Milk supplementation facilitates appetite control in obese women during weight loss: a randomised, single-blind, placebo-controlled trial. Br J Nutr. 2011;105:133-143. [PMID: 21205360 DOI: 10.1017/S0007114510003119]

Alternative biological functions of lactose: a narrative review

Lactose, commonly known as "milk sugar," offers various health benefits beyond its role as an energy source. As a precursor for essential molecules, lactose impacts calcium absorption, has low cariogenicity, affects satiety, enhances athletic performance, and potentially functions as a prebiotic for gut health. However, not all individuals can digest lactose, with a minority of the population exhibiting gastrointestinal symptoms after its consumption. The ability to digest lactose during adulthood is a genetically conferred trait known as lactase persistence, which is also likely affected by epigenetic alterations and other endogenous factors. In the present review, we highlight the multifaceted health effects of lactose, including its impact on calcium absorption, its low cariogenicity, its role in satiety control, its ability to enhance athletic performance, and its potential benefits as a prebiotic for gut health. Since these benefits are inherently dependent on lactose intake trends and the digestion capacity of populations, we also present the latest available information on the current trends in lactose consumption around the world. Overall, the gathered evidence suggests that moderate lactose consumption is recommended, as it can foster multiple lifelong health benefits.

Calcium supplementation for people with overweight or obesity

BACKGROUND

Obesity is a major health problem worldwide as it can lead to high blood pressure, heart disease, stroke, diabetes, and insulin resistance. The prevalence of overweight and obesity is increasing worldwide across different age groups. There is evidence of an inverse relationship between calcium intake and body weight. The clinical relevance of a small reduction in body weight has been questioned. However, at a population level, a small effect could mitigate the observed global trends.

OBJECTIVES

To assess the effects of calcium supplementation on weight loss in individuals living with overweight or obesity.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS (Latin American and Caribbean Health Science Information database), and two clinical trials registries. The date of the last search of all databases (except Embase) was 10 May 2023. No language restrictions were applied.

SELECTION CRITERIA

We included randomised controlled trials evaluating the effect of calcium in participants with overweight or obesity of any age or gender. We excluded studies in participants with absorption problems. We included studies of any dose with a minimum duration of two months. We included the following comparisons: calcium supplementation versus placebo, calcium-fortified food or beverage versus placebo, or calcium-fortified food or beverage versus non-calcium-fortified food or beverage. We excluded studies that evaluated the effect of calcium and vitamin D or mixed minerals compared to placebo.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our primary outcomes were body weight, health-related quality of life, and adverse events. Our secondary outcomes were anthropometric measures other than body weight, all-cause mortality, and morbidity.

MAIN RESULTS

We found 18 studies that evaluated the effect of calcium compared to placebo or control, with a total of 1873 randomised participants (950 participants in the calcium supplementation groups and 923 in the control groups). All included studies gave oral calcium supplementation as the intervention. We did not find any studies evaluating calcium-fortified foods. We excluded 38 studies, identified four ongoing studies, and listed one study as 'awaiting classification'. Sixteen studies compared calcium supplementation to placebo; two studies compared different doses of calcium supplementation. Doses ranged from very low (0.162 g of calcium/day) to high (1.5 g of calcium/day). Most studies were performed in the USA and Iran, lasted less than six months, and included only women. Low-certainty evidence suggests that calcium supplementation compared to placebo or control may result in little to no difference in body weight (mean difference (MD) -0.15 kg, 95% confidence interval (CI) -0.55 to 0.24; P = 0.45, I2 = 46%; 17 studies, 1317 participants; low-certainty evidence). We downgraded the certainty of the evidence by two levels for risk of bias and heterogeneity. None of the included studies reported health-related quality of life, all-cause mortality, or morbidity/complications as outcomes. Only five studies assessed or reported adverse events. Low-certainty evidence suggests a low frequency of adverse events, with no clear difference between intervention and control groups. Moderate-certainty evidence shows that calcium supplementation compared to placebo or control probably results in a small reduction in body mass index (BMI) (MD -0.18 kg/m2,95% CI -0.22 to -0.13; P < 0.001, I2 = 0%; 9 studies, 731 participants) and waist circumference (MD -0.51 cm, 95% CI -0.72 to -0.29; P < 0.001, I2 = 0%; 6 studies, 273 participants). Low-certainty evidence suggests that calcium supplementation compared to placebo or control may result in a small reduction in body fat mass (MD -0.34 kg, 95% CI -0.73 to 0.05; P < 0.001, I2 = 97%; 12 studies, 812 participants).

AUTHORS' CONCLUSIONS

Calcium supplementation for eight weeks to 24 months may result in little to no difference in body weight in people with overweight or obesity. The current evidence is of low certainty, due to concerns regarding risk of bias and statistical heterogeneity. We found that the degree of heterogeneity might be partly explained by calcium dosage, the presence or absence of a co-intervention, and whether an intention-to-treat analysis was pursued. While our analyses suggest that calcium supplementation may result in a small reduction in BMI, waist circumference, and fat mass, this evidence is of low to moderate certainty. Future studies could investigate the effect of calcium supplementation on lean body mass to explore if there is a change in body composition.

The Role of Bovine and Non-Bovine Milk in Cardiometabolic Health: Should We Raise the "Baa"?

Although causality is yet to be confirmed, a considerable volume of research has explored the relationships between cow milk consumption, type II diabetes, and cardiovascular disease. Contrastingly, it has not been comprehensively examined whether milk of non-bovine origin can provide cardiometabolic protection. This narrative review outlines the marked differences in macronutrient composition, particularly protein and lipid content, and discusses how whole milk product (and individual milk ingredients) from different species could impact cardiometabolic health. There is some data, although primarily from compositional analyses, animal studies, and acute clinical trials, that non-bovine milk (notably sheep and goat milk) could be a viable substitute to cow milk for the maintenance, or enhancement, of cardiometabolic health. With a high content of medium-chain triglycerides, conjugated linoleic acid, leucine, and essential minerals, sheep milk could assist in the prevention of metabolic-related disorders. Similarly, albeit with a lower content of such functional compounds relative to sheep milk, goat and buffalo milk could be plausible counterparts to cow milk. However, the evidence required to generate nutritional recommendations for ‘non-bovine milk’ is currently lacking. Longer-term randomised controlled trials must assess how the bioactive ingredients of different species’ milks collectively influence biomarkers of, and subsequently incidence of, cardiometabolic health.

Comparison of the Effect of Milk and Pistachio Snacks on Anthropometric Indices in Overweight or Obese Women: A Randomized Crossover Trial

Background

Weight management is the key to prevent and treat the adverse consequences of overweight and obesity. The aim of this study was to compare the effect of consuming milk and pistachio snacks on anthropometric indices in overweight or obese women.

Methods

In this randomized crossover trial, 60 overweight or obese women with a mean age of 24 ± 4.2 years were randomly divided into two groups. Women in the milk group received 200 mL/day low-fat milk while women in the other group received 30 g/day pistachio for 4 weeks. After a 6-day washout period, the participants received a similar intervention in a crossover manner.

Results

Out of the total 60 participants, 52 completed the study. At the end of the study, the weight of women in the milk group significantly decreased (70.8 ± 8.4 vs. 69.9 ± 8.3, P value = 0.001). No statistically significant changes were observed in the weight of participants in the pistachio group (70.3 ± 8.4 vs. 70.6 ± 8.3, P value = 0.06). Further analyses showed a slightly significant beneficial effect on waist circumference (WC) (P-value =0.068) and body mass index (BMI) in the milk group P value = 0.01).

Conclusions

Based on the observed positive effects of milk intake on weight loss in this crossover study, milk consumption may be considered an appropriate snack in weight loss programs in overweight or obese women.

Effects of 12-week, non-energy-restricted dietary intervention with conventional yogurt οn appetite hormone responses of type 2 diabetic patients

Hunger-reducing effects and beneficial changes in gastrointestinal hormones have been reported, in overweight/obese individuals consuming dairy while yogurt takes pride of place due to its unique structure and composition. Although the contribution of yogurt to metabolic regulation has received growing attention, the research studies which examine its role on appetite are limited, especially regarding type 2 diabetes mellitus (T2DM) patients. The aim of the present study was to investigate the effects of non-fat, conventional yogurt consumption on appetite hormone responses of T2DM patients following a non-energy-restricted diet. Overweight subjects participated in a 12-week dietary intervention including 2 meals/day (2 × 200 g) of yogurt. At the beginning and the end of the intervention, a mixed meal tolerance test assessing the postprandial response of glucose, insulin, ghrelin, glucagon-like peptide-1 (GLP-1), and peptide-YY (PYY) was performed. Subjective appetite ratings were also evaluated. Area under the curve for glucose, insulin, ghrelin, GLP-1, and PYY responses did not differ after the 12-week intervention with yogurt (p > .05) as well as for subjective appetite ratings (p > .05). No significant differences were indicated at specific time points in any of the examined parameters. Regular consumption of non-fat, conventional yogurt for 12-week duration does not affect appetite hormone responses in overweight patients with T2DM following a non-energy-restricted diet.

Protein- and Calcium-Mediated GLP-1 Secretion: A Narrative Review

Glucagon-like peptide 1 (GLP-1) is an incretin hormone produced in the intestine that is secreted in response to nutrient exposure. GLP-1 potentiates glucose-dependent insulin secretion from the pancreatic β cells and promotes satiety. These important actions on glucose metabolism and appetite have led to widespread interest in GLP-1 receptor agonism. Typically, this involves pharmacological GLP-1 mimetics or targeted inhibition of dipeptidyl peptidase-IV, the enzyme responsible for GLP-1 degradation. However, nutritional strategies provide a widely available, cost-effective alternative to pharmacological strategies for enhancing hormone release. Recent advances in nutritional research have implicated the combined ingestion of protein and calcium with enhanced endogenous GLP-1 release, which is likely due to activation of receptors with high affinity and/or sensitivity for amino acids and calcium. Specifically targeting these receptors could enhance gut hormone secretion, thus providing a new therapeutic option. This narrative review provides an overview of the latest research on protein- and calcium-mediated GLP-1 release with an emphasis on human data, and a perspective on potential mechanisms that link potent GLP-1 release to the co-ingestion of protein and calcium. In light of these recent findings, potential future research directions are also presented.

Postprandial glycaemic dips predict appetite and energy intake in healthy individuals

Understanding how to modulate appetite in humans is key to developing successful weight loss interventions. Here, we showed that postprandial glucose dips 2-3 h after a meal are a better predictor of postprandial self-reported hunger and subsequent energy intake than peak glucose at 0-2 h and glucose incremental area under the blood glucose curve at 0-2 h. We explore the links among postprandial glucose, appetite and subsequent energy intake in 1,070 participants from a UK exploratory and US validation cohort, who consumed 8,624 standardized meals followed by 71,715 ad libitum meals, using continuous glucose monitors to record postprandial glycaemia. For participants eating each of the standardized meals, the average postprandial glucose dip at 2-3 h relative to baseline level predicted an increase in hunger at 2-3 h (r = 0.16, P < 0.001), shorter time until next meal (r = -0.14, P < 0.001), greater energy intake at 3-4 h (r = 0.19, P < 0.001) and greater energy intake at 24 h (r = 0.27, P < 0.001). Results were directionally consistent in the US validation cohort. These data provide a quantitative assessment of the relevance of postprandial glycaemia in appetite and energy intake modulation.

Meta-analysis of randomized controlled trials on calcium supplements and dairy products for changes in body weight and obesity indices

This meta-analysis was performed to investigate whether calcium supplements and dairy products change obesity indices including fat mass. Original articles published in English between July 2009 and August 2019 were identified. Ten and 14 randomised controlled trials (RCTs) with ≥ 12 weeks interventions of calcium supplements and dairy products among overweight or obese adults aged ≥18 were critically reviewed. Mean difference (MD) or standardised mean difference (SMD) with 95% confidence interval (CI) were obtained using a random effect meta-analysis. Dairy products significantly changed fat mass (SMD, 95% CI; -0.40 [-0.77, -0.02]) and BMI (MD, 95% CI: -0.46 kg/m2 [-0.67, -0.26]), and calcium supplements also showed changes in fat mass (SMD, 95% CI; -0.15[-0.28, -0.02]). However, in the analysis of RCTs with low risk of bias scores, the significant changes remained only in the dairy-products intervention. Our findings suggest that dairy products without distinction of fat percentage may help reduce fat mass and BMI, but calcium supplements may not.

Increased dairy product consumption as part of a diet and exercise weight management program improves body composition in adolescent females with overweight and obesity-A randomized controlled trial

BACKGROUND

Exercise can improve body composition in adolescents and adults with overweight/obesity. Consumption of dairy foods, as part of a healthy lifestyle program, can also promote favourable body composition changes in adults with overweight/obesity. However, the few studies examining these combined effects on body composition in adolescents are inconclusive.

OBJECTIVE

To determine whether increased dairy product consumption, as part of a lifestyle modification program featuring exercise training and dietary guidance promotes favourable body composition changes in adolescent females with overweight/obesity.

METHODS

Fifty-four participants (age: 14.8 ± 2.2y; BMI percentile: 95th ± 6) assigned to three groups completed the study. There were two experimental groups: recommended dairy (RDa; n = 24) and low dairy (LDa; n = 22), and a no-intervention control group (Con; n = 8). RDa and LDa participated in a 12-week, eucaloric, lifestyle modification intervention consisting of mixed-mode exercise (3x/week), and nutritional counselling. RDa was provided 4 servings/day of dairy foods, while LDa and Con maintained habitually low intakes (0-2 servings/day). Body weight/composition, waist/hip circumference, cardiovascular fitness and food intake were assessed at weeks 0 and 12.

RESULTS

Weight did not significantly change in any group. RDa significantly decreased fat mass (FM) and increased lean mass (LM) more than LDa and Con (FM: -1.3 ± 2.1 kg, -1.1 ± 2.0 kg, 0.8 ± 1.8 kg; LM: 1.5 ± 1.9 kg, 0.7 ± 1.6 kg, 0.5 ± 1.4 kg, respectively). LDa also significantly decreased FM and increased LM more than Con (P < .005; all interactions).

CONCLUSION

The inclusion of dairy foods in the diet of adolescent females with overweight/obesity, as part of a diet and exercise intervention, favourably improves body composition in the absence of weight loss.

Weight Loss, but Not Dairy Composition of Diet, Moderately Affects Satiety and Postprandial Gut Hormone Patterns in Adults

BACKGROUND

Inclusion of dairy in diet patterns has been shown to have mixed effects on weight loss. A prevailing hypothesis is that dairy improves weight loss by influencing endocrine systems associated with satiety and food intake regulation.

OBJECTIVES

The objective of the current study was to evaluate the effect of weight loss with or without adequate dietary dairy on subjective and objective appetitive measures.

METHODS

Men and women who were habitual low dairy consumers (n = 65, 20-50 y) participated in a 12-wk randomized controlled feeding weight loss trial. During the 12-wk intervention, a low-dairy (<1 serving dairy/d) was compared with an adequate-dairy (3-4 servings dairy/d) diet, both with a 500-kcal deficit/d. Test days, before and at the end of the intervention, began with 2 fasting blood draws and visual analog scale (VAS) measures, followed by a standard breakfast (25% of prescribed restricted calories), 5 postbreakfast blood draws and VASs, a standard lunch (40% of restricted energy amount), and 12 postlunch blood draws and VASs. Blood samples were used for satiety hormone measurements. On a separate day when matching standard meals were consumed, an ad libitum buffet meal was provided as dinner, at a self-selected time. Meal duration and intermeal interval were recorded.

RESULTS

Weight loss (-6.1 kg), irrespective of dairy, resulted in reduced fasting insulin (-20%) and leptin (-25%), and increased fasting acylated ghrelin (+25%) and VAS desire to eat (+18%) (P < 0.05). There were no effects of dairy on objective or subjective satiety measures. Weight loss marginally reduced the intermeal interval (289 min compared with 276 min, P = 0.059) between lunch and the ad libitum buffet.

CONCLUSIONS

These results do not support the hypothesis that inclusion of dairy in long-term dietary patterns influences appetite during weight loss. Weight loss per se has a modest impact on select systems that regulate hunger and satiety.This trial was registered at clinicaltrials.gov as NCT00858312.

Substitution among milk and yogurt products and the risk of incident type 2 diabetes in the EPIC-NL cohort

Background

Higher dairy consumption has been associated with lower type 2 diabetes (T2D) risk, whereas dairy product subtypes appear to differ in their T2D risk association. We investigated whether replacing one type of milk or yogurt product with another is associated with T2D incidence.

Methods

Participants of the European Prospective Investigation into Cancer and Nutrition‐Netherlands (EPIC‐NL) cohort (n = 35 982) were included in the present study. Information on milk and yogurt consumption at baseline was obtained by a validated food frequency questionnaire. T2D cases were identified by self‐report or linkage to the hospital discharge registry, and validated by consulting the general practitioner. Multivariable Cox proportional hazard models were used to estimate associations.

Results

During a mean of 15 years of follow‐up, 1467 indecent T2D cases were validated. Median total milk and yogurt intake was 1.5 servings (25th percentile to 75th percentile: 0.8–2.4). After adjustment for demographic and cardiovascular risk factors, replacement of one serving (200 g) of whole‐fat milk [hazard ratio (HR) = 0.93, 95% confidence interval (CI) = 0.60–1.44], buttermilk (HR = 0.88, 95% CI = 0.58‐1.34), skimmed milk (HR = 0.87, 95% CI = 0.57–1.32) or skimmed fermented milk (HR = 0.99, 95% CI = 0.63–1.54) with whole‐fat yogurt was not associated with T2D risk. Substitutions among other milk and yogurt products were also not associated with T2D risk. Sensitivity analysis investigating T2D risk halfway follow‐up suggested a lower risk for substitutions with whole‐fat yogurt.

Conclusions

No evidence was found for the association between substitutions among milk and yogurt products and the risk of incident T2D, although we cannot exclude possible attenuation of results as a result of dietary changes over time. This analysis should be repeated in a population with a wider consumption range of whole‐fat yogurt.

Overweight & obese Australian adults and micronutrient deficiency

Background

Micronutrients have been implicated as an important factor in regulating various metabolic processes and thus playing a role in the aetiology of obesity. Many studies have been conducted worldwide that clearly show a direct link between obesity and micronutrient deficiencies. The aim of this study was to assess the nutritional status of overweight and obese Australian adults to see if there were any associations between BMI and serum micronutrient levels.

Methods

Baseline serum micronutrient data of overweight and obese individuals with a body mass index (BMI) between 25 and 40 kg/m² and aged between 18 and 65 years was compared to the clinical micronutrient reference ranges for associations between BMI and micronutrient status.

Results

There were significant negative associations between BMI and serum vitamin D (p = 0.044), folate (p = 0.025), magnesium (p = 0.010) and potassium (p = 0.023).

Conclusions

Overweight and obesity appears to impact on the bioavailability and utilisation of micronutrients with absorption, excretion, storage/distribution (fat sequestering, tissue dispersion), metabolism (catabolic losses, possibly oxidative), increased physiologic requirements, and lower absolute total dietary intake being the current theory for observed differences. While vitamins D, folate, magnesium and potassium showed a negative relationship to BMI, other micronutrients did not. This may be explained by the fortification of certain processed foods, or the possibility of overweight and obese people eating more to satisfy their nutritional requirements.

The Impact of Dairy Products in the Development of Type 2 Diabetes: Where Does the Evidence Stand in 2019?

The prevalence of type 2 diabetes (T2D) has increased rapidly. Adopting a heathy diet is suggested as one of the effective behaviors to prevent or delay onset of T2D. Dairy consumption has been recommended as part of a healthy diet, but there remains uncertainty in both the scientific community and the public about the effect of different dairy products on T2D risk. In a recent workshop, the evidence on dairy products and T2D risk was presented and discussed by a group of experts. The main conclusions from the workshop are presented in this position paper and are as follows. 1) Available evidence from large prospective cohort studies and limited randomized controlled trials (RCTs) suggests that total dairy consumption has a neutral or moderately beneficial effect on T2D risk. 2) Increasing evidence from prospective cohort studies indicates that yogurt is most strongly associated with a lower T2D risk, but evidence from RCTs is scarce. 3) Fatty acids from dairy (medium-chain, odd, and very long-chain SFAs as well as trans-palmitoleic acid) are associated with lower T2D risk and improved metabolic health, but more research is needed on studies that explore cause and effect relations to exclude the possibility that the dairy fatty acids simply serve as markers of overall dairy consumption. 4) The food matrix can be a stronger determinant of health effects than SFA content. This review further identifies research gaps in the existing knowledge and highlights key research questions that need to be addressed to better understand the impact of dairy consumption on future T2D risk.

Association between Dietary Calcium Intake and Adiposity in Male Adolescents

The aim was to investigate the possible association of dietary calcium intake with adiposity, insulin resistance, and adipocytokine values in adolescent boys. In this cross-sectional study, participants were 123 adolescent boys aged 13–15 years, who were divided into tertiles according to their dietary calcium intake. Dietary calcium intake was assessed using three 24 h dietary recalls. In addition, energy intake, body composition, physical activity (PA), and blood biochemical values were also measured. Mean body fat%, fat mass (FM), trunk FM, trunk fat%, and leptin differed between high and low tertiles of calcium intake after adjustment for age, pubertal stage, and PA. For the entire cohort, mean calcium intake was 786 ± 380 mg/day and was related to body mass index (BMI), FM, and trunk fat% but not to insulin resistance or adipocytokine values after adjusting for possible confounders. In addition, only 15.4% of the participants obtained or exceeded their mean dietary calcium intake requirements. These subjects who met their dietary calcium intake had significantly lower body fat% in comparison with subjects not meeting their dietary calcium intake. Odds ratio of being in the highest tertile of FM, trunk FM, and trunk fat% was 3.2–4.4 (95% confidence interval 1.19–12.47; p < 0.05) times higher for boys in low calcium intake tertile, compared to those boys in high calcium intake tertile. In conclusion, dietary calcium intake is inversely associated with total body and abdominal adiposity values in a specific group of healthy male adolescents with different body mass values.

Increased Dairy Product Intake Modifies Plasma Glucose Concentrations and Glycated Hemoglobin: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Dairy product intake is inversely associated with the risk of type 2 diabetes (T2D) in numerous cohort studies; yet, the beneficial effects of increased dairy product intake on T2D risk factors such as fasting plasma glucose, fasting insulin, insulin resistance with the homeostasis model assessment, and glycated hemoglobin (HbA1c) remain inconclusive in clinical trials. The objective of this study was to systematically review clinical trials observing the effects of elevated compared with minimal intake of dairy products on T2D risk factors in subjects without diabetes. Five databases [Medline, EMBASE, Central, CINAHL, AMED (Allied and Complementary Medicine)] were searched to identify randomized controlled trials that used elevated quantities of dairy products from ruminant sources in comparison with a lower intake in control groups. The review outcomes were fasting blood glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and HbA1c. Risk of bias and quality of evidence according to Grading of Recommendations Assessment, Development, and Evaluation were addressed. From the 10,627 citations screened, 44 studies (3016 participants) were included, 38 of which were used in the meta-analyses. Fasting glucose was positively associated with elevated dairy intake [34 studies, n = 2678; mean difference (MD): 0.07 mmol/L; 95% CI: 0.01, 0.12 mmol/L; P = 0.01, I2 = 23%]. Fasting insulin (29 studies, n = 1902; MD: -2.97 pmol/L; 95% CI: -7.05, 1.10 pmol/L; P = 0.15, I2 = 21%) and HOMA-IR (13 studies, n = 840; standardized MD: -0.07; 95% CI: -0.26, 0.12; P = 0.49, I2 = 38%) were not associated with elevated dairy consumption. HbA1c was negatively associated with elevated dairy product intake in 4 studies (n = 512; MD: -0.09%; 95% CI: -0.09%, -0.03%; P = 0.005, I2 = 0%). Most studies had high risk of bias and the quality of evidence was very low or low. In conclusion, evidence suggests that elevated dairy product intake is associated with increased fasting plasma glucose concentrations together with reduced HbA1c in nondiabetic subjects. Hence, the clinical significance of these results remains uncertain. Additional well-designed, long-term studies are required.

Effects of Dairy Products Consumption on Body Weight and Body Composition Among Adults: An Updated Meta-Analysis of 37 Randomized Control Trials

SCOPE

Effects of dairy consumption on body weight and body composition have been inconsistently observed in randomized control trials (RCTs). Our meta-analysis aims to systematically evaluate the effects of dairy consumption on body weight and body composition among the adults.

METHODS AND RESULTS

We conducted a comprehensive search of the Cochrane Library, PubMed, and Embase databases of the relevant studies from 1966 to Mar 2017 regarding dairy consumption on body weight and body composition including body fat, lean mass, and waist circumference (WC). The summary results are pooled by using a random-effects meta-analysis. Thirty-seven RCTs with 184 802 participants are included in this meta-analysis. High dairy intervention increased body weight (0.01, 95% CI: -0.25, 0.26, I² = 78.3%) and lean mass (0.37, 95% CI: 0.11, 0.62, I² = 83.4%); decreased body fat (-0.23, 95% CI: -0.48, 0.02, I² = 78.2%) and WC (-1.37, 95% CI: -2.28, -0.46, I² = 98.9%) overall. In the subgroup analysis, we found that consumption of dairy products increases body weight (0.36, 95% CI: 0.01, 0.70, I² = 83.1%) among participants without energy restriction. Dairy consumption decreases body weight (-0.64, 95% CI: -1.05, -0.24, I² = 60.2%), body fat (-0.56, 95%CI: -0.95, -0.17, I² = 66.6%), and waist circumference (-2.18, 95%CI: -4.30, -0.06, I² = 99.0%) among the adults with energy restriction.

CONCLUSIONS

This meta-analysis suggests a beneficial effect of energy-restricted dairy consumption on body weight and body composition. However, high dairy consumption in the absence of caloric restriction may increase body weight.

Impact of a non-restrictive satiating diet on anthropometrics, satiety responsiveness and eating behaviour traits in obese men displaying a high or a low satiety phenotype

The aim of this study was to evaluate the impact of a non-restrictive satiating diet in men displaying various degrees of satiety efficiency. In all, sixty-nine obese men aged 41·5 (sd5·7) years were randomly assigned to a control (10–15, 55–60 and 30 % energy as protein, carbohydrate and lipid, respectively;n34) or satiating (20–25, 45–50 and 30–35 % energy as protein, carbohydrate and lipid, respectively;n35) diet for 16 weeks, and were classified as having a low (LSP) or high (HSP) satiety phenotype. Both diets were consumedad libitum. Changes in body weight, BMI, percent fat mass, waist circumference, satiety responsiveness and eating behaviour traits were assessed following the intervention. Dropout rates were higher in the control diet (44·1 %) compared with the satiating diet (8·6 %). Decreases in body weight, BMI and waist circumference were significant in both groups, yet HSP individuals lost more body weight than LSP individuals (P=0·048). Decreases in % fat mass were greater in the satiating diet (LSP: −2·1 (sd2·1) %;P<0·01 and HSP: −3·0 (sd2·5) %;P<0·001) compared with the control diet (LSP: −1·1 (sd2·5) % and HSP: −1·3 (sd2·6) %) (P=0·034). Satiety responsiveness was markedly improved in the satiating diet, whereas no significant changes were observed in the control group. Changes in dietary restraint (+3·3 (sd2·9) to +7·2 (sd5·5)), flexible control (+0·9 (sd1·4) to +2·3 (sd2·7)), rigid control (+2·2 (sd1·5) to +2·5 (sd2·8)), disinhibition (−2·8 (sd3·7) to −3·2 (sd2·6)) and susceptibility to hunger (−2·7 (sd4·1) to −4·6 (sd3·9)) were similar between the diets. Compared with the control diet, the satiating diet favoured adherence, decreased % fat mass and improved satiety responsiveness in both HSP and LSP individuals.

Weight Loss and Appetite Control in Women

PURPOSE OF REVIEW

The aim of this review is to describe and discuss weight loss-induced variations in appetite in women and factors responsible for these changes.

RECENT FINDINGS

Studies have shown postweight loss increases in fasting and postprandial appetite in individuals engaged in weight loss trials, especially in women. Similarly, appetite-related peptides associated to the homeostatic control of feeding, such as leptin, ghrelin and peptide YY, were also found to be altered in way that promotes increased appetite after weight loss interventions. Sustained caloric deficits also drive increases in the frequency and strength of food cravings, food reward and seem to enhance oro-sensory sensations in women who lost weight. The menstrual cycle has also been to shown to influence caloric intake in women, more specifically food cravings. On the other hand, caloric restriction seems to increase cognitive restraint, decrease habitual disinhibition and susceptibility to hunger among women engaged in weight loss trials. Neural analysis corroborates these results, showing increased activation in brain areas involved in food reward and self-control processing. In conclusion, evidence supports that weight loss increases appetite sensations, and promotes changes in homeostatic and non-homeostatic control of feeding, which collectively seem to upregulate appetite in women.

Effects of calcium supplementation on body weight: a meta-analysis

BACKGROUND

Whether calcium supplementation can reduce body weight and prevent obesity remains unclear because of inconsistent reports.

OBJECTIVE

We performed a meta-analysis to investigate the correlations between calcium supplementation and changes in body weight on the basis of age, sex, body mass index (BMI) of the subjects, and length of calcium intervention.

DESIGN

PubMed, EMBASE, Web of Knowledge, and China National Knowledge Infrastructure databases were systematically searched to select relevant studies that were published from January 1994 to March 2016. Both randomized controlled trials and longitudinal studies of calcium supplementation were included, and random- or fixed-effects models in a software program were used for the data analysis.

RESULTS

Thirty-three studies involving a total of 4733 participants were included in this meta-analysis. No significant differences in weight changes were shown between calcium intervention and control groups (mean: -0.01 kg; 95% CI -0.02, 0.00 kg; P = 0.12). However, negative correlations between calcium supplementation and weight changes were shown in children and adolescents (mean: -0.26 kg; 95% CI: -0.41, -0.11 kg; P < 0.001) and in adult men and either premenopausal or old (>60 y of age) women (mean: -0.91 kg; 95% CI: -1.38, -0.44 kg; P < 0.001) but not in postmenopausal women (mean: -0.14 kg; 95% CI: -0.54, 0.26 kg; P = 0.50). When BMI was considered, a negative correlation between calcium supplementation and weight changes was observed in subjects with normal BMI (mean: -0.53 kg; 95% CI: -0.89, -0.16 kg; P = 0.005) but not in overweight or obese subjects (mean: -0.35 kg; 95% CI: -0.81, 0.11 kg; P = 0.14). Compared with the control groups, no differences in weight changes were shown in the calcium-intervention groups when the lengths of calcium interventions were <6 mo (mean: -0.09 kg; 95% CI: -0.45, 0.26 kg; P = 0.60) or ≥6 mo (mean: -0.01 kg; 95% CI: -0.02, 0.01 kg; P = 0.46).

CONCLUSION

Increasing calcium intake through calcium supplements can reduce body weight in subjects who have a normal BMI or in children and adolescents, adult men, or premenopausal women.

Dairy Intake Enhances Body Weight and Composition Changes during Energy Restriction in 18-50-Year-Old Adults-A Meta-Analysis of Randomized Controlled Trials

Background/Aims: A meta-analysis of randomized controlled trials (RCTs) was performed to investigate the effects of dairy food or supplements during energy restriction on body weight and composition in 18–50-year-old. Methods: RCTs ≥ 4 weeks comparing the effect of dairy consumption (whole food or supplements) with control diets lower in dairy during energy restriction on body weight, fat and lean mass were identified by searching MEDLINE, EMBASE, Pubmed, Cochrane Central and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) until March 2016. Reports were identified and critically appraised in duplicate. Data were pooled using random-effects meta-analysis. Chi²- and I²-statistics indicated heterogeneity. Dose effect was assessed using meta-regression analysis. GRADE guidelines were used to rate the quality (QR) of the evidence considering risk of bias, inconsistency, indirectness, imprecision, publication bias and effect estimates. Results: 27 RCTs were reviewed. Participants consumed between 2 and 4 standard servings/day of dairy food or 20–84 g/day of whey protein compared to low dairy control diets, over a median of 16 weeks. A greater reduction in body weight (−1.16 kg [−1.66, −0.66 kg], p < 0.001, I² = 11%, QR = high, n = 644) and body fat mass (−1.49 kg [−2.06, −0.92 kg], p < 0.001, I² = 21%, n = 521, QR = high) were found in studies largely including women (90% women). These effects were absent in studies that imposed resistance training (QR = low-moderate). Dairy intake resulted in smaller loss of lean mass (all trials pooled: 0.36 kg [0.01, 0.71 kg], p = 0.04, I² = 64%, n = 651, QR = moderate). No between study dose-response effects were seen. Conclusions: Increased dairy intake as part of energy restricted diets resulted in greater loss in bodyweight and fat mass while attenuating lean mass loss in 18–50-year-old adults. Further research in males is needed to investigate sex effects.

Calcium and Vitamin D in Obesity and Related Chronic Disease

There is a pandemic of lifestyle-related diseases. In both developed and lesser developed countries of the world, an inadequacy of calcium intake and low vitamin D status is common. In this chapter, we explore a mechanistic framework that links calcium and vitamin D status to chronic conditions including obesity, systemic inflammation, endothelial dysfunction, dyslipidemia and cardiovascular disease, and type 2 diabetes mellitus. We also update the available clinical evidence, mainly from randomized controlled trials, to provide a synthesis of evidence in favor or against these hypotheses. There is consistent data to support calcium increasing whole body fat oxidation and increasing fecal fat excretion, while there is good cellular evidence for vitamin D reducing inflammation. Clinical trials support a marginal reduction in circulating lipids and some meta-analysis support an increase in insulin sensitivity following vitamin D. However, these mechanistic pathways and intermediate biomarkers of disease do not consistently transcribe into measurable health outcomes. Cementing the benefits of calcium and vitamin D for extraskeletal health needs a reexamination of the target 25(OH)D level to be achieved and the minimum duration of future trials.

Mechanisms of calcium intake in lowering serum cholesterol levels

Cardiovascular diseases (CVDs), a group of disorders of the heart and blood vessels, are the leading cause of death globally. An estimated 17.1 million people die of CVDs each year, more than 40% of whom die from coronary heart disease (CHD). Hypercholesterolemia is a major risk factor for increasing CHD morbidity and mortality, and serum cholesterol level is a key predictor of CHD development. A number of studies have demonstrated that calcium supplement can lower serum cholesterol levels, which means that calcium might play an important role in preventing the development of CVDs, especially CHD. In this paper, the mechanisms of calcium intake in lowering serum cholesterol levels are summarized, including increasing the excretion of bile acids, interfering with cholesterol absorption, inhibiting the absorption of saturated fatty acids, promoting energy metabolism, regulating plasma 1,25(OH)₂D levels, affecting blood insulin sensibility and controlling appetite.

Late-Pregnancy Salivary Cortisol Concentrations of Ghanaian Women Participating in a Randomized Controlled Trial of Prenatal Lipid-Based Nutrient Supplements

BACKGROUND

High circulating cortisol is associated with miscarriage, preterm birth, and low birth weight. Research in nonpregnant individuals suggests that improved nutrition may lower cortisol concentrations. It is unknown whether nutritional supplementation during pregnancy lowers cortisol.

OBJECTIVE

Our objective was to determine whether women receiving a lipid-based nutrient supplement (LNS) throughout pregnancy would have lower salivary cortisol at 36 wk gestation compared with women receiving other nutrient supplements.

METHODS

We conducted a randomized controlled trial in 1320 pregnant Ghanaian women at ≤20 wk gestation who were assigned to receive daily throughout pregnancy: 1) 60 mg iron + 400 μg folic acid (IFA), 2) multiple micronutrients (MMNs), or 3) 20 g LNS (containing 118 kcal, 22 micronutrients, and protein). Morning salivary cortisol was collected from a subsample at baseline and at 28 and 36 wk gestation.

RESULTS

A total of 758 women had cortisol measurements at 28 or 36 wk gestation. Salivary cortisol at 36 wk gestation did not differ between groups and was (mean ± SE) 7.97 ± 0.199 in the IFA group, 7.84 ± 0.191 in the MMN group, and 7.77 ± 0.199 nmol/L in the LNS group, when adjusted for baseline cortisol, time of waking, and time between waking and saliva collection (P = 0.67). There was an interaction between supplementation group and women's age (continuous variable, P-interaction = 0.03); and when age was dichotomized by the median, significant differences in salivary cortisol concentrations between groups were seen in women ≤26 y of age (IFA = 8.23 ± 0.284 nmol/L, MMN = 8.20 ± 0.274 nmol/L, and LNS = 7.44 ± 0.284 nmol/L; P = 0.03) but not in women >26 y old (IFA = 7.71 ± 0.281 nmol/L, MMN = 7.50 ± 0.274 nmol/L, and LNS = 8.08 ± 0.281 nmol/L; P = 0.13).

CONCLUSIONS

We conclude that supplementation with LNSs or MMNs during pregnancy did not affect the cortisol concentration in the study population as a whole, in comparison with IFA, but that LNS consumption among younger women may lead to lower cortisol at 36 wk gestation. This trial was registered at clinicaltrials.gov as NCT00970866.

Acute effects of protein composition and fibre enrichment of yogurt consumed as snacks on appetite sensations and subsequent ad libitum energy intake in healthy men

The objective of the study was to assess the impact of protein composition and/or fibre enrichment of yogurt on appetite sensations and subsequent energy intake. In this double-blind crossover study, 20 healthy men (aged 32.4 ± 9.1 years) were submitted to 5 randomized testing sessions, during which they had to consume 5 isocaloric and isonproteinemic yogurt snacks (120-g servings, ∼230 kJ, ∼4.5 g protein) differing by their casein-to-whey protein ratio (C:W) or dietary fibre content: (i) control C:W = 2.8:1; (ii) high whey (HW) C:W = 1.5:1, and fibre-enriched formulations using control; (iii) 2.4 g of inulin; (iv) 1.9 g of inulin and 0.5 g of β-glucan (+IN-βG); and (v) 0.5 g of β-glucan. Appetite sensations were assessed using 150-mm visual analog scales. Plasma variables (glucose, insulin, ghrelin) were measured at 30-min intervals post-yogurt consumption for 2 h. Finally, energy intakes during ad libitum lunches offered 2 h after yogurt snacks were recorded. None of the yogurts impacted appetite sensations. Ad libitum energy intake was significantly different only between HW and control yogurts (-812 kJ; p = 0.03). Regarding post-yogurt plasma variables, a significant difference was found only between ghrelin area under the curve of the +IN-βG and the HW yogurts (-15 510 pmol/L per 120 min, p = 0.04). In conclusion, although appetite sensations were not influenced by variations in yogurts' protein compositions, a reduced energy intake was observed during the ad libitum lunch after the HW yogurt that may be attributable to its lower C:W. Surprisingly, the fibre enrichments studied did not exert effect on appetite sensations and energy intake.

Effect of increasing dietary calcium through supplements and dairy food on body weight and body composition: a meta-analysis of randomised controlled trials

This meta-analysis of randomised controlled trials assessed the effect of Ca on body weight and body composition through supplementation or increasing dairy food intake. Forty-one studies met the inclusion criteria (including fifty-one trial arms; thirty-one with dairy foods (n 2091), twenty with Ca supplements (n 2711). Ca intake was approximately 900 mg/d higher in the supplement groups compared with control. In the dairy group, Ca intake was approximately 1300 mg/d. Ca supplementation did not significantly affect body weight (mean change ( - 0·17, 95% CI - 0·70, 0·37) kg) or body fat (mean change ( - 0·19, 95% CI - 0·51, 0·13) kg) compared to control. Similarly, increased dairy food intake did not affect body weight ( - 0·06, 95% CI - 0·54, 0·43) kg or body fat change ( - 0·36, 95% CI - 0·80, 0·09) kg compared to control. Sub-analyses revealed that dairy supplementation resulted in no change in body weight (nineteen studies, n 1010) ( - 0·32, 95% CI - 0·93, 0·30 kg, P= 0·31), but a greater reduction in body fat (thirteen studies, n 564) ( - 0·96, 95% CI - 1·46, - 0·46 kg, P < 0·001) in the presence of energy restriction over a mean of 4 months compared to control. Increasing dietary Ca intake by 900 mg/d as supplements or increasing dairy intake to approximately 3 servings daily (approximately 1300 mg of Ca/d) is not an effective weight reduction strategy in adults. There is, however, an indication that approximately 3 servings of dairy may facilitate fat loss on weight reduction diets in the short term.

Associations between yogurt, dairy, calcium, and vitamin D intake and obesity among U.S. children aged 8-18 years: NHANES, 2005-2008

The aim of this study was to investigate associations of yogurt and dairy consumption with energy, macronutrient, calcium, and vitamin D intakes, and associations with indicators of overweight/obesity in U.S. children in the National Health and Nutrition Examination Survey (NHANES 2005–2008). Using 24-hour recall data, children 8–18 years of age were classified to dairy consumption groups of <1, 1 to <2, or 2+ dairy servings, and yogurt consumers were those who reported eating yogurt during at least one of two dietary intake interviews. NHANES anthropometric measurements were used, and BMI and BMI-for-age percentiles were calculated. Yogurt and dairy consumption were associated with higher intakes of calcium, vitamin D and protein. Yogurt intake was associated with lower total fat and saturated fat intakes and body fat as measured by subscapular skinfold thickness. This study supports consumption of yogurt and higher amounts of dairy as eating patterns associated with greater intake of specific shortfall nutrients, and lower body fat in U.S. children.

Associations between dairy foods, diabetes, and metabolic health: potential mechanisms and future directions

Epidemiological evidence supports an inverse relationship between adequate intake of dairy foods and susceptibility to type 2 diabetes (T2D). The biological mechanisms responsible for this association remain to be established. This review provides a current perspective on proposed mechanisms that may underlie these effects, and highlights how randomized clinical trials can be applied to investigate these relationships. Results from epidemiological studies generally support that consumption of milk and dairy products is associated with a lower incidence of T2D or improvements in glucose homeostasis indices, and studies of animal and cell models support a positive effect of dairy-rich diets or components on metabolic and inflammation factors relevant to T2D and insulin resistance. Emerging evidence indicates that dairy components that alter mitochondrial function (e.g., leucine actions on silent information regulator transcript 1 (SIRT1)-associated pathways), promote gut microbial population shifts, or influence inflammation and cardiovascular function (e.g., Ca-regulated peptides calcitonin gene-related peptide [CGRP] or calcitonin) should be considered as possible mechanistic factors linking dairy intake with lower risk for T2D. The possibility that dairy-derived trans-palmitoleic acid (tC16:1) has metabolic bioactivities has also been proposed. Pre-clinical and clinical studies focusing specifically on these parameters are needed to validate hypotheses regarding the potential roles of dairy products and their components on the determinants of glucose tolerance, particularly insulin sensitivity, pancreatic endocrine function, and inflammation in individuals at-risk for T2D development. Such experiments would complement epidemiological studies and add to the evidence base for recommendations regarding consumption of dairy products and their individual components.

Effect of dairy calcium from cheese and milk on fecal fat excretion, blood lipids, and appetite in young men

BACKGROUND

Calcium from different dairy sources might affect blood lipids and fecal fat excretion differently because of differences in the food matrix and nutritional composition.

OBJECTIVE

We investigated whether milk- and cheese-based diets with similar calcium contents affect a saturated fatty acid-induced increase in blood lipids differently.

DESIGN

Fifteen healthy, young men participated in a randomized 3 × 2-wk crossover study in which the following 3 isocaloric diets that were similar in fat contents and compositions were compared: control diet [nondairy diet (~500 mg Ca/d)], milk diet [semiskimmed milk-based diet (1700 mg Ca/d)], and cheese diet [semihard cow-cheese-based diet (1700 mg Ca/d)]. Blood was drawn before and after each period, and feces were collected for 5 d during each period.

RESULTS

Saturated fatty acid-induced increases in total and low-density lipoprotein (LDL) cholesterol were lower with the milk diet (mean ± SD: 0.57 ± 0.13 and 0.53 ± 0.11 mmol/L, respectively) (P < 0.01) and cheese diet (0.41 ± 0.15 and 0.47 ± 0.12 mmol/L, respectively) (P < 0.05) than with the control diet (0.89 ± 0.12 and 0.84 ± 0.11 mmol/L, respectively). Fecal fat excretion increased more with the consumption of both the milk (5.2 ± 0.4 g/d) and cheese (5.7 ± 0.4 g/d) diets than with the control diet (3.9 ± 0.3 g/d) (P < 0.001). Changes in blood pressure, high-density lipoprotein cholesterol, triglycerides, and lipid ratios did not differ.

CONCLUSIONS

Compared with the control diet, milk- and cheese-based diets attenuated saturated fatty acid-induced increases in total and LDL cholesterol and resulted in increased fecal fat excretion; however, effects of milk and cheese did not differ. Because the diets contained similar amounts of saturated fat, similar increases in total and LDL cholesterol could be expected; however, both milk and cheese attenuated these responses, which seem to be explained by their calcium contents. This trial was registered at clinicaltrials.gov as NCT01317251.

Findings from the Quebec Family Study on the Etiology of Obesity: Genetics and Environmental Highlights

The Quebec Family Study (QFS) was an observational study with three cycles of data collection between 1979 and 2002 in Quebec City, Canada. The cohort is a mixture of random sampling and ascertainment through obese individuals. The study has significantly contributed to our understanding of the determinants of obesity and associated disease risk over the past 35 years. In particular, the QFS cohort was used to investigate the contribution of familial resemblance and genetic effects on body fatness and behaviors related to energy balance. Significant familial aggregation and genetic heritability were reported for total adiposity, fat-free mass, subcutaneous fat distribution, abdominal and visceral fat, resting metabolic rate, physical activity level and other behavioral traits. The resources of QFS were also used to study the contribution of several nontraditional (non-caloric) risk factors as predictors of excess body weight and gains in weight and adiposity over time, including low calcium and micronutrient intake, high disinhibition eating behavior trait, and short sleep duration. An important finding relates to the interactions between dietary macronutrient intake and exercise intensity on body mass and adiposity.

Appetite sensations and substrate metabolism at rest, during exercise, and recovery: impact of a high-calcium meal

The aim of this study was to investigate the effects of the calcium content of a high-carbohydrate, pre-exercise meal on substrate metabolism and appetite sensations before, during, and after exercise. Nine active males participated in 2 trials in a double-blind, randomised, crossover design. After consuming a high carbohydrate (1.5 g·kg−1 of body mass) breakfast with a calcium content of either 3 (control trial) or 9 mg·kg−1 of body mass (high milk-calcium (CAL)), participants ran at 60% peak oxygen uptake for 60 min. Following exercise, a recovery drink was consumed and responses were investigated for a further 90 min. Blood and expired gas were sampled throughout to determine circulating substrate and hormone concentrations and rates of substrate oxidation. Visual analogue scales were also administered to determine subjective appetite sensations. Neither whole-body lipid oxidation nor non-esterified fatty acid availability differed between trials. The area under the curve for the first hour following breakfast consumption was 16% (95% confidence interval: 0%–35%) greater for fullness and 10% (95% confidence interval: 2%–19%) greater for insulin in the CAL trial but these differences were transient and not apparent later in the trial. This study demonstrates that increasing the calcium content of a high carbohydrate meal transiently increases insulinemia and fullness but substrate metabolism is unaffected.

Dairy foods and dairy protein consumption is inversely related to markers of adiposity in obese men and women

A number of intervention studies have reported that the prevalence of obesity may be in part inversely related to dairy food consumption while others report no association. We sought to examine relationships between energy, protein and calcium consumption from dairy foods (milk, yoghurt, cheese, dairy spreads, ice-cream) and adiposity including body mass index (BMI), waist (WC) and hip circumference (HC), and direct measures of body composition using dual energy X-ray absorptiometry (% body fat and abdominal fat) in an opportunistic sample of 720 overweight/obese Australian men and women. Mean (SD) age, weight and BMI of the population were 51 ± 10 year, 94 ± 18 kg and 32.4 ± 5.7 kg/m², respectively. Reduced fat milk was the most commonly consumed dairy product (235 ± 200 g/day), followed by whole milk (63 ± 128 g/day) and yoghurt (53 ± 66 g/day). Overall dairy food consumption (g/day) was inversely associated with BMI, % body fat and WC (all p < 0.05). Dairy protein and dairy calcium (g/day) were both inversely associated with all adiposity measures (all p < 0.05). Yoghurt consumption (g/day) was inversely associated with % body fat, abdominal fat, WC and HC (all p < 0.05), while reduced fat milk consumption was inversely associated with BMI, WC, HC and % body fat (all p < 0.05). Within a sample of obese adults, consumption of dairy products, dairy protein, and calcium was associated with more favourable body composition.

Effect of a dairy- and calcium-rich diet on weight loss and appetite during energy restriction in overweight and obese adults: a randomized trial

BACKGROUND/OBJECTIVES

A diet rich in dairy and calcium (Ca) has been variably associated with improvements in body composition and decreased risk of type 2 diabetes. Our objective was to determine if a dietary pattern high in dairy and Ca improves weight loss and subjective appetite to a greater extent than a low dairy/Ca diet during energy restriction in overweight and obese adults with metabolic syndrome.

SUBJECTS/METHODS

A total of 49 participants were randomized to one of two treatment groups: Control (low dairy, ≈ 700 mg/day Ca, -500 kcal/day) or Dairy/Ca (high dairy, ≈ 1400 mg/day Ca, -500 kcal/day) for 12 weeks. Body composition, subjective ratings of appetite, food intake, plasma satiety hormones, glycemic response and inflammatory cytokines were measured.

RESULTS

Control (-2.2 ± 0.5 kg) and Dairy/Ca (-3.3 ± 0.6 kg) had similar weight loss. Based on self-reported energy intake, the percentage of expected weight loss achieved was higher with Dairy/Ca (82.1 ± 19.4%) than Control (32.2 ± 7.7%; P=0.03). Subjects in the Dairy/Ca group reported feeling more satisfied (P=0.01) and had lower dietary fat intake (P=0.02) over 12 weeks compared with Control. Compared with Control, Dairy/Ca had higher plasma levels of peptide tyrosine tyrosine (PYY, P=0.01) during the meal tolerance test at week 12. Monocyte chemoattractant protein-1 was reduced at 30 min with Dairy/Ca compared with Control (P=0.04).

CONCLUSIONS

In conclusion, a dairy- and Ca-rich diet was not associated with greater weight loss than control. Modest increases in plasma PYY concentrations with increased dairy/Ca intake, however, may contribute to enhanced sensations of satisfaction and reduced dietary fat intake during energy restriction.

25-Hydroxyvitamin D Supplementation and BMI Change: A Meta-Analysis of Randomized Controlled Trials

The impact of 25-hydroxyvitamin D (25[OH]D) supplementation on weight change remains controversial. The objective of this study was to summarize the effects of 25[OH]D supplementation (cholecalciferol or ergocalciferol) on BMI change through a meta-analysis of published clinical trials. We completed a systematic review of English articles, using MEDLINE (Ovid, Pubmed) from January 1, 1998 through January 1, 2013. The articles selected focused on 25[OH]D supplementation and body mass index (BMI) in randomized controlled trials (RCT’s). The association between 25[OH]D and mean BMI change was estimated utilizing a random effects model. A total of 30 studies were reviewed and 9 were included in the meta-analysis. Total participants included 1651 adults (82.6% women and mean age 47.9 years) and mean follow-up ranged between 6 to 196 weeks and mean daily 25[OH]D dose ranged from 200 IU to 1,110 IU. Five of the 9 studies included calcium supplementation in both groups. Average baseline BMI was 30.7 and 30.4 kg/m² in the intervention and control groups, respectively. Five studies suggested a beneficial effect for 25[OH]D supplementation for BMI change whereas 3 studies showed no effect of 25[OH]D supplementation on BMI change, and one showed a non-perceptible change. Meta-analysis of BMI values at end of trial showed no statistically significant difference in BMI change by use of 25[OH]D supplementation. Based on existing published trials, oral 25[OH]D supplementation does not significantly impact BMI change.

Dietary strategies to increase satiety

Obesity has a multifactorial etiology. Although obesity is widespread and associated with serious health hazards, its effective prevention and treatment have been challenging. Among the currently available treatment approaches, lifestyle modification to induce a negative energy balance holds a particularly larger appeal due to its wider reach and relative safety. However, long-term compliance with dietary modifications to reduce energy intake is not effective for the majority. The role of many individual nutrients, foods, and food groups in inducing satiety has been extensively studied. Based on this evidence, we have developed sample weight-loss meal plans that include multiple satiating foods, which may collectively augment the satiating properties of a meal. Compared to a typical American diet, these meal plans are considerably lower in energy density and probably more satiating. A diet that exploits the satiating properties of multiple foods may help increase long-term dietary compliance and consequentially enhance weight loss.

Dairy food consumption and meal-induced cortisol response interacted to influence weight loss in overweight women undergoing a 12-week, meal-controlled, weight loss intervention

Dairy food enhances weight loss in animal models, possibly by modifying the metabolic effects of cortisol. This study determined in overweight women (ages 20.0-45.9 y; n = 51) whether including dairy food in an energy-restricted diet affects cortisol concentrations and whether differences in provoked cortisol explain the magnitude of weight loss. Women received either an adequate amount of dairy food (AD), the equivalent of ≥711 mL/d milk, or a low amount of dairy food (LD), the equivalent to ≤238 mL/d milk, in a 12-wk, energy-restricted dietary intervention. Participants were tested in a 12-h laboratory visit, which included 2 standard meals and a dinner buffet that was consumed ad libitum. Salivary cortisol was measured from waking to bedtime. Energy restriction increased (P ≤ 0.04) the minimum and decreased (P ≤ 0.02) the diurnal amplitude in the salivary cortisol concentration from baseline to postintervention. Energy restriction enhanced the dinner meal-stimulated salivary cortisol response (DMR) (P ≤ 0.02) but only in the LD group. Compared with the LD treatment, the AD treatment induced (P ≤ 0.04) greater reductions in body weight and fat, but only in women characterized as having a baseline DMR (responders) (n = 26); weight and fat lost in the AD and LD groups were similar in nonresponders (n = 25). Overall, energy restriction dampened diurnal salivary cortisol fluctuations [symptomatic of hypothalamic-pituitary-adrenal (HPA) axis dysfunction] and enhanced dinner meal-stimulated salivary cortisol concentrations. The AD treatment prevented the latter. Furthermore, certain phenotypic markers of HPA axis function may help to expose the weight-reducing effects of consuming dairy food.

Effect of calcium intake on fat oxidation in adults: a meta-analysis of randomized, controlled trials

Calcium intake is likely to increase body fat loss during energy restriction. Part of this effect may be explained by increased fat oxidation in the presence of a similar energy balance, yet studies have not provided a conclusive answer. Therefore a meta-analysis was performed to determine whether chronic or acute high calcium intake increases fat oxidation. Randomized controlled trials of high calcium intake in human adults where measures of fat oxidation were taken were included. A random-effects meta-analysis was performed on outcomes expressed as standardized mean differences. Chronic high calcium intake increased fat oxidation by a standardized mean difference of 0.42 (95% confidence intervals: 0.14, 0.69; P= 0.003; estimated to correspond to an 11% increase), displaying low heterogeneity (I(2) = 18%), which was more prominent when habitual calcium intake was low (<700 mg d(-1) ). Acute high calcium intake increased fat oxidation by a standardized mean difference of 0.41 (0.04, 0.77; P = 0.03), with low heterogeneity (I(2) = 19%), yet sensitivity analysis revealed that this effect was relatively weak. In conclusion, chronic high calcium intake is likely to increase rates of fat oxidation. The effects of acute high calcium intake appear to point in the same direction, but further work is needed to permit a greater degree of certainty.

Effects of dairy intake on body weight and fat: a meta-analysis of randomized controlled trials

BACKGROUND

Some intervention studies have suggested that dairy products may influence body weight, but the results remain controversial.

OBJECTIVE

We identified and quantified the effects of dairy consumption on body weight and fat mass from randomized controlled trials (RCTs).

DESIGN

We conducted a comprehensive search of PubMed and EMBASE databases (to April 2012) of English reports of RCTs regarding dairy consumption on body weight, body fat, or body weight and body fat in adults. The results across studies were pooled by using a random-effects meta-analysis.

RESULTS

Twenty-nine RCTs were included with a total of 2101 participants. Overall, consumption of dairy products did not result in a significant reduction in weight (-0.14 kg; 95% CI: -0.66, 0.38 kg; I² = 86.3%). In subgroup analysis, consumption of dairy products reduced body weight in the context of energy restriction or short-term intervention (<1 y) trials but had the opposite effect in ad libitum dietary interventions or long-term trials (≥1 y). Twenty-two RCTs that reported results on body fat showed a modest reduction in the dairy group (-0.45 kg; 95% CI: -0.79, -0.11 kg; I² = 70.9%), and further stratified analysis indicated significant beneficial effects of dairy intervention on body fat in energy-restricted or short-term trials but not in long-term or ad libitum studies.

CONCLUSIONS

This meta-analysis does not support the beneficial effect of increasing dairy consumption on body weight and fat loss in long-term studies or studies without energy restriction. However, dairy products may have modest benefits in facilitating weight loss in short-term or energy-restricted RCTs.

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.

Mechanistic roles for calcium and vitamin D in the regulation of body weight

Low intakes of calcium and inadequate vitamin D status often cluster with higher prevalence rates of obesity. Consequently, there has been much interest in the mechanisms by which calcium and vitamin D could regulate body weight and adiposity. This review has focused on randomized controlled trials (RCTs) that have manipulated these nutrients and studied pathways of energy balance. Overall, there is consistent evidence that calcium and vitamin D increase whole body fat oxidation after single and multiple meals, and that calcium promotes a modest energy loss through increased faecal fat excretion. The evidence is equivocal for a greater diet-induced thermogenesis, increased lipolysis, suppression of key lipogenic enzymes, decreased hunger ratings or reduced energy/macronutrient intake. Emerging evidence suggests a potential improvement in insulin sensitivity following vitamin D that would impinge on food intake and substrate oxidation. However, the very few RCTs on supplemental vitamin D and energy balance have not explored postprandial avenues of the hormone's actions. Future efforts in this area need to define the threshold intake of these nutrients that would maximize metabolic and gastrointestinal outcomes. Such studies would provide a platform for endorsing the non-skeletal role of calcium and vitamin D in human pathophysiology.

Sleeping habits predict the magnitude of fat loss in adults exposed to moderate caloric restriction

OBJECTIVE

To verify whether sleep quantity and quality at baseline predict the magnitude of fat loss in adults subjected to moderate caloric restriction.

METHODS

A total of 123 overweight and obese men and women (age, 41.1 ± 6.0 years; BMI, 33.2 ± 3.6 kg/m2 (mean ± SD)) underwent a weight loss intervention consisting of a targeted 600-700 kcal/day decrease in energy intake supervised by a dietician. The length of the intervention varied between 15 and 24 weeks. Body fat mass (dual-energy X-ray absorptiometry), sleep quality (total Pittsburgh sleep quality index score) and sleep duration (h/night, self-reported from the Pittsburgh sleep quality index) were assessed at both baseline and at the end of the weight loss program.

RESULTS

The mean weight loss over the dietary intervention was 4.5 ± 3.9 kg, 76% of which came from fat stores. Using a multiple linear regression analysis, we observed a significant positive relationship between sleep duration and the loss of body fat, both in absolute (adjusted β = 0.72 kg/h; p < 0.05) as well as in relative terms (adjusted β = 0.77%/h; p < 0.01), after adjusting for age, sex, baseline BMI, length of the intervention, and change in total energy intake. Furthermore, we observed that a better sleep quality at baseline was associated with greater fat mass loss.

CONCLUSION

This study provides evidence that sleeping habits can influence the success of a weight loss intervention and should be taken into consideration when one decides to start a diet.