Effects of consuming a high-protein diet with or without soy protein during weight loss and maintenance: a non-inferiority, randomized clinical efficacy trial

Are oilseeds a new alternative protein source for human nutrition?

This review focuses on the potential use, nutritional value and beneficial health effects of oilseeds as a source of food protein. The process of extracting oil from oilseeds produces a by-product that is rich in proteins and other valuable nutritional and bioactive components. This product is primarily used for animal feed. However, as the demand for proteins continues to rise, plant-based proteins have a real success in food applications. Among the different plant protein sources, oilseeds could be used as an alternative protein source for human diet. The data we have so far show that oilseeds present a protein content of up to 40% and a relatively well-balanced profile of amino acids with sulphur-containing amino acids. Nevertheless, they tend to be deficient in lysine and rich in anti-nutritional factors (ANFs), which therefore means they have lower anabolic potential than animal proteins. To enhance their nutritional value, oilseed proteins can be combined with other protein sources and subjected to processes such as dehulling, heating, soaking, germination or fermentation to reduce their ANFs and improve protein digestibility. Furthermore, due to their bioactive peptides, oilseeds can also bring health benefits, particularly in the prevention and treatment of diabetes, obesity and cardiovascular diseases. However, additional nutritional data are needed before oilseeds can be endorsed as a protein source for humans.

Composition, functional properties, health benefits and applications of oilseed proteins: A systematic review

Common oilseeds, such as soybean, peanut, rapeseed, sunflower seed, sesame seed and chia seed, are key sources of edible vegetable oils. Their defatted meals are excellent natural sources of plant proteins that can meet consumers' demand for health and sustainable substitutes for animal proteins. Oilseed proteins and their derived peptides are also associated with many health benefits, including weight loss and reduced risks of diabetes, hypertension, metabolic syndrome and cardiovascular events. This review summarizes the current status of knowledge on the protein and amino acid composition of common oilseeds as well as the functional properties, nutrition, health benefits and food applications of oilseed protein. Currently, oilseeds are widely applied in the food industry regarding for their health benefits and good functional properties. However, most oilseed proteins are incomplete proteins and their functional properties are not promising compared to animal proteins. They are also limited in the food industry due to their off-flavor, allergenic and antinutritional factors. These properties can be improved by protein modification. Therefore, in order to make better use of oilseed proteins, methods for improving their nutrition value, bioactive activity, functional and sensory characteristics, as well as the strategies for reducing their allergenicity were also discussed in this paper. Finally, examples for the application of oilseed proteins in the food industry are presented. Limitations and future perspectives for developing oilseed proteins as food ingredients are also pointed out. This review aims to foster thinking and generate novel ideas for future research. It will also provide novel ideas and broad prospects for the application of oilseeds in the food industry.

The effects of a low carbohydrate diet combined with partial meal replacement on obese individuals

OBJECTIVE

We explored the dietary effects of replacing normal dietary staple foods with supplementary nutritional protein powder, dietary fiber, and fish oil on several metabolic parameters. We examined weight loss, glucose and lipid metabolism, and intestinal flora in obese individuals when compared with individuals on a reduced staple food low carbohydrate diet.

METHODS

From inclusion and exclusion criteria, 99 participants (28 kg/m² ≤ body mass index (BMI) ≤ 35 kg/m²) were recruited and randomly assigned to control and intervention 1 and 2 groups. Physical examinations and biochemical indices were performed/gathered before the intervention and at 4 and 13 weeks post intervention. After 13 weeks, feces was collected and 16s rDNA sequenced.

RESULTS

After 13 weeks, when compared with controls, body weight, BMI, waist circumference, hip circumference, systolic blood pressure, and diastolic blood pressure values in intervention group 1 were significantly reduced. In intervention group 2, body weight, BMI, waist circumference, and hip circumference were significantly reduced. Triglyceride (TG) levels in both intervention groups were significantly reduced. Fasting blood glucose, glycosylated hemoglobin, glycosylated albumin, total cholesterol, and apolipoprotein B levels in intervention group 1 were decreased, while high density lipoprotein cholesterol (HDL-c) decreased slightly. Glycosylated albumin, TG, and total cholesterol levels in intervention group 2 decreased, while HDL-c decreased slightly, High sensitive C-reactive protein, MPO, Ox-LDL, LEP, TGF-β₁, IL-6, GPLD1, pro NT, GPC-4, and LPS levels in both intervention groups were lower when compared with controls. Adiponectin (ADPN) levels in intervention groups were higher when compared with controls. Tumor necrosis factor-α (TNF-α) levels in intervention group 1 were lower when compared with controls. There is no obvious difference in α diversity and β diversity between intestinal flora of 3 groups. Among the first 10 species of Phylum, only the control group and the intervention group 2 had significantly higher Patescibacteria than the intervention group 1. Among the first 10 species of Genus, only the number of Agathobacter in intervention group 2 was significantly higher than that in control group and intervention group 1.

CONCLUSIONS

We showed that an LCD, where nutritional protein powder replaced some staple foods and dietary fiber and fish oil were simultaneously supplemented, significantly reduced weight and improved carbohydrate and lipid metabolism in obese individuals when compared with an LCD which reduced staple food intake.

The health effects of soy: A reference guide for health professionals

Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.

A Comparison Study on the Therapeutic Effect of High Protein Diets Based on Pork Protein versus Soybean Protein on Obese Mice

In this study, an obese C57BL/6J mice model was induced to compare the effect of different high protein diets (soybean protein and pork protein) on obesity. The obese mice were randomly divided into four groups: natural recovery (NR), high-fat diet (HF), high soybean protein diet (HSP), and high pork protein diet (HPP) groups. After 12 weeks of dietary intervention, the obesity-related indexes of mice were measured, such as body weight, fat coefficients, blood lipid indexes and so on. Results showed that HSP and HPP decreased the weight and fat coefficients of mice, the levels of serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and leptin (p < 0.05). Soybean protein was shown to be more effective in reducing the weight and fat mass of obese mice, although pork protein seemed to have a better effect on regulating serum triglyceride (TG). In addition, the two high protein diets both alleviated hepatic fat deposition effectively. Furthermore, HPP and HSP decreased the expression of hepatic peroxisome proliferator-activated receptor-γ (PPAR-γ) and increased the protein expression of phosphorylated AMP-activated protein kinase (pAMPK), phosphorylated acetyl CoA carboxylase (pACC), and uncoupling protein 2 (UCP2) (p < 0.05). In conclusion, the study shows that high protein diets based on both pork protein and soybean protein alleviated abdominal obesity in mice effectively by regulating lipid metabolism, probably via the UCP2-AMPK-ACC signaling pathway.

Effects of Lean Pork on Microbiota and Microbial-Metabolite Trimethylamine-N-Oxide: A Randomized Controlled Non-Inferiority Feeding Trial Based on the Dietary Guidelines for Americans

SCOPE

Trimethylamine-N-oxide (TMAO) is a microbiota-dependent and primarily animal-protein-derived proatherogenic metabolite. The ecological impact of pork-the most popular animal protein worldwide-on the human microbiome, and in the physiological context of TMAO and other biogenic amines, remains unclear. Poultry being the recommended heart-healthier animal protein, we inquired-if pork intake results in inferior-to-chicken TMAO-response while consuming a US. Dietary Guidelines (DGA)-diet?

METHODS AND RESULTS

In a randomized, controlled, all-food-provided, crossover, feeding trial, healthy adults consumed 156 g/day of lean-pork or chicken (active-control) as primary proteins. Mixed-effect modeling shows pork as noninferior to chicken for circulating TMAO response and microbiota-generated essential TMAO-precursor-trimethylamine (97.5% CI, n = 36/protein). Markers of lipid metabolism, inflammation and oxidative stress, serum levels of betaine, choline, L-carnitine, composition and functional-capability of the microbiota, and association of baseline TMAO-levels with TMAO-response (both, r>0.6, p = 0.0001) were nondistinguishable between the protein groups. TMAO reduction and similar shifts in microbiota and biogenic-amine signatures postdiet in both groups indicate a background DGA-effect.

CONCLUSIONS

Unlike extrapolating negative results, we present noninferiority-testing based evidence that consuming pork as a predominant protein within an omnivorous DGA-diet does not exacerbate TMAO-response. Results highlight the importance of understanding protein-TMAO interactions within dietary patterns. This article is protected by copyright. All rights reserved.

Effect of different protein diets on weight loss, inflammatory markers, and cardiometabolic risk factors in obese women

BACKGROUND

Reducing and maintaining body weight has become more important than ever as obesity is becoming increasingly common worldwide. This study was aimed to investigate the effects of diets with different protein contents administered to obese women on anthropometric measurements, inflammatory markers, and cardiometabolic risk factors.

MATERIALS AND METHODS

This randomized controlled trial was conducted with sixty volunteering obese women aged between 20 and 45 years. The subjects were divided into two groups in equal numbers. The high-protein (HP) group (n = 30) was administered an iso-caloric HP diet (25% protein, 30% fat, and 45% carbohydrate), and the control group (n = 30) an isocaloric low-protein diet (15% protein, 30% fat, and 55% carbohydrate), and both groups were followed up for 8 weeks. The subjects' descriptive data, anthropometric measurements, homeostatic model assessment-insulin resistance (HOMA-IR), lipid profiles, and high-sensitive C-reactive protein (hs-CRP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) levels were analyzed.

RESULTS

There was no significant difference at baseline (except for low-density lipoprotein cholesterol [LDL-C]), and end-of-study (except for IL-6, systolic blood pressure [SBP], and diastolic blood pressure) values of parameters between the two groups; after adjusted for baseline measurements, a significant difference was observed between the groups for body weight, body mass index, waist circumference, HOMA-IR, LDL-C, hs-CRP, TNF-α, IL-6, and SBP (P = 0.004, P = 0.001, P = 0.003, P = 0.029, P = 0.004, P = 0.016, P = 0.004, P = 0.010, and P = 0.000, respectively) and were greater in the HP group than in the control group (P < 0.05).

CONCLUSION

The HP diet was effective on improvement in HOMA-IR, SBP, LDL-C, hs-CRP, TNF-α, IL-6, and resulted in body weight loss.

Evaluation of the impact of a community-based, pharmacist-led weight loss program focused on a high-protein diet on risk factors for cardiovascular disease

BACKGROUND

Lifestyle choices such as poor diet, physical inactivity, and smoking contribute to modifiable cardiovascular (CV) risk factors.

OBJECTIVES

To evaluate clinical outcomes (blood pressure, glycosylated hemoglobin [A1C] level, lipid profile, weight, and waist circumference) that affect CV disease and the American Heart Association (AHA) Life's Simple 7 score before and after completion of a weight loss program focusing on a high-protein, low-calorie, low-carbohydrate, and low-fat diet.

PRACTICE DESCRIPTION

Independent pharmacy in Richmond, VA.

PRACTICE INNOVATION

Pharmacist-led weight loss program focusing on a high-protein, low-calorie, low-carbohydrate, and low-fat diet.

EVALUATION METHODS

A retrospective analysis of electronic patient records was conducted to evaluate a pharmacist-led weight loss program focusing on a high-protein, low-calorie, low-carbohydrate, and low-fat diet. Baseline information included age, gender, race, height, comorbid conditions, diet, physical activity, and smoking status. Clinical CV outcomes (blood pressure, A1C level, lipid profile, weight, and waist circumference) were compared from baseline and at completion. Participants beginning calculated AHA Life's Simple 7 score was compared with the calculated score at completion. The Wilcoxon signed-rank test was used to analyze data.

RESULTS

Fourteen participants completed the program. Improvements in risk factors included systolic blood pressure (5.79 ± 5.56 mm Hg, P < 0.005), diastolic blood pressure (2.57 ± 3.37 mm Hg, P < 0.012), A1C level (0.6% ± 0.99%, P < 0.001), total cholesterol (22.21 ± 17.79 mg/dL, P < 0.001), low-density lipoprotein cholesterol (18 mg/dL, P < 0.041), weight (11.06 ± 5.65 kilograms, P < 0.001), and waist circumference (5.44 ± 4.24 centimeters, P < 0.001). The AHA Life's Simple 7 scores increased after the weight loss program (3.21 ± 0.89, P < 0.001).

CONCLUSION

A community-based, pharmacist-led weight loss program focusing on a high-protein, low-calorie, low-carbohydrate, and low-fat diet improved participants' AHA Life's Simple 7 scores and modifiable risk factors for CV disease.

A comparison study of the influence of milk protein versus whey protein in high-protein diets on adiposity in rats

High-protein diets are known to reduce weight and fat deposition. However, there have been only a few studies on the efficacy of different types of high-protein diets in preventing obesity. Therefore, the emphasis of this study lies in comparing the efficacy of two high-protein diets (milk protein and whey protein) in preventing obesity and exploring specific mechanisms. Eighty Sprague Dawley rats were divided into two groups and fed with milk protein concentrate (MPC) and whey protein concentrate (WPC) for 12 weeks. Each group was divided into four levels: two low-fat regimens with either low or high protein content (L-14%, L-40%) and two high-fat regimens with either low or high protein content (H-14%, H-40%). The studies we have performed showed that rats treated with MPC at the 40% protein level had significantly reduced body weight, fat weight and fat ratio gain induced by a high-fat diet, while the protein level in the WPC group had no effect on body weight or body fat in rats fed with a high-fat diet. What is more, rats fed with MPC at the H-40% energy level showed a significant decrease in plasma triglyceride, total cholesterol and low-density lipoprotein cholesterol levels and a significant increase in plasma high-density lipoprotein cholesterol levels compared with the H-14% energy level group. In contrast, in the WPC groups, increasing the protein content in high-fat diets had no significant influence on plasma lipid levels. The results of the amino acid composition of the two proteins and plasma showed that the MPC diet of 40% protein level increased the transsulfuration pathway in rats, thereby increasing the level of H₂S. This research work has shown that not all types of high-protein diets can effectively prevent obesity induced by high-fat diets, as effectiveness depends on the amino acid composition of the protein.

A Comprehensive Critical Assessment of Increased Fruit and Vegetable Intake on Weight Loss in Women

No previous reviews or meta-analyses have specifically assessed the effects of increased fruit and vegetable (FV) intake on weight loss with a primary focus on women. Several studies show differences between men and women in how increased FV intake affects their weight loss and maintenance, risk of becoming overweight or obese, and the influence of eating speed and frequency on weight control. This analysis provides a comprehensive and visual assessment of the effects of increasing FV intake and long-term weight change from observational studies and weight loss from randomized controlled trials (RCTs) in women. Consistent evidence from prospective studies and RCTs shows that increased intake of FV is a chief contributor to weight loss in women. This effect is enhanced with concurrent dietary restriction of high energy density (ED) or high-fat foods. Yet, the type of FV differentially impacts weight loss in women. Whole FV intake may influence weight through a variety of mechanisms including a reduction in eating rate, providing a satisfying, very-low to low energy density, low glycemic load or low-fat content. Also, FV are the primary source of dietary fiber, which can provide additional support for weight loss in women when consumed at adequate levels.

Soy Products Ameliorate Obesity-Related Anthropometric Indicators in Overweight or Obese Asian and Non-Menopausal Women: A Meta-Analysis of Randomized Controlled Trials

Background: The effect of soy products on the weight of overweight or obese people is controversial, so we aimed to conduct a systematic review and a meta-analysis of published randomized controlled trials to analyze whether supplementation with soy products can help them to lose weight. Methods: The relevant data before January 2019 in PubMed, Embase and Cochrane Library were searched. A random-effect model was adopted to calculate the weighted average difference of net changes of body weight, body mass index (BMI), body fat percentage, fat mass, waist circumference, etc. Results: A total of 22 trials (870 overweight or obese participants) were reflected in the present meta-analysis. Analysis showed that soy products significantly reduced body weight, BMI, body fat percent and waist circumference in overweight or obese Asian populations (−0.37 kg, P = 0.010; −0.27 kg/m², P = 0.042; −0.36%, P = 0.032; −0.35 cm, P = 0.049) and more significant effects were observed in non-menopausal women reduced body weight (−0.59 kg, P = 0.041), BMI (−0.59, P = 0.041) and waist circumference (−0.59 cm, P = 0.041) in overweight or obese populations. Conclusion: This meta-analysis showed that soy products have weight loss effects, mainly due to soy protein, isoflavone and soy fiber.

Dietary modifications for weight loss and weight loss maintenance

Worldwide obesity rates remain at a rise, and to treat obesity is at the top of the global public health agenda. In 2013, the AHA/ACC/TOS obesity management guidelines were published, in essence suggesting that any dietary scheme seems to be effective for weight loss, as long as it can induce a sustainable energy deficit. In the present review, we update and critically discuss available information regarding dietary modifications for weight loss and weight loss maintenance, published after the 2013 guidelines. Regarding weight loss, we found no proof to support that a single dietary scheme, be it nutrient-, food group- or dietary pattern- based, is more efficacious of the other for achieving weight loss. For weight loss maintenance, published interventions point towards the same direction, although inconclusively. Most research explores the effect of weight loss regimes on weight loss maintenance and not the effect of the diet during weight loss maintenance, and this literature gap should be more thoroughly investigated.