogenesis, coagulation, vascular tone and permeability, cellular migration, nutrient metabolism). ADMA is considered as a biomarker of endothelial dysfunction and it has been associated with an increased risk of atherosclerosis and cardiovascular diseases. The increased generation of ADMA and reactive oxygen species in subjects with persistent hyperglycaemia could lead to an impairment of nitric oxide synthesis.

First-borns have a higher metabolic rate and carry a higher metabolic risk in young women attending a weight loss clinic.

BACKGROUND: Birth order has been associated with variability in early life growth and subsequent obesity risk, but the consequent metabolic risks have not been assessed. OBJECTIVE: To quantify the metabolic risk in young adulthood of being first-born relative to those born second or subsequently. METHODS: Body composition, resting metabolic rate and metabolic risk were assessed in 383 women, aged 18-35 years, from a clinical setting in southern Italy. RESULTS: First-borns had increased body mass index, adiposity and metabolic risk (p<0.05) and increased resting metabolic rate adjusted for fat-free mass (p<0.05) in the Italian women. CONCLUSION: First-born status is associated with significantly elevated metabolic risk in a clinical population of overweight and obese young women attending a weight loss clinic. If these findings are confirmed in other studies, they may suggest that the prevalence of the metabolic syndrome worldwide may increase as a function of the trend to smaller family size.

Angiogenesis and biomarkers of cardiovascular risk in adults with metabolic syndrome.

OBJECTIVES: Metabolic syndrome (MetSyn) is associated with an increased risk of atherosclerosis and fatal cardiovascular events. Angiogenesis is thought to contribute to this risk as it might be involved in the progression of atherosclerotic plaques. We investigated the levels of circulating biomarkers of angiogenesis and cardiovascular risk in adults with MetSyn and assessed their association with established metabolic risk factors. DESIGN: The Genetic Park project is a highly inclusive cross-sectional survey (about 80% of residents) conducted in three isolated populations in Southern Italy. A total of 1000 men and women (age range: 18-98 years) were included in the analysis. Anthropometric and blood pressure measurements were recorded. Metabolic and cardiovascular biomarkers included glucose, triglycerides, total cholesterol, HDL, vascular endothelial growth factor, placental growth factor (PlGF), soluble fms-like tyrosine kinase-1, high-sensitivity C-reactive protein, high-sensitivity troponin T (hs-TnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP). RESULT: Subjects with MetSyn had higher levels of PlGF and NT-proBNP after adjustment for age, smoking and body mass index. Circulating levels of PlGF, hs-TnT and NT-proBNP were directly related to the number of criteria of MetSyn, and this association interacted with gender. There was a strong correlation between ageing and cardiovascular risk. CONCLUSIONS: The increase in circulating levels of biomarkers of angiogenesis and cardiac function in subjects with MetSyn mirrors the pathophysiological changes occurring in the cardiovascular system. Over time, these changes might accelerate the formation and progression of atherosclerotic plaques and contribute significantly to cardiovascular morbidity and mortality risk.

Use of the cellular model of body composition to describe changes in body water compartments after total fasting, very low calorie diet and low calorie diet in obese men.

INTRODUCTION: The cellular model of body composition divides the body in body cell mass (BCM), extracellular solids and extracellular fluids. This model has been infrequently applied for the evaluation of weight loss (WL) programmes. OBJECTIVES: (1) To assess changes in body compartments in obese men undergoing fasting, very low calorie diet (VLCD) and low calorie diet (LCD); (2) to evaluate two cellular models for the determination of changes in BCM, fat mass (FM) and body fluids. MATERIALS AND METHODS: Three groups of six, obese men participated in a total fast (F) for 6 days, a VLCD (2.5 MJ per day) for 3 weeks or an LCD (5.2 MJ per day) for 6 weeks. Body composition was measured at baseline and after small ( approximately 5%) and moderate ( approximately 10%) WL. FM was measured using a four-compartment model. Total body water (TBW) and extracellular water (ECW) were, respectively, measured by deuterium and sodium bromide dilution and intracellular water (ICW) calculated by difference. Two cellular models were used to measure BCM, FM and body fluids distribution. RESULTS: After about 5%WL changes in TBW were F=-3.2+/-1.2 kg (P<0.01), VLCD=-1.2+/-0.6 kg (P<0.01), LCD=-0.3+/-0.9 kg(n.s.). The contribution of TBW to total body mass loss was indirectly associated with FM loss. ECW increased during fasting (+1.5+/-3.1 kg, n.s.), decreased during the VLCD (-2.0+/-1.5 kg, P<0.05) and remained unchanged at the end of the LCD (-0.3+/-1.6 kg, n.s.). ICW significantly decreased during fasting (-4.7+/-3.9 kg, P<0.05) but did not change in the LCD and VLCD groups. The loss of BCM was more significant in the fasting group and it was directly associated with changes in ICW. CONCLUSIONS: After a 6-day period of fasting we observed more ICW losses and less fat mobilization compared with VLCD and LCD. The cellular model of body composition is suitable for the characterization of changes in body fluids distribution during WL.

Sarcopenia Prevalence Using Different Definitions in Older Community-Dwelling Canadians.

OBJECTIVES: Sarcopenia is a debilitating condition affecting millions of individuals worldwide and is defined with different criteria. The objective of this study was to determine the prevalence of sarcopenia in older Canadians using three internationally accepted criteria. DESIGN: Observational cohort study. SETTINGS AND PARTICIPANTS: Data from 12,592 subjects [6,314 males (50.1%), 6,278 females (49.9%)] ≥65 years old in the Canadian Longitudinal Study on Aging were included. MEASUREMENTS: Appendicular lean mass (ALM; kg) and appendicular lean mass index (ALM kg/height in m2) were collected from dual X-ray absorptiometry measurements. Physical performance was assessed using the 4-m gait speed test, and muscle strength was measured by hand dynamometry. Sarcopenia was defined according to criteria put forth by the International Working Group on Sarcopenia (IWGS), Foundation for the National Institutes of Health (FNIH) Sarcopenia Project, and revised European Working Group on Sarcopenia in Older People (EWGSOP). Positive and negative percent agreements and Cohen's kappa (κ) described the agreement among sarcopenia definitions. RESULTS: Among the evaluated criteria, gait speed ≤ 1.0 m/s (IWGS definition of slowness) was the most frequently identified deficit (56.8% males, 57.2% females). The prevalence of sarcopenia ranged from 1.4 to 5.2% in males and 1.6 to 7.2 % in females among the different definitions. Positive percent agreement values among criteria were generally low (range: 1.5 - 55.3%) and corresponded to κ indicating none to minimal agreement (0.01 - 0.23). Negative percent agreement values were ≥ 95%. CONCLUSION: Sarcopenia prevalence was relatively low in older Canadian adults and current definitions had poor agreement in diagnosing individuals as sarcopenic.

The contribution of psychosocial stress to the obesity epidemic: an evolutionary approach.

The Thrifty Gene hypothesis theorizes that during evolution a set of genes has been selected to ensure survival in environments with limited food supply and marked seasonality. Contemporary environments have predictable and unlimited food availability, an attenuated seasonality due to artificial lighting, indoor heating during the winter and air conditioning during the summer, and promote sedentariness and overeating. In this setting the thrifty genes are constantly activated to enhance energy storage. Psychosocial stress and sleep deprivation are other features of modern societies. Stress-induced hypercortisolemia in the setting of unlimited food supply promotes adiposity. Modern man is becoming obese because these ancient mechanisms are efficiently promoting a positive energy balance. We propose that in today's plentifully provisioned societies, where sedentariness and mental stress have become typical traits, chronic activation of the neuroendocrine systems may contribute to the increased prevalence of obesity. We suggest that some of the yet unidentified thrifty genes may be linked to highly conserved energy sensing mechanisms (AMP kinase, mTOR kinase). These hypotheses are testable. Rural societies that are becoming rapidly industrialized and are witnessing a dramatic increase in obesity may provide a historical opportunity to conduct epidemiological studies of the thrifty genotype. In experimental settings, the effects of various forms of psychosocial stress in increasing metabolic efficiency and gene expression can be further tested.

Validity of some prediction equations to assess resting energy expenditure (REE) in 29 elderly obese subjects (>60 years).

BACKGROUND AND AIMS: Recent estimates in US have shown that more than a third of 65 years old subjects are obese. The objective of this study was to test the accuracy of six prediction equations to estimate resting energy expenditure (REE) in elderly obese subjects (age >60 years). METHODS: Twenty-nine obese Caucasian male (n=8) and female (n=21) subjects (age range: 60-77 years) attended the Outpatient Clinic of the Neuroscience Department of Naples "Federico II" University Medical School (Italy), Section of Aging and Nutrition from January 2005 to January 2006. Weight, height, BMI and body composition (bioimpedance) were measured. REE was measured using a ventilated-hood indirect calorimetry and compared to six prediction equations (Harris-Benedict, Fredrix, Mifflin, Owen, WHO, Livingston). RESULTS: Mean age and body mass index (BMI) were 65.9+/-4.8 years and 36.8+/-5.3 kg/m2, respectively. The measured REE was 1658+/-289 kcal/day. The Harris-Benedict', Owen' and Livingston's equations performed less well than the other equations and they showed a tendency towards underestimation. The equation with the best REE prediction was the Fredrix's one (DeltaREE=-19.4kcal/day) with 66% of REE predictions lying within 10% of measured REE. CONCLUSIONS: These data support the utilization of the Fredrix's equation to calculate REE in obese elderly subjects.

Ethnic differences in the association between body mass index and impedance index (Ht2/Z) in adult women and men using a leg-to-leg bioimpedance method.

BACKGROUND: Ethnic differences in the association between body mass index (BMI) and body fat suggest that body composition varies across ethnic groups. OBJECTIVE: To investigate the association between impedance index - a measure of tissue resistivity - and BMI in adults of different ethnic groups (Asian Indians, West Africans and White Caucasians) living in their native countries. METHODS: Male (n=329) and female (n=277) adult subjects (18-50 years) living in urban areas in the UK, The Gambia and Pakistan were studied. Body weight and height were measured and BMI calculated. The same leg-to-leg bioimpedance instrument was used in each study and impedance index (height(2) (cm)/impedance (Omega)) used as measure of tissue resistivity. RESULTS: In women, Asian Indians and West Africans had a significantly greater increase in impedance index per unit increase in BMI compared with white Caucasians (P<0.001). In men, Asian Indians had a significantly lower impedance index compared with West Africans and white Caucasians (P<0.001). CONCLUSION: Different ethnic groups may have different tissue resistivity for the same BMI indicative of systematic differences in body composition.

Why do normal weight young women look for diet-therapy? Findings from a pilot study in a clinical and non-clinical population.

The behavioural factors that drive a normal weight woman to embark on a diet and to look for nutritional support in weight loss clinics are still not completely understood. A pilot cross-sectional study was carried out in 70 young (age range: 18-35 yr), normal weight women attending a weight loss clinic in South of Italy (Naples). They were compared to a population of 94 normal weight students (age range:17-23 yr) who had never attended a weight loss clinic. Subjects with eating disorders have been excluded. Weight and height were measured and body mass index (BMI) was calculated. Eating behaviour was assessed using a validated Italian version of the Eating Disorders Inventory (EDI) questionnaire. The two groups were matched for BMI (22.4 vs 22.1 kg/m2), smoking and physical activity. Students were more educated and less likely to be on a diet at the time of the study. Students had statistically significant lower scores for drive for thinness, body dissatisfaction, inadequacy and interpersonal disrupt. The bulimia scale was the only significant predictor (p<0.05) of BMI in the patients' group; body dissatisfaction (p<0.05) predicted BMI in the control group. This study has shown that weight concern and health awareness are not the only factors that lead a normal weight woman to look for nutritional counselling but there is an underlying substrate of psychological and social distress behind the request, which should be properly assessed before starting any nutritional therapy in the clinical practice.

Effects of vitamin C supplementation on glycaemic control: a systematic review and meta-analysis of randomised controlled trials.

Randomised controlled trials (RCTs) have observed contrasting results on the effects of vitamin C on circulating biomarkers of glycaemic and insulin regulation. We conducted a systematic review and meta-analysis of RCTs testing the effect of vitamin C administration on glucose, HbA1c and insulin concentrations. Four databases (PubMed, Embase, Scopus and Cochrane Library) were used to retrieve RCTs published from inception until April 2016 and testing the effects of vitamin C in adult participants. The screening of 2008 articles yielded 22 eligible studies (937 participants). Overall, vitamin C did not modify glucose, HbA1c and insulin concentrations. However, subgroup analyses showed that vitamin C significantly reduced glucose concentrations (-0.44 mmol/l, 95% CI: -0.81, -0.07, P=0.01) in patients with type 2 diabetes and in interventions with a duration greater than 30 days (-0.53%, 95% CI: -0.79, -0.10, P=0.02). Vitamin C administration had greater effects on fasting (-13.63 pmol/l, 95% CI: -22.73, -4.54, P<0.01) compared to postprandial insulin concentration. Meta-regression analyses showed that age was a modifier of the effect of vitamin C on insulin concentration. Furthermore, the effect size was associated with baseline BMI and plasma glucose levels, and with the duration of the intervention. In conclusion, greater reduction in glucose concentrations observed in patients with diabetes, older individuals and with more prolonged supplementation. Personalised interventions with vitamin C may represent a feasible future strategy to enhance benefits and efficacy of interventions. Nevertheless, results need to be interpreted cautiously due to limitations in the primary studies analysed.