alvina 162 ABSTRACT Menopause is a natural event to be experienced by every woman and appears to be associated with increased risk for developing type 2 diabetes mellitus. It has been postulated that a diet high in legumes may be beneficial for the prevention of glycosuria. These unique components of soy have been shown to have beneficial effects on glucose and insulin homeostasis. The objective of the present study was to examine the possibility of an association between soy food consumption and risk of glycosuria in postmenopausal women. A cross-sectional study was conducted among 94 postmenopausal women attending Mampang Prapatan Health Center, Mampang Prapatan subdistrict, South Jakarta. Anthropometric measurements were taken using standard instruments and dietary intake was assessed with a validated food-frequency questionnaire. A dipstick semiquantitative assay for urinary glucose was used to define glycosuria (positive). The results showed that 12.8% of postmenopausal women had glycosuria and mean isoflavone intake was 69.5 ± 61.4 g/d. Intake of isoflavone was inversely associated with risk of glycosuria. Compared to women in the lowest quintile of isoflavone intake (Q1), postmenopausal women in the highest quintile (Q5) had a lower risk for glycosuria of 0.30 times that of Q1, which risk was however statistically not significant (OR = 0.30; 95% CI = 0.02 – 3.14). In conclusion, isoflavone may play a role in the prevention of glycosuria (an important indicator of diabetes) among postmenopausal women. Keywords : Isoflavone, intake, glycosuria, postmenopausal women *Professional Study Program, Medical Faculty, Trisakti University Correspondence Nurmillah, SKed. Professional Study Program, Medical Faculty, Trisakti University Jl. Kyai Tapa No.260 Grogol - Jakarta 11440 Univ Med 2010;29:114-24. Soyfood consumption and risk of glycosuria in post-menopausal women Nurmillah*, Irena Stefani Yolantha*, and Victor Livinus* September-December, 2010September-December, 2010September-December, 2010September-December, 2010September-December, 2010 Vol.29 - No.3 Vol.29 - No.3 Vol.29 - No.3 Vol.29 - No.3 Vol.29 - No.3 UNIVERSA MEDICINA INTRODUCTION S o m e f a c t s a b o u t m e n o p a u s e a r e applicable to all women, since menopause is a natural event to be experienced by every woman. The common denominator is cessation of menstrual cycles. On the other hand, in r e l a t i o n t o t h e s y m p t o m s a n d r i s k s f o r osteoporosis, cardiovascular diseases, cancer and Alzheimer disease, every woman is unique. Menopausal women suffer from deleterious effects of lowered estrogen levels, including r e d u c t i o n o f b o n e m a s s , m e n o p a u s a l symptoms, and hypercholesterolemia. These effects are pronounced during early post m e n o p a u s e b e c a u s e o f d r a s t i c e s t r o g e n reduction, and tend to become attenuated during late post menopause. Menopause 163 Univ Med Vol.29 No.3 appears to be associated with a decrease in p a n c r e a t i c i n s u l i n s e c r e t i o n a s w e l l a s increased insulin resistance. These changes are thought to contribute to the increased risk for developing type 2 diabetes mellitus (DM) after menopause. The prevalence of type 2 DM has been increasing rapidly worldwide;(1) thus knowledge of risk factors and protective factors associated with type 2 DM is essential for the development of prevention strategies. Phytoestrogens can potentially alleviate hypo- estrogen related deleterious effects. Soy and isoflavone dietary supplements are regularly used by millions of North Americans for s y m p t o m s a s s o c i a t e d w i t h m e n o p a u s a l t r a n s i t i o n o r f o r o t h e r p u r p o r t e d h e a l t h b e n e f i t s . ( 2 ) P h y t o e s t r o g e n s a r e n a t u r a l l y occurring plant compounds that are structurally and functionally similar to estradiol. There are four major classes of phytoestrogens: i) isoflavones, found in soy beans and soy products; ii) lignans, found in whole grains, cereals and oilseeds; iii) flavonoids, found in some fruits and legumes; and iv) coumestans found in bean and alfafa sprouts.(3) Isoflavones are phytoestrogens with the most potent estrogenic activity, comprising genistein, daidzein and glycitein found in soybeans, the l a t t e r b e i n g a m a j o r d i e t a r y s o u r c e o f isoflavones. Asians consume 10–100 times more isoflavones than do Westerners, and osteoporosis-related fractures are less frequent in Asian than Western communities, possibly b e c a u s e o f t h e l a rg e q u a n t i t i e s o f phytoestrogen-rich soybeans and vegetables in the Asian diet.(4) Soybean, a member of the legume family, is a rich source of plant protein, fiber, vitamins, minerals, and phytoestrogens (isoflavones).(5) These unique components of soy have been shown to have beneficial effects on glucose and insulin homeostasis. Animal studies have d e m o n s t r a t e d t h a t s o y p r o t e i n a n d s o y isoflavones improve glycemic control, lower insulin requirement, and increase insulin sensitivity.(6) Similar benefits have also been documented in several intervention studies with soy supplements (soy protein, soy fiber, and soy isoflavones), but results have been inconsistent.(7,8) One cross-sectional study examined the effect of usual dietary intake of isoflavones on glucose metabolism and observed an inverse association with insulin level.(9) An animal study revealed that soy protein and isoflavone content could improve control of glycemic levels, and increase insulin sensitivity. Similar benefits were documented in several studies with soy-derived supplements, but the results were inconsistent. The main point is that soy food has a low glycemic level, which is linked to blood glucose levels.(10,11) The present study a i m e d t o d e t e r m i n e t h e e x i s t e n c e o f a n association between isoflavone intake and the risk of glycosuria in postmenopausal women in Mampang Prapatan subdistrict, South Jakarta. METHODS Design of the study A cross-sectional study was conducted from 16 January 2010 to 2 February 2010 to determine the possiblity of an association between soyfood intake and glycosuria in postmenopausal women at a primary health center in Mampang Prapatan sub-district, South Jakarta. Study subjects The subjects who participated in this study were postmenopausal women attending the primary health center at Mampang Prapatan subdistrict, South Jakarta. The inclusion criteria used in this study were: female with cessation of menstruation for one year or longer, able to communicate, and willing to participate in this study. Data collection Personal interviews were conducted to o b t a i n i n f o r m a t i o n o n d e m o g r a p h i c a n d 164 socioeconomic features, tobacco and alcohol u s e , p h y s i c a l a c t i v i t y, m e n s t r u a l a n d reproductive history, lifetime occupational history, as well as medical history, including diabetes mellitus, coronary heart disease, s t r o k e , h y p e r t e n s i o n , a n d o t h e r c h r o n i c diseases ever diagnosed by a physician, along with use of selected medicines, including postmenopausal hormones. Anthropometric measurements, including weight and height, were performed on all study participants according to a standard protocol. Body mass index (BMI) was calculated as weight in kilograms divided by the square of height in meters. BMI levels were categorized as normal weight (< 23.0 kg/m2), overweight or obese (> 2 3 . 0 k g / m 2) a c c o r d i n g t o t h e c r i t e r i a established for Asian populations.(11) Dietary assessment Data on nutrient intake were obtained by p e r s o n a l i n t e r v i e w u s i n g a s o y f o o d q u e s t i o n n a i r e l i s t i n g 1 4 s o y f o o d i t e m s r e s p o n s i b l e f o r t h e m a j o r i t y o f s o y consumption, comprising steamed tofu, dried tofu, Bandung tofu, soft tofu, steamed tempeh, tempe bacem, regular soy milk, tahu kuning, soy bean sangria, fried soy beans, steamed soy b e a n s , s o y s a u c e , t a h u b u n g k u s , f r i e d tempeh.(12,13) Study participants were asked to r e c a l l t h e f r e q u e n c y o f c o n s u m p t i o n o f individual food items (number of times per day, week, month, and year) and estimated portion size, using local weight units (50 g) or natural units (cup, bowl) per unit time. The USA FDA F o o d C o m p o s i t i o n Ta b l e ( 1 3 ) w a s u s e d t o estimate the intake levels of isoflavone for study participants. Urinary glucose test A dipstick semi-quantitative assay for random urinary glucose was performed on study participants who gave a spot urine sample. A cutoff point of greater than trace for urinary glucose was used to define glycosuria (positive) in this study. Sample size The number of subjects required for this study was calculated on the basis of the formula for sample size for surveys with a prevalence of glycosuria of 0.1, alpha level of 0.05 and acceptable margin of error for proportion being estimated of 0.05.(14) The sample was taken by consecutive non-random sampling, where persons attending the health center and meeting the inclusion criteria were designated as respondents until the required sample size was obtained. Statistical analysis Study participants were divided into five categories according to quintile distribution of total soy protein intake (an equivalence of total soy food intake) among the study participants. The lowest quintile was treated as the reference group. Logistic regression analysis was used to obtain maximum likelihood estimates of the odds ratios (ORs) and their 95% confidence intervals (CIs) to measure the association between soy food consumption and glycosuria. Variables adjusted for multiple regression models included age, education, regular physical activity during the past 5 years, and BMI. All statistical tests were based on two- sided probability using SPSS, version 15.0. RESULTS T h e s t u d y p a r t i c i p a n t s w e r e 9 4 postmenopausal women with mean age of 58.7 ± 7.7 years (range 43-89 years). Around half of the women (59.6%) was married, 85.1% was u n e m p l o y e d , 6 8 . 1 % h a d a l o w l e v e l o f education and 97.9% did not smoke (Table 1). For most respondents (40.4%) the duration of menopause was more than 10 years, normal and underweight BMI (<22.9) accounted for 50% of respondents, and 56.4% of respondents performed moderate activity (Table 2). Glycosuria was present in 12.8% of respondents, while mean isoflavone intake was 69.5 ± 61.4 g/d (Table 3). Nurmillah, Yolantha, Livinus Soyfood consumption and glycosuria 165 Univ Med Vol.29 No.3 Table 4 shows that compared to women in the lowest quintile of isoflavone intake (Q1), postmenopausal women in the highest quintile of isoflavone (Q5) had a 0.30 times lower risk for glycosuria, but the difference was not statistically significant (OR = 0.30;95% CI = 0.02 – 3.14). DISCUSSION In the present study, the prevalence of glycosuria in postmenopausal women with mean age of 58.7 ± 7.7 years was 12.8%, differing from that of a large cross-sectional study of Chinese women, where the prevalence was 8.2%.(11) In our study, postmenopausal women with higher isoflavone intakes had a l o w e r r i s k o f g l y c o s u r i a , a l t h o u g h t h e association was not statistically significant. However, in the abovementioned Chinese cross-sectional study there was a significant inverse association between soy intake and glycosuria among postmenopausal women.(16) Our study found a mean isoflavone intake of 69.5 ± 61.4 g/d. In traditional Asian diets, soy intake is usually high, with a mean level of 100 g/d, which corresponds to an approximate soy protein intake of 10 g/d.(15) There are few studies on the relationship between isoflavone intake and glycosuria in postmenopausal women in Indonesia. Glycosuria is a strong predictor of diabetes, and our results suggest a potential role for soy foods in the prevention of diabetes. Although no previous study has evaluated regular consumption of soy foods in relation to the risk of diabetes, our findings are supported by the existing evidence from animal and human studies showing that several major components of soy foods have beneficial effects on glucose and insulin homeostasis. Animal studies have revealed that feeding soy protein results in elevated glucose disposal rates, decreased pancreatic insulin release, and increased hepatic insulin removal.(16) Although glycosuria is a powerful predictor of diabetes, its value in diagnosis of diabetes has been Factors n (%) Glycosu ria Posi tive Negative Isofl avone intake (g/d) * Quintile 1 Quintile 2 Quintile 3 Quintile 4 Quintile 5 12 (12.8) 82 (87.2) 69.5 ± 61.4 16.9 ± 5.8 31.2 ± 4.9 50.2 ± 8.6 87.1 ± 13.1 159.2 ± 75.0 Table 3. Glycosuria prevalence and isoflavone intake in postmenopausal women (n=94) * Mean ± S.D. Table 2. Distributions of duration of menopause, BMI dan activity of respondents (n=94) Factors n (%) Duration of menopause (years) 1 – 5 5 – 10 > 10 Body mass index ≤ 22.9 = 23.0 Activity Inacti ve Moderate High 29 (30.9) 27 (28.7) 38 (40.4) 47 (50) 47 (50) 34 (36.2) 53 (56.4) 7 (7.4) Demographic n (%) Age (years)* Level of education ** Low Medium High Employmen t Unemployed Employed Mari tal status Married Widowed Single 58.7 ± 7.7 64 (68.1) 19 (20.2) 11 (11.7) 85.1 14.9 59.1 39.4 1.1 Table 1. Distribution of demographic characteristics of postmenopausal women (n=94) *Mean ± SD; **Low: No education, primary school; Medium: junior high school; High: Senior high school and academy/university 166 questioned. In a large prospective, population- based study of middle-aged Chinese women, a h i g h e r i n t a k e o f l e g u m e s , s o y b e a n s i n particular, was associated with a reduced risk of type 2 DM.(17) Soy intake is generally low in Western populations, which limits the ability o f e p i d e m i o l o g i c s t u d i e s t o d e t e r m i n e associations between soy intake and type 2 DM in these populations. Phytoestrogens have a molecular structure similar to that of estrogens and are weakly e s t r o g e n i c i n c o n d i t i o n s o f e n d o g e n o u s estrogen depletion.(18) Among postmenopausal w o m e n , p r e v i o u s s t u d i e s h a v e f o u n d a n a s s o c i a t i o n b e t w e e n i n t a k e s o f d i e t a r y isoflavone and isoflavone supplements on the one hand and improved insulin resistance on the other.(8,19) In addition, there is evidence that soy consumption in postmenopausal women also increases sex hormone-binding globulin level,(20) the latter being inversely associated with impaired glucose tolerance. In a double- blind, randomized, placebo-controlled trial involving 203 postmenopausal Chinese women aged 48 to 62 years, the investigators found that soy isoflavone supplementation for a period of one year presumably could decrease fasting glucose levels.(21) In contrast, a 6-mo r a n d o m i z e d c o n t r o l l e d t r i a l c o u l d n o t convincingly demonstrate that soy protein with or without isoflavone supplementation had favorable effects on glycemic control and insulin sensitivity among postmenopausal Hong Kong Chinese women with prediabetes or early untreated diabetes.(22) Soy isoflavones, as a major category of p h y t o e s t r o g e n , c a n b i n d t o t h e e s t r o g e n receptors á and â, although more strongly to the latter.(23) Existing evidence has shown that isoflavones could act as estrogen agonists or antagonists, depending on the target tissues,(24) d o s e s a n d t y p e s o f i s o f l a v o n e s , ( 2 5 ) a n d endogenous circulating sex hormone profile.(20) A previous cross-sectional study in Shanghai r e p o r t e d t h a t s o y i n t a k e w a s a s s o c i a t e d d i ff e r e n t l y w i t h g l y c o s u r i a b e t w e e n premenopausal and postmenopausal women, i n d i c a t i n g t h a t m e n o p a u s a l s t a t u s a n d endogenous estrogen levels may modify the phytoestrogen activity of soy.(11) Legumes have been indirectly linked to a protective role in the development of type 2 DM as components of a prudent diet, which is associated with a lower risk of type 2 DM.(27,28) Conversely, in another study, high consumption of legumes was linked to a dietary pattern associated with an increased risk of type 2 DM.(29) N e v e r t h e l e s s , o u r s t u d y h a s s e v e r a l limitations. The primary concern of this study is the accuracy of the method used to detect urinary glucose. A published study, however, has demonstrated that the dipstick assay for urinary glucose is quite accurate, showing a very good agreement with the quantitative e s t i m a t i o n ( k c o e ff i c i e n t = 0 . 8 ) . ( 3 0 ) T h e p o s s i b i l i t y o f o t h e r s o u r c e s o f b i a s i s minimized because of the use of validated FFQ. Owing to the inherent limitations of a cross- sectional study design, the temporal sequence o f s o y f o o d i n t a k e a n d d e v e l o p m e n t o f glycosuria cannot be firmly established in this study. Isoflavone intake (g/d) n OR ( 95% CI) Quintile 1 Quintile 2 Quintile 3 Quintile 4 Quintile 5 18 19 19 19 19 1.0 0 (r eference gr oup) 1.0 1 (0.24 – 6.13) 1.0 0 (0.23 - 5.72) 0.6 3 (0.16 – 4.38) 0.3 0 (0.02 – 3.14 Table 4. Odds Ratio (OR) and 95% confidence interval (CI) for glycosuria associated with isoflavone intake among postmenopausal women Nurmillah, Yolantha, Livinus Soyfood consumption and glycosuria 167 Univ Med Vol.29 No.3 CONCLUSIONS Regular isoflavone intake was inversely associated with the risk of glycosuria among postmenopausal women, suggesting a potential protective effect of soy foods in the prevention of diabetes. ACKNOWLEDGEMENTS We thank the health workers and the postmenopausal women of Mampang Prapatan subdistrict for their important contributions to the study. We also thank Prof. Dr. dr. Adi Hidayat, MS for his helpful comments and suggestions on the manuscript. REFERENCES 1. Zimmet P. Globalization, coca-colonization and the chronic disease epidemic: can the doomsday scenario be averted? J Intern Med 2000;247:301– 10. 2. Henderson V. Isoflavones: food for thoughtful consideration. Menopause 2003;10: 189-90. 3. Branca F, Lorezentti S. Health effects of phytoestrogens. Forum Nutr 2005;57:100-11. 4. Somekawa Y, Chiguchi M, Ishibashi T, Aso T. Soy intake related to menopausal symptoms, serum lipids, and bone mineral density in postmenopausal Japanese women. Obstet Gynecol 2001;97:109-15. 5. Chester EA. Soy for cardiovascular indications. Am J Health Syst Pharm 2001;58: 663–6. 6. Lavigne C, Marette A, Jacques H. Cod and soy proteins compared with casein improve glucose tolerance and insulin sensitivity in rats. Am J Physiol Endocrinol Metab 2000;278:491–500. 7. Hermansen K, Sondergaard M, Hoie L, Carstensen M, Brock B. Beneficial effects of a soy-based dietary supplement on lipid levels and cardiovascular risk markers in type 2 diabetic subjects. Diabetes Care 2001;24:228–33. 8. Jayagopal V, Albertazzi P, Kilpatrick ES, Howarth EM, Jennings PE, Hepburn DA, et al. Beneficial effects of soy phytoestrogen intake in postmenopausal women with type 2 diabetes. Diabetes Care 2002;25:1709–14. 9. Goodman-Gruen D, Kritz-Silverstein D. Usual dietary isoflavone intake is associated with cardiovascular disease risk factors in postmenopausal women. J Nutr 2001;131: 1202- 6. 10. Foster-Powell K, Holt SH, Brand-Miller JC. International table of glycemic index and glycemic load values. Am J Clin Nutr 2002;76:5- 56. 11. Zhou BF. Cooperative meta-analysis group of the working group on obesity in China. Predictive values of body mass index and waist circumference for risk factors of certain related diseases in Chinese adults: study on optimal cut- off points of body mass index and waist circumference in Chinese adults. Biomed Environ Sci 2002;15:83-96. 12. Fred Hutchinson Cancer Research Center. Soy food questionnaire;2002. Available at: http:// www.fhcrc.org/science/shared_resources/ nutrition/other_questionnaires/soy.pdf. Accessed December 12, 2009. 13. Nutrient Data Laboratory Beltsville Human Nutrition Research Center Agricultural Research Service U.S. Department of Agriculture. USDA. Database for the isoflavone content of selected foods. Release 2.0. Baltimore: U.S. Department of Agriculture Agricultural Research Service; 2008. 14. Bartlett JE II, Kotrlik JW, Higgins CC. Organizational research: determining appropriate sample size in survey research. Info Technol Learn Perform J 2001;19:43-50. 15. Nagata C, Takatsuka N, Shimizu H. Soy and fish oil intake and mortality in a Japanese community. Am J Epidemiol 2002;156:824-31. 16. Lavigne C, Marette A, Jacques H. Cod and soy proteins compared with casein improve glucose tolerance and insulin sensitivity in rats. Am J Physiol Endocrinol Metab 2000;278:491-500. 17. Villegas R, Gao YT, Yang G, Li HL, Elasy TA, Zheng W, et al. Legume and soy food intake and the incidence of type 2 diabetes in the Shanghai Women’s Health Study. Am J Clin Nutr 2008;87: 162-7. 18. Bhathena SJ, Velasquez MT. Beneficial role of dietary phytoestrogens in obesity and diabetes. Am J Clin Nutr 2002;76;1191-201. 19. Goodman-Gruen D, Kritz-Silverstein D. Usual dietary isoflavone intake is associated with cardiovascular disease risk factors in postmenopausal women. J Nutr 2001; 131:1202- 6. 20. Pino AM, Valladares LE, Palma MA, Mancilla AM, Yanez M, Albala C. Dietary isoflavones affect sex hormone-binding globulin levels in postmenopausal women. J Clin Endocrinol Metab 2000;85:2797-800. 168 21. Ho SC, Chen YM, Ho SSS, Woo JLF. Soy isoflavone supplementation and fasting serum glucose and lipid profile among postmenopausal Chinese women: a double-blind, randomized, placebo-controlled trial. Menopause 2007;14: 905-12. 22. Liu ZM, Chen YM, Ho SC, Ho YP, Woo J. 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. Am J Clin Nutr 2010;91:1394-401. 23. Morito K, Hirose T, Kinjo J, Hirakawa T, Okawa M, Nohara T ,et al. Interaction of phytoestrogens with estrogen receptors alpha and beta. Biol Pharm Bull 2001; 24:351-6. 24. Safe SH, Pallaroni L, Yoon K, Gaido K, Ross S, Saville B, et al. Toxicology of environmental estrogens. Reprod Fertil Dev 2001;13:307-15. 25. Mueller SO, Simon S, Chae K, Metzler M, Korach KS. Phytoestrogens and their human metabolites show distinct agonistic and antagonistic properties on estrogen receptor alpha (ERalpha) and beta (ERbeta) in human cells. Toxicol Sci 2004;80:14–25. 26. Glazier MG, Bowman MA. A review of the evidence for the use of phytoestrogens as a replacement for traditional estrogen replacement therapy. Arch Intern Med 2001;161:1161-72. 27. Fung TT, Willett WC, Stampfer MJ, Manson JE, Hu FB. Dietary patterns and the risk of coronary heart disease in women. Arch Intern Med 2001; 161:1857-62. 28. van Dam RM, Rimm EB, Willett WC, Stampfer MJ, Hu FB. Dietary patterns and risk for type 2 diabetes mellitus in U.S. men. Ann Intern Med 2002;136:201-9. 29. Heidemann C, Hoffmann K, Spranger J, Klipstein-Grobusch K, Möhlig M, Pfeiffer AF, et al. A dietary pattern protective against type 2 diabetes in the European prospective investigation into cancer and nutrition (EPIC)–potsdam study cohort. Diabetologia 2005;48:1126-34. 30. Chaturvedi S, Jain N, Bhatia A. Evaluation of semi-quantitative methods for protein and sugar estimation in urine. Indian J Pathol Microbiol 2001;44:399-401. Nurmillah, Yolantha, Livinus Soyfood consumption and glycosuria