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

PURPOSE: Clinical trials have studied the use of soy protein for treating type 2 diabetes (T2D) and metabolic syndrome (MS). The purpose of this study was to outline evidence on the effects of soy protein supplementation on clinical indices in T2D and MS subjects by performing a meta-analysis of randomized controlled trials (RCTs). MATERIALS AND METHODS: We searched PubMed, EMBASE, and Cochrane databases up to March 2015 for RCTs. Pooled estimates and 95% confidence intervals (CIs) were calculated by the fixed-and-random-effects model. A total of eleven studies with eleven clinical variables met the inclusion criteria. RESULTS: The meta-analysis showed that fasting plasma glucose (FPG) [weighted mean difference (WMD), -0.207; 95% CI, -0.374 to -0.040; p=0.015], fasting serum insulin (FSI) (WMD, -0.292; 95% CI, -0.496 to -0.088; p=0.005), homeostasis model of assessment for insulin resistance index (HOMA-IR) (WMD, -0.346; 95% CI, -0.570 to -0.123; p=0.002), diastolic blood pressure (DBP) (WMD, -0.230; 95% CI, -0.441 to -0.019; p=0.033), low-density lipoprotein cholesterol (LDL-C) (WMD, -0.304; 95% CI, -0.461 to -0.148; p=0.000), total cholesterol (TC) (WMD, -0.386; 95% CI, -0.548 to -0.225; p=0.000), and C-reactive protein (CRP) (WMD, -0.510; 95% CI, -0.722 to -0.299; p=0.000) are significant reduced with soy protein supplementation, compared with a placebo control group, in T2D and MS patients. Furthermore, soy protein supplementation for longer duration (≥6 mo) significantly reduced FPG, LDL-C, and CRP, while that for a shorter duration (<6 mo) significantly reduced FSI and HOMA-IR. CONCLUSION: Soy protein supplementation could be beneficial for FPG, FSI, HOMA-IR, DBP, LDL-C, TC, and CRP control in plasma.

Antiatherogenic and antiperoxidative effects of garlic and soy proteins in alcohol fed rats.

Rats fed with alcohol (18%) at 3.76 g/day for 45 days showed significant reduction in body weight, glutathione (GSH) content and activities of superoxide dismutase (SOD) and catalase in liver. Lecithin cholesterol acyltransferase (LCAT) in plasma, levels of HDL cholesterol in serum, hepatic bile acid production and fecal excretion of neutral sterols also showed significant reduction. Simultaneous feeding of garlic protein (GP) or soy protein (SP) (500 mg/kg body weight/day for 45 days) to alcohol fed groups increased each of above parameters significantly towards normal values. Increase in GSH content and catalase activity in liver, was significantly higher for SP treated group than for GP treated group. However, increase in plasma LCAT was significantly higher for GP treated group than for SP treated group. Alcohol fed rats showed significant increase in liver weight, serum and tissue cholesterol, serum triacylglycerol (TAG), phospholipids (PL) and free fatty acid (FFA) levels and activity of HMGCoA reductase in liver and intestine. Lipid peroxidation, glucose-6 phosphate dehydrogenase (G6PD), glutathione peroxidase (GPx) and glutathione reductase (GR) in liver and incorporation of labeled acetate into liver cholesterol also showed significant increase. GP and SP treated rats showed decrease in these values towards normal. GP feeding showed a better effect than SP in lowering serum and heart total cholesterol, and in maintaining GPx at near normal level, while SP feeding showed a better effect in lowering serum FFA level and maintaining GR activity at near normal level. In suppressing incorporation of labeled acetate into serum cholesterol, GP feeding showed a better effect than SP. Antiatherogenic and antiperoxidative effects of these proteins may be due to lower lysine/arginine ratio.

Hepato and reno protective action of Calendula officinalis L. flower extract.

Flower extract of C. officinalis L. was evaluated for its protective effect against CCl4 induced acute hepatotoxicity and cisplatin induced nephrotoxicity. The activities of serum marker enzymes of liver injury like glutamate pyruvate transaminase (SGPT), glutamate oxaloacetate transaminase (SGOT) and alkaline phosphatase (ALP) which were increased by CCl4 injection was found to be significantly reduced by the pretreatment of the flower extract at 100 and 250 mg/kg body weight. The lipid peroxidation in liver, the marker of membrane damage and the total bilirubin content in serum were also found to be at significantly low level in the extract pretreated group, indicating its protective role. The kidney function markers like urea and creatinine were significantly increased in cisplatin treated animals. However, their levels were found to be lowered in the extract pretreated groups (100 and 250 mg/kg body weight). Moreover, cisplatin induced myelosuppression was ameliorated by the extract pretreatment. Treatment with the extract produced enhancement of antioxidant enzymes--superoxide dismutase and catalase and glutathione. Results suggest a protective role of the flower extract of C. officinalis against CCl4 induced acute hepatotoxicity and cisplatin induced nephrotoxicity. Extract has been found to contain several carotenoids of which lutein, zeaxanthin and lycopene predominates. Possible mechanism of action of the flower extract may be due to its antioxidant activity and reduction of oxygen radicals.

Effects of isoflavone on oxidative stress parameters and homocysteine in postmenopausal women complaining of insomnia

Sleep disorders have an increased incidence after menopause. The objective of this work was to evaluate the effects of isoflavone on some oxidative stress markers in postmenopausal women complaining of insomnia. Women aged between 50-65 years (n=38) were recruited and assigned to a double-blind placebo controlled study for 4 months. The treated group received 100 mg/day of isoflavones. Blood collections were conducted on three different occasions to assess total glutathione; superoxide dismutase and catalase in erythrocytes; lipid peroxidation; and homocysteine plasma concentrations. No differences between the groups were observed. However, all the patients seem to improve their oxidative stress status and homocysteine concentration after treatment. Superoxide dismutase activity was correlated with age and time of menopause at the beginning of the treatment, but these correlations were no longer observed by the end of the study. Soy isoflavones were not able to overcome the placebo effect for either oxidative stress parameters or homocysteine concentrations.

Plasma levels of genistein following a single dose of soy extract capsule in Indian women.

BACKGROUND & OBJECTIVE: Soy isoflavones are being used as therapy for menopausal syndrome in many countries. Marketed preparations show variability in bioavailability and there are variations in kinetics due to ethnicity and diet. Inspite of soy isoflavone being available in the Indian market there are no studies to show whether the preparation is likely to be effective in women. This study was carried out to determine circulating levels of genistein, a bioactive soy isoflavone, in Indian women after a single dose of soy extract. METHODS: Six healthy vegetarian women volunteers, between 36 and 62 yr and with a mean body mass index (BMI) 25.01+/-2.02 (kg/m2), were enrolled after an informed consent. Women with antibiotic or Soy food intake within 1 month of study were excluded. A single dose of standardized soy extract capsule containing 64.12 mg of total isoflavones (genistein content equivalent to 31.76 mg) was ingested under supervised fasting condition and multiple blood samples were collected at 0, 1, 2, 4, 6, 8 and 24 h. Genistein levels were measured by high performance liquid chromatography (HPLC) method with a detection level of 2.5 ng/100 microl of injection volume. The intra- and inter-assay coefficients of variation were < 5.32 per cent. RESULTS: Genistein was detected (10.3 to 16.2 ng/ml) in 3 volunteers in baseline samples. Within one hour genistein levels rose from 42 ng to 215 ng/ml with a maximum concentration of 117 to 380 ng/ml at 4 to 8 h. A secondary peak suggestive of enterohepatic circulation was seen between 4 and 6 h in 2 out of 6 volunteers. The mean Cmax was 315.5 +/- 57.1 ng/ml. All women had detectable levels from 25.2 to 109.3 ng/ml at 24 h. INTERPRETATION & CONCLUSION: Our study showed adequate circulating levels of genistein in Indian vegetarian women after a single dose of soy extract. Variability in plasma levels of the soy isoflavones may explain differences in responses to therapy.

Influence of diets varying in lipid and protein content on the histopathologic variety of murine salivary gland tumors induced by 9, 10-dimethyl-1, 2-benzanthracene (DMBA) / Influencia de dietas de diferente contenido lipídico y proteico sobre variantes histopatológicas de tumores de glándulas salivares murinos inducidos con 9, 10-dimethyl-1, 2-benzathraceno (DMBA)

The purpose of this study was to analyze the influence of diets varying in lipids and proteins on the histopathologic variety of murine salivary tumors induced by DMBA. 117 BALB/c mice were assigned to experiments one (E1: lipids, males) and two (E2: proteins, males and females), E1 comprising Soy oil (SO); Corn oil (CO, control); Fish oil (FO) and Olein (O) groups and E2, soy protein (SP) and casein (C) groups. Tumors were induced by DMBA and the animals were sacrificed at week 13- post-induction. Tumor volume was calculated. Tumor sections were stained with H-E for histopathologic evaluation. No significant association was found between tumor volume and dietary condition (p > 0.05). In E1, FO animals developed mainly carcinomas (C) (58.8%), the sarcomas (S) and carcinosarcomas (CS) being especially of high-grade type (tumors < 600 mm3). In E2, SP animals developed mainly C (55.6%). Although no significantly different (p > 0.05), S and C were more frequent in female and male mice, respectively. In both E1 and E2, the biggest tumors (> 600 mm3) were mainly high-grade S (87.5%-80%). Dietary fat and soy protein appear to influence the tumor histopathology and thus its prognosis.

El objetivo de este estudio fue analizar la influencia de dietas con diferente contenido de lípidos y proteínas sobre la variedad histopatológica de tumores salivares murinos inducidos por DMBA. Se asignaron 117 ratones BALB/c a los experimentos uno (E1: lípidos, machos) y dos (E2: proteínas, machos y hembras). E1 comprendió a los grupos aceite de soja (AS), aceite de maíz (AM, control), aceite de pescado (AP) y oleína (O), en tanto E2 incluyó a los grupos preteína de soja (PS) y caseína (C). Los tumores fueron inducidos por DMBA y los animales fueron sacrificados a la 13ª semana post-inducción. Se calculó el volumen tumoral. Los cortes de tumor fueron coloreados con Hematoxilina-Eosina para su evaluación histopatológica. No se encontró asociación entre volumen tumoral y condición dietaria (p>0.05). En E1, los animales del grupo AP desarrollaron principales carcinomas (C) (58,8%), en tanto que los sarcomas (S) y carcinosarcomas (CS) fueron de alto grado (tumores<600 mm³). En el E2, los animales del grupo PS desarrollaron principalmente C (55.6%). Aunque la diferencia no fue significativa (p>0.05), S y C fueron más frecuentes en ratones hembras y machos, respectivamente. Tanto el E1 com en E2, los tumores más voluminosos (> 600 mm³) fueron principalmente de alto grado (87.5%-80%) Los lípidos y la proteína de soja de la dieta parecen influenciar la histopatología de los tumores y, en consecuencia, su pronóstico.

Desenvolvimento e aceitação de almôndegas adicionadas de fibra de soja / Development and acceptance of meatballs added of soy fibers

As fibras são componentes alimentares de grande importância na dieta humana, pois promovem efeitos fisiológicos benéficos, como a laxação, atenuação do colesterol e glicose sangüínea. Neste trabalho, foi testada a adição de fibras de cotilédone de soja em um produto cárneo de baixo custo e grande aceitação pela população adulta e infantil: almôndegas. Formulações com adição de três níveis diferentes de fibra de soja foram avaliadas quanto à variação de peso durante o cozimento, composição centesimal, também foram realizadas análises microbiológicas e sensoriais. O trabalho conclui que a adição de até 6 por cento de fibra não acarretou diferenças sensoriais significativas quando comparadas às almôndegas sem adição de fibra. A adição de fibra ocasionou uma diminuição na perda de peso durante o cozimento, sendo esta diminuição proporcional ao teor de fibra adicionada.

Can organic and transgenic soy be used as a substitute for animal protein by rats?

We evaluated the protein quality of organic and transgenic soy fed to rats throughout life. Thirty female Wistar rats were divided into three groups (N = 10): organic soy group (OSG) receiving organic soy-based diet, genetically modified soy group (GMSG) receiving transgenic soy-based diet, and a control group (CG) receiving casein-based diet. All animals received water and isocaloric diet (10 percent protein), ad libitum for 291 days. After this, the weight of GMSG animals (290.9 ± 9.1 g) was significantly lower (P <= 0.04) than CG (323.2 ± 7.9 g). The weight of OSG (302.2 ± 8.7 g) was between that of the GMSG and the CG. Protein intake was similar for OSG (308.4 ± 6.8 g) and GMSG (301.5 ± 2.5 g), and significantly lower (P <= 0.0005) than the CG (358.4 ± 8.1 g). Growth rate was similar for all groups: OSG (0.80 ± 0.02 g), GMSG (0.81 ± 0.03 g) and CG (0.75 ± 0.02 g). In addition to providing a good protein intake and inducing less weight gain, both types of soy were utilized in a manner similar to that of casein, suggesting that the protein quality of soy is similar to that of the standard protein casein. The groups fed soy-based diet gained less weight, which may be considered to be beneficial for health. We conclude that organic and transgenic soy can be fed throughout life to rats in place of animal protein, because contain high quality protein and do not cause a marked increase in body weight.

Modificación enzimática de las propiedades funcionales, nutricias y sensoriales de la soya para alimentación especial / Enzimatic modification of the functional, nutritional and sensorial properties of soy protein for special nutrition

En la producción de fórmulas hipoalergénicas, bebidas fortificadas y nutracéuticos para alimentación especial, se requieren ingredientes ideales. En este estudio, se obtuvieron ingredientes proteicos por medio de hidrólisis y síntesis enzimática con metionina a la proteína de soya. La hidrólisis se realizó al 4 por ciento (p/v) con enzimas pancreáticas porcinas al 4 por ciento (p/p), 50ºC, 6h y pH 8. El hidrolizado seco se resuspendió al 20 por ciento (p/v) e incubó con 7,6 por ciento de metiléster de metionina (p/p), quimotripsina al 1 por ciento (p/p) y glicerol 3 M, 37ºC, 3 h y pH 7.0. Ates y después del enriquecimiento (E), el hidrolizado se fraccionó en 3 partes por ultrafiltración (UF): FI>10, 10>FII>3 y 3>FIII>1 kDa. A la proteína nativa y todas las fracciones se les evaluaron propiedades funcionales, aminoácidos, factores antifisiológicos y antigenicidad; así como la calidad proteica y características sensoriales a 2 de ellas. La hidrólisis y síntesis modificaron las propiedades proteicas y el enriquecimiento se dio en un mínimo de tiempo y metionina añadida. Después de la UF, las fracciones menores de 10 kDa presentaron solubilidad completa (pH 4 y 7), buena claridad y regular capacidad espumante. La FIII-E por su calidad nutricia, nulas antigenicidad y actividad antifisiológica, puede utilizarse en fórmulas infantiles hipoalergénicas. La FII-E por su composición de aminóacidos es adecuada para formúlas fortificadas solubles y como única proteína en nutracéuticos. La FI, semejante al aislado comercial, es utilizable amortizando costos. La FI-E por su contenido de metionina, la estabilidad de su espuma, su actividad emulsificante y buen sabor, puede utilizarse en papillas infantiles

Utilización de nutritientes en niños con diarrea aguda alimentados con formula a base de pollo y de soya / Nutrient utilization in children with acute diarrhea fed formulas with chicken or soybean protein

El objetivo de este trabajo fue comparar dos fórmulas, una a base de proteína de pollo y ocumo elaborada en base a la utilizada en el Hospital de Niños J.M. de los Ríos y otra a base de aislado proteico de soya en niños con diarrea aguda. Se realizó un estudio metabólico de 48h con dos grupos de 14 niños varones con edad promedio de 9 meses. Los niños alimentados con pollo consumieron mas proteina y menos grasa, ya que esta fórmula contenía mas proteína y menos grasa. La excreción fecal fue similar para los dos grupos (800 g/48h), sin embargo los niños que consumieron mas proteína (pollo) y grasa (soya) excretaron también una mayor cantidad de estos macronutrientes en las heces (diferencias no significativas). La absorción de grasa, nitrógeno y carbohidratos fue similar en ambos grupos y se aproximaron a 63 por ciento, 75 por ciento, y 78 por ciento, respectivamente; así como la retención de nitrógeno que fue del 55 por ciento. No se encontraron diferencias significativas en relación a los porcentajes de absorción y retención de energía de las dos fórmulas. La excreción de amoníaco fue mayor y de la creatinina menor que la de los niños sanos pero similar para los dos grupos de niños. No se encontraron diferencias en la excreción de urea. Los porcentajes de retención de Zn y Ca fueron similares para las dos fórmulas (47 por ciento y 72 por ciento, respectivamente). Se pudo detectar en ambos grupos una excreción urinaria de vitamina A que fue en promedio de 0,17 mg/48h. Los resultados señalan que desde el punto de vista nutricional la fórmula de soya fue utilizada tan apropiadamente como la fórmula hospitalaria de pollo para la alimentación durante la diarrea