Obesity and the metabolic syndrome: role of different dietary macronutrient distribution patterns and specific nutritional components on weight loss and maintenance

Prevalence and Related Risk Factors of Overweight and Obesity among the Adult Population in the Balearic Islands, a Mediterranean Region

OBJECTIVE

To assess the prevalence and risk factors of overweight (OW) and obesity (OB) by BMI and abdominal obesity (AO) by waist-to-height ratio, (WHtR) among the Balearic Islands' adult population.

METHODS

Cross-sectional nutritional survey carried out in the Balearic Islands (2009-2010). A random sample (n = 1,081) of young (18-35 years) and middle-aged adults (36-55 years) were interviewed and anthropometrically measured. OW (BMI 25.0-29.9 kg/m(2)) and OB (BMI ≥ 30 kg/m(2)) were defined according to WHO criteria. AO was defined as WHtR ≥ 0.5. Socio-economic and lifestyle determinants were considered.

RESULTS

The overall prevalence of OW/OB and AO was 29.4% (95% confidence interval (95% CI) 26.9-32.3%), 11.2% (95% CI 9.5-13.2%) and 33.1% (95% CI 30.4-36.0%), respectively. Men showed higher prevalence of OW (35.9%, 95% CI 31.6-40.5%) and AO (37.9%, 95% CI 33.6-42.5%) than women (OW 24.9%, 95% CI 21.7-28.4%; AO 29.7%, 95%CI 26.2-33.4%). Overall prevalence of OB was 11.8% (95% CI 9.1-15.1%) in men and 10.8% (95% CI 8.6-13.5%) in women. Age and no leisure-time physical activity (LTPA) were main risk factors associated with OW/OB and AO. Living with at least one child at home and to be married in men as well as to be unemployed, to be born in South America, and a low level of education in women were associated with AO.

CONCLUSIONS

Men showed higher prevalence of OW and AO than women. In both sexes, age is the main risk factor associated with OW/OB and AO; in men also the absence of LTPA plays a significant role.

A genetic risk tool for obesity predisposition assessment and personalized nutrition implementation based on macronutrient intake

There is little evidence about genetic risk score (GRS)-diet interactions in order to provide personalized nutrition based on the genotype. The aim of the study was to assess the value of a GRS on obesity prediction and to further evaluate the interactions between the GRS and dietary intake on obesity. A total of 711 seekers of a Nutrigenetic Service were examined for anthropometric and body composition measurements and also for dietary habits and physical activity. Oral epithelial cells were collected for the identification of 16 SNPs (related with obesity or lipid metabolism) using DNA zip-coded beads. Genotypes were coded as 0, 1 or 2 according to the number of risk alleles, and the GRS was calculated by adding risk alleles with such a criterion. After being adjusted for gender, age, physical activity and energy intake, the GRS demonstrated that individuals carrying >7 risk alleles had in average 0.93 kg/m(2) of BMI, 1.69 % of body fat mass, 1.94 cm of waist circumference and 0.01 waist-to-height ratio more than the individuals with ≤7 risk alleles. Significant interactions for GRS and the consumption of energy, total protein, animal protein, vegetable protein, total fat, saturated fatty acids, polyunsaturated fatty acids, total carbohydrates, complex carbohydrates and fiber intake on adiposity traits were found after adjusted for confounders variables. The GRS confirmed that the high genetic risk group showed greater values of adiposity than the low risk group and demonstrated that macronutrient intake modifies the GRS association with adiposity traits.

Personalized weight loss strategies-the role of macronutrient distribution

A large number of different dietary approaches have been studied in an attempt to achieve healthy, sustainable weight loss among individuals with overweight and obesity. Restriction of energy intake is the primary method of producing a negative energy balance leading to weight loss. However, owing to the different metabolic roles of proteins, carbohydrates and lipids in energy homeostasis, diets of similar overall energy content but with different macronutrient distribution can differentially affect metabolism, appetite and thermogenesis. Evidence increasingly suggests that the fuel values of calories provided by distinct macronutrients should be considered separately, as metabolism of specific molecular components generates differences in energy yield. The causes of variation in individual responses to various diets are currently under debate, and some evidence suggests that differences are associated with specific genotypes. This Review discusses all available systematic reviews and meta-analyses, and summarizes the results of relevant randomized controlled intervention trials assessing the influence of macronutrient composition on weight management. The initial findings of research into personalized nutrition, based on the interactions of macronutrient intake and genetic background and its potential influence on dietary intervention strategies, are also discussed.

Improved insulin sensitivity and body composition, irrespective of macronutrient intake, after a 12 month intervention in adolescents with pre-diabetes; RESIST a randomised control trial

Background

A higher protein to carbohydrate ratio in the diet may potentiate weight loss, improve body composition and cardiometabolic risk, including glucose homeostasis in adults. The aim of this randomised control trial was to determine the efficacy of two structured lifestyle interventions, differing in dietary macronutrient content, on insulin sensitivity and body composition in adolescents. We hypothesised that a moderate-carbohydrate (40-45% of energy), increased-protein (25-30%) diet would be more effective than a high-carbohydrate diet (55-60%), moderate-protein (15%) diet in improving outcomes in obese, insulin resistant adolescents.

Methods

Obese 10–17 year olds with either pre-diabetes and/or clinical features of insulin resistance were recruited at two hospitals in Sydney, Australia. At baseline adolescents were prescribed metformin and randomised to one of two energy restricted diets. The intervention included regular contact with the dietician and a supervised physical activity program. Outcomes included insulin sensitivity index measured by an oral glucose tolerance test and body composition measured by dual-energy x-ray absorptiometry at 12 months.

Results

Of the 111 adolescents recruited, 85 (77%) completed the intervention. BMI expressed as a percentage of the 95th percentile decreased by 6.8% [95% CI: −8.8 to −4.9], ISI increased by 0.2 [95% CI: 0.06 to 0.39] and percent body fat decreased by 2.4% [95% CI: −3.4 to −1.3]. There were no significant differences in outcomes between diet groups at any time.

Conclusion

When treated with metformin and an exercise program, a structured, reduced energy diet, which is either high-carbohydrate or moderate-carbohydrate with increased-protein, can achieve clinically significant improvements in obese adolescents at risk of type 2 diabetes.

Trial registration

Australian New Zealand Clinical Trail Registry ACTRN12608000416392. Registered 25 August 2008.

Maintenance of energy expenditure on high-protein vs. high-carbohydrate diets at a constant body weight may prevent a positive energy balance

BACKGROUND & AIMS

Relatively high-protein diets are effective for body weight loss, and subsequent weight maintenance, yet it remains to be shown whether these diets would prevent a positive energy balance. Therefore, high-protein diet studies at a constant body weight are necessary. The objective was to determine fullness, energy expenditure, and macronutrient balances on a high-protein low-carbohydrate (HPLC) diet compared with a high-carbohydrate low-protein (HCLP) diet at a constant body weight, and to assess whether effects are transient or sustained after 12 weeks.

METHODS

A randomized parallel study was performed in 14 men and 18 women [mean ± SD age: 24 ± 5 y; BMI (in kg/m(2)): 22.8 ± 2.0] on diets containing 30/35/35 (HPLC) or 5/60/35 (HCLP) % of energy from protein/carbohydrate/fat.

RESULTS

Significant interactions between dietary intervention and time on total energy expenditure (TEE) (P = 0.013), sleeping metabolic rate (SMR) (P = 0.040), and diet-induced thermogenesis (DIT) (P = 0.027) appeared from baseline to wk 12. TEE was maintained in the HPLC diet group, while it significantly decreased throughout the intervention period in the HCLP diet group (wk 1: P = 0.002; wk 12: P = 0.001). Energy balance was maintained in the HPLC diet group, and became positive in the HCLP diet group at wk 12 (P = 0.008). Protein balance varied directly according to the amount of protein in the diet, and diverged significantly between the diets (P = 0.001). Fullness ratings were significantly higher in the HPLC vs. the HCLP diet group at wk 1 (P = 0.034), but not at wk 12.

CONCLUSIONS

Maintenance of energy expenditure on HPLC vs. HCLP diets at a constant body weight may prevent development of a positive energy balance, despite transiently higher fullness. The study was registered on clinicaltrials.gov with Identifier: NCT01551238.

Independent, additive effects of five dietary variables on ad libitum energy intake in a residential study

OBJECTIVE

To examine the relationship between dietary characteristics of self-selected foods and energy balance in a cafeteria-style dining hall.

METHODS

Ad libitum dietary intake from a self-selection menu was measured over two days in 151 adults (70% female, mean age 41 years, mean BMI 24.9 kg/m(2) ). The associations of dietary variables with energy balance (calculated as measured energy intake/predicted energy requirements, pER) were assessed.

RESULTS

Measured energy intake was significantly correlated with pER (R(2) =0.83, P < 0.001). In mixed multiple regression models, percent energy from protein was negatively associated with energy balance (R(2) =0.04, P = 0.02), and percent energy from liquid sources (R(2)  = 0.02, P = 0.05), total dietary variety in females (R(2)  = 0.39, P < 0.001), and energy density (R(2)  = 0.57, P < 0.001) were positively associated with energy balance. In addition, glycemic index was inversely associated with energy balance in normal-weight individuals (R(2)  = 0.14, P < 0.001) but not in overweight or obese individuals.

CONCLUSIONS

There are independent associations of dietary protein, liquid calories, energy density, dietary variety, and glycemic index with energy balance, indicating additive effects of these dietary factors on energy intake and energy balance. Intervention studies are needed to determine whether dietary prescriptions combining these dietary factors facilitate long-term prevention of weight gain.

Taking Steps Together

Objectives. Successful childhood obesity intervention models that build sustainable behavioral change are needed, particularly in low-income, ethnic minority communities disparately affected by this problem. Method. Families were referred to Taking Steps Together (TST) by their primary care provider if at least one child had a body mass index ≥85%. The TST intervention comprised 16 weekly 2-hour classes including educational activities, group cooking/eating, and physical activities for parents and children. TST’s approach emphasized building self-efficacy, targeting both children and parents for healthy change, and fostering intrinsic motivation for healthier living. Pre–post intervention data were collected on health-related behaviors using a survey, and trained staff measured weight and height. Results. Adults ( n = 33) and children ( n = 62) were largely Hispanic/Latino and low-income. Adults and children significantly increased their fruit and vegetable consumption and weekly physical activity, and adults significantly decreased sugared beverage consumption and screen time. No change in body mass index was observed for adults or children. Conclusions. This family-focused childhood obesity intervention integrated evidence-based principles with a nonprescriptive approach and produced significant improvements in key healthy behaviors for both adults and children.

Plasma irisin depletion under energy restriction is associated with improvements in lipid profile in metabolic syndrome patients

OBJECTIVE

A recently discovered myokine, irisin, may have an important role in energy metabolism. This study aimed to evaluate the relationship between this hormone and the lipid profile of patients with metabolic syndrome (MetS) following a hypocaloric diet.

DESIGN

Ninety-three Caucasian adults (52 men/41 women) diagnosed with MetS followed an 8-week-long energy-restricted programme (-30% of the energy requirements). Anthropometric measurements, biochemical markers and plasma irisin levels were analysed before and after the nutritional intervention.

RESULTS

Global plasma irisin levels were significantly reduced at the end of the study (-72.0 ± 100.9 ng/ml, P < 0.001) accompanying the weight loss (-6.9%). The depletion of irisin significantly correlated with changes in some atherogenic-related variables: total cholesterol (B = 0.106, P = 0.018), total cholesterol/high-density lipoprotein cholesterol ratio (B = 0.002, P = 0.036), low-density lipoprotein cholesterol (B = 0.085, P = 0.037) and apolipoprotein B (B = 0.052, P = 0.002), independently of changes in body weight.

CONCLUSIONS

An association between the reduction in plasma irisin levels and the depletion of important lipid metabolism biomarkers was observed in patients with MetS undergoing an energy-restricted programme.

Defective regulation of the ubiquitin/proteasome system in the hypothalamus of obese male mice

In both human and experimental obesity, inflammatory damage to the hypothalamus plays an important role in the loss of the coordinated control of food intake and energy expenditure. Upon prolonged maintenance of increased body mass, the brain changes the defended set point of adiposity, and returning to normal weight becomes extremely difficult. Here we show that in prolonged but not in short-term obesity, the ubiquitin/proteasome system in the hypothalamus fails to maintain an adequate rate of protein recycling, leading to the accumulation of ubiquitinated proteins. This is accompanied by an increased colocalization of ubiquitin and p62 in the arcuate nucleus and reduced expression of autophagy markers in the hypothalamus. Genetic protection from obesity is accompanied by the normal regulation of the ubiquitin/proteasome system in the hypothalamus, whereas the inhibition of proteasome or p62 results in the acceleration of body mass gain in mice exposed for a short period to a high-fat diet. Thus, the defective regulation of the ubiquitin/proteasome system in the hypothalamus may be an important mechanism involved in the progression and autoperpetuation of obesity.

Body characteristics, [corrected] dietary protein and body weight regulation. Reconciling conflicting results from intervention and observational studies?

Background/Objectives

Physiological evidence indicates that high-protein diets reduce caloric intake and increase thermogenic response, which may prevent weight gain and regain after weight loss. Clinical trials have shown such effects, whereas observational cohort studies suggest an association between greater protein intake and weight gain. In both types of studies the results are based on average weight changes, and show considerable diversity in both directions. This study investigates whether the discrepancy in the evidence could be due to recruitment of overweight and obese individuals into clinical trials.

Subjects/Methods

Data were available from the European Diet, Obesity and Genes (DiOGenes) post-weight-loss weight-maintenance trial and the Danish Diet, Cancer and Health (DCH) cohort. Participants of the DCH cohort were matched with participants from the DiOGenes trial on gender, diet, and body characteristics. Different subsets of the DCH-participants, comparable with the trial participants, were analyzed for weight maintenance according to the randomization status (high or low protein) of the matched trial participants.

Results

Trial participants were generally heavier, had larger waist circumference and larger fat mass than the participants in the entire DCH cohort. A better weight maintenance in the high-protein group compared to the low protein group was observed in the subgroups of the DCH cohort matching body characteristics of the trial participants.

Conclusion

This modified observational study, minimized the differences between the RCT and observational data with regard to dietary intake, participant characteristics and statistical analysis. Compared with low protein diet the high protein diet was associated with better weight maintenance when individuals with greater body mass index and waist circumference were analyzed. Selecting subsets of large-scale observational cohort studies with similar characteristics as participants in clinical trials may reconcile the otherwise conflicting results.

Fat Preference: a novel model of eating behavior in rats

Obesity is a growing problem in the United States of America, with more than a third of the population classified as obese. One factor contributing to this multifactorial disorder is the consumption of a high fat diet, a behavior that has been shown to increase both caloric intake and body fat content. However, the elements regulating preference for high fat food over other foods remain understudied. To overcome this deficit, a model to quickly and easily test changes in the preference for dietary fat was developed. The Fat Preference model presents rats with a series of choices between foods with differing fat content. Like humans, rats have a natural bias toward consuming high fat food, making the rat model ideal for translational studies. Changes in preference can be ascribed to the effect of either genetic differences or pharmacological interventions. This model allows for the exploration of determinates of fat preference and screening pharmacotherapeutic agents that influence acquisition of obesity.

Response to deep brain stimulation in the lateral hypothalamic area in a rat model of obesity: in vivo assessment of brain glucose metabolism

PURPOSE

To investigate changes in glucose brain metabolism after deep brain stimulation (DBS) in the lateral hypothalamic area (LHA) in a rat model of obesity.

PROCEDURES

Ten obese male Zucker rats were divided into two groups: LHA-control and LHA-DBS. Concentric bipolar platinum-iridium electrodes were implanted bilaterally. After 7 days, DBS was applied for 15 days. Weight and food and water intake were monitored. 2-Deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) PET-CT imaging studies were performed the day after the end of DBS. Differences in glucose uptake between the groups were assessed with statistical parametric mapping.

RESULTS

A difference in weight gain of 3.19 percentage points was found between groups. Average food consumption during the first 15 days was lower in DBS-treated animals than in non-stimulated animals. DBS increased metabolism in the mammillary body, subiculum-hippocampal area, and amygdala, while a decrease in metabolism was recorded in the thalamus, caudate, temporal cortex, and cerebellum.

CONCLUSIONS

DBS produced significant changes in brain regions associated with the control of food intake and the brain reward system. DBS seems to normalize the impaired hippocampal functioning that has been described in obese rats. The smaller weight gain in the DBS group suggests that this technique could be considered an option for the treatment of obesity.

Smartphone-enabled health coach intervention for people with diabetes from a modest socioeconomic strata community: single-arm longitudinal feasibility study

BACKGROUND

Lower socioeconomic strata (SES) populations have higher chronic disease risks. Smartphone-based interventions can support adoption of health behaviors that may, in turn, reduce the risks of type 2 diabetes-related complications, overcoming the obstacles that some patients may have with regular clinical contact (eg, shiftwork, travel difficulties, miscommunication).

OBJECTIVE

The intent of the study was to develop and test a smartphone-assisted intervention that improves behavioral management of type 2 diabetes in an ethnically diverse, lower SES population within an urban community health setting.

METHODS

This single-arm pilot study assessed a smartphone application developed with investigator assistance and delivered by health coaches. Participants were recruited from the Black Creek Community Health Centre in Toronto and had minimal prior experience with smartphones.

RESULTS

A total of 21 subjects consented and 19 participants completed the 6-month trial; 12 had baseline glycosylated hemoglobin (HbA1c) levels >7.0% and these subjects demonstrated a mean reduction of 0.43% (SD 0.63) (P<.05) with minimal changes in medication.

CONCLUSIONS

This project supported the feasibility of smartphone-based health coaching for individuals from lower SES with minimal prior smartphone experience.

Protein leverage effects of beef protein on energy intake in humans

BACKGROUND

The protein leverage hypothesis requires specific evidence that protein intake is regulated more strongly than energy intake.

OBJECTIVE

The objective was to determine ad libitum energy intake, body weight changes, appetite profile, and nitrogen balance in response to 3 diets with different protein-to-carbohydrate + fat ratios over 12 consecutive days, with beef as a source of protein.

DESIGN

A 3-arm, 12-d randomized crossover study was performed in 30 men and 28 women [mean ± SD age: 33 ± 16 y; body mass index (in kg/m²): 24.4 ± 4.0] with the use of diets containing 5%, 15%, and 30% of energy (En%) from protein, predominantly from beef.

RESULTS

Energy intake was significantly lower in the 30En%-protein condition (8.73 ± 1.93 MJ/d) than in the 5En%-protein (9.48 ± 1.67 MJ/d) and 15En%-protein (9.30 ± 1.62 MJ/d) conditions (P = 0.001), stemming largely from lower energy intake during meals (P = 0.001). Hunger (P = 0.001) and desire to eat (P = 0.001) ratings were higher and fullness ratings were lower (P = 0.001) in the 5En%-protein condition than in the 15En%-protein and 30En%-protein conditions. Nitrogen excretion was lower in the 5En%-protein condition (4.7 ± 1.5 g/24 h; P = 0.001) and was higher in the 30En%-protein condition (15.3 ± 8.7 g/24 h; P = 0.001) compared with the 15En%-protein condition (10.0 ± 5.2 g/24 h). Nitrogen balance was maintained in the 5En%-protein condition and was positive in the 15En%- and 30En%-protein conditions (P = 0.001).

CONCLUSIONS

Complete protein leverage did not occur because subjects did not consume to a common protein amount at the expense of energy balance. Individuals did underconsume relative to energy requirements from high-protein diets. The lack of support for protein leverage effects on a low-protein diet may stem from the fact that protein intake was sufficient to maintain nitrogen balance over the 12-d trial.

Weight loss, glycemic control, and cardiovascular disease risk factors in response to differential diet composition in a weight loss program in type 2 diabetes: a randomized controlled trial

OBJECTIVE

To test whether a weight loss program promotes greater weight loss, glycemic control, and improved cardiovascular disease risk factors compared with control conditions and whether there is a differential response to higher versus lower carbohydrate intake.

RESEARCH DESIGN AND METHODS

This randomized controlled trial at two university medical centers enrolled 227 overweight or obese adults with type 2 diabetes and assigned them to parallel in-person diet and exercise counseling, with prepackaged foods in a planned menu during the initial phase, or to usual care (UC; two weight loss counseling sessions and monthly contacts).

RESULTS

Relative weight loss was 7.4% (95% CI 5.7-9.2%), 9.0% (7.1-10.9%), and 2.5% (1.3-3.8%) for the lower fat, lower carbohydrate, and UC groups (P < 0.001 intervention effect). Glycemic control markers and triglyceride levels were lower in the intervention groups compared with UC group at 1 year (fasting glucose 141 [95% CI 133-149] vs. 159 [144-174] mg/dL, P = 0.023; hemoglobin A1c 6.9% [6.6-7.1%] vs. 7.5% [7.1-7.9%] or 52 [49-54] vs. 58 [54-63] mmol/mol, P = 0.001; triglycerides 148 [134-163] vs. 204 [173-234] mg/dL, P < 0.001). The lower versus higher carbohydrate groups maintained lower hemoglobin A1c (6.6% [95% CI 6.3-6.8%] vs. 7.2% [6.8-7.5%] or 49 [45-51] vs. 55 [51-58] mmol/mol) at 1 year (P = 0.008).

CONCLUSIONS

The weight loss program resulted in greater weight loss and improved glycemic control in type 2 diabetes.

Dietary protein and urinary nitrogen in relation to 6-year changes in fat mass and fat-free mass

BACKGROUND

In contrast to the physiological expectation, observational studies show that greater protein intake is associated with subsequent body weight (BW) gain. An increase in fat-free mass (FFM) due to the anabolic effects of protein could explain this.

OBJECTIVE

To examine associations between protein intake and subsequent changes in fat mass (FM) and FFM in longitudinal, observational data.

DESIGN

A health examination, including measures of FM and FFM by bioelectrical impedance at baseline and follow-up 6 years later, was conducted. Diet history interviews (DHI) were performed, and 24-h urinary nitrogen collection at baseline was done. In total, 330 participants with DHI, of whom 227 had validated and complete 24-h urine collection data, were analyzed. Macronutrient energy substitution models were used.

RESULTS

Mean estimated protein intake was 14.6 E% from DHI and 11.3 E% from urinary nitrogen. Estimated from DHI, FM increased 46 g per year, with every 1 E% protein substituted for fat (95% confidence interval (CI) = 13, 79; P = 0.006), and FFM increased 15 g per year (1, 30; P = 0.046). Results were similar in other substitution models. Estimated from urinary nitrogen, FM increased 53 g per year, with 1 E% protein substituted for other macronutrients (24, 81; P < 0.0005), and FFM increased 18 g per year (6, 31; P = 0.004).

CONCLUSION

Within a habitual range, a greater protein intake was associated with BW gain, mostly in FM. This is in contrast to the expectations based on physiological and clinical trials, and calls for a better understanding of how habitual dietary protein influences long-term energy balance, versus how greater changes in dietary proteins may influence short-term energy balance.

Adipose tissue metabolism and inflammation are differently affected by weight loss in obese mice due to either a high-fat diet restriction or change to a low-fat diet

Restriction of a high-fat diet (HFD) and a change to a low-fat diet (LFD) are two interventions that were shown to promote weight loss and improve parameters of metabolic health in obesity. Examination of the biochemical and molecular responses of white adipose tissue (WAT) to these interventions has not been performed so far. Here, male C57BL/6JOlaHsd mice, harboring an intact nicotinamide nucleotide transhydrogenase gene, were fed a purified 40 energy% HFD for 14 weeks to induce obesity. Afterward, mice were divided into three dietary groups: HFD (maintained on HFD), LFD (changed to LFD with identical ingredients), and HFD-CR (restricted to 70 % of the HFD). The effects of the interventions were examined after 5 weeks. Beneficial effects were seen for both HFD-CR and LFD (compared to HFD) regarding physiological parameters (body weight and fat mass) and metabolic parameters, including circulating insulin and leptin levels. Macrophage infiltration in WAT was reduced by both interventions, although more effectively by HFD-CR. Strikingly, molecular parameters in WAT differed between HFD-CR and LFD, with increased activation of mitochondrial carbohydrate and fat metabolism in HFD-CR mice. Our results confirm that restriction of the amount of dietary intake and reduction in the dietary energy content are both effective in inducing weight loss. The larger decrease in WAT inflammation and increase in mitochondrial carbohydrate metabolism may be due to a larger degree of energy restriction in HFD-CR, but could also be due to superior effectiveness of dietary restriction in weight loss strategies.

Effects of 1-year intervention with a Mediterranean diet on plasma fatty acid composition and metabolic syndrome in a population at high cardiovascular risk

BACKGROUND & AIMS

Metabolic syndrome (MetS) has become an important public concern due to its increasing prevalence. An altered fatty acid composition has been associated with MetS, but the Mediterranean diet has been shown to have a protective effect. The aim of the present study was to analyze the influence of a Mediterranean dietary pattern, as assessed by the biomarkers of food supplied, on the plasma fatty acid composition and its relation with MetS after 1 year of intervention.

METHODS

A total of 424 subjects were randomly selected from the PREDIMED randomized dietary trial after completing a 1-year intervention program. Participants aged 55 to 80 years and at high risk of cardiovascular disease were randomly assigned to three dietary interventions: Mediterranean diet supplemented with virgin olive oil or nuts, or a low-fat diet.

RESULTS

After 1 year of intervention participants in the virgin olive oil group showed significantly increased plasma concentrations of palmitic and oleic acids, but reduced proportions of margaric, stearic, and linoleic acids. In turn, subjects in the nut group showed significantly increased levels of palmitic, linoleic, and α-linolenic acids, but reduced proportions of myristic, margaric, palmitoleic, and dihommo-γ-linoleic acids. Increases in the biomarkers of foods supplied to the Mediterranean diet groups, i.e., oleic and α-linolenic acids, were beneficially associated with the incidence, reversion and prevalence of MetS. No weight changes were observed among participants.

CONCLUSIONS

The nut and olive oil diets induced a fatty acid composition that has been shown to be beneficial in the face of MetS. Therefore, a Mediterranean diet rich in fats of vegetable origin may be a useful tool for the management of MetS without the need for concerns over weight gain due to its high fat content.

TRIAL REGISTRATION

Controlled-Trials.com ISRCTN35739639.

Serum metabolic profiles in overweight and obese women with and without metabolic syndrome

OBJECTIVE

To identify serum biomarkers through metabolomics approach that distinguishes physically inactive overweight/obese women with metabolic syndrome from those who are metabolically healthy, independent of body weight and fat mass.

METHODS

We applied nuclear magnetic resonance spectroscopy-based profiling of fasting serum samples to examine the metabolic differences between 78 previously physically inactive, body weight and fat mass matched overweight/obese premenopausal women with and without MetS. MetS was defined as the presence of at least three of the following five criteria: waist circumference ≥88 cm, serum triacylglycerol ≥1.7 mmol/L, and high density lipoprotein cholesterol (HDL-C) <1.30 mmol/L, blood pressure ≥ 130/85 mmHg and fasting glucose ≥5.6 mmol/L). Principal component analysis was used to reduce the large number of correlated variables to fewer uncorrelated factors.

RESULTS

Two metabolic factors were associated with MetS independent of BMI, fat mass, waist circumference and physical activity/fitness. Factor comprising branched-chain amino acids (BCAA) and aromatic amino acids (AAA) and orosomucoid was associated with all clinical risk factors (p < 0.01 for all).

CONCLUSION

Two metabolic factors distinguish overweight/obese women with metabolic syndrome from those who are metabolically healthy independent of body weight, fat mass and physical activity/fitness. In particular, factor comprising BCAA, AAA and orosomucoid seems auspicious biomarker determining metabolic health as it was associated with all clinical risk factors. Further research is needed to determine the public health and clinical significance of these results in terms of screening to identify those at greatest cardio-metabolic risk for whom appropriate intervention strategies should be developed.

Identification of lifestyle patterns associated with obesity and fat mass in children: the Healthy Growth Study

OBJECTIVE

To investigate possible associations of lifestyle patterns with obesity and fat mass in children.

DESIGN

Cross-sectional epidemiological study. Principal component analysis was used to identify lifestyle patterns.

SETTING

Primary schools from four regions in Greece.

SUBJECTS

A total of 2073 schoolchildren (aged 9-13 years).

RESULTS

Children in the fourth quartile of the lifestyle pattern combining higher dairy foods with more adequate breakfast consumption were 39·4%, 45·2% and 32·2% less likely to be overweight/obese and in the highest quartile of sum of skinfold thicknesses and fat mass, respectively, than children in the first quartile of this pattern. Similarly, children in the fourth quartile of a lifestyle pattern comprising consumption of high-fibre foods, such as fruits, vegetables and wholegrain products, were 27·4% less likely to be in the highest quartile of sum of skinfold thicknesses than children in the first lifestyle pattern quartile. Finally, children in the fourth quartile of a lifestyle pattern characterized by more time spent on moderate-to-vigorous physical activity and more frequent meals were 38·0%, 26·3% and 29·5% less likely to be overweight, centrally obese and in the highest quartile of fat mass, respectively, than their peers in the first quartile of this lifestyle pattern (all P < 0·05).

CONCLUSIONS

The current study identified three lifestyle patterns (i.e. one pattern comprising higher dairy consumption with a more adequate breakfast; a second pattern characterized by increased consumption of high-fibre foods; and a third pattern combining higher physical activity levels with more frequent meals), which were all related with lower odds of obesity and/or increased fat mass levels. From a public health perspective, promotion of these patterns among children and their families should be considered as one of the components of any childhood obesity preventive initiative.

Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial

BACKGROUND/OBJECTIVES

Short-term studies have suggested beneficial effects of a Palaeolithic-type diet (PD) on body weight and metabolic balance. We now report the long-term effects of a PD on anthropometric measurements and metabolic balance in obese postmenopausal women, in comparison with a diet according to the Nordic Nutrition Recommendations (NNR).

SUBJECTS/METHODS

Seventy obese postmenopausal women (mean age 60 years, body mass index 33 kg/m(2)) were assigned to an ad libitum PD or NNR diet in a 2-year randomized controlled trial. The primary outcome was change in fat mass as measured by dual-energy X-ray absorptiometry.

RESULTS

Both groups significantly decreased total fat mass at 6 months (-6.5 and-2.6 kg) and 24 months (-4.6 and-2.9 kg), with a more pronounced fat loss in the PD group at 6 months (P<0.001) but not at 24 months (P=0.095). Waist circumference and sagittal diameter also decreased in both the groups, with a more pronounced decrease in the PD group at 6 months (-11.1 vs-5.8 cm, P=0.001 and-3.7 vs-2.0 cm, P<0.001, respectively). Triglyceride levels decreased significantly more at 6 and 24 months in the PD group than in the NNR group (P<0.001 and P=0.004). Nitrogen excretion did not differ between the groups.

CONCLUSIONS

A PD has greater beneficial effects vs an NNR diet regarding fat mass, abdominal obesity and triglyceride levels in obese postmenopausal women; effects not sustained for anthropometric measurements at 24 months. Adherence to protein intake was poor in the PD group. The long-term consequences of these changes remain to be studied.

Impact of weight loss and maintenance with ad libitum diets varying in protein and glycemic index content on metabolic syndrome

OBJECTIVES

We investigated the effects of weight loss and maintenance with diets that varied with regard to protein content and glycemic index (GI) on metabolic syndrome (MetSyn) status.

METHODS

Secondary analyses were performed within the Diet, Obesity and Genes (DiOGenes) study (2006-2008), a randomized controlled dietary intervention. Nine hundred and thirty-eight overweight and obese adults from eight European countries entered an 8-wk low-calorie-diet period. Seven hundred and seventy-three adults who lost at least 8% of their body weights were randomized to one of five ad libitum diets for 6 mo: 1) low-protein (LP)/low-GI (LGI); 2) LP/high-GI (HGI); 3) high-protein (HP)/LGI; 4) HP/HGI; and 5) control diet. MetSyn prevalence and a standardized MetSyn score were assessed at baseline, after the low-calorie diet, and after the intervention.

RESULTS

Weight loss among participants while on the low-calorie diet significantly reduced MetSyn prevalence (33.9% versus 15.9%; P < 0.001) and MetSyn score (-1.48 versus -4.45; P < 0.001). During weight maintenance, significant changes in MetSyn score were observed between the groups, with the highest increase detected in the LP/HGI group (P = 0.039, partial η(2) = 0.023). Protein, GI, and their interaction did not have isolated effects on study outcomes.

CONCLUSIONS

Neither protein nor GI affected MetSyn status in this sample of European overweight and obese adults. However, a diet with a combination of an increased protein-to-carbohydrate ratio with low-GI foods had beneficial effects on MetSyn factors.

Effects of a novel school-based cross-curricular physical activity intervention on cardiovascular disease risk factors in 11- to 14-year-olds: the activity knowledge circuit

PURPOSE

This study investigates cardiovascular disease risk factor response in adolescents following introduction of brisk walking into curriculum lessons.

DESIGN

Quasi-experimental.

SETTING

School-based.

SUBJECTS

An intervention group consisted of 115 (aged 12.4 ± 0.5 y) year eight participants, and 77 (aged 12.1 ± 1.1 y) year seven and year nine participants formed a control.

INTERVENTION

An 18-week cross-curricular physical activity intervention was implemented in one secondary school.

MEASURES

Adiposity variables, blood pressure, lipids, lipoproteins, glucose, insulin, high-sensitivity C-reactive protein, high-molecular-weight adiponectin, aerobic fitness, physical activity behavior, and diet were assessed preintervention and postintervention.

ANALYSIS

Dependent and independent t-tests.

RESULTS

Prevalence of elevated waist circumference (9.8% vs. 6.9%), systolic blood pressure (3.3% vs. 0%), triglycerides (2.5% vs. 1.2%), and reduced high density lipoprotein cholesterol (3.7% vs. 2.7%) decreased in the intervention group. Significant improvements in high density lipoprotein cholesterol to total cholesterol ratio (mean ± SD: 2% ± 4% [confidence interval (CI)(0.05)  =  1% to 2%], t(80)  =  -3.5, p  =  .001) and glucose (-.1 ± .4 mmol/L [CI(0.05)  =  -.2% to 0%], t(79)  =  3.2, p  =  .002) were evident for the intervention group.

CONCLUSION

The Activity Knowledge Circuit may prove to be a sustainable, effective, and cost-effective strategy to engage schoolchildren in physical activity on a daily basis. A longer-duration intervention is required to fully understand risk factor response in adolescents.

SERPINE1, PAI-1 protein coding gene, methylation levels and epigenetic relationships with adiposity changes in obese subjects with metabolic syndrome features under dietary restriction

Plasminogen activator inhibitor 1 (PAI-1) has been associated with metabolic disorders, through different mechanisms, which could involve changes in DNA methylation. This work aimed to assess the potential relationships of the cytosine methylation levels within SERPINE1 gene transcriptional regulatory region, which codes for PAI-1, in peripheral white blood cells with anthropometrical, metabolic and inflammatory features. Forty-six obese subjects with metabolic syndrome features followed Control or Metabolic Syndrome Reduction in Navarra (RESMENA) energy-restricted (−30%E) diets for 8 weeks. SERPINE1 transcriptional regulatory region methylation at baseline was analyzed by a microarray technical. Both dietary strategies reduced anthropometric and biochemical parameters. The Control group significantly reduced plasma PAI-1 concentrations but not the RESMENA group. Participants from both nutritional interventions with higher SERPINE1 methylation levels at baseline showed significantly major reductions in body weight, total fat mass, android fat mass, total cholesterol and triglycerides, as compared with those with lower initial SERPINE1 methylation levels. In conclusion, the DNA methylation levels of SERPINE1 transcriptional regulatory region were associated with some metabolic and anthropometric changes in obese subjects with metabolic syndrome under energy restriction, suggesting a complex epigenetic network in the regulation of this recognized pro-inflammatory marker. (www.clinicaltrials.gov; NCT01087086)

Dietary Salba (Salvia hispanica L) seed rich in α-linolenic acid improves adipose tissue dysfunction and the altered skeletal muscle glucose and lipid metabolism in dyslipidemic insulin-resistant rats

This work reports the effect of dietary Salba (chia) seed rich in n-3 α-linolenic acid on the morphological and metabolic aspects involved in adipose tissue dysfunction and the mechanisms underlying the impaired glucose and lipid metabolism in the skeletal muscle of rats fed a sucrose-rich diet (SRD). Rats were fed a SRD for 3 months. Thereafter, half the rats continued with SRD while in the other half, corn oil (CO) was replaced by chia seed for 3 months (SRD+chia). In control group, corn starch replaced sucrose. The replacement of CO by chia seed in the SRD reduced adipocyte hypertrophy, cell volume and size distribution, improved lipogenic enzyme activities, lipolysis and the anti-lipolytic action of insulin. In the skeletal muscle lipid storage, glucose phosphorylation and oxidation were normalized. Chia seed reversed the impaired insulin stimulated glycogen synthase activity, glycogen, glucose-6-phosphate and GLUT-4 protein levels as well as insulin resistance and dyslipidemia.

Dietary strategies to reduce metabolic syndrome

Metabolic syndrome (MetS) is a cluster of metabolic abnormalities characterized by central obesity, dyslipidemias, hypertension, high fasting glucose, chronic low-grade inflammation and oxidative stress. This condition has become an increasing problem in our society where about 34 % of adults are diagnosed with MetS. In parallel with the adult situation, a significant number of children present lipid abnormalities and insulin resistance, which can be used as markers of MetS in the pediatric population. Changes in lifestyle including healthy dietary regimens and increased physical activity should be the first lines of therapy to decrease MetS. In this article, we present the most recent information on successful dietary modifications that can reduce the parameters associated with MetS. Successful dietary strategies include energy restriction and weight loss, manipulation of dietary macronutrients--either through restriction of carbohydrates, fat, or enrichment in beneficial fatty acids, incorporation of functional foods and bioactive nutrients, and adherence to dietary and lifestyle patterns such the Mediterranean diet and diet/exercise regimens. Together, the recent findings presented in this review serve as evidence to support the therapeutic treatment of MetS through diet.

Diet composition modulates expression of sirtuins and renin-angiotensin system components in adipose tissue

OBJECTIVE

The aim of this study was to evaluate the expression of RAS components and SIRTs enzymes in the adipose tissue of mice fed diets with different macronutrient composition.

DESIGN AND METHODS

The body weight, food intake, and energy intake (kcal) were evaluated. Blood parameters (insulin sensitivity, glucose tolerance, total cholesterol, HDL-C triglyceride, and glucose levels) were also assessed. Real-time PCR was performed in epididymal adipose tissue samples to analyze the expression of renin, angiotensinogen (AGT), angiotensin-converting enzyme 1 and 2 (ACE and ACE2), and SIRTs 1-7. Male FVB/N mice were divided into 5 groups (N = 10 each) that were fed with experimental diets for 60 days. Test diets were divided into standard (ST), AIN-93M, high glucose (HG), high protein (HP) and high lipid (HL).

RESULTS

The main results showed that HL diet treatment induced reduction in HDL-C and triglyceride plasma levels; increased ACE (Ang II marker) expression and decreased ACE2 (Ang-[1-7] catalyzer) expression in adipose tissue; and also increased SIRT4 expression.

CONCLUSION

Diets with high lipid content induced a degenerative state associated with deregulation of adipose tissue enzymes expression.

Lipoprotein receptor-related protein 1 variants and dietary fatty acids: meta-analysis of European origin and African American studies

OBJECTIVE

Low-density lipoprotein-related receptor protein 1 (LRP1) is a multi-functional endocytic receptor and signaling molecule that is expressed in adipose and the hypothalamus. Evidence for a role of LRP1 in adiposity is accumulating from animal and in vitro models, but data from human studies are limited. The study objectives were to evaluate (i) relationships between LRP1 genotype and anthropometric traits, and (ii) whether these relationships were modified by dietary fatty acids.

DESIGN AND METHODS

We conducted race/ethnic-specific meta-analyses using data from 14 studies of US and European whites and 4 of African Americans to evaluate associations of dietary fatty acids and LRP1 genotypes with body mass index (BMI), waist circumference and hip circumference, as well as interactions between dietary fatty acids and LRP1 genotypes. Seven single-nucleotide polymorphisms (SNPs) of LRP1 were evaluated in whites (N up to 42 000) and twelve SNPs in African Americans (N up to 5800).

RESULTS

After adjustment for age, sex and population substructure if relevant, for each one unit greater intake of percentage of energy from saturated fat (SFA), BMI was 0.104 kg m(-2) greater, waist was 0.305 cm larger and hip was 0.168 cm larger (all P<0.0001). Other fatty acids were not associated with outcomes. The association of SFA with outcomes varied by genotype at rs2306692 (genotyped in four studies of whites), where the magnitude of the association of SFA intake with each outcome was greater per additional copy of the T allele: 0.107 kg m(-2) greater for BMI (interaction P=0.0001), 0.267 cm for waist (interaction P=0.001) and 0.21 cm for hip (interaction P=0.001). No other significant interactions were observed.

CONCLUSION

Dietary SFA and LRP1 genotype may interactively influence anthropometric traits. Further exploration of this, and other diet x genotype interactions, may improve understanding of interindividual variability in the relationships of dietary factors with anthropometric traits.

A new dietary strategy for long-term treatment of the metabolic syndrome is compared with the American Heart Association (AHA) guidelines: the MEtabolic Syndrome REduction in NAvarra (RESMENA) project

The long-term effects of dietary strategies designed to combat the metabolic syndrome (MetS) remain unknown. The present study evaluated the effectiveness of a new dietary strategy based on macronutrient distribution, antioxidant capacity and meal frequency (MEtabolic Syndrome REduction in NAvarra (RESMENA) diet) for the treatment of the MetS when compared with the American Heart Association guidelines, used as Control. Subjects with the MetS (fifty-two men and forty-one women, age 49 (se 1) years, BMI 36·11 (se 0·5) kg/m²) were randomly assigned to one of two dietary groups. After a 2-month nutritional-learning intervention period, during which a nutritional assessment was made for the participants every 15 d, a 4-month self-control period began. No significant differences were found between the groups concerning anthropometry, but only the RESMENA group exhibited a significant decrease in body weight ( - 1·7%; P= 0·018), BMI ( - 1·7%; P= 0·019), waist circumference ( - 1·8%; P= 0·021), waist:hip ratio ( - 1·4%; P= 0·035) and android fat mass ( - 6·9%; P= 0·008). The RESMENA group exhibited a significant decrease in alanine aminotransferase and aspartate aminotransferase (AST) concentrations ( - 26·8%; P= 0·008 and - 14·0%; P= 0·018, respectively), while the Control group exhibited a significant increase in glucose (7·9%; P= 0·011), AST (11·3%; P= 0·045) and uric acid (9·0%; P< 0·001) concentrations. LDL-cholesterol (LDL-C) concentrations were increased (Control group: 34·4%; P< 0·001 and RESMENA group: 33·8%; P< 0·001), but interestingly so were the LDL-C:apoB ratio (Control group: 28·7%; P< 0·001, RESMENA group: 17·1%; P= 0·009) and HDL-cholesterol concentrations (Control group: 21·1%; P< 0·001, RESMENA group: 8·7; P= 0·001). Fibre was the dietary component that most contributed to the improvement of anthropometry, while body-weight loss explained changes in some biochemical markers. In conclusion, the RESMENA diet is a good long-term dietary treatment for the MetS.

Lupin protein positively affects plasma LDL cholesterol and LDL:HDL cholesterol ratio in hypercholesterolemic adults after four weeks of supplementation: a randomized, controlled crossover study

BACKGROUND

A couple of studies indicate a favorable impact of lupin protein on cardiovascular risk factors in humans. These studies, however, used relatively high doses of > 33 g/d, which can hardly be consumed under physiological conditions. Therefore, we investigated the effect of 25 g/d lupin protein isolate (LPI) on selected cardiovascular markers and on serum amino acids.

METHODS

A total of 33 hypercholesterolemic subjects participated in a randomized, controlled, double-blind crossover study. LPI and the active comparator milk protein isolate (MPI) were incorporated in protein drinks and consumed over 8 wk separated by a 4 wk washout period. Anthropometric data, blood pressure, and nutrient intake were assessed at baseline and after 8 wk of both protein interventions. Blood was sampled at baseline, wk 4 and wk 8. All 33 subjects were included in final statistical analyses using repeated measures ANOVA with the general linear model or using linear mixed model.

RESULTS

Except for higher HDL cholesterol at wk 4 of LPI (P ≤ 0.036), anthropometric parameters, blood pressure, and plasma lipids did not differ among LPI and MPI intervention. Compared to baseline, the primary outcome LDL cholesterol was significantly reduced after 4 wk of both interventions (P ≤ 0.008), while LDL:HDL cholesterol ratio was decreased only by LPI (P = 0.003). These time effects were restricted to subjects with higher hypercholesterolemia and disappeared after 8 wk. Blood pressure was reduced after 8 wk of LPI (P ≤ 0.044). Almost all serum amino acids were higher at wk 4 but not at wk 8 of MPI compared to LPI. Following 4 wk and 8 wk of LPI intervention, most amino acids remained unchanged. Both interventions caused a slight, but significant rise in body weight and body fat after 8 wk (P ≤ 0.045).

CONCLUSION

In conclusion, 25 g LPI can beneficially modulate plasma LDL cholesterol at least over short-term. Using appropriate dietetic conditions that improve consumer compliance and avoid changes in energy intake as well as in body composition, lupin protein could positively impact cardiovascular risk factors particularly in individuals with higher hypercholesterolemia.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01304992.

Low-carbohydrate, high-protein diet score and risk of incident cancer; a prospective cohort study

BACKGROUND

Although carbohydrate reduction of varying degrees is a popular and controversial dietary trend, potential long-term effects for health, and cancer in specific, are largely unknown.

METHODS

We studied a previously established low-carbohydrate, high-protein (LCHP) score in relation to the incidence of cancer and specific cancer types in a population-based cohort in northern Sweden. Participants were 62,582 men and women with up to 17.8 years of follow-up (median 9.7), including 3,059 prospective cancer cases. Cox regression analyses were performed for a LCHP score based on the sum of energy-adjusted deciles of carbohydrate (descending) and protein (ascending) intake labeled 1 to 10, with higher scores representing a diet lower in carbohydrates and higher in protein. Important potential confounders were accounted for, and the role of metabolic risk profile, macronutrient quality including saturated fat intake, and adequacy of energy intake reporting was explored.

RESULTS

For the lowest to highest LCHP scores, 2 to 20, carbohydrate intakes ranged from median 60.9 to 38.9% of total energy intake. Both protein (primarily animal sources) and particularly fat (both saturated and unsaturated) intakes increased with increasing LCHP scores. LCHP score was not related to cancer risk, except for a non-dose-dependent, positive association for respiratory tract cancer that was statistically significant in men. The multivariate hazard ratio for medium (9-13) versus low (2-8) LCHP scores was 1.84 (95% confidence interval: 1.05-3.23; p-trend = 0.38). Other analyses were largely consistent with the main results, although LCHP score was associated with colorectal cancer risk inversely in women with high saturated fat intakes, and positively in men with higher LCHP scores based on vegetable protein.

CONCLUSION

These largely null results provide important information concerning the long-term safety of moderate carbohydrate reduction and consequent increases in protein and, in this cohort, especially fat intakes. In order to determine the effects of stricter carbohydrate restriction, further studies encompassing a wider range of macronutrient intakes are warranted.

Long-term effects of low-fat diets either low or high in protein on cardiovascular and metabolic risk factors: a systematic review and meta-analysis

BACKGROUND

Meta-analyses of short-term studies indicate favorable effects of higher protein vs. lower protein diets on health outcomes like adiposity or cardiovascular risk factors, but their long-term effects are unknown.

METHODS

Electronic databases (MEDLINE, EMBASE, Cochrane Trial Register) were searched up to August 2012 with no restriction to language or calendar date. A random effect meta-analysis was performed using the Software package by the Cochrane Collaboration Review Manager 5.1. Sensitivity analysis was performed for RCTs with a Jadad Score ≥ 3, and excluding type 2 diabetic subjects (T2D).

RESULTS

15 RCTs met all objectives and were included in the present meta-analysis. No significant differences were observed for weight, waist circumference, fat mass, blood lipids (i.e. total cholesterol, LDL-cholesterol, HDL-cholesterol, triacylglycerols), C-reactive protein, diastolic and systolic blood pressure, fasting glucose and glycosylated hemoglobin. In contrast, improvements of fasting insulin was significantly more pronounced following high protein diets as compared to the low protein counterparts (weighted mean difference: -0.71 μIU/ml, 95% CI -1.36 to -0.05, p = 0.03). Sensitivity analysis of high quality RCTs confirmed the data of the primary analyses, while exclusion of studies with diabetic subjects resulted in an additional benefit of high-protein diets with respect to a more marked increase in HDL-cholesterol.

CONCLUSION

According to the present meta-analysis of long-term RCTs, high-protein diets exerted neither specific beneficial nor detrimental effects on outcome markers of obesity, cardiovascular disease or glycemic control. Thus, it seems premature to recommend high-protein diets in the management of overweight and obesity.

Low-density lipoprotein receptor-related protein 1 variant interacts with saturated fatty acids in Puerto Ricans

OBJECTIVE

Low-density lipoprotein receptor-related protein 1 (LRP1) is a multifunctional endocytic receptor that is highly expressed in adipocytes and the hypothalamus. Animal models and in vitro studies support a role for LRP1 in adipocyte metabolism and leptin signaling, but genetic polymorphisms have not been evaluated for obesity in people.

DESIGN AND METHODS

We examined whether dietary fats (eg., saturated, polyunsaturated) modulated the association of LRP1 rs1799986 with anthropometric traits. We studied a population-based sample of Puerto Ricans (n = 920, aged 45-74 y) living in the Boston area.We examined whether dietary fats (eg., saturated, polyunsaturated) modulated the association of LRP1 rs1799986 with anthropometric traits. We studied a population-based sample of Puerto Ricans (n = 920, aged 45-74 y) living in the Boston area.

RESULTS

In multivariable linear regression models, we dichotomized saturated fat intake and found significant interaction terms between total saturated fatty acids and LRP1 rs1799986 genotype for BMI (P=0.006) and hip (P = 0.002). High intake of saturated fat was associated with higher BMI (P = 0.001), waist (P = 0.008) and hip (P=0.003) in minor allele carriers (CT+TT) compared to CC participants. Further analysis of dichotomized individual saturated fatty acids revealed that interactions were strongest for two individual longer chain fatty acids. High intake of palmitic acid (C16:0; P = 0.0007) and high stearic acid intake (C18:0; P = 0.005) were associated with higher BMI in T carriers. Interactions were not detected for polyunsaturated fatty acids.

CONCLUSIONS

Gene-diet interactions at the LRP1 locus support the hypothesis that susceptibility to weight gain based on saturated fatty acids is modified by genotype and possibly by chain length. These results may facilitate the development of a panel of genetic candidates for use in optimizing dietary recommendations for obesity management.

Metabolic syndrome and inflammation: a critical review of in vitro and clinical approaches for benefit assessment of plant food supplements

Metabolic syndrome is defined as the clustering in an individual of several metabolic abnormalities associated with insulin resistance, type 2 diabetes, and obesity, in which low-grade chronic inflammatory activity is commonly observed. Part of the European Project PlantLIBRA is concerned with methods to assess the benefits of plant food supplements (PFSs) in countering inflammatory activity and metabolic syndrome. This paper summarizes the current methods used for benefit assessment of PFS, taking into consideration only in vitro, in silico, and clinical methodologies used to investigate the anti-inflammatory properties of plants. No in silico studies (using computer simulation) related to metabolic syndrome were found; these methods appear to be used exclusively for identifying or testing potentially effective compounds in drug development. Most in vitro methods for the assessment of beneficial effects of botanicals or plant food supplements in diabetes were based on a quantitative polymerase chain reaction (PCR), whereas the preferred kind of clinical study was the double-blind randomized controlled clinical trial. Only two parameters were observed to change after treatment with botanicals in both in vitro and in vivo studies: interleukin-6 and tumour necrosis factor-α, and these biomarkers should be carefully considered in future studies for PFS benefit assessment.

Short-term role of the dietary total antioxidant capacity in two hypocaloric regimes on obese with metabolic syndrome symptoms: the RESMENA randomized controlled trial

Background

Dietary strategies seem to be the most prescribed therapy in order to counteract obesity regarding not only calorie restriction, but also bioactive ingredients and the composition of the consumed foods. Dietary total antioxidant capacity (TAC) is gaining importance in order to assess the quality of the diet.

Methods

Ninety-six obese adults presenting metabolic syndrome (MetS) symptoms completed an 8-week intervention trial to evaluate the effects of a novel dietary program with changes in the nutrient distribution and meal frequency and to compare it with a dietary pattern based on the American Heart Association (AHA) guidelines.

Anthropometric and biochemical parameters were assessed at baseline and at the endpoint of the study, in addition to 48-hours food dietary records.

Results

Both diets equally (p > 0.05) improved MetS manifestations. Dietary TAC was the component which showed the major influence on body weight (p = 0.034), body mass index (p = 0.026), waist circumference (p = 0.083) and fat mass (p = 0.015) reductions. Transaminases (ALT and AST) levels (p = 0.062 and p = 0.004, respectively) were associated with lower TAC values.

Conclusion

RESMENA diet was as effective as AHA pattern for reducing MetS features. Dietary TAC was the most contributing factor involved in body weight and obesity related markers reduction.

Trial registration

http://www.clinicaltrials.gov; NCT01087086

Protein leverage affects energy intake of high-protein diets in humans

BACKGROUND

The protein leverage hypothesis requires specific evidence that protein intake is regulated more strongly than energy intake.

OBJECTIVE

The objective was to determine ad libitum energy intake, body weight changes, and appetite profile in response to protein-to-carbohydrate + fat ratio over 12 consecutive days and in relation to age, sex, BMI, and type of protein.

DESIGN

A 12-d randomized crossover study was performed in 40 men and 39 women [mean ± SD age: 34.0 ± 17.6 y; BMI (in kg/m(2)): 23.7 ± 3.4] with the use of diets containing 5%, 15%, and 30% of energy from protein from a milk or plant source.

RESULTS

Protein-content effects did not differ by age, sex, BMI, or type of protein. Total energy intake was significantly lower in the high-protein (7.21 ± 3.08 MJ/d) condition than in the low-protein (9.33 ± 3.52 MJ/d) and normal-protein (9.62 ± 3.51 MJ/d) conditions (P = 0.001), which was predominantly the result of a lower energy intake from meals (P = 0.001). Protein intake varied directly according to the amount of protein in the diet (P = 0.001). The AUC of visual analog scale appetite ratings did not differ significantly, yet fluctuations in hunger (P = 0.019) and desire to eat (P = 0.026) over the day were attenuated in the high-protein condition compared with the normal-protein condition.

CONCLUSIONS

We found evidence to support the protein leverage hypothesis in that individuals underate relative to energy balance from diets containing a higher protein-to-carbohydrate + fat ratio. No evidence for protein leverage effects from diets containing a lower ratio of protein to carbohydrate + fat was obtained. It remains to be shown whether a relatively low protein intake would cause overeating or would be the effect of overeating of carbohydrate and fat. The study was registered at clinicaltrials.gov as NCT01320189.

Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials

BACKGROUND

It is currently unclear whether altering the carbohydrate-to-protein ratio of low-fat, energy-restricted diets augments weight loss and cardiometabolic risk markers.

OBJECTIVE

The objective was to conduct a systematic review and meta-analysis of studies that compared energy-restricted, isocaloric, high-protein, low-fat (HP) diets with standard-protein, low-fat (SP) diets on weight loss, body composition, resting energy expenditure (REE), satiety and appetite, and cardiometabolic risk factors.

DESIGN

Systematic searches were conducted by using MEDLINE, EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials to identify weight-loss trials that compared isocalorically prescribed diets matched for fat intake but that differed in protein and carbohydrate intakes in participants aged ≥18 y. Twenty-four trials that included 1063 individuals satisfied the inclusion criteria.

RESULTS

Mean (±SD) diet duration was 12.1 ± 9.3 wk. Compared with an SP diet, an HP diet produced more favorable changes in weighted mean differences for reductions in body weight (-0.79 kg; 95% CI: -1.50, -0.08 kg), fat mass (FM; -0.87 kg; 95% CI: -1.26, -0.48 kg), and triglycerides (-0.23 mmol/L; 95% CI: -0.33, -0.12 mmol/L) and mitigation of reductions in fat-free mass (FFM; 0.43 kg; 95% CI: 0.09, 0.78 kg) and REE (595.5 kJ/d; 95% CI: 67.0, 1124.1 kJ/d). Changes in fasting plasma glucose, fasting insulin, blood pressure, and total, LDL, and HDL cholesterol were similar across dietary treatments (P ≥ 0.20). Greater satiety with HP was reported in 3 of 5 studies.

CONCLUSION

Compared with an energy-restricted SP diet, an isocalorically prescribed HP diet provides modest benefits for reductions in body weight, FM, and triglycerides and for mitigating reductions in FFM and REE.

'Sarcobesity': a metabolic conundrum

Two independent but inter-related conditions that have a growing impact on healthy life expectancy and health care costs in developed nations are an age-related loss of muscle mass (i.e., sarcopenia) and obesity. Sarcopenia is commonly exacerbated in overweight and obese individuals. Progression towards obesity promotes an increase in fat mass and a concomitant decrease in muscle mass, producing an unfavourable ratio of fat to muscle. The coexistence of diminished muscle mass and increased fat mass (so-called 'sarcobesity') is ultimately manifested by impaired mobility and/or development of life-style-related diseases. Accordingly, the critical health issue for a large proportion of adults in developed nations is how to lose fat mass while preserving muscle mass. Lifestyle interventions to prevent or treat sarcobesity include energy-restricted diets and exercise. The optimal energy deficit to reduce body mass is controversial. While energy restriction in isolation is an effective short-term strategy for rapid and substantial weight loss, it results in a reduction of both fat and muscle mass and therefore ultimately predisposes one to an unfavourable body composition. Aerobic exercise promotes beneficial changes in whole-body metabolism and reduces fat mass, while resistance exercise preserves lean (muscle) mass. Current evidence strongly supports the inclusion of resistance and aerobic exercise to complement mild energy-restricted high-protein diets for healthy weight loss as a primary intervention for sarcobesity.

Short- and long-term effects of continuous versus intermittent restrictive diet approaches on body composition and the metabolic profile in overweight and obese postmenopausal women: a pilot study

OBJECTIVE

The objective of this study was to compare changes in body composition and the metabolic profile between women taking an intermittent diet (ID) and women taking a continuous diet (CD).

METHODS

Twenty-five obese postmenopausal women were randomized to an ID (n = 13) or a CD (n = 12). In the ID, 5-week energy restriction periods were followed by 5-week weight stabilization periods. In the CD, 15 weeks of energy restriction was followed by 5 weeks of weight stabilization. Outcome measures before, during, and after weight loss, as well as after a 1-year follow-up, were body weight and composition, waist circumference, resting metabolic rate, and fasting lipid and glucose levels.

RESULTS

Body weight, waist circumference, percentage fat mass, and fat mass decreased significantly and similarly in both groups (P < 0.0001). Both groups showed similar overall decreases in plasma total cholesterol and triglycerides (all P < 0.05). Low-density lipoprotein cholesterol improved significantly in the CD group only, whereas fasting glucose decreased significantly in the ID group only. High-density lipoprotein cholesterol and resting metabolic rate remained stable in both groups. Fasting plasma triglyceride and glucose levels were the only metabolic variables to further improve after the fifth week of the protocol. At the 1-year follow-up, both interventions were associated with successful and similar weight loss maintenance and improvements in fasting plasma glucose levels.

CONCLUSIONS

The ID resulted in similar short- and long-term changes in body composition and metabolic profile compared with a CD. Most improvements occurred during the first 5 weeks of treatment in both interventions.

Dietary protein in weight management: a review proposing protein spread and change theories

A large volume of human clinical data supports increased dietary protein for favorable changes to body composition, but not all data are conclusive. The aim of this review is to propose two theories, "protein spread theory" and "protein change theory" in an effort to explain discrepancies in the literature. Protein spread theory proposed that there must have been a sufficient spread or % difference in g/kg/day protein intake between groups during a protein intervention to see body composition and anthropometric differences. Protein change theory postulated that for the higher protein group, there must be a sufficient change from baseline g/kg/day protein intake to during study g/kg/day protein intake to see body composition and anthropometric benefits. Fifty-one studies met inclusion criteria. In studies where a higher protein intervention was deemed successful there was, on average, a 58.4% g/kg/day between group protein intake spread versus a 38.8% g/kg/day spread in studies where a higher protein diet was no more effective than control. The average change in habitual protein intake in studies showing higher protein to be more effective than control was +28.6% compared to +4.9% when additional protein was no more effective than control. Providing a sufficient deviation from habitual intake appears to be an important factor in determining the success of additional protein in weight management interventions. A modest increase in dietary protein favorably effects body composition during weight management interventions.

Diet supplementation with donkey milk upregulates liver mitochondrial uncoupling, reduces energy efficiency and improves antioxidant and antiinflammatory defences in rats

Dietary PUFA, mainly those of the n-3 family, are known to play essential roles in the maintenance of energy balance and in the reduction of body fat deposition through the upregulation of mitochondrial uncoupling that is the main source of reactive oxygen species. We hypothesized that rat supplementation with raw donkey's milk (DM), characterized by low-fat content and higher n3:n6 ratio, may affect energy balance, lipid metabolism, and prooxidant status as compared to animals treated with cow's milk. In the present study, the effects of drinking raw DM (for 4 weeks) on energy balance, lipid metabolism, antiinflammatory, and antioxidant/detoxifying defences was compared to that produced by rat intake of an iso-energetic amount of raw cow's milk. The hypolipidemic effect produced by DM paralleled with the enhanced mitochondrial activity/proton leakage and with the increased activity or expression of mitochondrial markers namely, carnitine palmitoyl transferase and uncoupling protein 2. The association of decreased energy efficiency with reduced proinflammatory signs (TNF-α and LPS levels) with the significant increase antioxidant (total thiols) and detoxifying enzyme activities (glutathione-S-transferase NADH quinone oxidoreductase) in DM-treated animals, indicated that beneficial effects were attributable, at least in part, to the activation of nuclear factor 2 erythroid-related factor 2 pathway.