Copyright
©The Author(s) 2016.
World J Nephrol. May 6, 2016; 5(3): 233-257
Published online May 6, 2016. doi: 10.5527/wjn.v5.i3.233
Published online May 6, 2016. doi: 10.5527/wjn.v5.i3.233
Table 1 Single arm intervention studies of soy protein and kidney function
| Ref. | Studydesign | Kidney function | Subjects/group | Amount of soy protein used | Control/comparator protein | Duration of intervention | Outcomes | Notes |
| Cupisti et al[93] | Single arm dietary intervention study | Renal transplant patients with moderate HC | 13 subjects completed study (7M, 6F) | Goal was to replace 25 g/d animal protein with soy protein (dietary counseling only) | Animal protein (baseline) | 5 wk on soy diet | Significant decrease in urinary creatinine after 5 wk on soy protein compared to baseline (P < 0.05) | |
| Soy protein resulted in significant decrease in TC (P < 0.05) and LDL-C (P < 0.01) after 5 wk compared to baseline; no change in HDL-C | ||||||||
| Cupisti et al[94] | Single arm dietary intervention | Renal transplant patients and and age, sex-matched healthy controls (latter for vascular measure comparisons only) | 20 per group (12M, 8F) | Goal was to replace 25 g/d animal protein with soy protein (dietary counseling only) | Animal protein (baseline and WO) | 5 wk on soy diet followed by 5 wk WO | Renal transplant patients had significantly reduced FMD compared to age- and sex-matched control subject (P < 0.001) with no differences between groups in non-endothelium-mediated vasodilation | First study to show improvement in endothelial function in brachial arteries of renal transplant patients when animal protein substituted with soy protein |
| Soy diet did not change total dietary protein intake, BW, renal function, urinary protein excretion, serum Ca or P | ||||||||
| Soy diet reduced TC and LDL-C and LOOH (P < 0.01) compared to baseline diet | ||||||||
| Soy diet resulted in improvement in FMD (P = 0.003) compared to baseline while reactive hyperemia and endothelium-independent vasodilation was unchanged; FMD returned to baseline after WO | ||||||||
| Increase in FMD correlated to increase in L-arg/ADMA ratio (P < 0.05) with soy diet | ||||||||
| D’Amico et al[95,96] | Single arm dietary intervention | Nephrotic patients with proteinuria > 1-5 g/24 h over 25 mo and HL | 20 subjects (13M, 7F) | 0.7-0.8 g/kg per day mostly from soy protein in test diet; test diet also contained vegetable oils and no cholesterol | 0.7–0.8 g/kg per day animal protein (baseline and WO) | 8 wk baseline diet followed by 8 wk soy diet and then 8 wk WO | TC, LDL-C, HDL-C, apoAI and apoB decreased on soy diet compared to baseline diet (P < 0.001); no change in TG; lipids tended to revert to baseline during WO | Fibre, type of fat and no cholesterol were also other components of the soy protein arm that were different from the control diet; there was a modest but significant decrease in BW on the soy protein diet (no change in BMI) |
| Urinary protein, urea, Na and P excretion were reduced significantly from baseline during the soy diet (P < 0.001) | ||||||||
| Soy diet results in significant decrease in CrCl with no change in serum creatinine; this persisted during WO | ||||||||
| BP did not change |
Table 2 Chronic controlled intervention studies of soy protein and kidney function
| Ref. | Study design | Kidney function | Subjects/group | Amount of soy protein used | Control/comparator protein | Duration of intervention | Outcomes | Notes |
| Liu et al[128] | RC | Pre-hypertensive PM women | 90 subjects/group (85, 87 and 81 completed study in the soy, daidzein and placebo groups, respectively) | 40 g soy flour/d, 12.8 g soy protein/d | 40 g lowfat milk powder (placebo) or 40 g lowfat milk powder with 63 mg/d daidzein | 6 mo | No significant changes in most renal parameters were observed between groups | All subjects were equol producers |
| Soy flour intake resulted in less decrease in eGFRCockcroft (P = 0.044) and % change in eGFR (P = 0.031) after 6 mo compared to the milk placebo group (P = 0.044) | ||||||||
| Effect of soy flour consumption to increase eGFR was greater in women with higher initial plasma cystatin C concentrations (Cys-C > 1.14 mg/L) (P = 0.001 for eGFRCockcroft) compared to milk placebo | ||||||||
| Ahmed et al[131] | RC | Glomerulo-pathy with proteinuria (non-diabetic) | 9 subjects/group, | 0.8 g/kg per day soy protein | 0.8 g/kg per day an animal protein or 0.8 g/kg per day a soy protein + fiber | 8 wk | No significant changes in anthropometric measures, serum lipids or proteinuria between diet groups | Significant decreases from baseline in overall energy and protein intake in all groups confounds end of study comparisons |
| total 27 subjects (4M, 23F) | ||||||||
| Soroka et al[129] | RC | Non-diabetic, non-nephrotic CRF patients (urinary protein excretion < 3 g/d) | 9 completed study (5M, 4F) | 0.71 g/kg BW protein, mostly soy protein with egg (VPD) | 0.85 g/kg per day APD (1:1, animal sources:grains) | 6 mo | No difference in renal function between groups seen; both groups saw reduction in rate of GFR decline | High dropout and small number of subjects |
| BUN, Urinary N excretion, PCR, 24 h urinary creatinine and phosphate were lower in VPD group | Differences in total energy and protein intake in VPD and APD | |||||||
| D’Amico et al[102], Gentile et al[103] | RC | Non-diabetic, nephrotic patients with proteinuria > 2.5 g/24 h for a mean of 24 mo and HC | 20 subjects (9M, 11F) | Protein intake at end of study was calculated from urinary urea excretion to be 1.16 ± 0.04 g/kg per day (98% of this estimated to be soy protein) | Soy protein used in both experimental arms of study; baseline diet was comparator | 8 wk for each arm (baseline diet, soy ± 5 g/d fish oil in random order) followed by WO for 3 mo on baseline diet) | Soy diet significantly reduced TC, LDL-C, HDL-C, apoB (P < 0.0001) and apoAI (P < 0.01) compared to baseline; TGs were unaffected; lipids tended towards baseline values after WO | Both diet interventions resulted in modest decrease in BW and BMI (-4%) which was significantly different from baseline; both values tended towards baseline during WO |
| Addition of 5 g/d fish oil to soy diet resulted in significant elevation of TC and apoB compared to soy diet alone (P < 0.01) | ||||||||
| Urinary protein, urea, P, Na and creatinine excretion was significantly decreased by both diet interventions (P < 0.01); measures tended towards baseline after WO | ||||||||
| Blood glucose was significantly reduced by both diet interventions (P < 0.01) however soy diet alone reduced blood glucose more than soy diet and fish oil (P < 0.01) | ||||||||
| Anderson et al[97] | RC | T2D with proteinuria, obese, and HTN | 8 M | 1.0 g/kg per day protein, 50% soy protein in soy test diet | 1.0 g/kg per day protein, 50% ground beef in animal test diet | 8 wk, 4 wk WO | TC and TG decreased by soy diet (P < 0.05) vs animal protein diet | Low number of subjects |
| SUN sig decreased by soy protein (P < 0.05) | ||||||||
| Change in GFR similar with both diets | ||||||||
| Urine protein excretion increased by soy vs animal protein diet (P = 0.028) | ||||||||
| Azadbakht et al[98] | RP | T2D subjects with nephropathy, proteinuria, HTN | 41 subjects: 18 M, 23 F | 0.8 g/kg per day protein, 35% soy protein (textured soy protein), 35% animal protein, 30% vegetable protein | 0.8 g/kg per day protein, 70% animal and 30% vegetable protein | 4 yr | Decreased FPG in soy group (P = 0.03 | |
| Soy protein group decreased TC (P < 0.01), LDL-C (P = 0.01) and TG (P = 0.01 | ||||||||
| Serum CRP decreased (P = 0.02) on soy protein diet | ||||||||
| Soy protein diet reduced proteinuria (P = 0.001) and urinary creatinine (P = 0.01) | ||||||||
| Miraghajani et al[108,113] | RC | T2D subjects with nephropathy | 25 subjects completed the study (10 M, 15 F) | 2.5 g soy protein (240 mL soymilk/d) | 3.3 g cow milk protein (240 mL milk/d) | 4 wk interventions with 2 wk WO | Soy protein consumption resulted in a significant difference in % change of fibrin D-dimer concentrations compared to milk protein (P = 0.04); there were no differences in % changes in TNFα, IL-6, CRP, MDA or fibrinogen concentrations between groups | Amount of soy protein used in diet intervention was low |
| Soy protein consumption resulted in significant decrease in systolic BP compared to cow milk protein (-4.50% vs + 5.89%, P = 0.02) | ||||||||
| Teixeira et al[106] | RC | T2D subjects with nephropathy | 14 male subjects | 0.5 g/kg per day soy protein (Approximately equal 50% of total daily intake) | 0.5 g/kg per day casein | 8 wk interventions with 4 wk WO | Urinary albumin-creatinine ratio was significantly reduced by ISP (P < 0.0001) and increased by casein (P = 0.002) | |
| Change in urinary albumin-creatinine ratio correlated inversely with plasma isoflavone levels (P = 0.012) | ||||||||
| CrCl did not change (GFR) with either diet | ||||||||
| HDL-C was increased after ISP (P = 0.0041) while it tended to be lower after casein (P = 0.0847) | ||||||||
| TC and LDL-C not changed by either diet | ||||||||
| Total and glycated hemoglobin did not change in either group | ||||||||
| No differences in BP between groups; however soy diet resulted in higher plasma arg/lys ratios (P = 0.0097) which persisted after fasting | ||||||||
| Stephens et al[104] | RC | T1D subjects with hyper-filtration GFR > 120 mL/min/1.73 m2 | 12 subjects completed study (6 M, 6 F 0) | 45-55 g/d soy protein to substitute for animal protein in control diet | 45-55 g/d animal protein | 8 wk interventions; no WO | GFR sig lower in soy group vs control group (P = 0.02) | No washout between interventions |
| Excretion of urinary creatinine, urea and Na not diff between groups | ||||||||
| Microalbuminuria within normal ranges and unaffected by diet | ||||||||
| TC and LDL-C significantly reduced in soy group (P < 0.02, 0.05, respectively) whereas TG and HDL-C not diff between groups | ||||||||
| Serum glucose was not affected by soy protein diet but was significantly increased on the control diet (P < 0.05) compared to baseline | ||||||||
| Serum albumin did not change but total serum protein decreased in soy group (P < 0.05) | ||||||||
| Chen et al[101] | RP | Nondiabetic hemodialysis patients | Soy group: 10 HL (7 F, 3 M) and 8 NL (6 F, 2 M) | 30 g/d soy protein | 30 g/d milk protein | 12 wk | No significant differences between groups in serum nutritional parameters or hemodialysis adequacy | Test proteins consumed on top of usual hemodialysis diet |
| TC and TG decreased in HL subjects consuming soy vs milk protein over time (P < 0.05 at 12 wk) | ||||||||
| Control group: 9 HL (7 F, 2 M) and 10 NL (7 F, 3 M) | Non-HDL-C, apoB, TC/HDL-C ratio and insulin decreased in HL subjects consuming soy vs milk protein at 12 wk (P < 0.05) | |||||||
| Non-significant differences between protein groups in NL subjects | ||||||||
| Soy protein resulted in significant decrease in fasting insulin in NL group at 12 wk compared to values at baseline (P < 0.05) | ||||||||
| Chen et al[100] | RP | Non-diabetic hemodialysis patients with HC | Soy group: 13 (9 M, 4 F) | 30 g/d soy protein | 30 g/d milk protein | 12 wk | No significant differences between groups in serum nutritional parameters or hemodialysis adequacy | Not clear if some of the subject are the same as reported in Chen et al[101] as study protocols are the same |
| Milk group: 13 (10 M, 3 F) | TC, non-HDL-C, apoB, TC/HDL-C and LDL-C/HDL-C ratios decreased in subjects consuming soy vs milk protein at 12 wk (P < 0.05) | |||||||
| No differences in TG between soy and milk groups | ||||||||
| Soy protein resulted in significant decrease in fasting insulin at 12 wk compared to milk protein group (P < 0.05) | ||||||||
| Imani et al[110] | RP | PD patients | 18 subjects | 14 g soy protein at dinner each day | Meat instead of soy protein at dinner | 8 wk | Soy protein diet resulted in significant 17% reduction in plasma coagulation factor IX activity compared to control group (P < 0.05) | Study was not blinded |
| Soy group (9 M, 9 F), | No significant changes in oxLDL, P, fibrinogen or activities of coagulation factors VII and X between groups | Mean energy and protein intakes were less than recommended amounts (30 kcal/kg per day and 1.2 g/kg per day, respectively) which is common among PD patients | ||||||
| Control group (9 M, 9 F) | ||||||||
| Fanti et al[112] | RP | ESRD patients on chronic HD with elevated CRP (> 10 mg/L) | Soy group = 15; control milk group = 10 | 25 g/d | 25 g/d milk protein | 8 wk | 5 to 10-fold increase in mean serum IF concentration in soy group at end of study (P < 0.001) | Small number of subjects |
| No significant change in CRP between groups, however, significant inverse correlation of CRP with IF concentration | Test proteins provided as beverages, a cereal-type product and as snack bar | |||||||
| Significant positive correlation of serum IF concentration and serum albumin and IGF-1 | ||||||||
| Siefker et al[109] | RP | HD patients | 17 subjects | 25 g soy protein (4 times per week) | Whey protein (exact amount not specified); provided 4 times per week | 4 wk | No difference between groups on serum markers of renal function except creatinine; whey protein showed a significant decrease in creatinine from baseline (P < 0.05) whereas there was no change in the soy protein group from baseline | Small number of subjects |
| 8 subjects on soy protein diet; 9 on whey protein | oxLDL was significantly decreased after soy protein consumption (P < 0.05) compared to baseline; the % change in oxLDL compared to the whey group was significantly different (P < 0.05) | |||||||
| No differences in plasma concentrations of 8-iso-PGF2α, TNFα, or CRP between diet groups | ||||||||
| Tomayko et al[114] | RP | MHD patients | Soy group = 12 | 27 g/d soy protein | 27 g whey protein or noncaloric placebo powder (2 g Crystal Light) | 6 mo | A significant time x treatment effect for IL-6 levels (P = 0.036) with both whey and soy protein groups decreasing compared to control group | First study to observe improvements in inflammation and physical function after intradialytic nutritional support in MHD patients with serum albumin ≥ 3.9 g/dL (i.e., not malnourished) |
| Whey group = 11 | Soy diet resulted in a significant decrease in neutrophil-lymphocyte ratio (systemic inflammation marker) compared to control or whey diet (P = 0.02) | |||||||
| Placebo control = 15 | Alkaline phosphatase, a marker of bone turnover, was increased in the control diet compared with both protein diet groups (P = 0.04) | |||||||
| A significant time by treatment interaction was seen for gait speed when all 3 groups analyzed (P = 0.048); both soy and whey groups indicated improved gait speed while control diet had a decline | ||||||||
| Shuttle walk test time was significantly improved in the whey group (P < 0.05) and when protein groups were combined (P < 0.05) versus the control group; shuttle walk test time was increased in the soy group but was not significant compared to the control group (which had decreased test times) |
Table 3 Human studies with soy protein and renal isoflavone metabolism
| Ref. | Study design | Kidney function | Subjects/group | Amount of soy protein used | Control/comparator protein | Duration of intervention | Outcomes | Notes |
| Fanti et al[115], Franke et al[192] | 3 separate protocols: | ESRD patients on HD and normal healthy subjects | 23 HD subjects and 10 healthy subjects for baseline IF measures | 20 g soy protein | Baseline diet is self-selected standard renal diet | Single meal interventions | 55%-65% of HD patients had undetectable serum IFs and 35%-45% had concentrations > 200 nM on standard renal diet | First study to report blood levels of genistein and daidzein in ESRD patients |
| Assessment of baseline serum concentrations of IFs | 7 HD patients and 8 healthy subjects for meal intervention study (8 h only); 2 healthy subjects and 3 HD subjects had multiple serum and urine timepts collected | Serum concentrations of IFs greater post-soy protein ingestion compared to baseline for both groups (P < 0.001); concentrations in HD subjects after 8 h of soy protein consumption were greater than those in healthy subjects (P < 0.05) | Daidzein metabolites equol and O-DMA were not detected in sera of any of the subjects | |||||
| Post-ingestion concentrations of IFs | 5 HD patients for pre- and post-dialysis IF measures | Half-lives of genistein and daidzein averaged 3.5 and 6 h in healthy subjects, respectively but were increased to an average of 47 and 58 h in HD patients | ||||||
| Effects of hemodialysis on IF concentrations | HD did not effectively remove IFs from serum since (due to higher molecular weight of conjugates and large proportion of unconjugated IFs are bound to albumin) | |||||||
| Fanti et al[116] | Observational | Randomly selected HD patients residing in the United States, Japan or Thailand | Subjects from: | Habitual dietary intake of soy was assessed by questionnaires developed by their renal replacement therapy programme dieticians | Study aim was to compare habitual dietary intake of soy in 3 countries | N/A | Serum IF concentrations significantly higher in HD patients from Japan compared to United States or Thailand (P < 0.0001) | |
| United States = 20 | Significant correlation between soya intake and genistein (P < 0.0001), daidzein (P < 0.0001), glycitein (P < 0.001) and O-DMA (P < 0.01) in subjects from all 3 countries | |||||||
| Japan = 20 | ESRD HD patients displayed consistently higher concentrations of daidzein compared to genistein, while the reverse occurs in healthy subjects | |||||||
| Thailand = 17 | Concentrations of sulphated and unconjugated compounds in HD subjects (Japan only studied) are comparable to those detected in healthy subjects | |||||||
| Locati et al[117] | Single arm intervention study | Renal transplant patients | 16 subjects (11 M, 5 F) | 25 g soy protein substituted for 25 g animal protein | 25 g animal protein (as habitual diet) | 5 wk | Serum IFs were measured and 5 different groups were identified on the basis of the IF profiles: (1) 4 subjects had no detectable IFs; (2) only genistein was quantifiable in 7 patients; (3) 3 patients had only detectable genistein and daidzein; (4) 2 subjects only had detectable genistein and equol; and (5) 1 subject had the highest observed genistein and daidzein with detectable dihydrogenistein and equol | Concentrations of serum IFs in the renal transplant patients were similar to those observed in healthy subjects |
Table 4 Human studies with soy protein on renal calcium metabolism
| Ref. | Study design | Kidney function | Subjects/group | Amount of soy protein used | Control/comparator protein | Duration of intervention | Outcomes | Notes |
| Breslau et al[119] | RC | Normal | 15 subjects completed animal and ovo-vegetarian diet phases; 10 completed all 3 phases (including vegetarian) | Soy protein accounted for most of the 75 g protein/d in vegetarian phase; accounted for an unspecified but lower amount in ovo-vegetarian phase | Animal protein accounted for most of the 75 g per day in the animal protein phase; consisted of dairy, beef, chicken and fish | 12 d No WO | Serum uric acid concentrations were significantly lower with the vegetarian and ovo-vegetarian diets compared to the animal protein diet (P < 0.01); urinary uric acid excretion was significantly lower in ovo-vegetarian diet vs animal diet only (P < 0.02) | Diets were constant for Ca, P, Na and total protein |
| Urinary Ca and P were significantly lower in vegetarian diet compared to beef diet (P < 0.02); urinary oxalate was significantly higher in vegetarian vs beef diet (P < 0.02) | ||||||||
| Animal protein diet resulted in lower PTH level vs vegetarian diet (P < 0.05) | ||||||||
| Serum 1,25-(OH)2D was higher in the vegetarian vs animal protein diet(P < 0.01) | ||||||||
| Roughead et al[120] | RC | Normal PM women | 13 female subjects | 25 g soy protein substituted for 25 g meat protein | 25 g meat protein in control diet | 7 wk | Ca retention was not affected by substituting soy protein for meat protein | |
| Urinary pH was higher on the soy diet compared to the control diet (P < 0.0001); renal acid excretion was lower during soy diet (P = 0.0001) however urinary Ca excretion was similar between soy and meat diets | ||||||||
| Substitution of soy protein for meat protein did not affect bone metabolism as indicated by no differences between diets in a number of specific bone biomarkers | ||||||||
| No differences between soy and meat protein diets in plasma lipid or hemostatic measures |
Table 5 Single meal intervention studies of soy protein and kidney function
| Ref. | Study design | Kidney Function | Subjects/group | Amount of soy protein used | Control/comparator protein | Duration of intervention | Outcomes | Notes |
| Bilo et al[122] | Single meal intervention study (crossover) | Normal healthy subjects | 6 normal subjects; 5 M, 1 F | Studies in normal subjects only: 80 g soy protein in single oral administration | Studies in normal subjects only: 80 g lactoprotein or beef protein or 36 g amino acids | Normal subjects: 8 individual renal function tests run on separate days | Soy protein ingestion induced significantly lower rises in GFR and ERPF compared to beef protein but not compared to lactoprotein or 36 g amino acid ingestion | Subjects with chronic renal insufficiency (PKD, NS, or MGP) were studied in a separate series of experiments in this publication, but were not used to evaluate soy protein |
| Buzio et al[127] | Single meal intervention study (crossover) | Normal healthy subjects | 7 (gender not specified) | 80 g (0.9-1.3 g.kg BW) | 80 g red meat or 80 g dairy (cheese) | Single meal interventions conducted 1 wk apart | CrCl and urinary protein were not different between protein loads | Publication describes 2 separate experiments; soy protein effects on renal function only assessed in second experimental protocol |
| UAp was significantly lower after soy protein meal versus red meat or cheese meals (P < 0.01) (samples taken 4 h post-meal) | ||||||||
| Water excretion rate was higher after soy protein load versus meat (P < 0.05) or cheese (P < 0.01) | ||||||||
| Serum total protein was lower after soy protein load compared to meat (P < 0.01) or cheese (P < 0.01) loads | ||||||||
| Deibert et al[126] | Single meal intervention study (crossover) | Normal healthy and metabolic syndrome subjects; all with normal kidney function | 10 subjects per group (All males) | 1st intervention: 1 g/kg/BW soy protein: Milk protein (83% soy protein); | N/A | Single meal intervention in normal healthy subjects; 2 meal interventions in subjects with metabolic syndrome (1 wk apart) | Patients with metabolic syndrome had significantly elevated baseline GFR and ERPF compared to healthy subjects (P = 0.02) | 0.3 g/kg/BW is amount of protein used in meal replacement therapy |
| 2nd intervention same protein source at 0.3 g/kg BW | After ingestion of 1 g/kg/BW protein, GFR and ERPF increased in both groups however the subjects with metabolic syndrome had significantly higher increases in GFR (P < 0.002) and ERPF (P < 0.02) compared to normal subjects; no significant effect of ingestion of 0.3 g/kg per BW protein on renal parameters in subjects with metabolic syndrome | |||||||
| Howe et al[118] | Single meal intervention study (Latin square crossover) | Healthy PM women | 8 F subjects | 45 g soy protein | 0 g protein, 45 g beef or dairy protein (cottage cheese) | Single meal intervention; 6 meal interventions (1 wk apart) | Urinary Ca excretion was significantly greater after 45 g protein meal for all proteins compared to basal (0 g protein) meal (P < 0.05) | |
| % Ca resorbed by the kidney was significantly reduced after the dairy and soy protein meals (P < 0.05) | ||||||||
| Serum ionized Ca was unaffected, however, serum P was significantly lowered by all protein meals (P < 0.05) compared to 0 g protein meal | ||||||||
| Soy protein meal significantly reduced calcitonin versus baseline (P < 0.05) however, all protein means tended to lower calcitonin compared to baseline | ||||||||
| Dairy protein significantly increased PTH (P < 0.05) compared to baseline, however all protein meals tended to elevate PTH compared to baseline | ||||||||
| Serum insulin was significantly increased by all protein meals (over time) compared 0 g protein meal (P < 0.05) | ||||||||
| Kontessis et al[70] | Single meal intervention study (crossover) | Normal healthy subjects | 7 M subjects | 80 g soy protein | 80 g lean beef | 2 separate single meal interventions | GFR and ERPF increased significantly after acute beef protein load (P < 0.005 compared to baseline) but did not increase with soy protein load | Amount of soy protein in vegetable protein diet in the reported chronic study was not specified so is therefore not summarized |
| Renal vascular resistance fell significantly after beef load (P < 0.05) but was unchanged after soy protein load; plasma 6-keto-PGF1α rose significantly after meat load (P < 0.05) but not after soy protein load | ||||||||
| Fractional albumin and IgG clearance rose after beef load (P < 0.05 and P < 0.001, respectively) but did not change significantly after soy protein load; plasma protein concentrations were not different between different protein loads; UAp was not different between groups | ||||||||
| Plasma glucagon increase was higher after meat load (P < 0.05) compared to soy protein load; no differences were seen between proteins on plasma insulin or growth hormone | ||||||||
| Nakamura et al[123] | Single meal intervention study (crossover) | Healthy and T2D subjects (T2D divided into 3 groups based on AER: Group A ≤ 20 μg/min (Normal); B = 20-200 μg/min; C ≥ 200 μg/min | 11 healthy subjects (8M, 3F); 20 T2D patients (10 M, 10 F) | 1g/kg soy protein (as bean curd) | 1 g/kg tuna fish protein | Meals fed on separate days | In healthy subjects, eGFR increased (P < 0.01) after tuna meal but no significant difference after soybean curd meal | |
| In Grp A, eGFR increased with tuna meal (P < 0.01) but not after soybean curd | ||||||||
| In Group B there was no difference in GFR with either protein | ||||||||
| In group C, GFR sig decreased after tuna meal (P < 0.05) but not with soy protein | ||||||||
| No changes in AER with any protein in any group | ||||||||
| Nakamura et al[124] | Single meal intervention study (crossover) | Healthy and T2D subjects | 10 healthy subjects and 6 T2D subjects | 0.7 g/kg soy protein (as bean curd) | 0.7 g/kg tuna fish protein or egg white protein or dairy protein (cheese) | Meals fed on separate days | eGFR was only significantly increased after ingestion of tuna fish protein (P < 0.001) and not after consumption of soy, egg white or dairy proteins | |
| Orita et al[125] | Single meal intervention study (crossover) | Healthy subjects | 6 male subjects | 86.9 g soy protein | 86.9 g beef protein or fasting (0 g protein) | Meals fed 1 wk apart | Inulin clearance (GFR) was significantly increased over baseline at 2 h post beef or soy protein compared to fasting (P < 0.005 and P < 0.05, respectively) | First study to show an increase in GFR after a soy protein load in healthy subjects |
| Creatinine clearance (GFR) was significantly increased by both beef and soy proteins at 2 and 3 h post-ingestion compared to fasting (P < 0.01) | ||||||||
| Plasma glucagon was significantly increased at 1 to 3 h post-ingestion by both beef and soy protein compared to fasting (P < 0.01) |
- Citation: McGraw NJ, Krul ES, Grunz-Borgmann E, Parrish AR. Soy-based renoprotection. World J Nephrol 2016; 5(3): 233-257
- URL: https://www.wjgnet.com/2220-6124/full/v5/i3/233.htm
- DOI: https://dx.doi.org/10.5527/wjn.v5.i3.233