Effect of dairy proteins on appetite, energy expenditure, body weight, and composition: a review of the evidence from controlled clinical trials

Effect of oral supplementation with whey protein on muscle mass in adults with type 2 diabetes mellitus: a systematic review of randomized controlled trials

OBJECTIVE

To investigate the overall effect of whey protein supplementation on skeletal muscle mass in adults with type 2 diabetes mellitus (T2DM).

METHODS

Systematic review of reports on corporal muscle mass from clinical trials that assessed the use of whey protein supplementation by means of validated techniques in patients with T2DM. PubMed, SCOPUS, Web of Science, LILACS, and SciELO databases were searched up to April 2022. Risk of bias was assessed by the Cochrane Collaboration Risk of Bias tool. We conducted a qualitative synthesis of information.

RESULTS

Four studies (424 participants) that met the selection criteria were identified out of 1,787 records. Of these, 3 studies assessed the total muscle mass using dual-energy X-ray absorptiometry (DXA), and 1 reported changes to the transverse diameter of the vastus lateralis muscle with ultrasound imaging. In the intervention groups, DXA assessments demonstrated an increase in total muscle mass in 3 studies and in the appendicular muscle mass in 2. Changes to the proportion of muscle mass were not seen in the DXA studies and only a discrete difference was seen in the comparative groups studied by ultrasound imaging.

CONCLUSION

Following the administration of whey protein supplementation in patients with T2DM, a partially positive effect was seen in skeletal muscle mass gain with a moderate certainty of evidence.

Mice Regulate Dietary Amino Acid Balance and Energy Intake by Selecting between Complementary Protein Sources

BACKGROUND

A balanced intake of protein and constituent amino acids (AAs) requires adjustments to total food intake (protein leverage [PL]) and food selection to balance deficits and excesses (complementary feeding). We provided mice with choices of casein and whey, 2 protein sources that are complementary in AA balance, across a range of protein concentrations (P%) of digestible energy (DE).

OBJECTIVES

We aimed to determine if: 1) PL operates similarly for casein and whey; 2) one protein source is preferred at control P%; 3) the preference changes as P% falls; and 4) AA intakes under control and low P% levels identify AAs that drive changes in protein selection.

METHODS

Food intake and plasma fibroblast growth factor-21 (FGF21) concentrations were measured in mice at various P% (P7.5%-P33%). For direct comparisons, defined diets were used in which the protein source was either casein or whey. In food choice studies, mice had access to foods in which both casein and whey were provided at the same P% level at the same time.

RESULTS

PL operated at different P% thresholds in casein (13%)- and whey (10%)-based diets, and the magnitude of PL was greater for casein. Although mice preferred casein under control conditions (P23%), a pronounced preference shift to whey occurred as P% fell to P13% and P10%. At low P%, increases in food intake were accompanied by increases in plasma FGF21, a protein hunger signal. Among AAs deficient in casein and enriched in whey, the intake of Cys was the most invariant as P% changed between P23% and P10%, appearing to drive the switch in protein preference.

CONCLUSIONS

Mice selected between complementary protein sources, casein and whey, achieving stable total energy intake and regulated intake of AAs as P% varied. Supplementation of low P% casein diets with one whey-enriched AA, Cys, suppressed plasma FGF21 and total food intake.

Metabolic Syndrome and Biotherapeutic Activity of Dairy (Cow and Buffalo) Milk Proteins and Peptides: Fast Food-Induced Obesity Perspective-A Narrative Review

Metabolic syndrome (MS) is defined by the outcome of interconnected metabolic factors that directly increase the prevalence of obesity and other metabolic diseases. Currently, obesity is considered one of the most relevant topics of discussion because an epidemic heave of the incidence of obesity in both developing and underdeveloped countries has been reached. According to the World Obesity Atlas 2023 report, 38% of the world population are presently either obese or overweight. One of the causes of obesity is an imbalance of energy intake and energy expenditure, where nutritional imbalance due to consumption of high-calorie fast foods play a pivotal role. The dynamic interactions among different risk factors of obesity are highly complex; however, the underpinnings of hyperglycemia and dyslipidemia for obesity incidence are recognized. Fast foods, primarily composed of soluble carbohydrates, non-nutritive artificial sweeteners, saturated fats, and complexes of macronutrients (protein-carbohydrate, starch-lipid, starch-lipid-protein) provide high metabolic calories. Several experimental studies have pointed out that dairy proteins and peptides may modulate the activities of risk factors of obesity. To justify the results precisely, peptides from dairy milk proteins were synthesized under in vitro conditions and their contributions to biomarkers of obesity were assessed. Comprehensive information about the impact of proteins and peptides from dairy milks on fast food-induced obesity is presented in this narrative review article.

Are There Any Correlations between Vitamin D, Calcium, and Magnesium Intake and Coronary and Obesity Indices?

OBJECTIVE

The association between nutrient intake and obesity and coronary problems has received great attention. So, this study aimed to examine the association between vitamin D, calcium, and magnesium intake and obesity and coronary indices.

METHODS

A total of 491 male and female university employees (18-64 years) were randomly included in a cross-sectional study. Blood samples were drawn, and the lipid profile was analyzed. Different anthropometrics were measured. Obesity and coronary indices were calculated based on standard formulas. A 24-h recall was used to measure the average dietary intake of vitamin D, calcium, and magnesium.

RESULTS

For the total sample, vitamin D had a significantly weak correlation with the abdominal volume index (AVI) and weight-adjusted waist index (WWI). However, calcium intake had a significant moderate correlation with the AVI and a weak correlation with the conicity index (CI), body roundness index (BRI), body adiposity index (BAI), WWI, lipid accumulation product (LAP), and atherogenic index of plasma (AIP). In males, there was a significant weak correlation between calcium and magnesium intake and the CI, BAI, AVI, WWI, and BRI. Additionally, magnesium intake had a weak correlation with the LAP. In female participants, calcium and magnesium intake had a weak correlation with CI, BAI, AIP, and WWI. Additionally, calcium intake showed a moderate correlation with the AVI and BRI and a weak correlation with the LAP.

CONCLUSION

Magnesium intake had the greatest impact on coronary indices. Calcium intake had the greatest impact on obesity indices. Vitamin D intake had minimal effects on obesity and coronary indices.

Association between dairy products consumption and the prevalences of combined prediabetes and type 2 diabetes mellitus in Brazilian adolescents: a cross-sectional study

The association between dairy products consumption in adults and the likelihood of type 2 diabetes mellitus (T2DM) has been described, but more information on the adolescent population is needed. This nationally representative, cross-sectional school-based study aimed to describe the consumption of dairy products and their subtypes and to evaluate their association with prediabetes and T2DM in adolescents. The Study of Cardiovascular Risks in Adolescents (ERICA) includes adolescents aged 12-17 years. Dairy products consumption was evaluated by 24-h food recall. Associations with fasting glucose, glycated hemoglobin (HbA1c) and insulin resistance, as measured by homeostatic model assessment-insulin resistance (HOMA-IR), were evaluated by multivariate linear regression. Poisson regression was also used to assess the association between dairy products consumption and the combined prevalence of prediabetes and T2DM. Models were adjusted for sociodemographic, nutritional, behavioural and anthropometrics. The final sample analysed consisted of 35 614 adolescents. Total intake of dairy products was inversely associated with fasting blood glucose levels after adjusting for all covariates (β = -0·452, 95 % CI -0·899, -0·005). The associations were stronger for overweight and obese adolescents. Findings were similar for full-fat dairy products and yogurt. Higher consumption of low-fat dairy products and cheese were associated with a 46 % (prevalence ratio, PR 1·46, 95 % CI 1·18, 1·80) and 33 % (PR 1·33, 95 % CI 1·14, 1·57) higher combined prevalence of prediabetes and T2DM, respectively. The total consumption of dairy products and full-fat dairy products was associated with a lower combined prevalence of prediabetes and T2DM, while the consumption of cheese and low-fat dairy products was associated with higher combined prevalence of prediabetes and T2DM in Brazilian adolescents.

Whey protein hydrolysates improve high-fat-diet-induced obesity by modulating the brain-peripheral axis of GLP-1 through inhibition of DPP-4 function in mice

PURPOSE

Obesity is a growing global health concern. Recent literature indicates a prominent role of glucagon-like peptide-1 (GLP-1) in glucose metabolism and food intake. The synergistic action of GLP-1 in the gut and brain is responsible for its satiety-inducing effect, suggesting that upregulation of active GLP-1 levels could be an alternative strategy to combat obesity. Dipeptidyl peptidase-4 (DPP-4) is an exopeptidase known to inactivate GLP-1, suggesting that its inhibition could be a crucial strategy for effectively extending the half-life of endogenous GLP-1. Peptides derived from partial hydrolysis of dietary proteins are gaining traction due to their inhibitory activity on DPP-4.

METHODS

Whey protein hydrolysate from bovine milk (bmWPH) was produced using simulated in situ digestion, purified using RP-HPLC, and characterized for DPP-4 inhibition. The antiadipogenic and antiobesity activity of bmWPH was then studied in 3T3-L1 preadipocytes and high-fat diet-induced obesity (HFD) mice model, respectively.

RESULTS

The dose-dependent inhibitory effect of bmWPH on the catalytic activity of DPP-4 was observed. Additionally, bmWPH suppressed adipogenic transcription factors and DPP-4 protein levels, leading to a negative effect on preadipocyte differentiation. In an HFD mice model, co-administration of WPH for 20 weeks downregulated adipogenic transcription factors, resulting in a concomitant reduction in whole body weight and adipose tissues. Mice fed with bmWPH also showed a marked reduction in DPP-4 levels in WAT, liver, and serum. Furthermore, HFD mice fed with bmWPH exhibited increased serum and brain GLP levels, which led to a significant decrease in food intake.

CONCLUSION

In conclusion, bmWPH reduces body weight in HFD mice by suppressing appetite through GLP-1, a satiety-inducing hormone, in both the brain and peripheral circulation. This effect is achieved through modulation of both the catalytic and non-catalytic activity of DPP-4.

Postprandial effects of dietary protein source on metabolic responses, appetite, and arterial stiffness indices in overweight and obese men: the study protocol for a randomized crossover clinical trial

BACKGROUND

Different dietary protein sources are supposed to have various effects on metabolic responses and arterial stiffness in the postprandial period. This study aims to assess the postprandial effects of dietary protein sources, including animal-based protein (AP) and plant-based protein (PP), as part of a high-protein breakfast on appetite response, energy metabolism, and arterial stiffness in overweight and obese men.

METHODS

This acute randomized crossover clinical trial will be conducted at the Persian study research center at Imam Reza Hospital, affiliated with the Mashhad University of Medical Sciences, located in the northeast of Iran. Forty-six healthy overweight, and obese men aged 18-60 years will be enrolled based on the eligibility criteria. The subjects will complete two interventions (high-protein AP and PP meals) with 1 week washout period. The primary outcome will be the acute effect of the two test meals on appetite response, energy metabolism parameters, including resting metabolism rate (RMR), diet-induced thermogenesis (DIT), and substrate oxidation (SO), and arterial stiffness indices, including pulse wave velocity (PWV) and pulse wave analysis (PWA). The secondary outcomes include changes in lipemia, glycemia, and insulinemia.

DISCUSSION

The findings of this study will provide novel insight regarding the acute effects of different protein sources on energy metabolism, appetite, and arterial stiffness as a significant cardiovascular disease (CVD) risk factor. It will help dieticians develop effective and efficient meal plans to improve weight reduction and maintenance in overweight/obese individuals.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials; code: IRCT20211230053570N1; registered on February 10, 2022.

Protein Source Influences Acute Appetite and Satiety but not Subsequent Food Intake in Healthy Adults

BACKGROUND

Although current recommendations encourage plant-based dietary patterns, data is limited as to whether the equivalent substitution of animal-based protein-rich foods with plant-based versions impacts ingestive behavior.

OBJECTIVE

To compare higher-protein preloads, varying in protein source, on appetite, satiety, and subsequent energy intake.

METHODS

Thirty-two adults (Age: 25±1y; Body Mass Index (BMI): 24.2±0.5kg/m) randomly consumed 250kcal, protein-preload beverages (24g protein), varying in protein source (whey, soy, pea protein isolates (WHEY, SOY, PEA) or micellar casein (CAS)) each morning for 3 acclimation days/preload. On day 4, participants completed a 4-h clinical testing day in which the respective preload was consumed followed by blood sampling and questionnaires every 30min for appetite and satiety. An ad libitum lunch was provided 4-h post-preload. On day 5, participants consumed the respective preload at home followed by an ad libitum breakfast 30min afterwards. For normally-distributed data, repeated-measures analysis of variance (ANOVA) or Friedman non-parametric test were utilized to compare main effects of protein source on study outcomes. Post-hoc pairwise comparisons using least significant differences (LSD) were then performed.

RESULTS

CAS (-3330±690mm*240min) and PEA (-2840±930mm*240min) reduced 4-h appetite vs. SOY (-1440±936mm*240min; both, P<0.05). WHEY was not different (-2290±930mm*240min). CAS (3520±84pg/ml*240min) and PEA (3860±864pg/ml*240min) increased 4-h PYY concentrations vs. SOY (2200±869pg/ml*240min; both, P<0.05). WHEY was not different (3870±932pg/ml*240 min). No differences in ad libitum energy intake were observed.

CONCLUSIONS

CAS and PEA, but not WHEY, elicited greater acute changes in appetite and satiety vs. SOY in healthy adults, supporting that not all protein sources are equivalent. This trial is registered at clinicaltrials.gov (NCT03154606).

Effects of the maize-derived protein zein, and the milk proteins casein, whey, and α-lactalbumin, on subjective measures of satiety and food intake in normal-weight young men

Protein is considered to be the most satiating food macronutrient and the satiating effect may be dependent on the source of the protein. The maize-derived protein zein and milk protein casein have been shown previously to lower stomach emptying rate more than dairy whey protein, but the effect of zein on satiety has not been evaluated. The objective was to compare the satiating effects of zein and casein, with whey protein and its protein component α-lactalbumin. The study was a randomised crossover design with thirteen normal-weight men (mean age 27.8 years and mean BMI 24.4 kg/m2) consuming isoenergetic (∼4000 kJ, ∼990 kcal) preload mixed meals enriched with Zein, Casein, whey protein isolate (Whey), α-lactalbumin (ALac), or maltodextrin carbohydrate (Carb). Consumption of an ad libitum standardised test meal of chicken fried rice and water provided 360 min following ingestion of the preload meal was measured, and subjective feelings of appetite (hunger, fullness, desire to eat, and prospective food consumption) were assessed using 100-mm visual analogue scales (VAS). There were no differences among the five preload mixed meals in the amount of chicken fried rice consumed at the ad libitum test meal (mean ± sem: 531.6 ± 35.0 g, p = 0.47) or total (preload + test meal) energy intakes (mean ± sem: 5780.5 ± 146.0 kJ, p = 0.29). The subjective VAS appetite ratings and total area under the curve responses for hunger, fullness, desire to eat, and prospective food consumption, were not different following consumption of all five preload mixed meals (p > 0.05). The findings indicate that the effects of zein and casein on satiety were not different from the satiating effects of whey protein and α-lactalbumin.

Does the concept of "ultra-processed foods" help inform dietary guidelines, beyond conventional classification systems? NO

The Nova classification of ultra-processed foods (UPFs) rests on poorly defined food processes and the presence of food additives from a chemically heterogeneous group, easily leading to misclassification. UPFs are claimed to promote overconsumption of energy and obesity due to high palatability, but little evidence supports effects beyond those that can be accounted for by nutrient composition, energy density, and food matrices. Observational studies link dietary intake of UPFs with obesity, but none have demonstrated independent associations after controlling for likely confounders. A highly cited randomized controlled feeding study that compared a UPF diet with an unprocessed diet showed a rapidly weaning effect on energy intake that can be entirely explained by more conventional and quantifiable dietary factors, including energy density, intrinsic fiber, glycemic load, and added sugar. Clearly, many aspects of food processing can affect health outcomes, but conflating them into the notion of ultra-processing is unnecessary, because the main determinants of chronic disease risk are already captured by existing nutrient profiling systems. In conclusion, the Nova classification adds little to existing nutrient profiling systems; characterizes several healthy, nutrient-dense foods as unhealthy; and is counterproductive to solve the major global food production challenges.

Different Protein Sources Enhance 18FDG-PET/MR Uptake of Brown Adipocytes in Male Subjects

Background: The unique ability of brown adipocytes to increase metabolic rate suggests that they could be targeted as an obesity treatment. Objective: The objective of the study was to search for new dietary factors that may enhance brown adipose tissue (BAT) activity. Methods: The study group comprised 28 healthy non-smoking males, aged 21–42 years old. All volunteers underwent a physical examination and a 75 g oral glucose tolerance test (75g-OGTT). Serum atrial and brain natriuretic peptide (ANP, BNP), PRD1-BF1-RIZ1 homologous domain containing 16 (PRDM16) and eukaryotic translation initiation factor 4E (eIF4E) measurements were taken, and 3-day food intake diaries were completed. Body composition measurements were assessed using dual-energy X-ray absorptiometry (DXA) scanning and bioimpedance methods. An fluorodeoxyglucose-18 (FDG-18) uptake in BAT was assessed by positron emission tomography/magnetic resonance (PET/MR) in all participants after 2 h cold exposure. The results were adjusted for age, daily energy intake, and DXA lean mass. Results: Subjects with detectable BAT (BAT⁽⁺⁾) were characterized by a higher percentage of energy obtained from dietary protein and fat and higher muscle mass (p = 0.01, p = 0.02 and p = 0.04, respectively). In the BAT⁽⁺⁾ group, animal protein intake was positively associated (p= 0.04), whereas the plant protein intake negatively correlated with BAT activity (p = 0.03). Additionally, the presence of BAT was inversely associated with BNP concentration in the 2 h of cold exposure (p = 0.002). Conclusion: The outcomes of our study suggest that different macronutrient consumption may be a new way to modulate BAT activity leading to weight reduction.

Acute supplementation with whey protein or collagen does not alter appetite in healthy women: a randomised double-blind and crossover pilot study

Protein quality has an important role in increasing satiety. Evidence suggests that whey protein (WP) provides satiety via gastrointestinal hormone secretion. Hydrolysed collagen supplementation can also stimulate the production of incretins and influence satiety and food intake. Thus, we sought to compare the effect of acute supplementation of WP or hydrolysed collagen on post-intervention appetite and energy consumption. This was a randomised, double-blind, crossover pilot study with ten healthy adult women (22·4 years/old) who were submitted to acute intake (single dose) of a beverage containing WP (40 g of concentrated WP) or hydrolysed collagen (40 g). Subjective appetite ratings (feelings of hunger, desire to eat and full stomach) were measured using the Visual Analog Scale (VAS), energy intake was quantified by ad libitum cheese bread consumption 2 hours after supplementation and blood was collected for leptin and glucose determination. There was no difference between treatment groups in the perception of hunger (P = 0·983), desire to eat (P = 0·326), full stomach feeling (P = 0·567) or food consumption (P = 0·168). Leptin concentrations at 60 min post supplementation were higher when subjects received hydrolysed collagen (P = 0·006). Acute supplementation with hydrolysed collagen increased leptin levels in comparison with WP, but had no effect on appetite measured by feelings of hunger, desire to eat, full stomach feeling (VAS) or energy consumption.

The Role of Milk on Children's Weight Status: An Epidemiological Study among Preadolescents in Greece

Milk consumption contributes greatly to children's diet, playing a pivotal role in the development and structure of bones and the functioning of the musculoskeletal system and the heart. This study investigated the association between the type of milk and childhood overweight/obesity. In the school period 2014-2016, 1728 students aged 10-12 years and their parents participated. The measurement and classification of their weight status were performed through the criteria of the International Obesity Task Force. Among others, the type of milk consumption was recorded. Four categories of the type of milk children consumed were classified (white milk, chocolate milk, both types of milk, and no milk at all). Children consuming only white milk were 33.1% less likely to be overweight/obese in comparison with children who were not consuming milk at all [OR (95% CI): 0.669 (0.516, 0.867), p = 0.002]. The consumption of chocolate milk showed a protective role against childhood overweight/obesity although its association was not consistently significant. This study highlights the significant contribution of milk (and particularly of white milk) consumption to weight management, and thus its promotion should be consistently encouraged. More studies are needed to shed light on the effects of different dairy foods on weight status in childhood.

Similar effects of milk protein and blends of milk and plant-based protein on appetite-related hormones in 7- to 8-year-old healthy Danish children: secondary analyses from the PROGRO randomised trial

AIM

The effect of different protein sources on the appetite-related hormones in children is largely unknown. We investigated the effect of milk protein versus blends of milk and rapeseed protein on plasma leptin and adiponectin in children.

METHODS

We included 88 Danish 7- to 8-year-old children randomised to receive 35 g protein/day for 4 weeks in 2018 as either milk protein or blends of milk and rapeseed protein (ratio 54:46 or 30:70). Outcomes included absolute and fat mass-adjusted adiponectin and leptin measured at baseline, Weeks 1 and 4.

RESULTS

There was no difference in changes in absolute and fat mass-adjusted adiponectin and leptin after 1 or 4 weeks between the three groups (p ≥ 0.100). Leptin increased within all groups (p ≤ 0.046). Combining the three groups, leptin and fat mass-adjusted leptin increased by 23% (95% CI 11;35) and 17% (6.4;29) during the intervention respectively (both p ≤ 0.001). Adiponectin variables did not change during the intervention period.

CONCLUSION

There were no differences between milk protein and blends of milk and rapeseed protein on absolute and fat mass-adjusted leptin and adiponectin in healthy children with a habitual intake of milk. However, leptin increased within all three groups. Future studies should further investigate effect on appetite-related hormones of rapeseed protein alone.

A systematic review of whey protein supplementation effects on human glycemic control: A mechanistic insight

BACKGROUND/AIMS

Some studies showed that dietary factors such as whey protein (WP) are effective on glycemic regulation. Due to the current controversy about WP effects and mechanisms of its action on glycemic control, we conducted this systematic review to shed light on the subject.

METHODS

Web of Science, Medline (Pubmed), and Scopus online databases were searched from 2012 up to February 2022 using the following keywords: "whey protein" and "glycemic control"/"glycemia"/"glucose"/"insulin". The search included original English articles, human clinical trials with WP supplementation and measurement of glucose or insulin as an outcome, studies on healthy individuals/patients with diabetes mellitus (DM)/impaired fasting glucose (IFG).

RESULTS

Title/abstract of 1991 studies were reviewed. After excluding studies due to inappropriate full title and duplication, and exercising inclusion criteria, 58 studies were reviewed in detail. Ample evidence showed that WP decreased postprandial glucose incremental area under the curve (iAUC) and increased iAUCs of insulin and incretin hormones. WP affects glycemic control mainly through stimulating insulin and incretins secretion, slowing gastric emptying, and appetite suppression.

CONCLUSION

Although most of the recent evidence showed beneficial effects of WP supplementation on glycemic response, further long-term clinical trials are required which assess the long-term impact of WP supplementation and its exact mechanisms.

Diets Containing Egg or Whey Protein and Inulin Fiber Improve Energy Balance and Modulate Gut Microbiota in Exercising Obese Rats

SCOPE

Dietary protein, prebiotic fiber and exercise individually have been shown to aid in weight loss; however less is known of their combined effects on energy balance. We determined the effects of diets high in protein and fiber, with exercise, on energy balance, hormones and gut microbiota.

METHODS AND RESULTS

Obese male rats were fed high-fat diets with high protein and fiber contents from egg protein and cellulose, egg protein and inulin, whey protein and cellulose, or whey protein and inulin, together with treadmill exercise. We found that inulin enriched diets decreased energy intake and respiratory quotient, increased energy expenditure, and upregulated transcripts for cholecystokinin (CCK), peptide YY and proglucagon in distal gut. Notably, CCK1-receptor blockade attenuated the hypophagic effects of diets and in particular whey-inulin diet, and β-adrenergic blockade reduced energy expenditure across all diets. Egg-cellulose, egg-inulin and whey-inulin diets decreased weight gain, adiposity, hepatic lipidosis and decreased lipogenic transcripts, improved glycemic control and up-regulated hepatic glucose metabolism transcripts, and decreased plasma insulin and leptin. Importantly, diet was linked to altered gut microbial composition and plasma metabolomics, and a subset of predicted metagenome pathways and plasma metabolites significantly correlated, with plasma butyric acid the most strongly associated to metagenome function.

CONCLUSION

Combination of dietary egg or whey protein with inulin and exercise improved energy balance, glucose metabolism, upregulated anorectic hormones, and selectively modulated gut microbiota and plasma metabolites. This article is protected by copyright. All rights reserved.

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.

Plasma glucagon-like peptide-1 responses to ingestion of protein with increasing doses of milk minerals rich in calcium

A high dose of whey protein hydrolysate fed with milk minerals rich in calcium (Capolac®) results in enhanced glucagon-like peptide-1 (GLP-1) concentrations in lean individuals; however, the effect of different calcium doses ingested alongside protein is unknown. The present study assessed the dose response of calcium fed alongside 25 g whey protein hydrolysate on GLP-1 concentrations in individuals with overweight/obesity. Eighteen adults (mean ± sd: 8M/10F, 34 ± 18 years, 28·2 ± 2·9 kgm-2) completed four trials in a randomised, double-blind, crossover design. Participants consumed test solutions consisting of 25 g whey protein hydrolysate (CON), supplemented with 3179 mg (LOW), 6363 mg (MED) or 9547 mg (HIGH) Capolac® on different occasions, separated by at least 48 h. The calcium content of test solutions equated to 65, 892, 1719 and 2547 mg, respectively. Arterialised-venous blood was sampled over 180 min to determine plasma concentrations of GLP-1TOTAL, GLP-17-36amide, insulin, glucose, NEFA, and serum concentrations of calcium and albumin. Ad libitum energy intake was measured at 180 min. Time-averaged incremental AUC (iAUC) for GLP-1TOTAL (pmol·l-1·min-1) did not differ between CON (23 ± 4), LOW (25 ± 6), MED (24 ± 5) and HIGH (24 ± 6). Energy intake (kcal) did not differ between CON (940 ± 387), LOW (884 ± 345), MED (920 ± 334) and HIGH (973 ± 390). Co-ingestion of whey protein hydrolysate with Capolac® does not potentiate GLP-1 release in comparison with whey protein hydrolysate alone. The study was registered at clinical trials (NCT03819972).

Proteins in Food Systems-Bionanomaterials, Conventional and Unconventional Sources, Functional Properties, and Development Opportunities

Recently, food companies from various European countries have observed increased interest in high-protein food and other products with specific functional properties. This review article intends to present proteins as an increasingly popular ingredient in various food products that frequently draw contemporary consumers’ attention. The study describes the role of conventional, unconventional, and alternative sources of protein in the human body. Furthermore, the study explores proteins’ nutritional value and functional properties, their use in the food industry, and the application of proteins in bionanomaterials. Due to the expected increase in demand for high-protein products, the paper also examines the health benefits and risks of consuming these products, current market trends, and consumer preferences.

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.

Effect of dairy intake with or without energy restriction on body composition of adults: overview of systematic reviews and meta-analyses of randomized controlled trials

CONTEXT

Some studies suggest that consumption of dairy products can aid in weight loss, while others suggest a negative effect or no effect.

OBJECTIVE

An overview of systematic reviews and meta-analyses was conducted to examine the effect of dairy product consumption on changes in body composition.

DATA SOURCES

PRISMA guidelines were followed to ensure transparent reporting of evidence. The MEDLINE, Embase, Cochrane Central Database of Systematic Reviews, and Web of Science databases were searched from inception to April 2018.

STUDY SELECTION

Six systematic reviews and 47 associated meta-analyses (which included the results of 58 different randomized controlled trials) published in English or Spanish and reporting data on dairy intake and changes in weight, fat mass, lean mass, or waist circumference were included.

DATA EXTRACTION

Two authors independently extracted the data and assessed the risk of bias using the AMSTAR2 tool.

RESULTS

Dairy consumption interventions without dietary energy restriction had no significant effects on weight, fat mass, lean mass, or waist circumference. Interventions in energy-restricted settings had significant effects on fat mass and body weight.

CONCLUSIONS

Increasing total dairy intake without energy restriction in adults does not affect body composition. In the context of an energy-restricted diet, however, increased dairy intake results in lower fat mass and body weight but has no conclusive effects on waist circumference or lean mass.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42018094672.

A novel oral nutritional supplement improves gait speed and mitochondrial functioning compared to standard care in older adults with (or at risk of) undernutrition: results from a randomized controlled trial

Undernutrition in older adults is mainly addressed by oral nutritional supplements, which do not affect physical functioning. In this study, we tested a novel oral nutritional supplement that included whey and casein protein, ursolic acid, free branch-chained amino acids and vitamin D against a standard supplement. We included older adults (>65y) with (or at risk of) undernutrition (n=82) and randomized them to 12 weeks of novel or standard supplement.

Both groups showed significant increases in body mass. No within or between-group differences in lean body mass were observed. Fat mass increased significantly more in the standard than the novel supplement group (time*treatment effect P=0.045). The novel supplement group showed a larger improvement in walking performance on distances of 4m (treatment x time interaction P=0.048) and 400m (treatment x time interaction P=0.038) than the standard treatment group. Gene sets related to mitochondrial functioning and oxidative phosphorylation were upregulated in the novel supplement group and downregulated in the standard supplement group.

We conclude that a 12-week intervention with the novel supplement improved walking performance both during short and long distance as compared to a standard supplement, which can largely be explained by increased mitochondrial functioning in the group receiving the novel supplement.

Impact of Protein Intake during Weight Loss on Preservation of Fat-Free Mass, Resting Energy Expenditure, and Physical Function in Overweight Postmenopausal Women: A Randomized Controlled Trial

INTRODUCTION

Weight loss in old age increases the risk of sarcopenia caused by the age-related reduction of fat-free mass (FFM). Due to the strong correlation between FFM and resting energy expenditure (REE), the maintenance of this must also be considered. Besides, the physical function (PF) must be maintained.

OBJECTIVE

The impact of protein intake on changes in FFM, REE, and PF during weight loss in overweight postmenopausal women was investigated.

METHODS

Fifty-four postmenopausal women (BMI 30.9 ± 3.4; age 59 ± 7 years) were randomized into 2 groups receiving energy-restricted diets with either 0.8 g (normal protein; NP) or 1.5 g protein/kg body weight (high protein; HP) for 12 weeks, followed by a 6-month follow-up phase with an ad libitum food intake. FFM, REE, and PF (strength, endurance, and balance) were measured at baseline, after weight loss, and after follow-up.

RESULTS

Forty-six women completed the weight loss intervention and 29 were followed up. The weight loss was -4.6 ± 3.6 kg (HP) and -5.2 ± 3.4 kg (NP; both p < 0.001) and the weight regain during follow-up was 1.3 ± 2.8 kg (HP; p = 0.03) and 0.4 ± 2.5 kg (NP; p = 0.39), with no differences between groups. Similar decreases in FFM (-0.9 ± 1.1 [HP] vs. -1.0 ± 1.3 kg [NP]) and REE (-862 ± 569 [HP] vs. -1,000 ± 561 kJ [NP]; both p < 0.001) were observed in both groups. During follow-up, no changes in FFM were detected in either group, whereas in the NP group the REE increased again (+138 ± 296; p = 0.02). The main determinants of FFM loss were the energy deficit and the speed of weight loss. In the NP group, the Short Physical Performance Battery score improved with weight loss (+0.6 ± 0.8; p < 0.001) and handgrip strength decreased (-1.7 ± 3.4 kg; p < 0.001), whereas no changes were observed in the HP group.

CONCLUSIONS

An HP weight-loss diet without exercise had no impact on preservation of FFM and REE but may help to maintain muscle strength in postmenopausal women.

Effects of Dietary Defatted Meat Species on Metabolomic Profiles of Murine Liver, Gastrocnemius Muscle, and Cecal Content

In both humans and animals, meat not only constitutes one of the sources of protein, but also includes various water-soluble bioactive substances such as imidazole peptides (carnosine and anserine) and taurine. Previous studies demonstrated that dietary meat species could differently affect physiological functions; however, the mechanisms of this remain unclear. To explore the physiological effects of dietary defatted meat species, especially on metabolism, we investigated their influence on the metabolomic profiles of the liver, gastrocnemius muscle, and cecal content in mice. Casein (control) or a defatted meat species (beef leg, pork leg, chicken leg, or chicken breast) was supplied as the major protein source in the diet for four weeks, and metabolism-related molecules were measured by gas chromatography–mass spectrometry. We found that various metabolite levels in tissues and cecal content differed according to the types of dietary protein consumed. Specifically, differences in carnosine, 1,5-anhydro-glucitol, inositol, butyric acid, and propionic acid were clearly observed. Among them, the highest carnosine intake by dietary pork leg was clearly related to the highest carnosine level in the liver. In addition, taurine intake was suggested to be linked to some metabolic pathways including taurine and hypotaurine metabolism in cecal content. These results provide additional knowledge of the effects of different dietary meat species on human and animal health.

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.

Role of Bioactive Peptide Sequences in the Potential Impact of Dairy Protein Intake on Metabolic Health

For years, there has been an increasing move towards elucidating the complexities of how food can interplay with the signalling networks underlying energy homeostasis and glycaemic control. Dairy foods can be regarded as the greatest source of proteins and peptides with various health benefits and are a well-recognized source of bioactive compounds. A number of dairy protein-derived peptide sequences with the ability to modulate functions related to the control of food intake, body weight gain and glucose homeostasis have been isolated and characterized. Their being active in vivo may be questionable mainly due to expected low bioavailability after ingestion, and hence their real contribution to the metabolic impact of dairy protein intake needs to be discussed. Some reports suggest that the differential effects of dairy proteins-in particular whey proteins-on mechanisms underlying energy balance and glucose-homeostasis may be attributed to their unique amino acid composition and hence the release of free amino acid mixtures enriched in essential amino acids (i.e., branched-chain-amino acids) upon digestion. Actually, the research reports reviewed in this article suggest that, among a number of dairy protein-derived peptides isolated and characterized as bioactive compounds in vitro, some peptides can be active in vivo post-oral administration through a local action in the gut, or, alternatively, a systemic action on specific molecular targets after entering the systemic circulation. Moreover, these studies highlight the importance of the enteroendocrine system in the cross talk between food proteins and the neuroendocrine network regulating energy balance.

Gastrointestinal Digestion of Food Proteins under the Effects of Released Bioactive Peptides on Digestive Health

The gastrointestinal tract represents a specialized interface between the organism and the external environment. Because of its direct contact with lumen substances, the modulation of digestive functions by dietary substances is supported by a growing body of evidence. Food-derived bioactive peptides have demonstrated a plethora of activities in the organism with increasing interest toward their impact over the digestive system and related physiological effects. This review updates the biological effects of food proteins, specifically milk and soybean proteins, associated to gastrointestinal health and highlights the study of digestion products and released peptides, the identification of the active form/s, and the evaluation of the mechanisms of action underlying their relationship with the digestive cells and receptors. The approach toward the modifications that food proteins and peptides undergo during gastrointestinal digestion and their bioavailability is a crucial step for current investigations on the field. The recent literature on the regulation of digestive functions by peptides has been mostly considered in terms of their influence on gastrointestinal motility and signaling, oxidative damage and inflammation, and malignant cellular proliferation. A final section regarding the actual challenges and future perspectives in this scientific topic is critically discussed.

Effect of Increasing the Dietary Protein Content of Breakfast on Subjective Appetite, Short-Term Food Intake and Diet-Induced Thermogenesis in Children

Dietary protein affects energy balance by decreasing food intake (FI) and increasing energy expenditure through diet-induced thermogenesis (DIT) in adults. Our objective was to investigate the effects of increasing the dietary protein in an isocaloric breakfast on subjective appetite, FI, blood glucose, and DIT in 9-14 y children. Two randomized repeated measures designs were used. In experiment 1, 17 children (9 boys, 8 girls) consumed isocaloric meals (450 kcal) on four separate mornings containing: 7 g (control), 15 g (low protein, LP), 30 g (medium protein, MP) or 45 g (high protein, HP) of protein. Blood glucose and subjective appetite were measured at baseline and regular intervals for 4 h, and FI was measured at 4 h. In experiment 2, 9 children (6 boys, 3 girls) consumed the control or HP breakfast on two separate mornings, and both DIT and subjective appetite were determined over 5 h. In experiment 1, all dietary protein treatments suppressed subjective appetite compared to control (p < 0.001), and the HP breakfast suppressed FI compared with the LP breakfast and control (p < 0.05). In experiment 2, DIT was higher after HP than control (p < 0.05). In conclusion, increasing the dietary protein content of breakfast had favorable effects on satiety, FI, and DIT in children.

Effects of whey protein on glycemic control and serum lipoproteins in patients with metabolic syndrome and related conditions: a systematic review and meta-analysis of randomized controlled clinical trials

Background

This systematic review and meta-analysis aimed to assess the effects of whey protein on serum lipoproteins and glycemic status in patients with metabolic syndrome (MetS) and related disorders.

Methods

Online databases, such as Web of Science, Cochrane Library, PubMed and Scopus were systematically searched by two independent authors from inception until 30th April 2020 for English randomized clinical trials investigating the efficacy of whey protein administration in subjects with Mets or related conditions on the parameters of glycemic and lipid control compared to certain control. In order to evaluate the included studies’ methodological quality, Cochrane Collaboration risk of bias tool was applied. Using Cochrane’s Q test and I-square (I²) statistic, the included trials’ heterogeneity was also examined. Using a random-effects model, data were pooled, and weighted mean difference (WMD) was considered as the overall effect size.

Results

Twenty-two studies were selected to be included in this meta-analysis. Consumption of whey protein resulted in significant reduction of HbA1c (WMD: -0.15; 95% CI: − 0.29, − 0.01) insulin (WMD: -0.94; 95% CI: − 1.68, − 0.21) and homeostasis model assessment-estimated insulin resistance (HOMA-IR) (WMD: -0.20; 95% CI: − 0.36, − 0.05). A significant reduction in triglycerides levels (WMD: -17.12; 95% CI: − 26.52, − 7.72), total cholesterol (WMD: -10.88; 95% CI -18.60, − 3.17), LDL-cholesterol levels (WMD: -8.47 95% CI: − 16.59, − 0.36) and total cholesterol/HDL-cholesterol ratio (WMD: -0.26; 95% CI: − 0.41, − 0.10) was found as well.

Conclusions

This meta-analysis suggests that supplementation with whey protein had beneficial effect on several indicators of glycemic control and lipid parameters in patients with MetS and related conditions.

Screening ultrafiltration membranes to separate lactose and protein from sheep whey: application of simplified model

Several studies demonstrated that protein from whey milk could be a new strategy to reduce energy intake and increase satiety. Sheep whey has high protein content, but it is also rich in lactose. The aim of this study was to screening different ultrafiltration membranes to separate protein and lactose from sheep whey in one step. Protein was recovered in the concentrate feed, and lactose passed through three membranes and was recovered in the permeate feed. Membranes with different chemical composition and molecular weight cut-offs were assayed, and the influence of operating pressure and lactose concentration feed in the permeate flux and lactose rejection coefficients were studied. Lactose separation was not affected by pressure in GR60PP or GR90PP, and 85% and 80%, respectively of the lactose was separated into permeate feed. When the feed concentration increased, lactose separation remained stable in all three membranes, being GR60PP the most efficient, as 90% of the disaccharides were separated. In all cases 100% of the protein was recovered. Finally, the Spiegler-Kedem-Katchalsky model perfectly fitted the results obtained about lactose rejection coefficients.

Very-Low-Calorie Ketogenic Diets With Whey, Vegetable, or Animal Protein in Patients With Obesity: A Randomized Pilot Study

CONTEXT

We compared the efficacy, safety, and effect of 45-day isocaloric very-low-calorie ketogenic diets (VLCKDs) incorporating whey, vegetable, or animal protein on the microbiota in patients with obesity and insulin resistance to test the hypothesis that protein source may modulate the response to VLCKD interventions.

SUBJECTS AND METHODS

Forty-eight patients with obesity (19 males and 29 females, homeostatic model assessment (HOMA) index ≥ 2.5, aged 56.2 ± 6.1 years, body mass index [BMI] 35.9 ± 4.1 kg/m2) were randomly assigned to three 45-day isocaloric VLCKD regimens (≤800 kcal/day) containing whey, plant, or animal protein. Anthropometric indexes; blood and urine chemistry, including parameters of kidney, liver, glucose, and lipid metabolism; body composition; muscle strength; and taxonomic composition of the gut microbiome were assessed. Adverse events were also recorded.

RESULTS

Body weight, BMI, blood pressure, waist circumference, HOMA index, insulin, and total and low-density lipoprotein cholesterol decreased in all patients. Patients who consumed whey protein had a more pronounced improvement in muscle strength. The markers of renal function worsened slightly in the animal protein group. A decrease in the relative abundance of Firmicutes and an increase in Bacteroidetes were observed after the consumption of VLCKDs. This pattern was less pronounced in patients consuming animal protein.

CONCLUSIONS

VLCKDs led to significant weight loss and a striking improvement in metabolic parameters over a 45-day period. VLCKDs based on whey or vegetable protein have a safer profile and result in a healthier microbiota composition than those containing animal proteins. VLCKDs incorporating whey protein are more effective in maintaining muscle performance.

High-Protein Diet Associated with Resistance Training Improves Performance and Decreases Adipose Index in Rats

The study tested the hypothesis that a high protein diet based on isolated whey protein (IWP) associated with strength training improves performance and reduces body fat without promoting health damage. Male Wistar rats, 45 days old, were divided into four groups (n = 8/group): normoprotein sedentary (IWP 14%; NS); hyperprotein sedentary (IWP 35%; HS); normoprotein trained (IWP 14%; NT) and hyperprotein trained (IWP 35%; HT). All groups performed the maximum load test at the beginning and after the vertical ladder training protocol for 6 weeks (3x/week). The performance improved in HT when compared to other groups. There was no difference in the plasma levels of testosterone, IGF-1 and the hematological parameters remained normal. The relative weights of the kidneys were higher in the groups fed with high protein; the liver was higher in HT compared to NS and NT, and the heart was higher in HS compared to NS and NT. Concerning relative muscle weight, quadriceps, and gastrocnemius, HT showed higher value compared to NT. Diet containing 35% isolate whey protein associated with resistance training improved performance as well as increased muscles and organs weight of the animals, without damaging the tissues related to protein metabolism (confirmed by unchanged hematological parameters), which may minimize the risk of developing cardiometabolic disorders.

Effects of High-Intensity Resistance Training on Fitness and Fatness in Older Men With Osteosarcopenia

To date, there has been no study on the long-term effects of resistance exercise on sarcopenia and obesity indices for people with sarcopenia. The present study thus aimed to determine the effect of 18 months of periodized, high-velocity/intensity/effort progressive resistance training (HIT-RT) on body composition and strength in older men with osteosarcopenia. Using a single-blind, two-group parallel design, 43 community-dwelling men, 72 years and older, with osteopenia and sarcopenia in Erlangen-Nürnberg, Germany, were randomly assigned to two study arms by drawing lots: (1) an exercise group that conducted a consistently supervised periodized high-velocity/intensity/effort protocol (HIT-RT; n = 21) on machines twice a week for 18 months or (2) a control group (CG; n = 22) that maintained their physical activity/exercise habits. Both groups were supplied with protein, cholecalciferol, and calcium according to current recommendations. The study outcomes were lean body mass (LBM), total and abdominal body fat as determined by dual-energy X-ray absorptiometry and maximum hip/leg extensor strength as assessed on an isokinetic leg press at baseline and after 8, 12, and 18 months of follow-up. The intention-to-treat principle and multiple imputation were applied to calculated study outcomes. After 18 months of HIT-RT, altogether five participants were lost to follow up (HIT-RT: n = 2, CG: n = 3). The attendance rates (95%) for HIT-RT were high; relevant adverse effects were not observed. Significant effects (i.e., differences between HIT-RT vs. CG) in favor of HIT-RT were determined for LBM (+1.73 kg, 95% CI: +1.13 to +2.32 kg), total body fat mass (-2.44 kg, 95% CI: -1.28 to 3.60 kg), abdominal body fat percentage (-2.68, 95% CI: -1.70 to -3.66), and maximum hip/leg extensor strength (+533 N, 95% CI: +397 to +670 N; all p < 0.001). Even after adjusting for multiple testing, all effects remained significant. Of note, after 8 months of HIT-RT, only slight (LBM and fat indices) to moderate (maximum strength) ongoing effects were observed. Carefully introduced, continuously supervised HIT-RT is an effective, attractive, feasible, and safe method to improve body composition and muscle strength in older community-dwelling men with sarcopenia. However, even when consequently applying principles of exercise intensity progression within the RT protocol, only slight further positive changes were observed after 8 months of exercise.

Milk whey from different animal species stimulates the in vitro release of CCK and GLP-1 through a whole simulated intestinal digestion

Milk whey is effective in enhancing satiety mainly due to its protein composition. Peptides and amino acids derived from digestion of whey protein can act as suppressants of appetite by stimulation of receptors of satiety gut hormones. But, the protein fraction of whey can vary depending on species of animal, season, lactation period, etc. The aim of this study is to evaluate the satiety effect of milk whey from different species of ruminants (cow, sheep, goat and a mixture of them) through a simulated in vitro digestion, which performed the whole gastrointestinal process, from oral digestion to colonic fermentation. The satiety effect of each sample was measured by the production of satiating hormones (CCK and GLP-1) secreted by enteroendocrine cell line (STC-1) after 2 hours of incubation with non-digested, digested and fermented whey. Digested samples have shown to be potent CCK and GLP-1 secretagogues followed by fermented and non-digested samples, showing that the last one showed a weak hormone stimulation. Digested goat whey was the most efficient stimulator of GLP-1 (86.33 ± 4.55 pg mL^-1) and fermented mixture whey produced the major release of CCK (80.78±1.81 pg mL^-1). This study demonstrates that milk whey is a suitable ingredient to stimulate satiety through the effect of peptides, amino acids produced from digestion, and metabolites released by fermentation.

Impact of Protein Intake in Older Adults with Sarcopenia and Obesity: A Gut Microbiota Perspective

The continuous population increase of older adults with metabolic diseases may contribute to increased prevalence of sarcopenia and obesity and requires advocacy of optimal nutrition treatments to combat their deleterious outcomes. Sarcopenic obesity, characterized by age-induced skeletal-muscle atrophy and increased adiposity, may accelerate functional decline and increase the risk of disability and mortality. In this review, we explore the influence of dietary protein on the gut microbiome and its impact on sarcopenia and obesity. Given the associations between red meat proteins and altered gut microbiota, a combination of plant and animal-based proteins are deemed favorable for gut microbiota eubiosis and muscle-protein synthesis. Additionally, high-protein diets with elevated essential amino-acid concentrations, alongside increased dietary fiber intake, may promote gut microbiota eubiosis, given the metabolic effects derived from short-chain fatty-acid and branched-chain fatty-acid production. In conclusion, a greater abundance of specific gut bacteria associated with increased satiation, protein synthesis, and overall metabolic health may be driven by protein and fiber consumption. This could counteract the development of sarcopenia and obesity and, therefore, represent a novel approach for dietary recommendations based on the gut microbiota profile. However, more human trials utilizing advanced metabolomic techniques to investigate the microbiome and its relationship with macronutrient intake, especially protein, are warranted.

Postprandial Metabolic Response to Rapeseed Protein in Healthy Subjects

Plant proteins have become increasingly important for ecological reasons. Rapeseed is a novel source of plant proteins with high biological value, but its metabolic impact in humans is largely unknown. A randomized, controlled intervention study including 20 healthy subjects was conducted in a crossover design. All participants received a test meal without additional protein or with 28 g of rapeseed protein isolate or soy protein isolate (control). Venous blood samples were collected over a 360-min period to analyze metabolites; satiety was assessed using a visual analog scale. Postprandial levels of lipids, urea, and amino acids increased following the intake of both protein isolates. The postprandial insulin response was lower after consumption of the rapeseed protein than after intake of the soy protein (p < 0.05), whereas the postmeal responses of glucose, lipids, interleukin-6, minerals, and urea were comparable between the two protein isolates. Interestingly, the rapeseed protein exerted stronger effects on postprandial satiety than the soy protein (p < 0.05). The postmeal metabolism following rapeseed protein intake is comparable with that of soy protein. The favorable effect of rapeseed protein on postprandial insulin and satiety makes it a valuable plant protein for human nutrition.

Whey protein supplementation reducing fasting levels of anandamide and 2-AG without weight loss in pre-menopausal women with obesity on a weight-loss diet

Background

Despite the importance of dairy proteins in modifying of metabolic abnormalities, no attention has been given to their effects on endocannabinoids.

Methods

A total number of 60 obese women were recruited in a 2-month randomized clinical trial. Following random allocation, they were assigned to one of the two groups: control (n = 30) and intervention (n = 30). Then, all the subjects followed a hypocaloric diet of 800 kcal below estimated energy needs. The intervention group received isocaloric weight-loss diet and whey protein powders (30 g/day). Baseline and 2-month fasting anthropometric, blood glucose, serum insulin, insulin resistance, lipid profile, AEA, and 2-AG were measured.

Results

The study groups were homogenous in terms of baseline characteristics (p > 0.05) except for MUFA intake (p = 0.021). There were no significant differences in energy and macronutrient intakes in the intervention group compared to the control group at the end of the study (p > 0.05). The results of the ANCOVA did not show significant reductions in body weight and BMI of the intervention group compared to the control group (p > 0.05); however, WC, body fat, FBS, AEA, 2-AG, total cholesterol, and triglyceride decreased and HDL-c significantly increased in the intervention group compared to the control group (p < 0.05).

Conclusions

In this study, the effects of simultaneous weight-loss diet and whey protein supplementation on the reduction of endocannabinoids were determined.

Trial registration

Iranian Registry of Clinical Trials IRCT2017021410181N8. Registered on March 2017.

[Iron status, weight changes and body composition during anemia recovery in an experimental model: the effect of fermented goat or cow milk]

Introduction

Objective: to provide detailed information on iron status, body changes, food intake, hepatosomatic index, and body composition during recovery from severe iron deficiency anemia with fermented cow or goat milk. Material and methods: sixty male Wistar albino rats were divided into two experimental groups (control and anemic) and fed ad libitum an AIN-93G diet for 40 days, receiving a normal Fe diet (45 mg/kg of diet) or a low-Fe diet (5 mg/kg of diet), respectively. After induction of anemia, both the control and anemic groups were additionally fed for 30 days either a fermented cow milk-based or fermented goat milk-based diet with normal Fe content. Hematological and iron-related biochemical parameters, weight changes, food intake, hepatosomatic index, and body composition were assessed. Results: The hepatosomatic index was higher in the anemic group versus the control group. In both groups fed a fermented goat milk-based diet the hepatosomatic index was higher due to lower body weight and a higher liver weight. Food intake, weight gain, and total body fat were lower, whereas lean mass and free and total water were higher in the anemic group as compared to the control group. In both animal groups fed a fermented goat milk-based diet body weight and body fat were lower and the percentages of lean mass and free water and total water were higher. Conclusion: Iron deficiency decreased weight gain, lean mass, and body fat, indicating lower energy stores. Fermented goat milk-based diet recovers more efficiently iron status, decreased adiposity, and increased energy expenditure.

Challenging energy balance - during sensitivity to food reward and modulatory factors implying a risk for overweight - during body weight management including dietary restraint and medium-high protein diets

Energy balance is a key concept in the etiology and prevalence of obesity and its co-morbidities, as well as in the development of possible treatments. If energy intake exceeds energy expenditure, a positive energy balance develops and the risk for overweight, obesity, and its co-morbidities increases. Energy balance is determined by energy homeostasis, and challenged by sensitivity to food reward, and to modulatory factors such as circadian misalignment, high altitude, environmental temperature, and physical activity. Food reward and circadian misalignment increase the risk for overweight and obesity, while high altitude, changes in environmental temperature, or physical activity modulate energy balance in different directions. Modulations by hypobaric hypoxia, lowering environmental temperature, or increasing physical activity have been hypothesized to contribute to body weight loss and management, yet no clear evidence has been shown. Dietary approach as part of a lifestyle approach for body weight management should imply reduction of energy intake including control of food reward, thereby sustaining satiety and fat free body mass, sustaining energy expenditure. Green tea catechins and capsaicin in red pepper in part meet these requirements by sustaining energy expenditure and increasing fat oxidation, while capsaicin also suppresses hunger and food intake. Protein intake of at least 0,8 g/kg body weight meets these requirements in that it, during decreased energy intake, increases food intake control including control of food reward, and counteracts adaptive thermogenesis. Prevention of overweight and obesity is underscored by dietary restraint, implying control of sensitivity to challenges to energy balance such as food reward and circadian misalignment. Treatment of overweight and obesity may be possible using a medium-high protein diet (0,8-1,2 g/kg), together with increased dietary restraint, while controlling challenges to energy balance.

Effects of dietary supplementation in sport and exercise: a review of evidence on milk proteins and amino acids

Dietary supplements, especially protein, are used by athletes to achieve the exercise and training daily demands, and have been receiving research focus on their role regarding recovery and performance. Protein supplements are preferred over traditional protein sources because of their ease of availability and use. In addition to consuming a complete protein supplement, such as whey protein, the ingestion of a supplement containing only amino acids has been of interest for promoting skeletal muscle anabolism and high-quality weight loss. The aim of this study was to review the existing evidence on the effects of protein and amino acid supplementation on exercise. The preponderance of evidence suggests that protein supplementation, especially milk proteins, potentiate muscle protein synthesis, lean mass and exercise recovery. Unlike proteins, amino acids supplementation (branched-chain amino acids, glutamine or leucine) results from research are equivocal and are not warranted.

The Appetite-Suppressant and GLP-1-Stimulating Effects of Whey Proteins in Obese Subjects are Associated with Increased Circulating Levels of Specific Amino Acids

The satiating effect of whey proteins depends upon their unique amino acid composition because there is no difference when comparing whey proteins or a mix of amino acids mimicking the amino acid composition of whey proteins. The specific amino acids underlying the satiating effect of whey proteins have not been investigated to date.

AIMS AND METHODS

The aim of the present study was to evaluate the appetite-suppressant effect of an isocaloric drink containing whey proteins or maltodextrins on appetite (satiety/hunger measured by a visual analogue scale or VAS), anorexigenic gastrointestinal peptides (circulating levels of glucagon-like peptide 1 (GLP-1) and peptide tyrosine tyrosine (PYY)) and amino acids (circulating levels of single, total [TAA] and branched-chain amino acids [BCAA]) in a cohort of obese female subjects (n = 8; age: 18.4 ± 3.1 years; body mass index, BMI: 39.2 ± 4.6 kg/m²).

RESULTS

Each drink significantly increased satiety and decreased hunger, the effects being more evident with whey proteins than maltodextrins. Similarly, circulating levels of GLP-1, PYY and amino acids (TAA, BCAA and alanine, arginine, asparagine, citrulline, glutamine, hydroxyproline, isoleucine, histidine, leucine, lysine, methionine, ornithine, phenylalanine, proline, serine, threonine, tyrosine, and valine) were significantly higher with whey proteins than maltodextrins. In subjects administered whey proteins (but not maltodextrins), isoleucine, leucine, lysine, methionine, phenylalanine, proline, tyrosine, and valine were significantly correlated with hunger (negatively), satiety, and GLP-1 (positively).

CONCLUSIONS

Eight specific amino acids (isoleucine, leucine, lysine, methionine, phenylalanine, proline, tyrosine, and valine) were implicated in the appetite-suppressant and GLP-1-stimulating effects of whey proteins, which may be mediated by their binding with nutrient-sensing receptors expressed by L cells within the gastrointestinal wall. The long-term satiating effect of whey proteins and the effectiveness of a supplementation with these amino acids (i.e., as a nutraceutical intervention) administered during body weight reduction programs need to be further investigated.