Weight loss and total lipid profile changes in overweight women consuming beef or chicken as the primary protein source

Beef Consumption and Cardiovascular Disease Risk Factors: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background

Results from observational studies suggest associations of red meat intake with increased risk of cardiovascular disease (CVD); however, RCTs have not clearly demonstrated a link between red meat consumption and CVD risk factors. Further, the specific effects of beef, the most consumed red meat in the United States, have not been extensively investigated.

Objectives

This study aimed to perform a systematic review and meta-analysis of RCT data evaluating the effects of minimally or unprocessed beef intake on CVD risk factors in adults.

Methods

A search of the literature was conducted using PubMed and CENTRAL databases. RCTs in adults that provided diets with fresh or minimally processed beef were included. Data were extracted, and pooled estimates from random-effects models were expressed as standardized mean differences (SMDs) between the beef intervention and comparator intervention with less or no beef. Sensitivity and subgroup analyses were also performed.

Results

Twenty relevant RCTs that met the criteria were included. Beef intake did not impact blood pressure or most lipoprotein-related variables, including total cholesterol, HDL-cholesterol, triglycerides, non-HDL-cholesterol, apolipoprotein A or B, and VLDL-cholesterol. Beef consumption had a small but significant effect on LDL-cholesterol (0.11; 95% CI: 0.008, 0.20; P = 0.03), corresponding to ∼2.7 mg/dL higher LDL-cholesterol in diets containing more beef than that in low-beef or -o beef comparator diets. Sensitivity analyses show this effect was lost when 1 influential study was removed.

Conclusions

Daily unprocessed beef intake do not significantly affect most blood lipids, apolipoproteins, or blood pressures, except for a small increase in LDL-cholesterol compared with diets with less or no beef. Thus, there may be other factors influencing the association of red meat and beef on CVD risk that deserve further investigation.This study was registered at INPLASY as 202420013.

Impacts of dietary animal and plant protein on weight and glycemic control in health, obesity and type 2 diabetes: friend or foe?

It is well established that high-protein diets (i.e. ~25-30% of energy intake from protein) provide benefits for achieving weight loss, and subsequent weight maintenance, in individuals with obesity, and improve glycemic control in type 2 diabetes (T2D). These effects may be attributable to the superior satiating property of protein, at least in part, through stimulation of both gastrointestinal (GI) mechanisms by protein, involving GI hormone release and slowing of gastric emptying, as well as post-absorptive mechanisms facilitated by circulating amino acids. In contrast, there is evidence that the beneficial effects of greater protein intake on body weight and glycemia may only be sustained for 6-12 months. While both suboptimal dietary compliance and metabolic adaptation, as well as substantial limitations in the design of longer-term studies are all likely to contribute to this contradiction, the source of dietary protein (i.e. animal vs. plant) has received inappropriately little attention. This issue has been highlighted by outcomes of recent epidemiological studies indicating that long-term consumption of animal-based protein may have adverse effects in relation to the development of obesity and T2D, while plant-based protein showed either protective or neutral effects. This review examines information relating to the effects of dietary protein on appetite, energy intake and postprandial glycemia, and the relevant GI functions, as reported in acute, intermediate- and long-term studies in humans. We also evaluate knowledge relating to the relevance of the dietary protein source, specifically animal or plant, to the prevention, and management, of obesity and T2D.

White meat consumption and risk of cardiovascular disease and type 2 diabetes: a systematic review and meta-analysis

Objectives

The aim was to systematically review the associations among white meat consumption, cardiovascular diseases (CVD), and type 2 diabetes (T2D).

Methods

Databases MEDLINE, Embase, and Cochrane Central Register of Controlled Trials and Scopus were searched (15th October 2021) for randomized intervention trials (RCTs, ≥ 4 weeks of duration) and prospective cohort studies (≥12 month of follow-up) assessing the consumption of white meat as the intervention/exposure. Eligible outcomes for RCTs were cardiometabolic risk factors and for cohorts, fatal and non-fatal CVD and incident T2D. Risk of bias was estimated using the Cochrane's RoB2 and Risk of Bias for Nutrition Observational Studies. Meta-analysis was conducted in case of ≥3 relevant intervention studies or ≥5 cohort studies using random-effects models. The strength of evidence was evaluated using the World Cancer Research Fund's criteria.

Results

The literature search yielded 5,795 scientific articles, and after screening 43 full-text articles, 23 cohort studies and three intervention studies were included. All included intervention studies matched fat content of intervention and control diets, and none of them showed any significant effects on the selected outcomes of white meat when compared to red meat. Findings from the cohort studies generally did not support any associations between white meat intake and outcomes. Meta-analyses were conducted for CVD mortality (RR: 0.95, 95% CI: 0.87-1.02, P = 0.23, I2 = 25%) and T2D incidence (RR: 0.98, 95% CI: 0.87-1.11, P = 0.81, I2 = 82%).

Conclusion

The currently available evidence does not indicate a role, beneficial or detrimental, of white meat consumption for CVD and T2D. Future studies investigating potentially different health effects of processed versus unprocessed white meat and substitution of red meat with white meat are warranted.Registration: Prospero registration CRD42022295915.

Comparative analysis of lifestyle behaviors and dietary intake among obese and non-obese individuals following bariatric surgery: a secondary data analysis from 2020 to 2022

Objective

The aim of this research is to perform a comparative examination of lifestyle habits and dietary consumption between obese and non-obese subjects who have undergone bariatric surgery. This is done with the intent of investigating the disparities in obesity outcomes attributable to these elements.

Method

This study involves a secondary analysis of cross-sectional data obtained from the Sharik Diet and Health National Survey (SDHNS). To ensure a representative distribution of participants, the SDHNS employs a proportional quota sampling strategy, with stratification based on age, sex, and geographic location within Saudi Arabia's 13 administrative regions, utilizing the ZDataCloud® system for this purpose. The data, collected between 2020 and 2022 from over 15,000 participants, were screened to identify the eligible records of individuals who underwent bariatric surgery.

Results

Within the entire sample, a mere 5.0% (806 individuals) had undertook bariatric surgery, with females comprising 54% of this specific subgroup. The average age within this group was 38.85 years (SD 13.02) and range (18-87). Post-operative results showed that 33% of these individuals remained classified as obese. Utilizing the backward likelihood ratio regression model, it was determined that factors including age, decreased consumption of fresh juices and chicken, as well as current tobacco use, were significantly associated with persistent obesity.

Conclusion

The findings of this study suggest an association between the non-obese group and healthier lifestyle choices, including the consumption of high-protein diets and fresh juices, alongside a decreased prevalence of smoking. These observations underscore the significance of maintaining a healthy lifestyle for positive weight loss outcomes following bariatric surgery.

Poultry Consumption and Human Cardiometabolic Health-Related Outcomes: A Narrative Review

Poultry meats, in particular chicken, have high rates of consumption globally. Poultry is the most consumed type of meat in the United States (US), with chicken being the most common type of poultry consumed. The amounts of chicken and total poultry consumed in the US have more than tripled over the last six decades. This narrative review describes nutritional profiles of commonly consumed chicken/poultry products, consumption trends, and dietary recommendations in the US. Overviews of the scientific literature pertaining to associations between, and effects of consuming chicken/poultry on, body weight and body composition, cardiovascular disease (CVD), and type II diabetes mellitus (T2DM) are provided. Limited evidence from randomized controlled trials indicates the consumption of lean unprocessed chicken as a primary dietary protein source has either beneficial or neutral effects on body weight and body composition and risk factors for CVD and T2DM. Apparently, zero randomized controlled feeding trials have specifically assessed the effects of consuming processed chicken/poultry on these health outcomes. Evidence from observational studies is less consistent, likely due to confounding factors such as a lack of a description of and distinctions among types of chicken/poultry products, amounts consumed, and cooking and preservation methods. New experimental and observational research on the impacts of consuming chicken/poultry, especially processed versions, on cardiometabolic health is sorely needed.

Total meat (flesh) supply may be a significant risk factor for cardiovascular diseases worldwide

Consumption of red meat instead of white meat has typically been associated with cardiovascular diseases (CVDs). Reflecting actual diet patterns, this study explored the role of total meat (red + white) in predicting CVD incidence. Data from 217 countries were extracted from United Nations agencies for the analyses in five steps. Bivariate correlations were applied to examine the relationship between total meat and CVD incidence globally and regionally. Partial correlation was applied to identify that total meat was an independent predictor of CVD incidence while socioeconomic status, obesity, and urbanization were statistically constant. Stepwise linear regression was conducted for selecting the significant predictor of CVD incidence. SPSS 28 and Microsoft Excel were used for correlation analyses. Globally, total meat correlated to CVD incidence strongly and significantly in bivariate correlation models. This relationship remained significant in partial correlation when socioeconomic status, obesity, and urbanization were statistically kept constant. Stepwise multiple regression identified that, second to socioeconomic status, total meat was a significant predictor of CVD incidence. Total meat correlated to CVD incidence in different country groupings. However, the correlations between total meat and CVD incidence were significantly stronger in developing countries than in developed countries. Worldwide, total meat (flesh) consumption correlated to CVD incidence independently, but significantly stronger in developing countries than in developed countries. This correlation is worth exploring further in longitudinal cohort studies.

Effect of Consuming Beef with Varying Fatty Acid Compositions as a Major Source of Protein in Volunteers under a Personalized Nutritional Program

Beef is an excellent source of nutrients; unfortunately, most nutritional recommendations suggest limiting or even avoiding it. Studies have shown that the fatty acid composition of meat influences weight loss. This randomized controlled clinical trial evaluated the anthropometric and serum lipid changes after a food intervention that included frequent beef consumption (120 g consumed four days/week for four weeks). Volunteers were randomly assigned to the commercial or Wagyu-Cross beef groups, with the latter beef possessing higher fat and MUFA contents. Both groups exhibited reductions in body measurements and lipid profiles; however, the Wagyu-Cross group exhibited greater changes in weight (-3.75 vs. -2.90 kg) and BMI (-1.49 vs. -1.03) than the commercial group, without a significant difference between them. No significant group differences in lipid profiles were observed; however, the Wagyu-Cross group exhibited a more favorable change in decreasing the TC concentration (-7.00 mg/dL) and LDL-C concentration (-12.5 mg/dL). We suggest that high MUFA beef could be included in weight-loss programs since it does not affect weight loss and hasn't a negative influence on lipid metabolism.

Effects of Thai native chicken breast meat consumption on serum uric acid level, biochemical parameters, and antioxidant activities in rats

This study aimed to evaluate the effect of a high protein diet comprising breast meat from commercial broiler (BR), Thai native (PD), and commercial broiler × Thai native crossbred (KKU-ONE) chicken on serum uric acid, biochemical parameters, and antioxidant activities in rats. Male Sprague–Dawley rats were divided into four groups. The control group received a standard chow diet, and the other three groups were fed a high protein diet (70% standard diet + 30% BR, PD, or KKU-ONE chicken breast) for five weeks. The PD- and KKU-ONE-fed rats had lower plasma total cholesterol and triglyceride levels than the control rats. A decrease in HDL-c was also observed in rats fed a diet containing BR. Liver weight, liver enzyme, plasma ALP, xanthine oxidase activity, serum uric acid, creatinine, superoxide production, and plasma malondialdehyde levels increased in BR-fed rats. The findings of this study might provide evidence to support the use of Thai native and Thai native crossbred chicken breast meat as functional foods.

Is protein the forgotten ingredient: Effects of higher compared to lower protein diets on cardiometabolic risk factors. A systematic review and meta-analysis of randomised controlled trials

BACKGROUND AND AIMS

Higher protein (HP) diets may lead to lower cardiometabolic risk, compared to lower protein (LP) diets. This systematic review and meta-analysis aims to investigate the effects of HP versus LP diets on cardiometabolic risk factors in adults, using the totality of the current evidence from randomised controlled trials (RCTs).

METHODS

Systematic searches were conducted in electronic databases, up to November 2020. Random effects meta-analyses were conducted to pool the standardised mean differences (SMD) and 95% confidence intervals (CI). The main outcomes were weight loss, body mass index (BMI), waist circumference, fat mass, systolic and diastolic BP, total cholesterol, HDL-and LDL-cholesterol, triacylglycerol, fasting glucose and insulin, and glycated haemoglobin.

RESULTS

Fifty-seven articles reporting on 54 RCTs were included, involving 4344 participants (65% female, mean age: 46 (SD 10) years, mean BMI: 33 (SD 3) kg/m²), with a mean study duration of 18 weeks (range: 4 to 156 weeks). Compared to LP diets (range protein (E%):10-23%), HP diets (range protein (E%): 20-45%) led to more weight loss (SMD -0.13, 95% CI: -0.23, -0.03), greater reductions in fat mass (SMD -0.14, 95% CI: -0.24, -0.04), systolic BP (SMD -0.12, 95% CI: -0.21, -0.02), total cholesterol (SMD -0.11, 95% CI: -0.19, -0.02), triacylglycerol (SMD -0.22, 95% CI: -0.30, -0.14) and insulin (SMD -0.12, 95% CI: -0.22, -0.03). No significant differences were observed for the other outcomes.

CONCLUSIONS

Higher protein diets showed small, but favourable effects on weight loss, fat mass loss, systolic blood pressure, some lipid outcomes and insulin, compared to lower protein diets.

Improvement of serum lipid parameters in consumers of Mexican Wagyu-Cross beef: A randomized controlled trial

Beef is considered an excellent source of high-quality protein and micronutrients. The high saturated fatty acid (SFA) composition of beef has been associated with cardiovascular diseases; however, this is a controversial issue because at present, no evidence has scientifically proven such an association. Wagyu cattle have been used as an option to generate high-quality fatty acids (FAs) in beef and have been crossed with local beef cattle (Wagyu-Cross). In Mexico, Wagyu-Cross is marketed assuming the same quality as purebred Wagyu meat without scientific support. This study aimed to determine whether the differences in the FA composition of Wagyu-Cross and commercial beef affected lipid metabolism in frequent consumers of beef. The study is a randomized, controlled, double-blinded phase IV clinical trial. Thirty-four volunteers completed treatments in which 120 g ground beef was consumed 3 days per week for 2 weeks. Volunteers were randomized to the "A" (commercial meat) or "B" (Wagyu-Cross meat) groups. The beef fat content was 87% higher, the SFA content was 2.3% lower, and the monounsaturated fatty acid (MUFA) C18:1 n-9 concentrations were higher in Wagyu-Cross beef than in commercial beef. The B group exhibited a significantly larger change from baseline in the serum lipid profile in total cholesterol (TC) (-4.7% versus +6.9%), low-density lipoprotein (LDL) (-4.1% versus +10.0%), nonhigh-density lipoprotein (non-HDL) (-6.1% versus +4.9%), and the ratio of three atherogenic indexes-TC/HDL (-3.5% versus +6.4%), LDL/HDL (-2.8% versus +14.6%), and non-HDL/HDL (-4.7% versus +9.3%)-than the A group. This result confirms that meat FA composition is a key point for redirecting cattle breeding strategies and promotes beef as a healthful protein source. PRACTICAL APPLICATION: Here, we found new evidence based on a clinical trial that beef with a favorable fatty acid composition (i.e., monounsaturated fatty acid and polyunsaturated fatty acid content) is a key factor in improving parameters associated with consumer health. This information will support the design of cattle breeding strategies as an option to promote beef consumption as a healthier protein source and create opportunities for the development of the functional food industry.

The impact of type of dietary protein, animal versus vegetable, in modifying cardiometabolic risk factors: A position paper from the International Lipid Expert Panel (ILEP)

Proteins play a crucial role in metabolism, in maintaining fluid and acid-base balance and antibody synthesis. Dietary proteins are important nutrients and are classified into: 1) animal proteins (meat, fish, poultry, eggs and dairy), and, 2) plant proteins (legumes, nuts and soy). Dietary modification is one of the most important lifestyle changes that has been shown to significantly decrease the risk of cardiovascular (CV) disease (CVD) by attenuating related risk factors. The CVD burden is reduced by optimum diet through replacement of unprocessed meat with low saturated fat, animal proteins and plant proteins. In view of the available evidence, it has become acceptable to emphasize the role of optimum nutrition to maintain arterial and CV health. Such healthy diets are thought to increase satiety, facilitate weight loss, and improve CV risk. Different studies have compared the benefits of omnivorous and vegetarian diets. Animal protein related risk has been suggested to be greater with red or processed meat over and above poultry, fish and nuts, which carry a lower risk for CVD. In contrast, others have shown no association of red meat intake with CVD. The aim of this expert opinion recommendation was to elucidate the different impact of animal vs vegetable protein on modifying cardiometabolic risk factors. Many observational and interventional studies confirmed that increasing protein intake, especially plant-based proteins and certain animal-based proteins (poultry, fish, unprocessed red meat low in saturated fats and low-fat dairy products) have a positive effect in modifying cardiometabolic risk factors. Red meat intake correlates with increased CVD risk, mainly because of its non-protein ingredients (saturated fats). However, the way red meat is cooked and preserved matters. Thus, it is recommended to substitute red meat with poultry or fish in order to lower CVD risk. Specific amino acids have favourable results in modifying major risk factors for CVD, such as hypertension. Apart from meat, other animal-source proteins, like those found in dairy products (especially whey protein) are inversely correlated to hypertension, obesity and insulin resistance.

Producing high-oleic acid beef and the impact of ground beef consumption on risk factors for cardiovascular disease: A review

This review summarizes the effects of high-oleic acid oil and high-oleic acid ground beef interventions on risk factors for cardiovascular disease (CVD) in human trials, and also summarizes studies designed to increase the amount of oleic acid (18:1n-9) in beef. In three human trials, high-oleic acid oils and high-oleic acid ground beef increased plasma high-density lipoprotein cholesterol over baseline values or over high-carbohydrate diets. Neither low-oleic acid nor high-oleic acid ground beef increased risk factors for CVD, confirming earlier studies that used high-oleic acid oils. High-oleic acid beef can be obtained from cattle fed a corn-based finishing diet to USDA Grade of USDA Choice or greater; from beef from cattle with Japanese genetics; and from the brisket. Beef from grass-fed cattle contains more n-3 fatty acids than beef from conventionally-fed cattle, but also contains greater amounts of saturated and trans-fatty acids.

Combined effect of ultrasound and sodium bicarbonate marination on chicken breast tenderness and its molecular mechanism

The objective of this study was to explore the combined effect of ultrasound (20 kHz ultrasound probe (12 mm diameter), an output power of 350 W for 5 min (on-time and off-time pulse durations of 2 s and 3 s, respectively)) with low concentration (0.2 M) sodium bicarbonate solution (USB) on chicken breast tenderness and its preliminary molecular mechanism. Therefore, myofibril fragmentation index (MFI), filtering residues, cooking loss, shear force, histology of meat as well as SDS-PAGE, circular dichroism (CD), synchronous fluorescence spectroscopy, differential scanning calorimetrv (DSC) of actomyosin were investigated and compared with untreated (Control), deionized water (DW), ultrasound in deionized water (UDW), 0.2 M sodium bicarbonate solution (SB), respectively. The results showed that USB can effectively increase MFI, and reduce filtering residues, cooking loss and shear force by compared with UDW or SB. Furthermore, myofibril was presented with the largest interfibrillary spaces and the highest degree of actomyosin dissociation in USB group. The increase in α-helix content and decrease in fluorescence intensity of tyrosine and tryptophan implied that USB caused the conformation change in actomyosin. Additionally, actomyosin in USB group became more sensitive to temperature. Therefore, the treatment of ultrasound combined with low concentration of sodium bicarbonate accelerated actomyosin degeneration was considered as a promising and efficient technique in meat processing, especially for the fitness enthusiasts.

Effects of red meat, white meat, and nonmeat protein sources on atherogenic lipoprotein measures in the context of low compared with high saturated fat intake: a randomized controlled trial

BACKGROUND

Dietary recommendations to limit red meat are based on observational studies linking intake to cardiovascular disease (CVD) risk together with the potential of its saturated fatty acid (SFA) content to raise low-density lipoprotein (LDL) cholesterol. However, the relation of white meat to CVD risk, and the effects of dietary protein source on lipoprotein particle subfractions, have not been extensively evaluated.

OBJECTIVE

We tested whether levels of atherogenic lipids and lipoproteins differed significantly following consumption of diets with high red meat content compared with diets with similar amounts of protein derived from white meat or nonmeat sources, and whether these effects were modified by concomitant intake of high compared with low SFAs.

METHODS

Generally healthy men and women, 21-65 y, body mass index 20-35 kg/m2, were randomly assigned to 1 of 2 parallel arms (high or low SFA) and within each, allocated to red meat, white meat, and nonmeat protein diets consumed for 4 wk each in random order. The primary outcomes were LDL cholesterol, apolipoprotein B (apoB), small + medium LDL particles, and total/high-density lipoprotein cholesterol.

RESULTS

Analysis included participants who completed all 3 dietary protein assignments (61 for high SFA; 52 for low SFA). LDL cholesterol and apoB were higher with red and white meat than with nonmeat, independent of SFA content (P < 0.0001 for all, except apoB: red meat compared with nonmeat [P = 0.0004]). This was due primarily to increases in large LDL particles, whereas small + medium LDL and total/high-density lipoprotein cholesterol were unaffected by protein source (P = 0.10 and P = 0.51, respectively). Primary outcomes did not differ significantly between red and white meat. Independent of protein source, high compared with low SFA increased LDL cholesterol (P = 0.0003), apoB (P = 0.0002), and large LDL (P = 0.0002).

CONCLUSIONS

The findings are in keeping with recommendations promoting diets with a high proportion of plant-based food but, based on lipid and lipoprotein effects, do not provide evidence for choosing white over red meat for reducing CVD risk. This trial was registered at Clinicaltrials.gov as NCT01427855.

The Impact of Different Animal-Derived Protein Sources on Adiposity and Glucose Homeostasis during Ad Libitum Feeding and Energy Restriction in Already Obese Mice

Low-fat diets and energy restriction are recommended to prevent obesity and to induce weight loss, but high-protein diets are popular alternatives. However, the importance of the protein source in obesity prevention and weight loss is unclear. The aim of this study was to investigate the ability of different animal protein sources to prevent or reverse obesity by using lean or obese C57BL/6J mice fed high-fat/high-protein or low-fat diets with casein, cod or pork as protein sources. Only the high-fat/high-protein casein-based diet completely prevented obesity development when fed to lean mice. In obese mice, ad libitum intake of a casein-based high-fat/high-protein diet modestly reduced body mass, whereas a pork-based high-fat/high-protein diet aggravated the obese state and reduced lean body mass. Caloric restriction of obese mice fed high-fat/high-protein diets reduced body weight and fat mass and improved glucose tolerance and insulin sensitivity, irrespective of the protein source. Finally, in obese mice, ad libitum intake of a low-fat diet stabilized body weight, reduced fat mass and increased lean body mass, with the highest loss of fat mass found in mice fed the casein-based diet. Combined with caloric restriction, the casein-based low-fat diet resulted in the highest loss of fat mass. Overall, the dietary protein source has greater impact in obesity prevention than obesity reversal.

Dietary Proteins, Brown Fat, and Adiposity

High protein diets have become popular for body weight maintenance and weight loss despite controversies regarding efficacy and safety. Although both weight gain and weight loss are determined by energy consumption and expenditure, data from rodent trials consistently demonstrate that the protein:carbohydrate ratio in high fat diets strongly influences body and fat mass gain per calorie eaten. Here, we review data from rodent trials examining how high protein diets may modulate energy metabolism and the mechanisms by which energy may be dissipated. We discuss the possible role of activating brown and so-called beige/BRITE adipocytes including non-canonical UCP1-independent thermogenesis and futile cycles, where two opposing metabolic pathways are operating simultaneously. We further review data on how the gut microbiota may affect energy expenditure. Results from human and rodent trials demonstrate that human trials are less consistent than rodent trials, where casein is used almost exclusively as the protein source. The lack of consistency in results from human trials may relate to the specific design of human trials, the possible distinct impact of different protein sources, and/or the differences in the efficiency of high protein diets to attenuate obesity development in lean subjects vs. promoting weight loss in obese subjects.

Effect of Nigella sativa supplementation on obesity indices: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & OBJECTIVE(S)

No meta-analysis is available on the effect of Nigella sativa (NS) on obesity indices. This systematic review and meta-analysis was conducted to systematically review the available Randomized Clinical Trials (RCTs) that examined the effects of NS on Body Weight (BW), Body Mass index (BMI), and Waist Circumference (WC) in adults.

METHODS

Relevant articles published up to January 2018 were searched through PubMed/Medline, SCOPUS, Cochrane Library, and Google Scholar databases, using relevant keywords. All RCTs that examined the effect of NS supplementation on BW, BMI, or WC were included.

RESULTS

Overall, thirteen RCTs, including 875 subjects (64% males) were included in this study. Combining effect sizes from ten studies, NS supplementation significantly reduced BW (Weighted Mean Differences (WMD): -1.76 kg, 95% CI: -3.34 to -0.17, I² = 87.4%), as compared to placebo. Subgroup analysis by the intervention type (I² = 0.0%), participants' gender (I² = 0.0%), and age (I² = 5.5%) removed between-study heterogeneity. A significant reduction was seen in BMI (WMD: -0.85 kg/m², 95% CI: -1.23, -0.46, I² = 70.6%) after NS supplementation than placebo among eleven trials. Subgroup analysis based on study duration (I² = 0.0%), participants' gender (females: I² = 0.0% & both genders: I² = 20.9%), an age (I² = 35.9%) disappeared the heterogeneity. However, no significant reduction was found in WC comparing NS supplementation to placebo (WMD: -4.04 cm, 95% CI: 11.37, 3.27, I² = 97.8%) in five studies.

CONCLUSIONS

We find a significant effect of NS supplementation on BW and BMI in adults. However, the effect of NS supplementation on WC was not significant in this meta-analysis.

Dietary Intake of Protein from Different Sources and Weight Regain, Changes in Body Composition and Cardiometabolic Risk Factors after Weight Loss: The DIOGenes Study

An increase in dietary protein intake has been shown to improve weight loss maintenance in the DIOGenes trial. Here, we analysed whether the source of the dietary proteins influenced changes in body weight, body composition, and cardiometabolic risk factors during the weight maintenance period while following an energy-restricted diet. 489 overweight or obese participants of the DIOGenes trial from eight European countries were included. They successfully lost >8% of body weight and subsequently completed a six month weight maintenance period, in which they consumed an ad libitum diet varying in protein content and glycemic index. Dietary intake was estimated from three-day food diaries. A higher plant protein intake with a proportional decrease in animal protein intake did not affect body weight maintenance or cardiometabolic risk factors. A higher plant protein intake from non-cereal products instead of cereal products was associated with benefits for body weight maintenance and blood pressure. Substituting meat protein for protein from other animal sources increased insulin and HOMA-IR (homeostasis model assessment of insulin resistance). This analysis suggests that not only the amount of dietary proteins, but also the source may be important for weight and cardiometabolic risk management. However, randomized trials are needed to test the causality of these associations.

Comparison of High-Protein, Intermittent Fasting Low-Calorie Diet and Heart Healthy Diet for Vascular Health of the Obese

AIM

It has been debated whether different diets are more or less effective in long-term weight loss success and cardiovascular disease prevention among men and women. To further explore these questions, the present study evaluated the combined effects of a high-protein, intermittent fasting, low-calorie diet plan compared with a heart healthy diet plan during weight loss, and weight loss maintenance on blood lipids and vascular compliance of obese individuals.

METHODS

The experiment involved 40 obese adults (men, n = 21; women, n = 19) and was divided into two phases: (a) 12-week high-protein, intermittent fasting, low-calorie weight loss diet comparing men and women (Phase 1) and (b) a 1-year weight maintenance phase comparing high-protein, intermittent fasting with a heart healthy diet (Phase 2). Body weight, body mass index (BMI), blood lipids, and arterial compliance outcomes were assessed at weeks 1 (baseline control), 12 (weight loss), and 64 (12 + 52 week; weight loss maintenance).

RESULTS

At the end of weight loss intervention, concomitant reductions in body weight, BMI and blood lipids were observed, as well as enhanced arterial compliance. No sex-specific differences in responses were observed. During phase 2, the high-protein, intermittent fasting group demonstrated a trend for less regain in BMI, low-density lipoprotein (LDL), and aortic pulse wave velocity than the heart healthy group.

CONCLUSION

Our results suggest that a high-protein, intermittent fasting and low-calorie diet is associated with similar reductions in BMI and blood lipids in obese men and women. This diet also demonstrated an advantage in minimizing weight regain as well as enhancing arterial compliance as compared to a heart healthy diet after 1 year.

Weight-Loss Outcomes: A Systematic Review and Meta-Analysis of Intermittent Energy Restriction Trials Lasting a Minimum of 6 Months

The aim of this systematic review and meta-analysis is to summarise the effects of intermittent energy restriction on weight and biological markers in long term intervention studies of >6 months duration. An electronic search was performed using the MEDLINE, EMBASE and the Cochrane Library databases for intervention trials lasting 6 months or longer investigating the effects of intermittent energy restriction. A total of nine studies were identified as meeting the pre-specified criteria. All studies included an intermittent energy restriction arm, with six being directly compared to continuous energy restriction. A total of 981 subjects were enrolled and randomised, with weight loss observed in all intermittent energy restriction arms regardless of study duration or follow up length. Eight interventions in six trials were used for the meta-analyses, with results indicating neither intermittent or continuous energy restriction being superior with respect to weight loss, 0.084 ± 0.114 (overall mean difference between groups ± standard error; p = 0.458). The effects of intermittent energy restriction in the long term remain unclear. The number of long term studies conducted is very limited, and participant numbers typically small (less than 50 completers), indicating the need for larger, long term trials of 12 months or more, to be conducted in order to understand the impact of intermittent energy restriction on weight loss and long term weight management. Blood lipid concentrations, glucose, and insulin were not altered by intermittent energy expenditure in values greater than those seen with continuous energy restriction.

β-carotene and retinol contents in the meat of herbivorous ungulates with a special reference to their public health importance

The aim of this study was to estimate total carotenoids, β-carotene and retinol concentrations in the livers and muscles of some ungulates (cattle, buffalo, sheep, goats and horses) in comparison with the Wistar rats as a control. Cattle and horses had the highest contents of total carotenoids and β-carotene. Unexpectedly, sheep was the highest accumulator of retinol with a mean concentration of 203 ± 23.34 µg/g, while the least accumulator was buffalo, having a mean value of 58.28 ± 13.77 µg/g. Livers had higher contents of the examined phytochemicals than muscles. Consumption of these tissues may provide human with some needs from these important phytochemicals, though ingestion of livers, especially that of the sheep, is not advisable for the pregnant women.

Transcriptomic Profiling of Spleen in Grass-Fed and Grain-Fed Angus Cattle

The grass-fed cattle obtain nutrients directly from pastures containing limited assimilable energy but abundant amount of fiber; by contrast, grain-fed steers receive a diet that is comprised mainly of grains and serves as an efficient source of high-digestible energy. Besides energy, these two types of diet differ in a large number of nutritional components. Additionally, animals maintained on rich-energy regimen are more likely to develop metabolic disorders and infectious diseases than pasture raised individuals. Thus, we hypothesize that spleen–a relevant immune organ–may function differently under disparate regimes. The objective of this study was to find the differentially expressed genes in the spleen of grass-fed and grain-fed steers, and furtherly explore the potential involved biopathways. Through RNA sequencing (RNA-Seq), we detected 123 differentially expressed genes. Based on these genes, we performed an Ingenuity Pathway Analysis (IPA) and identified 9 significant molecular networks and 13 enriched biological pathways. Two of the pathways, Nur77 signaling in T lymphocytes and calcium-induced T lymphocyte apoptosis which are immune related, contain a pair of genes HLA-DRA and NR4A1 with dramatically altered expression level. Collectively, our results provided valuable insights into understanding the molecular mechanism of spleen under varied feeding regimens.

Consumption of Branched-Chain Amino Acids Is Inversely Associated with Central Obesity and Cardiometabolic Features in a Population of Brazilian Middle-Aged Men: Potential Role of Leucine Intake

OBJECTIVE

To assess the potential associations of branched-chain amino acids (BCAA) consumption with central obesity (CObesity) and cardiometabolic risk factors in a population of Brazilian middle-aged men. Special attention was given to leucine intake.

DESIGN

Cross-sectional study.

SETTING

Universidade Federal de Viçosa, Viçosa, Brazil.

PARTICIPANTS

Two-hundred ninety-six middle-aged men (Age: 50.5 ± 5.0 years; Body mass index: 25.8 ± 3.5 kg/m2).

MEASUREMENTS

Anthropometry, lifestyle features, blood biochemical parameters were assessed and dietary intake was estimated by a food frequency questionnaire. Participants were classified by the occurrence of CObesity, hypertriglyceridemia (HTG), hypertriglyceridemic waist phenotype (HWP) and metabolic syndrome (MetS).

RESULTS

Subjects in the BCAA highest tertile (≥0.17 g/kg/d) presented lower occurrence of CObesity (36.0% vs 72.4%, P<0.01, z=-5.10), HTG (17.0% vs 30.6% P<0.032, z=-2.32), HWP (23.0% vs 46.9%, P<0.01, z=-3.57) and MetS (19.0% vs 34.7%, P<0.01, z=-2.57). They also exhibited lower values for Castelli index (total cholesterol:HDL-c) and triglycerides: HDL-c ratio than those in the first tertile, regardless of interfering factors (i.e. habitual physical activity, work position, smoking habit, and energy intake). Interestingly, leucine consumption showed similar associations with cardiometabolic risk factors, as compared to BCAA consumption (P<0.05).

CONCLUSION

BCAA consumption was cross-sectionally and negatively associated with relevant cardiometabolic risk factors in a population of Brazilian middle-aged men. The content of leucine in BCAA consumption may have contributed to such relationship.

A comparison of regular consumption of fresh lean pork, beef and chicken on body composition: a randomized cross-over trial

Pork is the most widely eaten meat in the world and recent evidence shows that diets high in pork protein, with and without energy restriction, may have favourable effects on body composition. However, it is unclear whether these effects on body composition are specific to pork or whether consumption of other high protein meat diets may have the same benefit. Therefore we aimed to compare regular consumption of pork, beef and chicken on indices of adiposity. In a nine month randomised open-labelled cross-over intervention trial, 49 overweight or obese adults were randomly assigned to consume up to 1 kg/week of pork, chicken or beef, in an otherwise unrestricted diet for three months, followed by two further three month periods consuming each of the alternative meat options. BMI and waist/hip circumference were measured and body composition was determined using dual energy x-ray absorptiometry. Dietary intake was assessed using three day weighed food diaries. Energy expenditure was estimated from activity diaries. There was no difference in BMI or any other marker of adiposity between consumption of pork, beef and chicken diets. Similarly there were no differences in energy or nutrient intakes between diets. After three months, regular consumption of lean pork meat as compared to that of beef and chicken results in similar changes in markers of adiposity of overweight and obese Australian middle-aged men and women.

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.

Dyslipidemia Management for Secondary Prevention in Women with Cardiovascular Disease: What Can We Expect From Non-pharmacologic Strategies?

Cardiovascular disease is the leading cause of death in women and the treatment of dyslipidemia is a cornerstone of secondary prevention. Pharmacologic therapy with statins can lower LDL-C by 30-50% and reduce the risk of recurrent coronary heart disease in both men and women. While significant reductions in LDL-C can be achieved with statin therapy, diet and lifestyle modification remain an essential part of the treatment regimen for cardiovascular disease. Moreover, a large proportion of the U.S. population is sedentary, overweight, and does not consume a heart-healthy diet. Non-pharmacologic treatment strategies also improve other cardiovascular risk factors and are generally easily accessible. In this review, we examine the effect of non-pharmacologic therapy on lipids as part of the secondary prevention strategy of cardiovascular disease in women.

Dietary protein and beef consumption predict for markers of muscle mass and nutrition status in older adults

OBJECTIVE

To determine the relationship of beef and protein intake to nutrition status, body composition, strength, and biochemical measures of vitamin and mineral status, inflammation and blood lipids in older adults.

DESIGN

Cross-sectional observational study.

SETTING

State of Ohio, U.S.A.

PARTICIPANTS

142 adults ages 60-88.

MEASUREMENTS

Subjects completed a Diet History Questionnaire, and questionnaires related to nutrition status and activity. Subjects also underwent measurements of body composition and strength, and a subset took part in a blood draw for biochemical measurements.

RESULTS

Beef intake (g/d) was positively correlated to muscle mass measured by mid-arm muscle area (R=0.128, p=0.030). From multiple linear regression analysis, a 1oz/d (~28g/d) increase in beef consumption predicts for a 2.3cm(2) increase in mid-arm muscle area. Beef intake was negatively correlated to total (R=-0.179, p=0.035) and HDL (R=-0.247, p=0.004) cholesterol, and there was no association between beef and LDL-cholesterol, triglycerides, liver enzymes, or inflammatory markers. Protein intake (% of total energy) was positively correlated to nutrition status measured by the Mini Nutrition Assessment (R=0.196, p=0.020), and calf circumference (R=0.190, p=0.024), and these correlations remained when potential confounders were accounted for in multiple linear regression models. Protein intake was also positively correlated with BMI when analyzed with multiple linear regression.

CONCLUSIONS

Beef intake was positively associated with mid-arm muscle area, and protein intake was positively associated with nutrition status, calf circumference, and BMI in older adults. Consuming lean cuts of beef in moderation may be a healthy way in which older adults can increase protein intake, preserve muscle mass and improve nutrition status.

Frequent consumption of selenium-enriched chicken meat by adults causes weight loss and maintains their antioxidant status

To assess the effects of a moderately high-protein intake on the body composition, biochemical, and antioxidant status parameters in young adults depending on either selenium- (Se) or non-enriched chicken consumption. The volunteers (n = 24) that completed the 10-week nutritional intervention were distributed in two parallel groups and randomly assigned to follow an isocaloric diet with moderately high content in protein (30% energy), either with the consumption of four 200 g portions/week of Se- or non-enriched chicken breasts. Blood samples were taken at the beginning and at the end of the study and body composition was monitored during the trial. There was a significant reduction in weight, accompanying a decrease on fat mass in both groups, while fat-free mass remained unchanged during the 10 weeks of intervention, without differences between both dietary groups. Selenium blood levels and plasma glutathione peroxidase activity, as well as lipid, glucose, and selected inflammation biomarkers remained stable during the intervention period in both dietary groups. Frequent chicken consumption, within a controlled diet with a moderately high content in protein, produced a slight but statistically significant weight reduction mainly due to the loss of fat mass. An extra Se supplementation (22 μg/day) in the Se-enriched chicken breast did not affect tachyphylactic antioxidant status of the participants neither inflammatory-related markers after weight loss.

Effect of proteins from different sources on body composition

High-protein diets have beneficial effects on body fat regulation, but the difference in effect of various types of protein is not known. Thus, this review examines whether proteins from different sources have similar effects on body composition and energy balance. Animal proteins, especially those from dairy, seem to support better muscle protein synthesis than plant proteins. This could potentially enhance energy expenditure, but no conclusion can be drawn from the scant evidence. Some studies, but not all, demonstrate the higher satiating effect of whey and fish proteins than other protein sources. The evidence from intervention studies comparing the effects of different protein sources on body weight is inconclusive. However, body composition was not evaluated precisely in these studies and the literature is still incomplete (e.g. comparative data are missing for legumes and nuts). Protein intake enhances energy expenditure, satiety and fat loss, but there is no clear evidence to indicate whether there is a difference in the effect dependent on the source of the protein, i.e. from animal or plant-based foods.

Intermittent versus daily calorie restriction: which diet regimen is more effective for weight loss?

Dietary restriction is an effective strategy for weight loss in obese individuals. The most common form of dietary restriction implemented is daily calorie restriction (CR), which involves reducing energy by 15-60% of usual caloric intake every day. Another form of dietary restriction employed is intermittent CR, which involves 24 h of ad libitum food consumption alternated with 24 h of complete or partial food restriction. Although both diets are effective for weight loss, it remains unknown whether one of these interventions produces superior changes in body weight and body composition when compared to the other. Accordingly, this review examines the effects of daily CR versus intermittent CR on weight loss, fat mass loss and lean mass retention in overweight and obese adults. Results reveal similar weight loss and fat mass loss with 3 to 12 weeks' intermittent CR (4-8%, 11-16%, respectively) and daily CR (5-8%, 10-20%, respectively). In contrast, less fat free mass was lost in response to intermittent CR versus daily CR. These findings suggest that these diets are equally as effective in decreasing body weight and fat mass, although intermittent CR may be more effective for the retention of lean mass.

The evolution of lean beef: identifying lean beef in today's U.S. marketplace

Changes in cattle breeding and management coupled with extensive trimming of visible fat from retail cuts have resulted in the wide-spread availability of lean beef to U.S. consumers. Despite these changes, there is limited awareness regarding the reduced total fat content and the favorable fatty acid profile of beef. Relative to the calories it contributes, the impact of beef on the nutritional quality of the American diet via its contribution of protein and certain key micronutrients is often under appreciated. The following discussion documents the progressive reduction in fat content of U.S. beef during the past 30 years, highlights ongoing efforts to update United States Department of Agriculture nutrient data for beef, and summarizes findings from randomized controlled trials of beef and plasma lipid outcomes. Beef is a popular, nutrient-dense food and the availability of at least 29 lean cuts of beef in the U.S. marketplace can help consumers meet their cardiovascular health goals.

A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef

Growing consumer interest in grass-fed beef products has raised a number of questions with regard to the perceived differences in nutritional quality between grass-fed and grain-fed cattle. Research spanning three decades suggests that grass-based diets can significantly improve the fatty acid (FA) composition and antioxidant content of beef, albeit with variable impacts on overall palatability. Grass-based diets have been shown to enhance total conjugated linoleic acid (CLA) (C18:2) isomers, trans vaccenic acid (TVA) (C18:1 t11), a precursor to CLA, and omega-3 (n-3) FAs on a g/g fat basis. While the overall concentration of total SFAs is not different between feeding regimens, grass-finished beef tends toward a higher proportion of cholesterol neutral stearic FA (C18:0), and less cholesterol-elevating SFAs such as myristic (C14:0) and palmitic (C16:0) FAs. Several studies suggest that grass-based diets elevate precursors for Vitamin A and E, as well as cancer fighting antioxidants such as glutathione (GT) and superoxide dismutase (SOD) activity as compared to grain-fed contemporaries. Fat conscious consumers will also prefer the overall lower fat content of a grass-fed beef product. However, consumers should be aware that the differences in FA content will also give grass-fed beef a distinct grass flavor and unique cooking qualities that should be considered when making the transition from grain-fed beef. In addition, the fat from grass-finished beef may have a yellowish appearance from the elevated carotenoid content (precursor to Vitamin A). It is also noted that grain-fed beef consumers may achieve similar intakes of both n-3 and CLA through the consumption of higher fat grain-fed portions.

Protein Intake during Energy Restriction: Effects on Body Composition and Markers of Metabolic and Cardiovascular Health in Postmenopausal Women

OBJECTIVE

The primary aim of this study was to assess the effects of dietary protein intake on energy restriction (ER)-induced changes in body mass and body composition. Clinical markers of metabolic and cardiovascular diseases were also measured.

DESIGN

54 postmenopausal women, age 58 +/- 2 y, body mass index 29.6 +/- 0.8 kg/m(2), were assigned to one of four groups. For 9 weeks, three ER groups ate a 1000 kcal/d lacto-ovo vegetarian basal diet plus 250 kcal/d of either beef (BEEF, n = 14), chicken (CHICKEN, n = 15), or carbohydrate/fat foods (CARB (lacto-ovo), n = 14), while a control group (CON, n = 11) consumed their habitual diets.

RESULTS

Energy intake was lower in the ER groups compared to CON (BEEF, 1114 +/- 155 kcal/d, CHO: PRO: FAT, 46:24:30 % of energy intake; CHICKEN, 1098 +/- 203 kcal/d, 51:25:24; CARB 1158 +/- 341 kcal/d, 59:17:24; CON, 1570 +/- 633 kcal/d, 47:20:33), but did not differ among ER groups. For all ER subjects combined, body mass (-6.7 +/- 2.4 kg, 9 %), fat mass (-4.6 +/- 1.9 kg, 13 %), and fat-free mass (-2.1 +/- 1.1 kg, 5 %) decreased. These responses did not differ among the ER groups, except for body mass (CHICKEN -7.9 +/- 2.6 kg(a); BEEF -6.6 +/- 2.7 kg(a,b); CARB -5.6 +/- 1.8 kg(b); CON -1.2 +/- 1.2 kg(c); values with a difference superscript differ, p < 0.05). From PRE (week 0) to POST (week 9), total and LDL cholesterol decreased approximately 12%, with no differences among groups. Triacylglycerol, HDL cholesterol, C-reactive protein (CRP), glucose, insulin, leptin, and adiponectin were not changed over time or differentially affected by diet.

CONCLUSIONS

Overweight postmenopausal women can achieve significant weight loss and comparable short-term improvements in body composition and lipid-lipoprotein profile by consuming either a moderate-protein (25% of energy intake) poultry- or beef-containing diet or a lacto-ovo vegetarian protein (17% of energy intake) diet.

Dairy proteins and the regulation of satiety and obesity

Over the past decade there has been growing scientific evidence and public acceptance of the role that dietary protein plays in regulation of satiety, feed intake and obesity-related disorders. Dietary protein appears to suppress food intake and delay the return of hunger more than fats or carbohydrates in a manner not due to energy content alone. Also, high-protein diets support the maintenance of muscle mass when subjects reduce their energy intake, ensuring primarily adipose tissue loss. Some protein sources, particularly dairy, contain specific peptides or proteins that may elicit direct effects on satiety. The major proteins present in milk include β-lactalbumin, α-lactoglobulin, immunoglobulins, bovine serum albumin, and the various caseins. In addition, processed whey contains glycomacropeptide, which stimulates pancreatic and gastrointestinal secretion of hormones involved in satiety to a greater extent than whey alone. In the context of the literature, we show that a glycomacropeptide-rich whey protein isolate decreases feed intake and weight gain to a greater extent than a soy protein isolate in obese pigs. Also, insulin sensitivity is improved in pigs consuming high-protein diets, with these effects being independent of protein source. While, high-protein diets may decrease calcium balance and bone strength, it appears that these effects are attenuated by dairy proteins and dairy sources of calcium. These findings suggest that high-protein diets, and in particular those that contain whey proteins, may reduce hunger and food intake, thereby reducing fat deposition and improving insulin sensitivity.

Game and venison - meat for the modern consumer

This review focuses on how game meat from southern Africa and venison that are increasingly being imported into Europe and the US addresses consumer issues as pertaining to production (wild, free range or intensive production) and harvesting methods, healthiness (chemical composition, particularly fatty acid composition), and traceability. Although African game meat species are farmed extensively, deer species are farmed using extensive to intensive production systems. However, the increasingly intensive production of the cervids and the accompanying practices associated with this (castration, velvetting, feeding of balanced diets, etc.) may have a negative impact in the near future on the consumer's perception of these animals. These alternative meat species are all harvested in a sustainable manner using acceptable methods. All these species have very low muscle fat contents consisting predominantly of structural lipid components (phospholipid and cholesterol) that have high proportions of polyunsaturated fatty acids. This results in the meat having desirable polyunsaturated:saturated and n-6:n-3 fatty acid ratios. The South African traceability system is discussed briefly as an example on how these exporting countries are able to address the requirements pertaining to the import of meat as stipulated by the European Economic Community.