Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults

Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults 

[Obesity and eating disorders]

from American Journal of Clinical Nutrition current issue by Varady, K. A, Bhutani, S., Church, E. C, Klempel, M. C

Background: The ability of modified alternate-day fasting (ADF; ie, consuming 25% of energy needs on the fast day and ad libitum food intake on the following day) to facilitate weight loss and lower vascular disease risk in obese individuals remains unknown.

Objective: This study examined the effects of ADF that is administered under controlled compared with self-implemented conditions on body weight and coronary artery disease (CAD) risk indicators in obese adults.

Design: Sixteen obese subjects (12 women, 4 men) completed a 10-wk trial, which consisted of 3 phases: 1) a 2-wk control phase, 2) a 4-wk weight loss/ADF controlled food intake phase, and 3) a 4-wk weight loss/ADF self-selected food intake phase.

Results: Dietary adherence remained high throughout the controlled food intake phase (days adherent: 86%) and the self-selected food intake phase (days adherent: 89%). The rate of weight loss remained constant during controlled food intake (0.67 ± 0.1 kg/wk) and self-selected food intake phases (0.68 ± 0.1 kg/wk). Body weight decreased (P < 0.001) by 5.6 ± 1.0 kg (5.8 ± 1.1%) after 8 wk of diet. Percentage body fat decreased (P < 0.01) from 45 ± 2% to 42 ± 2%. Total cholesterol, LDL cholesterol, and triacylglycerol concentrations decreased (P < 0.01) by 21 ± 4%, 25 ± 10%, and 32 ± 6%, respectively, after 8 wk of ADF, whereas HDL cholesterol remained unchanged. Systolic blood pressure decreased (P < 0.05) from 124 ± 5 to 116 ± 3 mm Hg.

Conclusion: These findings suggest that ADF is a viable diet option to help obese individuals lose weight and decrease CAD risk. This trial was registered at clinicaltrials.gov as UIC-004-2009.

Circadian Timing of Food Intake Contributes to Weight Gain

Circadian Timing of Food Intake Contributes to Weight Gain

Deanna M. Arble1, Joseph Bass1,2, Aaron D. Laposky1, Martha H. Vitaterna1 and Fred W. Turek1

Abstract

Studies of body weight regulation have focused almost entirely on caloric intake and energy expenditure. However, a number of recent studies in animals linking energy regulation and the circadian clock at the molecular, physiological, and behavioral levels raise the possibility that the timing of food intake itself may play a significant role in weight gain. The present study focused on the role of the circadian phase of food consumption in weight gain. We provide evidence that nocturnal mice fed a high-fat diet only during the 12-h light phase gain significantly more weight than mice fed only during the 12-h dark phase. A better understanding of the role of the circadian system for weight gain could have important implications for developing new therapeutic strategies for combating the obesity epidemic facing the human population today.

A very low carbohydrate ketogenic diet improves glucose tolerance in ob/ob mice independently of weight loss

A very low carbohydrate ketogenic diet improves glucose tolerance in ob/ob mice independently of weight loss

by Badman, M. K., Kennedy, A. R., Adams, A. C., Pissios, P., Maratos-Flier, E.

In mice of normal weight and with diet-induced obesity, a high-fat, low-carbohydrate ketogenic diet (KD) causes weight loss, reduced circulating glucose and lipids, and dramatic changes in hepatic gene expression. Many of the effects of KD are mediated by fibroblast growth factor 21 (FGF21). We tested the effects of KD feeding on ob/ob mice to determine if metabolic effects would occur in obesity secondarily to leptin deficiency. We evaluated the effect of prolonged KD feeding on weight, energy homeostasis, circulating metabolites, glucose homeostasis, and gene expression. Subsequently, we evaluated the effects of leptin and fasting on FGF21 expression in ob/ob mice. KD feeding of ob/ob mice normalized fasting glycemia and substantially reduced insulin and lipid levels in the absence of weight loss. KD feeding was associated with significant increases in lipid oxidative genes and reduced expression of lipid synthetic genes, including stearoyl-coenzyme A desaturase 1, but no change in expression of inflammatory markers. In chow-fed ob/ob mice, FGF21 mRNA was elevated 10-fold compared with wild-type animals, and no increase from this elevated baseline was seen with KD feeding. Administration of leptin to chow-fed ob/ob mice led to a 24-fold induction of FGF21. Fasting also induced hepatic FGF21 in ob/ob mice. Thus, KD feeding improved ob/ob mouse glucose homeostasis without weight loss or altered caloric intake. These data demonstrate that manipulation of dietary macronutrient composition can lead to marked improvements in metabolic profile of leptin-deficient obese mice in the absence of weight loss.

Inflammation and impaired adipogenesis in hypertrophic obesity in man

Inflammation and impaired adipogenesis in hypertrophic obesity in man

by Gustafson, B., Gogg, S., Hedjazifar, S., Jenndahl, L., Hammarstedt, A., Smith, U.

Obesity is associated mainly with adipose cell enlargement in adult man (hypertrophic obesity), whereas the formation of new fat cells (hyperplastic obesity) predominates in the prepubertal age. Adipose cell size, independent of body mass index, is negatively correlated with whole body insulin sensitivity. Here, we review recent findings linking hypertrophic obesity with inflammation and a dysregulated adipose tissue, including local cellular insulin resistance with reduced IRS-1 and GLUT4 protein content. In addition, the number of preadipocytes in the abdominal subcutaneous adipose tissue capable of undergoing differentiation to adipose cells is reduced in hypertrophic obesity. This is likely to promote ectopic lipid accumulation, a well-known finding in these individuals and one that promotes insulin resistance and cardiometabolic risk. We also review recent results showing that TNF, but not MCP-1, resistin, or IL-6, completely prevents normal adipogenesis in preadipocytes, activates Wnt signaling, and induces a macrophage-like phenotype in the preadipocytes. In fact, activated preadipocytes, rather than macrophages, may completely account for the increased release of chemokines and cytokines by the adipose tissue in obesity. Understanding the molecular mechanisms for the impaired preadipocyte differentiation in the subcutaneous adipose tissue in hypertrophic obesity is a priority since it may lead to new ways of treating obesity and its associated metabolic complications.

The origin of intermuscular adipose tissue and its pathophysiological implications

The origin of intermuscular adipose tissue and its pathophysiological implications

by Vettor, R., Milan, G., Franzin, C., Sanna, M., De Coppi, P., Rizzuto, R., Federspil, G.

The intermuscular adipose tissue (IMAT) is a depot of adipocytes located between muscle bundles. Several investigations have recently been carried out to define the phenotype, the functional characteristics, and the origin of the adipocytes present in this depot. Among the different mechanisms that could be responsible for the accumulation of fat in this site, the dysdifferentiation of muscle-derived stem cells or other mesenchymal progenitors has been postulated, turning them into cells with an adipocyte phenotype. In particular, muscle satellite cells (SCs), a heterogeneous stem cell population characterized by plasticity and self-renewal that allow muscular growth and regeneration, can acquire features of adipocytes, including the abilities to express adipocyte-specific genes and accumulate lipids. Failure to express the transcription factors that direct mesenchymal precursors into fully differentiated functionally specialized cells may be responsible for their phenotypic switch into the adipogenic lineage. We proved that human SCs also possess a clear adipogenic potential that could explain the presence of mature adipocytes within skeletal muscle. This occurs under some pathological conditions (i.e., primary myodystrophies, obesity, hyperglycemia, high plasma free fatty acids, hypoxia, etc.) or as a consequence of thiazolidinedione treatment or simply because of a sedentary lifestyle or during aging. Several pathways and factors (PPARs, WNT growth factors, myokines, GEF-GAP-Rho, p66shc, mitochondrial ROS production, PKCß) could be implicated in the adipogenic conversion of SCs. The understanding of the molecular pathways that regulate muscle-to-fat conversion and SC behavior could explain the increase in IMAT depots that characterize many metabolic diseases and age-related sarcopenia.

Transdifferentiation properties of adipocytes in the adipose organ

Transdifferentiation properties of adipocytes in the adipose organ

by Cinti, S.

Mammals have two types of adipocytes, white and brown, but their anatomy and physiology is different. White adipocytes store lipids, and brown adipocytes burn them to produce heat. Previous descriptions implied their localization in distinct sites, but we demonstrated that they are mixed in many depots, raising the concept of adipose organ. We explain the reason for their cohabitation with the hypothesis of reversible physiological transdifferentiation; they are able to convert one into each other. If needed, the brown component of the organ could increase at the expense of the white component and vice versa. This plasticity is important because the brown phenotype of the organ associates with resistance to obesity and related disorders. Another example of physiological transdifferetiation of adipocytes is offered by the mammary gland; the pregnancy hormonal stimuli seems to trigger a reversible transdifferentiation of adipocytes into milk-secreting epithelial glands. The obese adipose organ is infiltrated by macrophages inducing chronic inflamation that is widely considered as a causative factor for insulin resistance. We showed that the vast majority of macrophages infiltrating the obese organ are arranged around dead adipocytes, forming characteristic crown-like structures. We recently found that visceral fat is more infiltrated than the subcutaneous fat despite a smaller size of visceral adipocytes. This suggests a different susceptibility of visceral and subcutaneous adipocytes to death, raising the concept of smaller critical death size that could be important to explain the key role of visceral fat for the metabolic disorders associated with obesity.

Exercise Training and Dietary Glycemic Load May Have Synergistic Effects on Insulin Resistance in Older Obese Adults

Exercise Training and Dietary Glycemic Load May Have Synergistic Effects on Insulin Resistance in Older Obese Adults

John P. Kirwana-d, Hope Barkoukisd, Latina M. Brooksa, b, Christine M. Marchettie, Bradley P. Stetzere, Frank Gonzalezf

  Abstract

Background/Aims: The aim of this study was to assess the combined effects of exercise and dietary glycemic load on insulin resistance in older obese adults. Methods: Eleven men and women (62 ± 2 years; 97.6 ± 4.8 kg; body mass index 33.2 ± 2.0) participated in a 12-week supervised exercise program, 5 days/week, for about 1 h/day, at 80-85% of maximum heart rate. Dietary glycemic load was calculated from dietary intake records. Insulin resistance was determined using the euglycemic (5.0 mM) hyperinsulinemic (40 mU/m2/min) clamp. Results: The intervention improved insulin sensitivity (2.37 ± 0.37 to 3.28 ± 0.52 mg/kg/min, p < 0.004), increased VO2max (p < 0.009), and decreased body weight (p < 0.009). Despite similar caloric intakes (1,816 ± 128 vs. 1,610 ± 100 kcal/day), dietary glycemic load trended towards a decrease during the study (140 ± 10 g before, vs. 115 ± 8 g during, p < 0.04). The change in insulin sensitivity correlated with the change in glycemic load (r = 0.84, p < 0.009). Four subjects reduced their glycemic load by 61 ± 8%, and had significantly greater increases in insulin sensitivity (78 ± 11 vs. 23 ± 8%, p < 0.003), and decreases in body weight (p < 0.004) and plasma triglycerides (p < 0.04) compared to the rest of the group. Conclusion: The data suggest that combining a low-glycemic diet with exercise may provide an alternative and more effective treatment for insulin resistance in older obese adults.

Effects of apple juice on risk factors of lipid profile, inflammation and coagulation, endothelial markers and atherosclerothic lesions in highcholesterolemic rabbits

Effects of apple juice on risk factors of lipid profile, inflammation and coagulation, endothelial markers and atherosclerothic lesions in highcholesterolemic rabbits

by Nafiseh Esmaeil

Background: Atherosclerosis which results from gradual deposition of lipids in medium and large arteries is a leading cause of mortality worldwide. The objective of this study was to determine the effect of apple juice on some risk factors of atherosclerosis and on the development of atherosclerosis in rabbits fed a high-cholesterol diet. Methods: Thirty two male rabbits were randomly divided into four groups: normal diet, high cholesterol diet (%1 cholesterol), 1 % cholesterol supplemented with 5ml apple juice(low dose) and 1 % cholesterol supplemented with 10ml apple juice (high dose) for 2 month. The C-reactive protein (CRP), nitrite, nitrate, fibrinogen,total cholesterol(TC) and factor VII were measured before the experiment and by the end of period. At the end ofstudy, fatty streak formation in right and left coronary arteries were determined using Chekanov method in all groups. Results: Both doses of apple juice significantly were decreased TC, TG, CRP, fibrinogen, factor VII levels, atherosclerotic lesion in right and left coronary arteries and increased nitrite and nitrate compared to cholesterolemic diet.Also using 10ml apple juice caused significant reduce in LDL-C and increase HDL-C , but 5 ml apple juice did not change these factors. Significant differences were observed between 5 and 10ml apple juice groups by LDL-C. No significant difference was found between 5 and 10 ml apple juice groups with regard to CRP, nitrite, nitrate, fibrinogen, factor VII, TG, HDL-C and TC concentrations. Conclusion: Apple juice can effectively prevent the progress of atherosclerosis.This is likely due to antioxidant and anti-inflammatory effect of apple juice.

Short-term effects of replacing milk with cola beverages on insulin-like growth factor-I and insulin-glucose metabolism: a 10 d interventional study in young men.

Short-term effects of replacing milk with cola beverages on insulin-like growth factor-I and insulin-glucose metabolism: a 10 d interventional study in young men.

Hoppe C, Kristensen M, Boiesen M, Kudsk J, Fleischer Michaelsen K, Mølgaard C.

Department of Human Nutrition, University of Copenhagen, Rolighedsvej 30, DK-1958 Fredericksberg, Denmark.

In the Western world, a trend towards increased consumption of carbonated soft drinks combined with a decreasing intake of milk is observed. This may affect circulating insulin-like growth factor I (IGF-I) and fasting insulin, as seen in pre-pubertal children. The present study was designed to reflect the trend of replacing milk with carbonated beverages in young men and to study the effects of this replacement on IGF-I, IGF-binding protein 3 (IGFBP-3), IGF-I:IGFBP-3 and glucose-insulin metabolism. A randomised, controlled crossover intervention study, in which eleven men aged 22-29 years were given a low-Ca diet in two 10 d periods with 10 d washout in between. In one period, they drank 2.5 litres of Coca Cola(R) per day and the other period 2.5 litres of semi-skimmed milk. Serum IGF-I, IGFBP-3 (RIA), insulin (fluoro immunoassay) and glucose (Cobas) were determined at baseline and end point of each intervention period. Insulin resistance and beta-cell function were calculated with the homeostasis model assessment. A decrease in serum IGF-I was observed in the cola period compared with the milk period (P < 0.05). No effects of treatment were observed on IGFBP-3, IGF-I:IGFBP-3, insulin, glucose, insulin resistance or beta-cell function. The present study demonstrates that high intake of cola over a 10 d period decreases total IGF-I compared with a high intake of milk, with no effect on glucose-insulin metabolism in adult men. It is unknown whether this is a transient phenomenon or whether it has long-term consequences.

Effects of a Low Carbohydrate Weight Loss Diet on Exercise Capacity and Tolerance in Obese Subjects

Effects of a Low Carbohydrate Weight Loss Diet on Exercise Capacity and Tolerance in Obese Subjects

Grant D. Brinkworth1, Manny Noakes1, Peter M. Clifton1 and Jonathan D. Buckley2

1Preventative Health Flagship, Commonwealth Scientific and Industrial Research Organisation–Human Nutrition, Adelaide, South Australia, Australia

2Australian Technology Network (ATN) Centre for Metabolic Fitness and Nutritional Physiology Research Centre, University of South Australia, Division of Health Sciences, Adelaide, South Australia, Australia

Correspondence: Grant D. Brinkworth (grant.brinkworth@csiro.au)

Received 11 May 2008; Accepted 8 October 2008; Published online 16 April 2009.

Abstract

Dietary restriction and increased physical activity are recommended for obesity treatment. Very low carbohydrate diets are used to promote weight loss, but their effects on physical function and exercise tolerance in overweight and obese individuals are largely unknown. The aim of this study was to compare the effects of a very low carbohydrate, high fat (LC) diet with a conventional high carbohydrate, low fat (HC) diet on aerobic capacity, fuel utilization during submaximal exercise, perceived exercise effort (RPE) and muscle strength. Sixty subjects (age: 49.2  1.2 years; BMI: 33.6  0.5 kg/m2) were randomly assigned to an energy restricted (~6–7 MJ, 30% deficit), planned isocaloric LC or HC for 8 weeks. At baseline and week 8, subjects performed incremental treadmill exercise to exhaustion and handgrip and isometric knee extensor strength were assessed. Weight loss was greater in LC compared with HC (8.4  0.4% and 6.7  0.5%, respectively; P = 0.01 time  diet). Peak oxygen uptake and heart rate were unchanged in both groups (P > 0.17). Fat oxidation increased during submaximal exercise in LC but not HC (P < 0.001 time diet effect). On both diets, perception of effort during submaximal exercise and handgrip strength decreased (P  0.03 for time), but knee extensor strength remained unchanged (P > 0.25). An LC weight loss diet shifted fuel utilization toward greater fat oxidation during exercise, but had no detrimental effect on maximal or submaximal markers of aerobic exercise performance or muscle strength compared with an HC diet. Further studies are required to determine the interaction of LC diets with regular exercise training and the long-term health effects.

Diet Quality Is Associated with Better Cognitive Test Performance among Aging Men and Women

Diet Quality Is Associated with Better Cognitive Test Performance among Aging Men and Women [Nutritional Epidemiology]

from Journal of Nutrition current issue by Wengreen, H. J., Neilson, C., Munger, R., Corcoran, C.

Most studies of association between diet and cognition among the elderly focus on the role of single nutrients or foods and ignore the complexity of dietary patterns and total diet quality. We prospectively examined associations between an index of diet quality and cognitive function and decline among elderly men and women of the Cache County Study on Memory and Aging in Utah. In 1995, 3634 resident men and women ?65 y of age completed a baseline survey that included a 142-item FFQ. Cognition was assessed using an adapted version of the Modified Mini-Mental State Examination (3MS) at baseline and 3 subsequent interviews spanning ~11 y. A recommended food score (RFS) and non-RFS were computed by summing the number of recommended foods (n = 57) and nonrecommended foods (n = 23) regularly consumed. Multivariable-mixed models were used to estimate associations between the RFS and non-RFS and average 3MS score over time. Those in the highest quartile of RFS scored 1.80 points higher on the baseline 3MS test than did those in the lowest quartile of RFS (P < 0.001). This effect was strengthened over 11 y of follow-up. Those with the highest RFS declined by 3.41 points over 11 y compared with the 5.2-point decline experienced by those with the lowest RFS (P = 0.0013). The non-RFS was not associated with cognitive scores. Consuming a diverse diet that includes a variety of recommended foods may help to attenuate age-related cognitive decline among the elderly.

Choline in anxiety and depression: the Hordaland Health Study

Choline in anxiety and depression: the Hordaland Health Study [Nutritional epidemiology and public health]

from American Journal of Clinical Nutrition current issue by Bjelland, I., Tell, G. S, Vollset, S. E, Konstantinova, S., Ueland, P. M

Background: Despite its importance in the central nervous system as a precursor for acetylcholine and membrane phosphatidylcholine, the role of choline in mental illness has been little studied.

Objective: We examined the cross-sectional association between plasma choline concentrations and scores of anxiety and depression symptoms in a general population sample.

Design: We studied a subsample (n = 5918) of the Hordaland Health Study, including both sexes and 2 age groups of 46–49 and 70–74 y who had valid information on plasma choline concentrations and symptoms of anxiety and depression measured by the Hospital Anxiety and Depression Scale—the latter 2 as continuous measures and dichotomized at a score ?8 for both subscales.

Results: The lowest choline quintile was significantly associated with high anxiety levels (odds ratio: 1.33; 95% CI: 1.06, 1.69) in the fully adjusted (age group, sex, time since last meal, educational level, and smoking habits) logistic regression model. Also, the trend test in the anxiety model was significant (P = 0.007). In the equivalent fully adjusted linear regression model, a significant inverse association was found between choline quintiles and anxiety levels (standardized regression coefficient = –0.027, P = 0.045). We found no significant associations in the corresponding analyses of the relation between plasma choline and depression symptoms.

Conclusion: In this large population–based study, choline concentrations were negatively associated with anxiety symptoms but not with depression symptoms.

Fish consumption during pregnancy, prenatal mercury exposure, and anthropometric measures at birth in a prospective mother-infant cohort study in Spain

Fish consumption during pregnancy, prenatal mercury exposure, and anthropometric measures at birth in a prospective mother-infant cohort study in Spain [Pregnancy and lactation]

from American Journal of Clinical Nutrition current issue by Ramon, R., Ballester, F., Aguinagalde, X., Amurrio, A., Vioque, J., Lacasana, M., Rebagliato, M., Murcia, M., Iniguez, C.

Background: Birth size has been shown to be related to maternal fish intake, although the results are inconsistent.

Objective: The objective was to assess the association of consumption of different types of fish and prenatal mercury exposure with birth weight, birth length, and classification as small for gestational age (SGA) in newborns.

Design: Cord blood total mercury was measured in 554 newborns in a population-based cohort born from 2004 to 2006. Fish consumption was classified in 4 frequency categories (<1 portion/mo, 1–3 portions/mo, 1 portion/wk, and ?2 portions/wk).

Results: When multivariate models were adjusted, newborns in the higher quartile of total mercury weighed 143.7 g less (95% CI: –251.8, –35.6; P for trend = 0.02) and had higher odds of being SGA for length (odds ratio: 5.3; 95% CI: 1.2, 23.9; P from likelihood ratio test = 0.03) without a linear relation (P for trend = 0.13) compared with those in the lowest quartile. Mothers consuming ?2 portions/wk of canned tuna had newborns who weighed more than those who consumed <1 portion/mo (P for trend = 0.03) and a lower risk of having infants who were SGA for weight (P for trend = 0.01). Consumption of ?2 portions/wk of large oily fish was associated with a higher risk of being SGA for weight and consumption of lean fish with a lower risk of being SGA for length compared with the consumption of <1 portion/mo, but in neither case was there a linear relation (P for trend >0.05).

Conclusions: The role of fish in fetal growth depends on the amount and type of fish consumed. The findings for mercury warrant further investigation in other settings.

Application of the Dietary Reference Intakes in developing a recommendation for pregnancy iron supplements in Canada

Application of the Dietary Reference Intakes in developing a recommendation for pregnancy iron supplements in Canada [Vitamins, minerals, and phytochemicals]

from American Journal of Clinical Nutrition current issue by Cockell, K. A, Miller, D. C, Lowell, H.

Background: For many pregnant Canadian women, usual iron intakes from food appear to be inadequate compared with Dietary Reference Intake requirement estimates.

Objective: Dietary intake modeling was undertaken to determine an amount of iron supplementation that would confer acceptably low prevalence of apparently inadequate and apparently excessive intakes.

Design: The distribution of usual dietary iron intakes was estimated with the use of 24-h recalls from pregnant women aged 19–50 y in the Canadian Community Health Survey, Cycle 2.2. The prevalence of usual intakes below the Estimated Average Requirement for pregnancy (22 mg/d) or above the Tolerable Upper Intake Level (45 mg/d) was estimated. Iterative modeling with incremental iron supplement was performed to determine a suitable supplement amount. Because the sample of pregnant women was small (148 day 1 recalls), estimates of the tails of the distributions had large SDs, and supporting analyses based on intake data from nonpregnant women (4540 day 1 recalls) were made.

Results: Daily supplementation shifted the intake distribution curve without changing its shape. Supplementation with 16 mg iron/d was consistent with low (<3%) prevalence of apparently inadequate intakes. This amount of supplementation should not be associated with an increase in apparently excessive intakes by pregnant women in this population.

Conclusions: On the basis of Dietary Reference Intakes, an iron supplement of 16 mg/d throughout pregnancy is justified as both efficacious and safe for healthy women living in Canadian households. This does not preclude the need for therapeutic iron doses for some individuals on the basis of iron status. The method can be applied to other populations if suitable baseline iron intake data are available.

Contribution of individual organ mass loss to weight loss-associated decline in resting energy expenditure

Contribution of individual organ mass loss to weight loss-associated decline in resting energy expenditure [Energy and protein metabolism]

from American Journal of Clinical Nutrition current issue by Bosy-Westphal, A., Kossel, E., Goele, K., Later, W., Hitze, B., Settler, U., Heller, M., Gluer, C.-C., Heymsfield, S. B, Muller, M. J

Background: Weight loss leads to reduced resting energy expenditure (REE) independent of fat-free mass (FFM) and fat mass (FM) loss, but the effect of changes in FFM composition is unclear.

Objective: We hypothesized that a decrease in REE adjusted for FFM with weight loss would be partly explained by a disproportionate loss in the high metabolic activity component of FFM.

Design: Forty-five overweight and obese women [body mass index (in kg/m2): 28.7–46.8] aged 22–46 y followed a low-calorie diet for 12.7 ± 2.2 wk. Body composition was measured by magnetic resonance imaging, dual-energy X-ray absorptiometry, and a 4-compartment model. REE measured by indirect calorimetry (REEm) was compared with REE calculated from detailed body-composition analysis (REEc) by using specific organ metabolic rates (ie, organ REE/mass).

Results: Weight loss was 9.5 ± 3.4 kg (8.0 ± 2.9 kg FM and 1.5 ± 3.1 kg FFM). Decreases in REE (–8%), free triiodothyronine concentrations (–8%), muscle (–3%), heart (–5%), liver (–4%), and kidney mass (–6%) were observed (all P < 0.05). Relative loss in organ mass was significantly higher (P < 0.01) than was the change in low metabolically active FFM components (muscle, bone, and residual mass). After weight loss, REEm – REEc decreased from 0.24 ± 0.58 to 0.01 ± 0.44 MJ/d (P = 0.01) and correlated with the decrease in free triiodothyronine concentrations (r = 0.33, P < 0.05). Women with high adaptive thermogenesis (defined as REEm – REEc < –0.17 MJ/d) had less weight loss and conserved FFM, liver, and kidney mass.

Conclusions: After weight loss, almost 50% of the decrease in REEm was explained by losses in FFM and FM. The variability in REEm explained by body composition increased to 60% by also considering the weight of individual organs.

Effect of vegetarian diets on bone mineral density: a Bayesian meta-analysis

Effect of vegetarian diets on bone mineral density: a Bayesian meta-analysis [Nutritional status, dietary intake, and body composition]

from American Journal of Clinical Nutrition current issue by Ho-Pham, L. T, Nguyen, N. D, Nguyen, T. V

Background: The association between vegetarian diets and bone mineral density (BMD) is controversial because of conflicting findings from previous studies.

Objective: The aim of this study was to estimate the effect of vegetarian diets on BMD by using a meta-analytic approach.

Design: A systematic electronic literature search was conducted to identify all relevant articles on the association between vegetarian diet and BMD. Nine studies of 2749 subjects (1880 women and 869 men) were included in the analysis. Traditional and Bayesian methods of meta-analysis were applied to synthesize the data.

Results: Overall, BMD was 4% lower in vegetarians than in omnivores (95% CI: 2%, 7%) at both the femoral neck and the lumbar spine. Compared with omnivores, vegans had a significantly lower lumbar spine BMD (6% lower; 95% CI: 2%, 9%), which was more pronounced than in lactoovovegetarians (2% lower; 95% CI: 1%, 4%). The probability that BMD was ?5% lower in vegetarians than in omnivores (or 0.3 SD) was 42% for the femoral neck and 32% for the lumbar spine. There was no evidence of publication bias. There was a moderate degree of between-study heterogeneity; the coefficient of heterogeneity varied between 46% and 51%.

Conclusion: The results suggest that vegetarian diets, particularly vegan diets, are associated with lower BMD, but the magnitude of the association is clinically insignificant.

Beverage intake of girls at age 5 y predicts adiposity and weight status in childhood and adolescence

Beverage intake of girls at age 5 y predicts adiposity and weight status in childhood and adolescence [Obesity and eating disorders]

from American Journal of Clinical Nutrition current issue by Fiorito, L. M, Marini, M., Francis, L. A, Smiciklas-Wright, H., Birch, L. L

Background: Increased consumption of sweetened beverage has been linked to higher energy intake and adiposity in childhood.

Objective: The objective was to assess whether beverage intake at age 5 y predicted energy intake, adiposity, and weight status across childhood and adolescence.

Design: Participants were part of a longitudinal study of non-Hispanic white girls and their parents (n = 170) who were assessed biennially from age 5 to 15 y. At each assessment, beverage intake (milk, fruit juice, and sweetened beverages) and energy intake were assessed by using three 24-h recalls. Percentage body fat and waist circumference were measured. Height and weight were measured and used to calculate body mass index. Multiple regression analyses were used to predict the girls' adiposity. In addition, at age 5 y, girls were categorized as consuming <1, ?1 and <2, or ?2 servings of sweetened beverages. A mixed modeling approach was used to assess longitudinal differences and patterns of change in sweetened beverage and energy intake, adiposity, and weight status by frequency of sweetened beverage intake.

Results: Sweetened beverage intake at age 5 y, but not milk or fruit juice intake, was positively associated with adiposity from age 5 to 15 y. Greater consumption of sweetened beverages at age 5 y (?2 servings/d) was associated with a higher percentage body fat, waist circumference, and weight status from age 5 to 15 y.

Conclusion: These findings provide new longitudinal evidence that early intake of sweetened beverages predicts adiposity and weight status across childhood and adolescence.

Effect of exercise on lipolysis in adipose tissue

Effect of exercise on lipolysis in adipose tissue

Jan Polak†, Magda Bajzova & Vladimir Stich

Adipose tissue is a major source of nonesterified fatty acids, which are involved in the etiopathogenesis of several metabolic diseases. Mechanisms regulating the processes of lipolysis are of major importance because they represent potential drug targets. Physical exercise is a cost-effective prevention strategy and important therapy for civilization diseases and is an important physiological stimulus of lipolysis in adipose tissue. Besides the traditional role of catecholamines in the regulation of lipolysis, other recently described lipolytic factors, for example, atrial natriuretic peptide and IL-6, are discussed in the context of lipolysis. In vitro as well as in vivo studies provide a substantial amount of data, which are sometimes contradictory. Exercise modifies the functional balance between β and α adrenergic receptors, increases atrial natriuretic peptide-induced lipolysis and improves sensitivity of adipose tissue to insulin. Actual lipolytic rate is the summary of these complex interactions.

Differential effects of casein versus whey on fasting plasma levels of insulin, IGF-1 and IGF-1/IGFBP-3: results from a randomized 7-day supplementation study in prepubertal boys.

Differential effects of casein versus whey on fasting plasma levels of insulin, IGF-1 and IGF-1/IGFBP-3: results from a randomized 7-day supplementation study in prepubertal boys.

Hoppe, C 1,2; Molgaard, C 1; Dalum, C 1; Vaag, A 3; Michaelsen, K F 1

AB Background/Objectives: Milk increases both fasting insulin and insulin-like growth factor 1 (IGF-1), and thereby growth, in healthy prepubertal boys. It is, however, unknown which components in milk are responsible for milk's growth-stimulating effect. 

Subjects/Methods: To get closer to the identification of which components in milk that stimulate growth, we have performed an intervention study with 57 eight-year-old boys in which we examined the effects of the two major milk protein fractions, whey and casein, and milk minerals (Ca and P) in a 2 x 2 factorial design on IGFs and glucose-insulin metabolism. The amounts of whey and casein were identical to the content in 1.5 l skim milk. The amounts of Ca and P were similar to 1.5 l skim milk in the high-mineral drinks, whereas the amounts of Ca and P were reduced in the low-mineral drinks. 

Results: There were no interactions between milk mineral groups (high, low) and milk protein groups (whey, casein). Serum IGF-1 increased by 15% (P<0.0001), whereas there was no change in fasting insulin (P=0.36) in the casein group. In the whey group, fasting insulin increased by 21% (P=0.006), with no change in IGF-1 (P=0.27). There were no independent effects of a high milk mineral intake on IGF-1 and insulin. 

Conclusions: The main milk protein fractions exhibit important but different growth-promoting effects by increasing either fasting insulin (whey) or IGF-1 (casein) levels.

Phosphate decreases urine calcium and increases calcium balance: A meta-analysis of the osteoporosis acid-ash diet hypothesis

Phosphate decreases urine calcium and increases calcium balance: A meta-analysis of the osteoporosis acid-ash diet hypothesis

Tanis R Fenton , Andrew W Lyon , Michael Eliasziw , Suzanne C Tough and David A Hanley


Background
The acid-ash hypothesis posits that increased excretion of "acidic" ions derived from the diet, such as phosphate, contributes to net acidic ion excretion, urine calcium excretion, demineralization of bone, and osteoporosis. The public is advised by various media to follow an alkaline diet to lower their acidic ion intakes. The objectives of this meta-analysis were to quantify the contribution of phosphate to bone loss in healthy adult subjects; specifically, a) to assess the effect of supplemental dietary phosphate on urine calcium, calcium balance, and markers of bone metabolism; and to assess whether these affects are altered by the b) level of calcium intake, c) the degree of protonation of the phosphate.

Methods
Literature was identified through computerized searches regarding phosphate with surrogate and/or direct markers of osteoporosis. Studies were assessed for methodological quality. Multiple linear regression analyses, weighted for sample size, were used to combine the study results. Tests of interaction included stratification by calcium intake and degree of protonation of the phosphate supplement.

Results
Twelve studies including 30 intervention arms manipulated 269 subjects' phosphate intakes. Three studies reported net acid excretion. All of the meta-analyses demonstrated significant decreases in urine calcium excretion in response to phosphate supplements whether the calcium intake was high or low, regardless of the degree of protonation of the phosphate supplement. None of the meta-analyses revealed lower calcium balance in response to increased phosphate intakes, whether the calcium intake was high or low, or the composition of the phosphate supplement.

Conclusions
All of the findings from this meta-analysis were contrary to the acid ash hypothesis. Higher phosphate intakes were associated with decreased urine calcium and increased calcium retention. This meta-analysis did not find evidence that phosphate intake contributes to demineralization of bone or to bone calcium excretion in the urine. Dietary advice that dairy products, meats, and grains are detrimental to bone health due to "acidic" phosphate content needs reassessment. There is no evidence that higher phosphate intakes are detrimental to bone health.