Nutr Metab Cardiovasc Dis. 2009 Feb;19(2):91-7. Epub 2008 Jun 19.

 

Diet with isolated soy protein reduces oxidative stress and preserves ventricular function in rats with myocardial infarction.

 

Hagen MK, Lehenbauer-Lüdke AR, Paludo AC, Schenkel P, Gonçalves L, Fernandes TG, Caron R, Llesuy S, Mill JG, Belló-Klein A.

 

Cardiovascular Physiology Laboratory, Federal University of Rio Grande do Sul, Av. Sarmento Leite 500, CEP 90050170, Porto Alegre, Brazil.

 

We investigated the effects of an isolated soy protein (ISP) diet offered over a 9-week period to rats in whom myocardial infarction (MI) had been induced, and a casein diet given as a control. Male Wistar rats were assigned to six groups after infarct size determination (n=8/group): Sham Casein (SC); Infarct Casein <25% (IC<25%); Infarct Casein >25% (IC>25%); Sham Soy (SS); Infarct Soy <25% (IS<25%); and Infarct Soy >25% (IS>25%). MI surgery was performed at the fifth week, and one month later, the animals were hemodynamically assessed to evaluate left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), contractility and relaxation indexes (+/-dP/dt). Lung and liver specimens were also collected for the estimation of organ congestion. Oxidative stress was evaluated in heart homogenates through chemiluminescence (CL), carbonyl groups, and antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Infarcted groups treated with casein showed cardiac hypertrophy, lung and liver congestion, increased LVEDP and decreased LVSP and +/-dP/dt, all typical signals of heart failure. Ventricular dysfunction was correlated with increased myocardial oxidative damage as seen by CL and carbonyl groups data in the groups IC<25% and IC>25% (3 and 10-fold increase, respectively). The ISP diet was able to improve ventricular systolic and diastolic function in the groups IS<25% and IS>25% (LVEDP was reduced by 44% and 24%, respectively) and to decrease myocardial oxidative stress. The overall results confirm the preventive role of soy-derived products in terms of post-MI myocardial dysfunction probably by an antioxidant action.

 

PMID: 18571392  [PubMed - indexed for MEDLINE]

 

http://www.ncbi.nlm.nih.gov/pubmed/18571392

 

J Nutr. 2005 Jul;135(7):1770-5.

 

Decreased consumption of dried mature beans is positively associated with urbanization and nonfatal acute myocardial infarction.

 

Kabagambe EK, Baylin A, Ruiz-Narvarez E, Siles X, Campos H.

 

Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA.

 

Legumes may protect against myocardial infarction (MI). The objective of this study was to determine whether consumption of dried mature beans (referred to as beans), the main legume in Latin America, is associated with MI. The cases (n = 2119) were survivors of a first acute MI and were matched by age, sex, and area of residence to randomly selected population controls (n = 2119) in Costa Rica. Dietary intake was assessed with a validated FFQ. Of the population, 69% consumed > or = 1 serving of beans/d (1 serving = one-third cup of cooked beans, approximately 86 g). Consumption of > or = 1 serving/d was significantly higher (P < 0.001) in rural (81%) than in urban (65%) areas. Individuals who never eat dried beans or whose consumption was < 1 time/mo were classified as nonconsumers. Compared with nonconsumers, intake of 1 serving of beans/d was inversely associated with MI in analyses adjusted for smoking, history of diabetes, history of hypertension, abdominal obesity, physical activity, income, intake of alcohol, total energy, saturated fat, trans fat, polyunsaturated fat, and cholesterol [odds ratio (OR) = 0.62; 95% CI: 0.45-0.88]. No further protection was observed with increased number of servings/d (OR = 0.73; 95% CI: 0.52-1.03 for > 1 serving/d). In summary, we found that consumption of 1 serving of beans/d is associated with a 38% lower risk of MI. No additional protection was observed at intakes > 1 serving/d. These findings are timely given the trend toward increased obesity, cardiovascular disease, and a reduction in the intake of beans in Latin American countries.

 

PMID: 15987863  [PubMed - indexed for MEDLINE]

 

http://www.ncbi.nlm.nih.gov/pubmed/15987863

Food Chem Toxicol. 2011 Feb;49(2):434-40. Epub 2010 Nov 17.

 

Glycine soya diet synergistically enhances the suppressive effect of tamoxifen and inhibits tamoxifen-promoted hepatocarcinogenesis in 7,12-dimethylbenz[α]anthracene-induced rat mammary tumor model.

 

Mishra R, Bhadauria S, Murthy PK, Murthy PS.

 

Division of Toxicology, Central Drug Research Institute, Council of Scientific and Industrial Research (CSIR), Lucknow, India. rajeevcdri@gmail.com

 

There is increasing interest in phytoestrogens as potential alternatives to synthetic selective estrogen receptor modulators (SERMs) in the prevention and therapy of breast cancer. The present study is aimed at determining whether dietary glycine soya (Glycine max seeds; GS), which is rich in phytoestrogens, can enhance the anti breast cancer efficacy of the SERM tamoxifen (TAM) and the effect of TAM and GS, either alone or in combination, on DMBA-initiated hepatocarcinogenesis in rat. For determination of enhancing effect, rats bearing palpable 7, 12-dimethylbenz[α] anthracene (DMBA)-induced mammary tumors were treated with TAM (10 mg kg(-1)/day) while being fed AIN-93G diet with or without added GS (3×10(4) mg kg(-1)), and the tumor growth was monitored up to 5 weeks of treatment. For determining the effect on hepatocarcinogenesis, DMBA-initiated rats were exposed to TAM and dietary GS as above for 6 weeks during promotion stage in a medium-term bioassay, and the development of placental form of glutathione-S-transferase (GST-P)-expressing preneoplastic liver lesions was quantified. Exposure to both TAM and dietary GS enhanced the anti tumor efficacy of TAM via a combination of tumor cell apoptosis (determined by TUNEL) and inhibition of tumor cell proliferation (determined by PCNA immunostaining) and suppressed the growth of GST-P-positive liver lesions. The findings show that dietary GS enhances the therapeutic efficacy of TAM against mammary tumors and minimizes TAM’s hepatocarcinogenesis promotion potential.

 

Copyright © 2010 Elsevier Ltd. All rights reserved.

JAMA. 2009 Dec 9;302(22):2437-43.

 

Soy food intake and breast cancer survival.

 

Shu XO, Zheng Y, Cai H, Gu K, Chen Z, Zheng W, Lu W.

 

Department of Medicine, Vanderbilt Epidemiology Center, 2525 West End Ave, Ste 600, Nashville, TN 37203-1738, USA. xiao-ou.shu@vanderbilt.edu

 

Comment in

    JAMA. 2009 Dec 9;302(22):2483-4.

 

CONTEXT: Soy foods are rich in isoflavones, a major group of phytoestrogens that have been hypothesized to reduce the risk of breast cancer. However, the estrogen-like effect of isoflavones and the potential interaction between isoflavones and tamoxifen have led to concern about soy food consumption among breast cancer patients.

 

OBJECTIVE: To evaluate the association of soy food intake after diagnosis of breast cancer with total mortality and cancer recurrence.

 

DESIGN, SETTING, AND PARTICIPANTS: The Shanghai Breast Cancer Survival Study, a large, population-based cohort study of 5042 female breast cancer survivors in China. Women aged 20 to 75 years with diagnoses between March 2002 and April 2006 were recruited and followed up through June 2009. Information on cancer diagnosis and treatment, lifestyle exposures after cancer diagnosis, and disease progression was collected at approximately 6 months after cancer diagnosis and was reassessed at 3 follow-up interviews conducted at 18, 36, and 60 months after diagnosis. Annual record linkage with the Shanghai Vital Statistics Registry database was carried out to obtain survival information for participants who were lost to follow-up. Medical charts were reviewed to verify disease and treatment information.

 

MAIN OUTCOME MEASURES: Total mortality and breast cancer recurrence or breast cancer-related deaths. Cox regression analysis was carried out with adjustment for known clinical predictors and other lifestyle factors. Soy food intake was treated as a time-dependent variable.

 

RESULTS: During the median follow-up of 3.9 years (range, 0.5-6.2 years), 444 deaths and 534 recurrences or breast cancer-related deaths were documented in 5033 surgically treated breast cancer patients. Soy food intake, as measured by either soy protein or soy isoflavone intake, was inversely associated with mortality and recurrence. The hazard ratio associated with the highest quartile of soy protein intake was 0.71 (95% confidence interval [CI], 0.54-0.92) for total mortality and 0.68 (95% CI, 0.54-0.87) for recurrence compared with the lowest quartile of intake. The multivariate-adjusted 4-year mortality rates were 10.3% and 7.4%, and the 4-year recurrence rates were 11.2% and 8.0%, respectively, for women in the lowest and highest quartiles of soy protein intake. The inverse association was evident among women with either estrogen receptor-positive or -negative breast cancer and was present in both users and nonusers of tamoxifen.

 

CONCLUSION: Among women with breast cancer, soy food consumption was significantly associated with decreased risk of death and recurrence.

 

PMCID: PMC2874068

PMID: 19996398  [PubMed - indexed for MEDLINE]

 

http://www.ncbi.nlm.nih.gov/pubmed/19996398

 

Climacteric. 2010 Aug;13(4):368-75.

 

Long-term endometrial and breast safety of a specific, standardized soy extract.

 

Palacios S, Pornel B, Vázquez F, Aubert L, Chantre P, Marès P.

 

Palacios Institute of Women’s Health, Antonio Acuña 9, Madrid, Spain.

 

OBJECTIVE: To assess the effects of an oral soy isoflavone extract (Phytosoya) on endometrium and breast in postmenopausal women treated for 3 years.

 

METHODS: A total of 395 postmenopausal women were included in this international prospective, open-label study. The number of patients who completed the 3-year study was 197. The women were treated for 3 years with a specific, standardized soy isoflavone extract (total 70 mg/day). Endometrial biopsy, transvaginal ultrasonography and mammography were performed before and after 3 years of treatment.

 

RESULTS: No case of hyperplasia/cancer was diagnosed among the 192 interpretable biopsies at 3 years. Only one case of simple hyperplasia was diagnosed among 197 post-baseline interpretable biopsies. The endometrial safety of this extract has been demonstrated (point estimate 0.5%). There was no statistically significant change in endometrial thickness after 3 years (98.4% inactive or atrophic and 0.3% proliferative endometrium at 1 year). Mammography results showed no notable change from baseline. No patient in any set developed an ACR classification of 4 or 5 after 3 years of treatment. The global safety was rated as either ‘excellent’ or ‘good’ by 99.1% of investigators and 99.0% of patients after 3 years of treatment. The adverse events were as follows: eight patients had metrorrhagia and seven patients had at least one breast adverse event: three patients had ‘breast pain’, two patients reported ‘breast tenderness’ and two patients had ‘hypertrophic breast’ (most of them were possibly treatment-related).

 

CONCLUSIONS: As no case of hyperplasia was diagnosed among the 301 interpretable biopsies at 1 year and there was only one case of simple hyperplasia in the 197 post-baseline biopsies at 3 years, the endometrial safety of this extract has been demonstrated. Furthermore, as demonstrated by the lack of change in endometrial thickness associated with the histologic results, we suggest that this extract does not exert a mitogenic effect on the endometrium. These results suggest that daily administration of 70 mg of a specific, standardized isoflavone extract for 3 years could be a safe treatment for both endometrium and breast.

 

PMID: 20380569  [PubMed - indexed for MEDLINE]

 

http://www.ncbi.nlm.nih.gov/pubmed/20380569

 

Singapore Med J. 2010 Oct;51(10):781-9.

 
Effects of a soybean protein diet on ovariectomised female albino rats subjected to myocardial infarction.

 
Hamed GM, Bahgat NM, El-Agaty SM, Soliman GZ, Emara MM.
Department of Physiology, Faculty of Medicine, Ain Shams University, Abbassia Square, Cairo 11566, Arab Republic of Egypt.

 

INTRODUCTION: Cardiovascular disease is the leading cause of death among menopausal women in developed countries, mostly due to the loss of endogenous oestrogen protection. Soybean protein (SP) is rich in isoflavone phytoestrogens. This study aimed to determine the effect of SP on ovariectomised rats subjected to myocardial infarction and its possible cardio-protection.

 

METHODS: The study was conducted on 30 adult female albino rats, which were divided into three groups: Group I comprised the sham-operated rats; Group II, the ovariectomised (OVX) rats fed a standard diet; and Group III, OVX rats fed a standard diet supplemented with SP (OVX plus SP). The rats were anaesthetised, and electrocardiograms were conducted. The rats were then sacrificed, after which their hearts and livers were removed, weighed and subjected to histopathological examination. Blood was collected to determine the lipid profile, and the levels of total triiodothyronine, tetraiodothyronine (T4), thyroid-stimulating hormone (TSH), creatinine phosphokinase (CPK), lactate dehydrogenase, superoxide dismutase (SOD) and malonedialdehyde (MDA).

 

RESULTS: The biochemical studies showed a significant increase in plasma CPK (Group II), MDA and triacylglycerol (Groups II and III) levels compared to Group I. The plasma SOD showed a significant decrease in Group II compared to Group I. Total cholesterol, low and very low density lipoprotein cholesterol levels showed a significant increase in Group II, and a significant decrease compared to Group I. Significant increases in T4 and TSH were found in Group III compared to Group II.

 

II. CONCLUSION: SP intake can be valuable in protecting the heart against an attack of acute myocardial infarction.

 

PMID: 21103813  [PubMed - indexed for MEDLINE]

 

http://www.ncbi.nlm.nih.gov/pubmed/21103813