Research

Soy Protein

85 peer-reviewed studies curated from PubMed and Semantic Scholar.

29
Meta-analyses
2
Systematic reviews
54
RCTs
0
Other studies
Meta-analyses (34%)
Systematic reviews (2%)
RCTs (64%)

Studies

Sorted by quality and recency

2025·Journal of health, population, and nutrition·Ali Gholami, Bahareh Amirkalali, Mitra Hariri

Can soy isoflavones in combination with soy protein change serum levels of C-reactive protein among patients with chronic inflammatory diseases? A systematic review and meta-analysis on randomized controlled trials.

Meta-analysisInflammation

Systematic review and meta-analysis of randomized controlled trials assessing the effect of soy isoflavones containing soy protein on serum levels of C-reactive protein (CRP) in adults with chronic inflammatory diseases. The analysis found that soy isoflavones significantly decreased CRP levels compared to control.

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2024·International urology and nephrology·Yu Zhixiang, Xu Yongxing, Liu Juan, et al

The effects of soy protein and soy isoflavones intake on chronic kidney disease: a systematic review and meta-analysis.

Meta-analysisn = 522Heart Health Inflammation -

This systematic review and meta-analysis assessed the impact of soy protein consumption compared to animal protein among individuals with chronic kidney disease. The results showed that soy protein consumption led to a significant decrease in total cholesterol, LDL, and proteinuria levels, but no significant impact on serum creatinine, triglycerides, calcium, C-reactive protein, HDL, uric acid, or phosphorus levels.

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2024·JNCI cancer spectrum·M Diana van Die, Kerry M Bone, Kala Visvanathan, et al

Phytonutrients and outcomes following breast cancer: a systematic review and meta-analysis of observational studies.

Meta-analysisWomens Health

Systematic review and meta-analysis of observational studies evaluating the impact of phytonutrients like soy isoflavones, enterolactone, and green tea on breast cancer survival outcomes. Soy isoflavones were associated with a reduced risk of recurrence and cancer-specific mortality, particularly in postmenopausal and estrogen receptor-positive survivors. Enterolactone showed an inverse association with cancer-specific and all-cause mortality. Green tea reduced recurrence risk in stage I and II breast cancer.

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2023·Sports medicine (Auckland, N.Z.)·Reza Zare, Asli Devrim-Lanpir, Silvia Guazzotti, et al

Effect of Soy Protein Supplementation on Muscle Adaptations, Metabolic and Antioxidant Status, Hormonal Response, and Exercise Performance of Active Individuals and Athletes: A Systematic Review of Randomised Controlled Trials.

Systematic reviewPhysical Performance Hormone Health

This systematic review evaluates the effects of soy protein supplementation in active individuals and athletes on muscle adaptations, metabolic and antioxidant status, hormonal response, and exercise performance. Soy protein was found to provide similar increases in lean mass compared to whey protein, improve antioxidant capacity, and potentially benefit exercise performance. The effects on testosterone and cortisol levels were inconsistent.

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2023·Nutrients·Isobel L Stoodley, Lily M Williams, Lisa G Wood

Effects of Plant-Based Protein Interventions, with and without an Exercise Component, on Body Composition, Strength and Physical Function in Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Meta-analysisPhysique Physical Performance -

Systematic review and meta-analysis of RCTs evaluating plant-based protein interventions, specifically soy protein, on body composition, strength, and physical function in older adults. The review found positive effects on muscle mass over time, with plant-protein interventions being comparable to controls in all outcomes.

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2022·Clinical nutrition ESPEN·Ali Gholami, Hamid Reza Baradaran, Mitra Hariri

Soy isoflavones plus soy protein effects on serum concentration of leptin in adults: A systematic review and meta-analysis of randomized clinical trials.

Meta-analysisn = 336

Systematic review and meta-analysis of RCTs assessing the effect of soy isoflavones plus soy protein on serum leptin concentration in adults. The combination had a borderline non-significant effect on reducing serum leptin levels, with some reduction observed in specific subgroups.

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2021·Nutrients·Agnieszka Barańska, Agata Błaszczuk, Wiesław Kanadys, et al

Effects of Soy Protein Containing of Isoflavones and Isoflavones Extract on Plasma Lipid Profile in Postmenopausal Women as a Potential Prevention Factor in Cardiovascular Diseases: Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Meta-analysisn = 2,305Heart Health

Systematic review and meta-analysis of RCTs evaluating the impact of soy protein containing isoflavones and soy isoflavones extract on lipid profile in 2305 postmenopausal women. The analysis showed statistically significant decreases in total cholesterol and increases in HDL-cholesterol, suggesting potential cardiovascular benefits.

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2021·Complementary therapies in medicine·Mitra Hariri, Ahmad Ghasemi, Hamid Reza Baradaran, et al

Beneficial effect of soy isoflavones and soy isoflavones plus soy protein on serum concentration of C-reactive protein among postmenopausal women: An updated systematic review and meta-analysis of randomized controlled trials.

Meta-analysisInflammation -

Systematic review and meta-analysis of RCTs assessing the effect of soy isoflavones and soy isoflavones plus soy protein on serum CRP concentrations in postmenopausal women. The study found no significant effect of either intervention on CRP levels.

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2021·Clinical and experimental pharmacology & physiology·Ali Gholami, Ensiyeh Mollanoroozy, Hamid Reza Baradaran, et al

The efficacy of soy isoflavones combined with soy protein on serum concentration of interleukin-6 and tumour necrosis factor-α among post-menopausal women? A systematic review and meta-analysis of randomized controlled trials.

Meta-analysisInflammation -

Systematic review and meta-analysis of randomized controlled trials assessing the effect of soy isoflavones plus soy protein on serum concentrations of IL-6 and TNF-α in post-menopausal women. The meta-analysis found no significant effect on these inflammatory markers.

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2021·Phytotherapy research : PTR·Mitra Hariri, Hamid Reza Baradaran, Ali Gholami

The effect of soy isoflavones and soy isoflavones plus soy protein on serum concentration of tumor necrosis factor-α? A systematic review and meta-analysis of randomized controlled trials.

Meta-analysis

Systematic review and meta-analysis of randomized controlled trials assessing the effect of soy isoflavones and soy isoflavones plus soy protein on serum concentration of TNF-alpha. The analysis found no significant effect on TNF-alpha levels following intake of these substances.

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2021·Nutrients·Agnieszka Barańska, Agata Błaszczuk, Małgorzata Polz-Dacewicz, et al

Effects of Soy Isoflavones on Glycemic Control and Lipid Profile in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Meta-analysisHeart Health Nutrition

Systematic review and meta-analysis of RCTs investigating soy protein and isoflavones on glucose homeostasis and lipid profile in type 2 diabetes. Significant decreases in total cholesterol and LDL-C were observed, while changes in glucose metabolism were statistically insignificant.

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2020·Phytotherapy research : PTR·Ali Gholami, Hamid Reza Baradaran, Mitra Hariri

Can soy isoflavones plus soy protein change serum levels of interlukin-6? A systematic review and meta-analysis of randomized controlled trials.

Meta-analysisInflammation

Systematic review and meta-analysis of RCTs assessing the effect of soy isoflavones plus soy protein on circulating IL-6 in adults. Overall, no significant effect on serum IL-6 concentrations was found, but subgroup analysis showed a reduction in IL-6 levels with high doses of isoflavones.

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2019·Nutrients·Yuze Mu, Tingyan Kou, Boyang Wei, et al

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

Meta-analysisn = 870Physique

Meta-analysis of 22 trials with 870 overweight or obese participants examining the effects of soy products on weight loss. Soy products significantly reduced body weight, BMI, body fat percentage, and waist circumference, with more pronounced effects in non-menopausal women.

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2018·Maturitas·Marija Glisic, Natyra Kastrati, Juna Musa, et al

Phytoestrogen supplementation and body composition in postmenopausal women: A systematic review and meta-analysis of randomized controlled trials.

Meta-analysisn = 1,880Physique

Systematic review and meta-analysis of 23 RCTs with 1880 postmenopausal women examining phytoestrogen supplementation's effects on body composition. No overall association with body weight or fat mass was found, but a slight decrease in waist-hip ratio was observed. Subgroup analysis showed mixed effects: a modest weight decrease in healthy women and an increase in those with metabolic disorders.

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2018·International journal of sport nutrition and exercise metabolism·Mark Messina, Heidi Lynch, Jared M Dickinson, et al

No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise.

Meta-analysisn = 266Physical Performance -Physique -

Meta-analysis comparing the effects of soy protein versus animal protein supplementation on strength and lean body mass (LBM) in response to resistance exercise training. The analysis of nine studies with 266 participants found no significant differences between soy and animal protein groups in terms of strength and LBM gains.

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2017·Food & function·Tingyan Kou, Qiuzhen Wang, Jing Cai, et al

Effect of soybean protein on blood pressure in postmenopausal women: a meta-analysis of randomized controlled trials.

Meta-analysisn = 1,551Heart Health

Meta-analysis of 12 RCTs involving 1551 postmenopausal women to assess the effect of soy protein on blood pressure. Soy protein intake of ≥25 g per day significantly reduced systolic and diastolic blood pressure, with greater effects observed with soy isoflavone intake ≥100 mg per day.

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2015·Clinical nutrition (Edinburgh, Scotland)·Zhou Jing, Yuan Wei-Jie

Effects of soy protein containing isoflavones in patients with chronic kidney disease: A systematic review and meta-analysis.

Meta-analysisn = 280Nutrition

This systematic review and meta-analysis evaluated the effects of soy protein intake in patients with chronic kidney disease (CKD). It included 12 studies with 280 participants and found that dietary soy significantly decreased serum creatinine, serum phosphorus, CRP, and proteinuria in predialysis patients. No significant changes were found in creatinine clearance and glomerular filtration rate. Soy protein intake maintained nutritional status in dialysis patients.

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2026·Journal of cachexia, sarcopenia and muscle·Xiaorong Wu, Kevin Junliang Lim, Yiwei Ma, et al

The Effects of Soy Protein-Rich Meals on Muscle Health of Older Adults Are Linked to Gut Microbiome Modifications.

RCTn = 84

A 12-week randomized controlled trial with 84 older adults investigated the effects of a soy protein-rich diet on muscle health and gut microbiota. The intervention group showed preserved calf circumference and beneficial changes in gut microbiota, suggesting improved muscle health through a healthier gut microbiome.

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2025·BMC geriatrics·Nene Sato, Yuji Terashima, Makoto Sugawara, et al

Continuous high-soy protein soymilk intake affects ordinary walking speed in the Japanese pre-frail and frail elderly: a randomized controlled trial.

RCTn = 70Physical Performance

RCT among Japanese pre-frail and frail elderly to assess the impact of high-soy protein soymilk on physical frailty. The high-soy protein group showed a significant increase in walking speed among participants with initially high walking speed and step counts, compared to the control group.

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2025·Nutrients·Daigo Sakamoto, Yuji Terashima, Makoto Sugawara, et al

The Effect of Routine High-Soy-Protein Soymilk Intake on the Skeletal Muscle Index (SMI) in Japanese Pre-Frail Elderly Individuals with an Ordinary Life: A Post Hoc Analysis of a Randomized Controlled Trial.

RCTn = 68Physical Performance

Post hoc analysis of a 12-week RCT on high-soy-protein soymilk intake in Japanese frail and pre-frail elderly individuals. No significant change in skeletal muscle index (SMI) was observed overall, but potential benefits were noted in pre-frail elderly with high physical activity and energy intake.

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2025·Food & function·Yueying Yao, Ian En-Kai Mak, Clarinda Nataria Sutanto, et al

Impact of quantity and source of dietary protein intake within a healthy dietary pattern on cardiovascular disease risk factors in Singapore older adults: a randomized controlled trial.

RCTn = 55Heart Health

This 16-week randomized controlled trial investigated the effects of high protein diets with different sources on cardiovascular disease risk factors in Singapore older adults. The study found that both casein and soy protein groups maintained lipid-lipoprotein profiles and CVD risk predictors, with the soy protein group showing a significant reduction in total cholesterol levels.

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2024·Nutrition (Burbank, Los Angeles County, Calif.)·Wuke Yuan, Min Chen, Yanqiu Chen, et al

Effects of soy protein-rich meals on muscle health of older adults in long-term care: A randomized clinical trial.

RCTn = 84Physical Performance

A 12-week randomized controlled trial investigated the effects of soy protein-rich meals on muscle health in older adults in long-term care. The intervention group consuming 30 g of soy protein per day showed significant increases in lean mass indicators and improved 6-m walk performance compared to the control group.

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2022·Terapevticheskii arkhiv·L Y Milovanova, M V Taranova, A V Volkov, et al

[Soy protein as part of a low-protein diet is a new direction in cardio- and nephroprotection in patients with 3B-4 stages of chronic kidney disease: prospective, randomized, controlled clinical study].

RCTn = 85Heart Health Nutrition

Prospective, randomized, controlled clinical study of 85 patients with stages 3B-4 CKD comparing low-protein diets with soy protein substitution versus animal protein. The soy protein group showed better nephro- and cardioprotection, with improved glomerular filtration rate, reduced left ventricular hypertrophy, and better maintenance of nutritional status over 12 months.

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2022·Journal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation·Ludmila Yu Milovanova, Alexey V Volkov, Svetlana Yu Milovanova, et al

Soy Protein as a Part of a Low-protein Diet is a New Direction in Cardio- and Nephroprotection in Patients With 3b-4 Stages of Chronic kidney Disease.

RCTn = 85Heart Health Nutrition

Prospective RCT comparing low-protein diets in CKD patients, substituting animal protein with soy protein. The soy protein group showed better nephro and cardioprotection, with delayed decrease in eGFR, reduced left ventricle hypertrophy, and improved nutritional status compared to the control group.

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2021·The American journal of clinical nutrition·Maarten C Bosland, Erika Enk, Joanne Schmoll, et al

Soy protein supplementation in men following radical prostatectomy: a 2-year randomized, placebo-controlled clinical trial.

RCTn = 93

This 2-year randomized controlled trial studied the effects of 20 g/d soy protein supplementation in men aged 44-75 years at risk of cancer recurrence following prostatectomy. Compared to a casein-based placebo, soy supplementation did not affect body weight, blood pressure, serum total cholesterol, iron status parameters, calcium, phosphorus, and thyroid hormones. Exploratory analysis suggested that equol production status may modify effects on body weight and blood pressure.

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2021·Nutrition and cancer·Maarten C Bosland, Jonathan Huang, Michael J Schlicht, et al

Impact of 18-Month Soy Protein Supplementation on Steroid Hormones and Serum Biomarkers of Angiogenesis, Apoptosis, and the Growth Hormone/IGF-1 Axis: Results of a Randomized, Placebo-Controlled Trial in Males Following Prostatectomy.

RCTHormone Health

RCT of soy protein isolate supplementation in middle-aged to older males post-prostatectomy to assess effects on steroid hormones and cancer biomarkers. Soy protein reduced circulating testosterone and SHBG but did not affect other biomarkers like estradiol, VEGF, and IGF-1.

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2020·Food & function·Kelli S George, Joseph Muñoz, Neda S Akhavan, et al

Is soy protein effective in reducing cholesterol and improving bone health?

RCTn = 90Joint Bone Health Nutrition -

RCT with 90 men and women comparing 40 g daily soy protein to casein protein for three months. Both proteins reduced bone alkaline phosphatase and body fat percentage, with soy protein more effectively increasing IGF-1 levels. Neither protein affected cholesterol or inflammation markers.

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2019·Journal of the American Heart Association·David J A Jenkins, Sonia Blanco Mejia, Laura Chiavaroli, et al

Cumulative Meta-Analysis of the Soy Effect Over Time.

Meta-analysisHeart Health

Cumulative meta-analysis of 46 randomized controlled trials identified by the FDA to assess the effect of soy protein on serum cholesterol. The analysis demonstrated that soy protein continues to provide small but significant reductions in total cholesterol and low-density lipoprotein cholesterol, supporting the original FDA heart health claim.

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2019·Critical reviews in food science and nutrition·Maedeh Moradi, Elnaz Daneshzad, Leila Azadbakht

The effects of isolated soy protein, isolated soy isoflavones and soy protein containing isoflavones on serum lipids in postmenopausal women: A systematic review and meta-analysis.

Meta-analysisHeart Health

This systematic review and meta-analysis assessed the effects of isolated soy protein, isolated soy isoflavones, and soy protein containing isoflavones on serum lipids in postmenopausal women. Soy consumption was associated with significant decreases in triglycerides, total cholesterol, LDL-C, and HDL-C. The effects were more pronounced with isolated soy protein compared to isolated soy isoflavones.

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2019·The Journal of nutrition·Sonia Blanco Mejia, Mark Messina, Siying S Li, et al

A Meta-Analysis of 46 Studies Identified by the FDA Demonstrates that Soy Protein Decreases Circulating LDL and Total Cholesterol Concentrations in Adults.

Meta-analysisHeart Health

Meta-analysis of 46 controlled trials identified by the FDA, examining the effects of soy protein on LDL and total cholesterol in adults. Soy protein at a median dose of 25 g/d decreased LDL cholesterol by 4.76 mg/dL and total cholesterol by 6.41 mg/dL compared with non-soy protein controls, supporting its cholesterol-lowering ability.

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2017·The Journal of nutrition·Tristan Chalvon-Demersay, Dalila Azzout-Marniche, Judith Arfsten, et al

A Systematic Review of the Effects of Plant Compared with Animal Protein Sources on Features of Metabolic Syndrome.

Systematic reviewHeart Health

Systematic review comparing plant and animal protein sources on metabolic syndrome features. Soy protein with isoflavones led to a greater decrease in total and LDL cholesterol compared to animal proteins, especially in individuals with high fasting cholesterol. Some observational studies suggested plant protein intake might lower blood pressure, but this was not confirmed by intervention studies.

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2016·Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research·Thozhukat Sathyapalan, Mo Aye, Alan S Rigby, et al

Soy Reduces Bone Turnover Markers in Women During Early Menopause: A Randomized Controlled Trial.

RCTn = 200Joint Bone Health Heart Health Hormone Health

RCT of 200 women within 2 years post-menopause comparing 15g soy protein with 66mg isoflavone (SPI) to 15g soy protein alone (SP) daily for 6 months. SPI supplementation significantly reduced bone turnover markers and improved cardiovascular risk markers, but increased TSH and reduced free thyroxine, indicating a potential negative effect on thyroid function.

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2016·Yonsei medical journal·Xi-Mei Zhang, Yun-Bo Zhang, Mei-Hua Chi

Soy Protein Supplementation Reduces Clinical Indices in Type 2 Diabetes and Metabolic Syndrome.

Meta-analysisHeart Health Inflammation Nutrition

Meta-analysis of RCTs assessing soy protein supplementation effects on clinical indices in type 2 diabetes and metabolic syndrome patients. Soy protein significantly reduced fasting plasma glucose, fasting serum insulin, insulin resistance, diastolic blood pressure, LDL cholesterol, total cholesterol, and C-reactive protein compared to placebo.

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2015·The Journal of nutrition·Emily Mt Padhi, Heather J Blewett, Alison M Duncan, et al

Whole Soy Flour Incorporated into a Muffin and Consumed at 2 Doses of Soy Protein Does Not Lower LDL Cholesterol in a Randomized, Double-Blind Controlled Trial of Hypercholesterolemic Adults.

RCTn = 243Heart Health -

RCT assessing the effect of whole soy flour incorporated into muffins on LDL cholesterol in hypercholesterolemic adults. Despite increased plasma isoflavones, neither high-dose nor low-dose soy protein significantly affected LDL cholesterol or other CHD risk factors compared to control.

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2014·European journal of clinical nutrition·J Zhang, J Liu, J Su, et al

The effects of soy protein on chronic kidney disease: a meta-analysis of randomized controlled trials.

Meta-analysisn = 197

Meta-analysis of nine trials with 197 subjects evaluating soy protein consumption versus animal protein in pre-dialysis CKD patients. Soy protein significantly reduced serum creatinine and phosphorus concentrations, and lowered serum triglycerides. No significant effects were observed for total cholesterol or calcium.

PubMedRead on PubMed
2013·Wei sheng yan jiu = Journal of hygiene research·Jing Wu, Jiayi Dong, Xia Jiang, et al

[Effects of soy protein supplement on overweight and obese population: meta-analysis of randomized controlled trials].

Meta-analysisPhysique

Meta-analysis of 13 RCTs studying the effects of soy protein supplementation on overweight and obese populations. Soy protein significantly decreased body weight, fat mass, and waist circumference, with protective effects observed in Western populations but not in Asian populations.

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2013·Nutrition and cancer·Sheng Hui Wu, Zhong Liu

Soy food consumption and lung cancer risk: a meta-analysis using a common measure across studies.

Meta-analysis

Meta-analysis exploring the association between daily soy protein intake and lung cancer risk, pooling data from 11 epidemiologic studies. Found a borderline statistically significant inverse association overall, with a significant inverse association in nonsmokers.

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2011·European journal of clinical nutrition·M R Wofford, C M Rebholz, K Reynolds, et al

Effect of soy and milk protein supplementation on serum lipid levels: a randomized controlled trial.

RCTn = 352Heart Health

A randomized, double-blind, 3-phase crossover trial among 352 US adults examined the effects of soy and milk protein supplementation on serum lipid levels compared to carbohydrate. Soy protein supplementation improved the lipid profile, reducing total cholesterol and total/HDL cholesterol ratio, and increasing HDL cholesterol compared to milk protein and carbohydrate.

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2011·Journal of the American College of Nutrition·James W Anderson, Heather M Bush

Soy protein effects on serum lipoproteins: a quality assessment and meta-analysis of randomized, controlled studies.

Meta-analysisHeart Health

This meta-analysis assessed the effects of soy protein on serum lipoproteins, analyzing 20 parallel-design and 23 crossover RCTs. Soy protein intake was associated with significant reductions in serum LDL-cholesterol and improvements in HDL-cholesterol and triacylglycerol levels, indicating a favorable impact on lipoprotein risk factors for coronary heart disease.

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2009·Human reproduction update·L Hooper, J J Ryder, M S Kurzer, et al

Effects of soy protein and isoflavones on circulating hormone concentrations in pre- and post-menopausal women: a systematic review and meta-analysis.

Meta-analysisHormone Health

Systematic review and meta-analysis of 47 studies assessing the effects of soy and isoflavones on circulating hormones in pre- and post-menopausal women. In premenopausal women, soy or isoflavones significantly reduced FSH and LH, and increased menstrual cycle length. In post-menopausal women, there was a non-significant increase in estradiol.

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2008·Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology·Martijn Verheus, Carla H van Gils, Sanne Kreijkamp-Kaspers, et al

Soy protein containing isoflavones and mammographic density in a randomized controlled trial in postmenopausal women.

RCTn = 202

A double-blind, randomized controlled trial was conducted with 202 Dutch postmenopausal women to compare the effects of soy protein intake containing 99 mg isoflavones daily with milk protein (placebo) over 1 year. Mammographic density decreased in both groups, but the decrease did not differ significantly between the intervention and placebo groups. Equol producer status did not modify the results.

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2006·The American journal of cardiology·Kristi Reynolds, Ashley Chin, Karen A Lees, et al

A meta-analysis of the effect of soy protein supplementation on serum lipids.

Meta-analysisHeart Health

Meta-analysis of 41 randomized controlled trials examining the effect of soy protein supplementation on serum lipid levels in adults. Soy protein supplementation was associated with significant reductions in total cholesterol, low-density lipoprotein cholesterol, and triglycerides, and a significant increase in high-density lipoprotein cholesterol.

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2005·Menopause (New York, N.Y.)·Linda Kok, Sanne Kreijkamp-Kaspers, Diederick E Grobbee, et al

A randomized, placebo-controlled trial on the effects of soy protein containing isoflavones on quality of life in postmenopausal women.

RCTn = 202

A double-blind randomized placebo-controlled trial was conducted with 202 postmenopausal women to assess the effects of soy protein containing isoflavones on quality of life. The soy group showed increases in some dimensions of the SF-36 and QLS(M), but no statistically significant differences were found between the soy and placebo groups in terms of quality of life improvements.

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2005·The American journal of clinical nutrition·Sanne Kreijkamp-Kaspers, Linda Kok, Michiel L Bots, et al

Randomized controlled trial of the effects of soy protein containing isoflavones on vascular function in postmenopausal women.

RCTn = 202Heart Health

A 12-month double-blind randomized trial compared the effects of soy protein containing 99 mg isoflavones per day with milk protein on blood pressure and endothelial function in 202 postmenopausal women. The study found no significant difference in endothelial function between groups, but systolic blood pressure increased more in the soy group. Equol producers in the soy group showed improved endothelial function and decreased blood pressure, while nonproducers showed the opposite.

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2005·The American journal of clinical nutrition·Siyan Zhan, Suzanne C Ho

Meta-analysis of the effects of soy protein containing isoflavones on the lipid profile.

Meta-analysisHeart Health

Meta-analysis of 23 RCTs assessing the effects of soy protein containing isoflavones on lipid profiles. Soy protein with isoflavones significantly reduced serum total cholesterol, LDL cholesterol, and triacylglycerol, and increased HDL cholesterol, with effects varying by intake level, duration, sex, and initial lipid concentrations.

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2005·Journal of the American College of Nutrition·Thomas M Badger, Martin J J Ronis, Rosalia C M Simmen, et al

Soy protein isolate and protection against cancer.

Meta-analysis

Meta-analyses of epidemiologic studies and animal experiments suggest that soy protein isolate (SPI) consumption reduces the risk of mammary, colon, and prostate cancer. In rats, SPI-containing diets reduced the incidence of chemically-induced tumors, potentially through mechanisms like increased mammary gland differentiation and decreased activation of procarcinogens.

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2003·Menopause (New York, N.Y.)·Gregory L Burke, Claudine Legault, Mary Anthony, et al

Soy protein and isoflavone effects on vasomotor symptoms in peri- and postmenopausal women: the Soy Estrogen Alternative Study.

RCTn = 241Womens Health -

RCT investigating the efficacy of dietary soy proteins with differing amounts of isoflavones on vasomotor symptoms in peri- and postmenopausal women. All groups showed a reduction in symptoms, but no significant differences were observed between the isoflavone doses and the control group.

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2025·Journal of strength and conditioning research·Jenna McClure, Abigail Sommer, William J Kraemer, et al

Effects of Soy Pretzel Consumption on Blood Biomarkers and Muscle Soreness After Intense Resistance Exercise in Healthy, Trained Males: A Preliminary Study.

RCTn = 10Inflammation Recovery Hormone Health

This preliminary study examined the effects of soy soft pretzel consumption on muscle soreness and blood biomarkers after intense resistance exercise in 10 trained male athletes. While soy pretzel intake affected hormonal and isoflavone responses, its impact on soreness and inflammatory markers was uncertain, suggesting the need for further study.

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2023·Nutrients·Julianne Rizzo, Mildred Min, Sarah Adnan, et al

Soy Protein Containing Isoflavones Improves Facial Signs of Photoaging and Skin Hydration in Postmenopausal Women: Results of a Prospective Randomized Double-Blind Controlled Trial.

RCTn = 44Skin Hair Health

This 6-month randomized double-blind controlled trial studied the effects of soy protein isolate with isoflavones on skin photoaging in 44 postmenopausal women. The SPII group showed significant improvements in wrinkle severity, facial pigment intensity, and skin hydration compared to the casein group.

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2021·Nutrition and cancer·Maarten C Bosland, Joanne Schmoll, Hiroko Watanabe, et al

Randomized, Placebo-Controlled Six-Month Intervention Study of Soy Protein Isolate in Men with Biochemical Recurrence after Radical Prostatectomy: A Pilot Study.

RCTn = 16Mens Health -

RCT of 16 men with biochemical recurrence after prostatectomy, comparing 20g soy protein supplementation to casein placebo over 6-8 months. Serum genistein levels increased and cholesterol decreased in the soy group, but PSA levels increased similarly in both groups, with no difference in PSA doubling times.

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2018·Journal of dietary supplements·Wilson Mejía, Diana Córdoba, Paola Durán, et al

Effect of Daily Exposure to an Isolated Soy Protein Supplement on Body Composition, Energy and Macronutrient Intake, Bone Formation Markers, and Lipid Profile in Children in Colombia.

RCTn = 107Nutrition Joint Bone Health Physique

RCT assessing the effect of a daily soy protein supplement on nutritional status, bone formation markers, lipid profile, and energy and macronutrient intake in children. Significant changes in body mass index, weight for age Z scores, and macronutrient intake were observed in the intervention group, suggesting benefits for bone health and development.

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2015·Clinical nutrition (Edinburgh, Scotland)·Rebecca L Thomson, Grant D Brinkworth, Manny Noakes, et al

Muscle strength gains during resistance exercise training are attenuated with soy compared with dairy or usual protein intake in older adults: A randomized controlled trial.

RCTn = 179Physical Performance

RCT with 179 older adults comparing the effects of high dairy protein, high soy protein, and usual protein intake combined with resistance training over 12 weeks. Soy protein intake attenuated muscle strength gains compared to dairy protein and usual protein intake.

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2013·Journal of hypertension·Zhao-Min Liu, Suzanne C Ho, Yu-Ming Chen, et al

Effect of soy protein and isoflavones on blood pressure and endothelial cytokines: a 6-month randomized controlled trial among postmenopausal women.

RCTn = 180Heart Health

A 6-month double-blind randomized controlled trial among 180 postmenopausal Chinese women with mild hyperglycemia tested the effects of soy protein and isoflavones on blood pressure and endothelial cytokines. No significant differences were observed overall, but subgroup analysis showed significant reductions in systolic blood pressure and sICAM-1 among pre and hypertensive women.

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2013·Journal of clinical oncology : official journal of the American Society of Clinical Oncology·Mara Z Vitolins, Leah Griffin, W Vic Tomlinson, et al

Randomized trial to assess the impact of venlafaxine and soy protein on hot flashes and quality of life in men with prostate cancer.

RCTn = 120Womens Health -

RCT of 120 androgen-deprived men with prostate cancer assessing the impact of venlafaxine and soy protein on hot flashes and quality of life. Neither venlafaxine nor soy protein significantly affected hot flash symptom severity, but soy protein improved quality of life measures.

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2011·Journal of clinical lipidology·Jennifer L Jones, Maria Luz Fernandez, Mark S McIntosh, et al

A Mediterranean-style low-glycemic-load diet improves variables of metabolic syndrome in women, and addition of a phytochemical-rich medical food enhances benefits on lipoprotein metabolism.

RCTn = 89Heart Health Inflammation

A 12-week RCT assessed the impact of a Mediterranean-style low-glycemic-load diet with or without a medical food containing phytosterols, soy protein, and extracts from hops and acacia on cardiometabolic risk variables in women with metabolic syndrome. The medical food enhanced reductions in lipoprotein metabolism and plasma homocysteine compared to the diet alone.

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2010·The American journal of clinical nutrition·Zhao-min Liu, Yu-ming Chen, Suzanne C Ho, et al

Effects of soy protein and isoflavones on glycemic control and insulin sensitivity: a 6-mo double-blind, randomized, placebo-controlled trial in postmenopausal Chinese women with prediabetes or untreated early diabetes.

RCTn = 180Nutrition -

This 6-month randomized, double-blind, placebo-controlled trial investigated the effects of soy protein and isoflavones on glycemic control and insulin sensitivity in 180 postmenopausal Chinese women with prediabetes or early untreated diabetes. The study found no favorable changes in glycemic control and insulin resistance markers with soy protein and isoflavone supplementation.

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2008·Nutrition and cancer·Jill M Hamilton-Reeves, Salome A Rebello, Will Thomas, et al

Effects of soy protein isolate consumption on prostate cancer biomarkers in men with HGPIN, ASAP, and low-grade prostate cancer.

RCTn = 58Mens Health

RCT of 58 men at high risk of prostate cancer or with low-grade prostate cancer consuming soy protein isolate (SPI+ or SPI-) or milk protein. SPI+ did not alter prostate cancer tumor markers, while SPI- showed mixed effects on Bax and PCNA expression. A lower rate of prostate cancer developed in the soy groups compared to the milk group.

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2005·Journal of the American College of Nutrition·Yunsheng Ma, David Chiriboga, Barbara C Olendzki, et al

Effect of soy protein containing isoflavones on blood lipids in moderately hypercholesterolemic adults: a randomized controlled trial.

RCTn = 159Heart Health -

RCT comparing the effects of soy protein with isoflavones to a milk-protein based control on blood lipid levels in 159 hyperlipidemic adults. No significant differences in blood lipid levels were observed between groups, and no significant associations between blood isoflavones and lipid levels were found.

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2005·The American journal of clinical nutrition·Kenneth F Adams, Paul D Lampe, Katherine M Newton, et al

Soy protein containing isoflavones does not decrease colorectal epithelial cell proliferation in a randomized controlled trial.

RCTn = 150

A 12-month randomized controlled trial tested the effect of soy protein containing isoflavones on colorectal epithelial cell proliferation in 150 participants with adenomatous polyps. The study found that supplementation did not reduce cell proliferation and actually increased proliferation measures in the sigmoid colon.

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2005·The American journal of clinical nutrition·Heather M Engelman, D Lee Alekel, Laura N Hanson, et al

Blood lipid and oxidative stress responses to soy protein with isoflavones and phytic acid in postmenopausal women.

RCTn = 55

Double-blind 6-week RCT in 55 postmenopausal women assessing the effects of soy protein components isoflavones and phytate on cardiovascular risk factors. Neither phytate nor isoflavones significantly affected oxidative stress indexes or blood lipid profiles.

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2004·Phytomedicine : international journal of phytotherapy and phytopharmacology·B H Arjmandi, D A Khalil, E A Lucas, et al

Soy protein may alleviate osteoarthritis symptoms.

RCTn = 135Joint Bone Health

Double-blind, placebo-controlled RCT with 135 individuals with osteoarthritis or chronic knee joint pain. Participants consumed 40g of soy protein or milk-based protein daily for 3 months. Soy protein improved symptoms such as range of motion and pain, particularly in men, supported by changes in biochemical markers of cartilage metabolism.

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2004·European journal of nutrition·Eva Lydeking-Olsen, Jens-Erik Beck-Jensen, Kenneth D R Setchell, et al

Soymilk or progesterone for prevention of bone loss--a 2 year randomized, placebo-controlled trial.

RCTn = 89Joint Bone Health

This 2-year RCT compared the effects of soymilk with isoflavones, transdermal progesterone, and their combination on bone mineral density in postmenopausal women. Soymilk with isoflavones prevented lumbar spine bone loss, while transdermal progesterone also had bone-sparing effects. However, the combination of both treatments resulted in greater bone loss than either treatment alone.

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2002·European journal of clinical nutrition·P Puska, V Korpelainen, L H Høie, et al

Soy in hypercholesterolaemia: a double-blind, placebo-controlled trial.

RCTn = 60Heart Health

RCT of 60 subjects comparing Abacor, a soy protein-based product, to placebo for 6 weeks. Abacor significantly reduced LDL-cholesterol and total cholesterol compared to placebo, with effects occurring within 6 weeks.

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2001·The American journal of clinical nutrition·C D Gardner, K A Newell, R Cherin, et al

The effect of soy protein with or without isoflavones relative to milk protein on plasma lipids in hypercholesterolemic postmenopausal women.

RCTn = 94Heart Health

RCT comparing the effects of soy protein with and without isoflavones to milk protein on plasma lipids in hypercholesterolemic postmenopausal women. LDL-cholesterol decreased more in the soy protein with isoflavones group than in the soy protein without isoflavones group, but neither was significantly different from the milk protein group. Results suggest an effect attributable to isoflavones, though changes may be due to study participation factors.

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2001·Menopause (New York, N.Y.)·A St Germain, C T Peterson, J G Robinson, et al

Isoflavone-rich or isoflavone-poor soy protein does not reduce menopausal symptoms during 24 weeks of treatment.

RCTn = 69Womens Health -

This double-blind 24-week RCT examined the effect of isoflavone-rich and isoflavone-poor soy protein on menopausal symptoms in 69 perimenopausal women. The study found no treatment effect on hot flushes, night sweats, or other vasomotor symptoms, suggesting no benefit from soy protein supplementation.

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1995·The New England journal of medicine·J W Anderson, B M Johnstone, M E Cook-Newell

Meta-analysis of the effects of soy protein intake on serum lipids.

Meta-analysisHeart Health

Meta-analysis of 38 controlled clinical trials examining the effects of soy protein intake on serum lipids in humans. Soy protein consumption significantly decreased serum concentrations of total cholesterol, LDL cholesterol, and triglycerides, with a nonsignificant increase in HDL cholesterol.

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2019·Appetite·Svetlana Nepocatych, Caroline E Melson, Takudzwa A Madzima, et al

Comparison of the effects of a liquid breakfast meal with varying doses of plant-based soy protein on appetite profile, energy metabolism and intake.

RCTn = 17Nutrition

RCT with 17 participants comparing the effects of liquid breakfast meals with varying doses of soy protein on appetite, energy metabolism, and intake. Higher doses of soy protein reduced energy intake at lunch and were rated as more satiating compared to a carbohydrate control meal.

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2014·The Journal of nutrition·Monique van Nielen, Edith J M Feskens, Annemarie Rietman, et al

Partly replacing meat protein with soy protein alters insulin resistance and blood lipids in postmenopausal women with abdominal obesity.

RCTn = 15Hormone Health Heart Health

Randomized crossover trial in 15 postmenopausal women with abdominal obesity comparing a diet with mixed protein sources to one partly replacing meat with soy protein. The soy-protein diet improved insulin sensitivity and reduced total and LDL cholesterol compared to the mixed-protein diet.

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2010·International journal of sport nutrition and exercise metabolism·Asok Kumar Ghosh, A Abdul Rahaman, Rabindarjeet Singh

Combination of sago and soy-protein supplementation during endurance cycling exercise and subsequent high-intensity endurance capacity.

RCTn = 8Physical Performance

RCT with 8 male recreational cyclists testing sago and soy protein supplementation during moderate-intensity cycling. The sago-soy combination increased endurance capacity by 84% compared to placebo and 37% compared to sago alone, suggesting improved physical performance.

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2009·The Journal of nutrition·Elizabeth A Pipe, Colleen P Gobert, Sarah E Capes, et al

Soy protein reduces serum LDL cholesterol and the LDL cholesterol:HDL cholesterol and apolipoprotein B:apolipoprotein A-I ratios in adults with type 2 diabetes.

RCTn = 29Heart Health

Double-blind, randomized, crossover, placebo-controlled intervention study in 29 adults with diet-controlled type 2 diabetes. Soy protein isolate consumption reduced serum LDL cholesterol, LDL cholesterol:HDL cholesterol ratio, and apolipoprotein B:apolipoprotein A-I ratio compared to milk protein isolate, indicating a beneficial effect on cardiovascular disease risk.

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2009·Journal of clinical lipidology·Robert H Lerman, Deanna M Minich, Gary Darland, et al

Subjects with elevated LDL cholesterol and metabolic syndrome benefit from supplementation with soy protein, phytosterols, hops rho iso-alpha acids, and Acacia nilotica proanthocyanidins.

RCTn = 24Heart Health

Subgroup analysis of a 12-week RCT in adults with metabolic syndrome and elevated LDL-C. The treatment group received a diet supplemented with soy protein, phytosterols, hops rho iso-alpha acids, and acacia proanthocyanidins, showing greater improvements in cholesterol-related markers compared to the control group.

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2009·Journal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation·Leila Azadbakht, Ahmad Esmaillzadeh

Soy-protein consumption and kidney-related biomarkers among type 2 diabetics: a crossover, randomized clinical trial.

RCTn = 14

A crossover, randomized clinical trial among 14 type 2 diabetic patients with nephropathy assessed the effects of soy-protein consumption on renal-related markers. Soy protein consumption reduced urinary urea nitrogen, proteinuria, blood sodium, and serum phosphorus compared to animal protein.

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2008·European journal of endocrinology·Anneke J A H van Vught, Arie G Nieuwenhuizen, Robert-Jan M Brummer, et al

Somatotropic responses to soy protein alone and as part of a meal.

RCTn = 6Physique

Randomized crossover study comparing the effects of oral ingestion of soy protein alone versus as part of a meal on GH secretion in six healthy women. GH responses were lower after ingestion of the meal compared to soy protein alone, while glucose and insulin responses were higher after the meal.

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2006·Maturitas·Nailza Maesta, Eliana A P Nahas, Jorge Nahas-Neto, et al

Effects of soy protein and resistance exercise on body composition and blood lipids in postmenopausal women.

RCTn = 46Physique -Heart Health

Controlled trial with 46 postmenopausal women randomized to soy protein, soy protein plus resistance exercise, placebo, or placebo plus resistance exercise. After 16 weeks, soy protein alone improved lipid profile with significant decreases in total cholesterol and LDL. Resistance exercise increased muscle mass and reduced waist circumference, but soy protein did not affect body composition indicators.

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2006·Journal of the American College of Nutrition·Helena J Teede, Dimitra Giannopoulos, Fabien S Dalais, et al

Randomised, controlled, cross-over trial of soy protein with isoflavones on blood pressure and arterial function in hypertensive subjects.

RCTn = 41Heart Health

A 6-month double-blind, placebo-controlled, cross-over trial with 41 hypertensive subjects examined the effects of soy protein with isoflavones on blood pressure and arterial function. Soy protein increased urinary isoflavones but had no significant effect on arterial function or average 24 hr ambulatory blood pressure parameters. However, daytime blood pressure and heart rates were higher after soy compared to gluten.

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2006·The Journal of nutrition·Jane E Kerstetter, Diane E Wall, Kimberly O O'Brien, et al

Meat and soy protein affect calcium homeostasis in healthy women.

RCTn = 20Nutrition

RCT with 20 healthy women comparing high- and low-protein diets from soy and meat sources. High-protein diets increased urinary calcium, but urinary calcium did not differ by protein type. Soy protein substitution for meat protein led to an acute decline in dietary calcium bioavailability.

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2005·The American journal of clinical nutrition·Lisa A Spence, Elaine R Lipscomb, Jo Cadogan, et al

The effect of soy protein and soy isoflavones on calcium metabolism in postmenopausal women: a randomized crossover study.

RCTn = 15

Randomized crossover study in 15 postmenopausal women testing the effects of soy isoflavones and soy protein on calcium metabolism. Urinary calcium excretion was significantly lower with soy diets compared to a control diet, but calcium retention was not improved. Soy isoflavones did not significantly affect calcium metabolism.

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2004·The Journal of nutrition·Sophie Desroches, Jean-François Mauger, Lynne M Ausman, et al

Soy protein favorably affects LDL size independently of isoflavones in hypercholesterolemic men and women.

RCTn = 36Heart Health

RCT assessing the effect of soy protein versus animal protein on LDL particle characteristics in 36 hypercholesterolemic men and women. Soy protein consumption was associated with a larger LDL peak particle size and a shift to a less atherogenic LDL particle distribution, independent of isoflavones.

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2004·Atherosclerosis·Yanwen Wang, Peter J H Jones, Lynne M Ausman, et al

Soy protein reduces triglyceride levels and triglyceride fatty acid fractional synthesis rate in hypercholesterolemic subjects.

RCTn = 20Heart Health

A four-phase randomized cross-over feeding trial examined the effects of soy protein versus animal protein on triglyceride and cholesterol biosynthesis in hyperlipidemic subjects. Soy protein reduced triglycerides by 12.4%, total cholesterol by 4.4%, and LDL cholesterol by 5.7% compared to animal protein. Isoflavones had no significant effect on triglycerides but reduced total cholesterol levels by 3.1%.

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2004·The Journal of clinical endocrinology and metabolism·Zamzam K Roughead, Janet R Hunt, Luann K Johnson, et al

Controlled substitution of soy protein for meat protein: effects on calcium retention, bone, and cardiovascular health indices in postmenopausal women.

RCTn = 13

Controlled feeding study in postmenopausal women comparing the effects of substituting 25 g soy protein for meat protein on calcium retention and bone and cardiovascular health indices. The study found no significant differences in calcium retention or health indicators between the soy and meat protein diets.

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1998·The American journal of clinical nutrition·S M Potter, J A Baum, H Teng, et al

Soy protein and isoflavones: their effects on blood lipids and bone density in postmenopausal women.

RCTn = 66Heart Health Joint Bone Health

A 6-month, double-blind RCT in 66 hypercholesterolemic, postmenopausal women comparing the effects of soy protein with different isoflavone concentrations on blood lipids and bone density. Both soy protein groups showed reduced non-HDL cholesterol and increased HDL cholesterol. The higher isoflavone group also showed increased bone mineral content and density in the lumbar spine.

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1994·Journal of the American College of Nutrition·H R Churella, M W Borschel, M R Thomas, et al

Growth and protein status of term infants fed soy protein formulas differing in protein content.

RCTn = 64Nutrition -

A randomized controlled trial comparing growth and protein status in term infants fed two soy-based formulas with different protein contents. No significant differences were found in growth measures or protein status, except for lower plasma urea nitrogen in the lower protein formula group.

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1984·The American journal of clinical nutrition·V R Young, M Puig, E Queiroz, et al

Evaluation of the protein quality of an isolated soy protein in young men: relative nitrogen requirements and effect of methionine supplementation.

RCTNutrition -

The study evaluated the protein nutritional value of isolated soy protein (Supro-620) in young men through nitrogen balance studies. Results showed that the isolated soy protein is of high nutritional quality, comparable to animal protein sources, and methionine supplementation did not provide additional benefits at higher nitrogen intake levels.

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1998·The American journal of clinical nutrition·J W Anderson, J E Blake, J Turner, et al

Effects of soy protein on renal function and proteinuria in patients with type 2 diabetes.

RCTn = 8Heart Health Nutrition -

Preliminary study of 8 type 2 diabetes patients with obesity, hypertension, and proteinuria examining the effects of substituting soy protein for animal protein. Soy protein intake had no distinct effects on renal function or proteinuria but was associated with a significant reduction in serum cholesterol and triacylglycerol concentrations.

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1978·The American journal of clinical nutrition·K K Carroll, P M Giovannetti, M W Huff, et al

Hypocholesterolemic effect of substituting soybean protein for animal protein in the diet of healthy young women.

RCTn = 10Heart Health

Two studies investigated the effect of substituting animal protein with soy protein on plasma cholesterol levels in healthy young women. The second study, using a cross-over design with 10 subjects, found significantly lower plasma cholesterol levels on the plant protein diet.

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