विषय

• स्तन कैंसर
• डिमेंशिया
• नवजात बच्चों के लिए फार्मूला
• जनाना गुण
• थायराइड
• सोयाबीन के लाभ
• जानकारी के स्रोत

स्तन कैंसर

सोया में आइसोफ्लेवोन्स होते हैं, जिनमें एस्ट्रोजन रिसेप्टर्स से जुड़ने की क्षमता होती है। सोया के एक बार के आहार में लगभग 25 मिलीग्राम आइसोफ्लेवोन्स होते हैं। 

सोयाबीन और स्तन कैंसर पर केस-कंट्रोल अध्ययन उन लोगों के लिए आम तौर पर उत्साहजनक रहे हैं जिनके आहार में सोया शामिल रहा है। लगभग आधे लोगों में पाया गया कि सोया के उपभोग से उनमें स्तन कैंसर के खतरे में कमी आई है और बाकी आधे लोगों में कोई प्रभाव नहीं दिखा है। 

संभावित अध्ययन, जिनमें आमतौर पर केस-कंट्रोल अध्ययनों की तुलना में उच्च स्तर का प्रमाण होता है, भी बहुत सकारात्मक रहे हैं। सोया का अधिक सेवन करने वाली आबादी (प्रतिदिन लगभग एक से दो बार सामान्य से अधिक सेवन की मात्रा है) पर किए गए छह अध्ययनों में से, सिंगापुर चीनी स्वास्थ्य अध्ययन (1), शंघाई महिला अध्ययन (2, 3), और जापान पब्लिक हेल्थ सेंटर अध्ययन (4) में पाया गया कि सोया का अधिक सेवन स्वास्थ्य के जोखिम को कम करता है। जापान सहयोगी समूह अध्ययन (5) और जापान जीवन अवधि अध्ययन (6) में भी इससे स्वास्थ्य के प्रति जोखिम बढ़ाने का कोई संबंध नहीं पाया गया।

ऑक्सफोर्ड के अध्ययन यूरोपियन प्रॉस्पेक्टिव इन्वेस्टिगेशन इनटू कैंसर (7), जिसमें बड़ी संख्या में शाकाहारी शामिल थे, ने भी सोया के प्रयोग का स्वास्थ्य जोखिम बढ़ने से कोई संबंध नहीं पाया। यूरोपीय अध्ययन में संबंध की कमी के बारे में, कुछ लोगों ने अनुमान लगाया है कि सोया से लाभ प्राप्त करने के लिए, किशोरावस्था में स्तनों के विकास के दौरान सोया का उपभोग करना आवश्यक है, जबकि पश्चिमी शाकाहारी अक्सर वयस्क होने पर अपने आहार में सोया शामिल करते हैं। 

स्तन कैंसर से पीड़ित महिलाओं के लिए, जिनमें एस्ट्रोजन के संपर्क में आने से विकसित होने वाले ट्यूमर (जिसे एस्ट्रोजन रिसेप्टर पॉजिटिव कहा जाता है) वाली महिलाएं भी शामिल हैं, हाल ही में प्रकाशित महिलाओं के स्वस्थ भोजन और जीवन अध्ययन (8) के लेखक लिखते हैं:

हमारा अध्ययन तीसरा महामारी विज्ञान अध्ययन है जिसमें स्तन कैंसर के ईलाज में सोया खाद्य पदार्थों के कोई प्रतिकूल प्रभाव नहीं देखा गया है। ये अध्ययन, जो जातीय संरचना (दो अमेरिका से और एक चीन से) और सोया उपभोग के स्तर और प्रकार के अनुसार भिन्न हैं, आवश्यक महामारी विज्ञान संबंधी प्रमाण प्रदान करते हैं कि चिकित्सकों को अब स्तन कैंसर से पीड़ित महिलाओं को सोयाबीन के सेवन के विरुद्ध सलाह देने की आवश्यकता नहीं है।

समूह के अध्ययनों के 2019 डोज-रेस्पॉन्स मेटा-विश्लेषण में पाया गया कि सोया आइसोफ्लेवोन के सेवन में 10 मिलीग्राम/दिन की वृद्धि स्तन कैंसर की मृत्यु दर में 9% की कमी के साथ जुड़ी थी, और सोया प्रोटीन सेवन में 5 ग्राम/दिन की वृद्धि स्तन कैंसर से मृत्यु में 12% की कमी के साथ जुड़ी थी (48)।

डिमेंशिया

2000 के होनोलूलू-एशिया एजिंग अध्ययन ने सोया को कम संज्ञानात्मक कार्य और कम मस्तिष्क संकुचन से जोड़ा। सोया और मानसिक संज्ञानात्मक क्षमता पर शोध की एक विस्तृत समीक्षा यहाँ दी गई है। 

एक सप्ताह से लेकर एक वर्ष तक चलने वाले बारह अल्पकालिक क्लिनिकल ​​परीक्षण हुए हैं। नौ ने सोया को लाभकारी बताया है (9, 10, 11, 12, 13, 14, 15, 16, 17), जबकि तीन ने सोया को कोई प्रभाव न डालने वाला बताया है (18, 19, 20)।

महामारी विज्ञान संबंधी अध्ययन (क्लिनिकल ​​परीक्षणों के विपरीत) विशिष्ट आबादी में सोया उपभोग और संज्ञानात्मक क्षमता के पैटर्न की जाँच करते हैं। ऐसे ही एक अध्ययन में टेम्पेह (एक फार्मेटेड सोया खाद्य पदार्थ) को बेहतर संज्ञानात्मक क्षमता से जुड़ा पाया गया (21)। महामारी विज्ञान संबंधी अध्ययनों की तीन रिपोर्टों ने टोफू को कुछ समूहों में कम संज्ञानात्मक क्षमता से जोड़ा है (21, 22, 23), लेकिन एक अन्य समूह में संज्ञानात्मक क्षमता में वृद्धि (24) पाया है, और अन्य में कोई प्रभाव न डालने वाला बताया है (23, 24)। महामारी विज्ञान संबंधी अध्ययनों में टोफू के बारे में हानिकारक निष्कर्ष संभवतः इस तथ्य से उत्पन्न भ्रम के कारण हैं कि एशियाई संस्कृतियों में निम्न आर्थिक स्थिति वाले लोग पारंपरिक रूप से अधिक टोफू खाते रहे हैं, साथ ही यह तथ्य भी कि कुछ इंडोनेशियाई टोफू फॉर्मेल्डिहाइड का उपयोग करके तैयार किए गए हैं।

समग्र रूप से यह शोध चिंता का कोई कारण नहीं बताता।

शिशु फ़ॉर्मूला 

शिशु फ़ॉर्मूला को लेकर चिंता स्वाभाविक है, क्योंकि शिशु अपने आहार का एक बड़ा हिस्सा सोया के रूप में खाते हैं। 

अमेरिकन एकेडमी ऑफ़ पीडियाट्रिक्स और नेशनल टॉक्सिकोलॉजी प्रोग्राम सोया फ़ॉर्मूला को सुरक्षित मानते हैं। 

अब तक का सबसे महत्वपूर्ण अध्ययन, जिसमें शिशुओं वाला सोया फ़ॉर्मूला खाने वाले वयस्कों पर नज़र रखी गई है, यह आश्वासन देता है कि थायरॉइड या प्रजनन क्षमता को लेकर चिंतित होने की कोई ज़रूरत नहीं है (25)।

द बिगिनिंग्स स्टडी, बच्चों के विकास पर सोया फ़ॉर्मूला के प्रभावों की जाँच करने वाला एक सतत अध्ययन है (26)। यह अभी शुरुआती दौर में है और इसमें केवल एक साल के बच्चों पर किए गए अध्ययन के निष्कर्ष शामिल हैं, लेकिन अब तक, जिन बच्चों को गाय का दूध दिया जाता है उनकी तुलना में सोया फ़ॉर्मूला खाने वाले बच्चों के विकास, यौन अंगों या तंत्रिका संबंधी विकास पर कोई नकारात्मक प्रभाव नहीं पाया गया है। 

कुछ शोध बताते हैं कि डीएचए युक्त सोया फ़ॉर्मूला चुनना सबसे अच्छा है, और यह ध्यान रखना ज़रूरी है कि सोया फ़ॉर्मूला समय से पहले जन्मे शिशुओं के लिए नहीं है।

जनाना लक्षण 

इस चिंता के संबंध में, कि सोयाबीन पुरुषों में जनाना लक्षण पैदा कर सकता है, दो केस स्टडीज़ हुई हैं। एक में, प्रतिदिन बारह बार सोया दूध खाने वाले एक पुरुष के स्तन ऊतक बढ़े हुए और संवेदनशील हो गए (27)। दूसरे में, टाइप 1 मधुमेह से पीड़ित एक पुरुष एक साल तक प्रतिदिन 14 बार ज़्यादातर प्रोसेस्ड सोया खाद्य पदार्थ खा रहा था और उसे स्तंभन दोष (28) हो गया, जो सोया बंद करने के बाद सामान्य हो गया। हालाँकि मैं इतना अधिक सोया खाने की सलाह नहीं दूँगा, एक अध्ययन में आइसोफ्लेवोन्स की और भी ज़्यादा मात्रा का इस्तेमाल किया गया और ज़्यादातर पुरुषों में कोई समस्या नहीं पाई गई (29)।

शुक्राणु की मात्रा और गुणवत्ता के संबंध में एक महामारी विज्ञान अध्ययन ने सोया और शुक्राणु की मात्रा (30) के बारे में मामूली चिंताएं जताईं, जबकि दो क्लिनिकल ​​अध्ययनों ने सोया का कोई दुष्प्रभाव नहीं दिखाया है (31, 32)।

थायराइड 

आइसोफ्लेवोन थायराइड हार्मोन के स्तर को प्रभावित कर सकते हैं, खासकर अगर किसी को आयोडीन की कमी हो। 2011 के एक क्लिनिकल ​​परीक्षण में पाया गया कि हल्के हाइपोथायरायडिज्म वाले लोगों में 16 मिलीग्राम/दिन आइसोफ्लेवोन लेने से स्पष्ट हाइपोथायरायडिज्म की ओर बढ़ने की दर में वृद्धि हुई (33)। 

नौ अन्य क्लिनिकल ​​परीक्षणों में, संभवतः स्वस्थ थायराइड वाले लोगों में प्लेसीबो की तुलना में सोया का थायराइड पर कोई प्रभाव नहीं देखा गया (34, 35, 36, 37, 38, 39, 40, 41, 42), जबकि शेष पाँच अध्ययनों में छोटे-मोटे बदलाव पाए गए, जिनका कोई शारीरिक महत्व नहीं था (43, 44, 45, 46, 47)। 

हाइपोथायरायडिज्म से पीड़ित लोगों को सोया से कोई समस्या नहीं होनी चाहिए, जब तक उन्हें पर्याप्त आयोडीन मिलता रहे, लेकिन जब तक हम और अधिक नहीं जानते, हल्के हाइपोथायरायडिज्म वाले लोग सुरक्षा के लिए सोया से परहेज कर सकते हैं।

सोया के लाभ 

जैसा कि ऊपर बताया गया है, स्तन कैंसर के जोखिम को कम करने के अलावा, सोया प्रोस्टेट कैंसर को रोकने, एलडीएल कोलेस्ट्रॉल को कम करने और रजोनिवृत्ति के लक्षणों में सुधार लाने में भी लाभकारी है। अधिक जानकारी के लिए कृपया सोया भाग 2—शोध देखें। सोया पर किए गए सभी शोधों को मिलाकर, यह सोचने का कोई कारण नहीं है कि प्रतिदिन दो सर्विंग ज़्यादातर लोगों के लिए हानिकारक हैं, और यह मानने का एक अच्छा कारण है कि सोया कुछ स्वास्थ्य लाभ प्रदान करता है।

References

Last updated April 2011

1. Butler LM, Wu AH, Wang R, Koh WP, Yuan JM, Yu MC. A vegetable-fruit-soy dietary pattern protects against breast cancer among postmenopausal Singapore Chinese women. Am J Clin Nutr. 2010 Apr;91(4):1013-9.

2. Wu AH, Koh WP, Wang R, Lee HP, Yu MC (2008) Soy intake and breast cancer risk in Singapore Chinese health study. Br J Cancer 99(1):196–200.

3. Lee SA, Shu XO, Li H, Yang G, Cai H, Wen W, Ji BT, Gao J, Gao YT, Zheng W. Adolescent and adult soy food intake and breast cancer risk: results from the Shanghai Women’s Health Study. Am J Clin Nutr. 2009 Jun;89(6):1920-6.

4. Yamamoto S, Sobue T, Kobayashi M, Sasaki S, Tsugane S; Japan Public Health Center-Based Prospective Study on Cancer Cardiovascular Diseases Group. Soy, isoflavones, and breast cancer risk in Japan. J Natl Cancer Inst. 2003 Jun 18;95(12):906-13.

5. Nishio K, Niwa Y, Toyoshima H, Tamakoshi K, Kondo T, Yatsuya H, Yamamoto A, Suzuki S, Tokudome S, Lin Y, Wakai K, Hamajima N, Tamakoshi A. Consumption of soy foods and the risk of breast cancer: findings from the Japan Collaborative Cohort (JACC) Study. Cancer Causes Control. 2007 Oct;18(8):801-8.

6. Key TJ, Sharp GB, Appleby PN, Beral V, Goodman MT, Soda M, Mabuchi K. Soya foods and breast cancer risk: a prospective study in Hiroshima and Nagasaki, Japan. Br J Cancer. 1999 Dec;81(7):1248-56.

7. Travis RC, Allen NE, Appleby PN, Spencer EA, Roddam AW, Key TJ. A prospective study of vegetarianism and isoflavone intake in relation to breast cancer risk in British women. Int J Cancer. 2008 Feb 1;122(3):705-10.

8. Caan BJ, Natarajan L, Parker BA, Gold EB, Thomson CA, Newman VA, Rock CL, Pu M, Al-Delaimy WK, Pierce JP. Soy Food Consumption and Breast Cancer Prognosis. Cancer Epidemiol Biomarkers Prev. 2011 Feb 25.

9. File SE, Jarrett N, Fluck E, Duffy R, Casey K, Wiseman H. Eating soya improves human memory. Psychopharmacology (Berl) 2001; 157:430-6.

10. Duffy R, Wiseman H, File SE. Improved cognitive function in postmenopausal women after 12 weeks of consumption of a soya extract containing isoflavones. Pharmacol Biochem Behav. 2003 Jun;75(3):721-9.

11. Thorp AA, Sinn N, Buckley JD, Coates AM, Howe PR. Soya isoflavone supplementation enhances spatial working memory in men. Br J Nutr. 2009 Nov;102(9):1348-54.

12. Kritz-Silverstein D, Von Mühlen D, Barrett-Connor E, Bressel MA. Isoflavones and cognitive function in older women: the Soy and Postmenopausal Health In Aging (SOPHIA) Study. Menopause. 2003 May-Jun;10(3):196-202.

13. Fournier LR, Ryan Borchers TA, Robison LM, Wiediger M, Park JS, Chew BP, McGuire MK, Sclar DA, Skaer TL, Beerman KA. The effects of soy milk and isoflavone supplements on cognitive performance in healthy, postmenopausal women. J Nutr Health Aging. 2007 Mar-Apr;11(2):155-64.

14. Islam F, Sparkes C, Roodenrys S, Astheimer L. Short-term changes in endogenous estrogen levels and consumption of soy isoflavones affect working and verbal memory in young adult females. Nutr Neurosci. 2008 Dec;11(6):251-62.

15. Celec P, Ostatnikova D, Hodosy J, Putz Z, Kúdela M. Increased one week soybean consumption affects spatial abilities but not sex hormone status in men. Int J Food Sci Nutr. 2007 Sep;58(6):424-8.

16. Ostatníková D, Celec P, Hodosy J, Hampl R, Putz Z, Kúdela M. Short-term soybean intake and its effect on steroid sex hormones and cognitive abilities. Fertil Steril. 2007 Dec;88(6):1632-6.

17. Celec P, Ostatníková D, Cagánová M, Zuchová S, Hodosy J, Putz Z, Bernadic M, Kúdela M. Endocrine and cognitive effects of short-time soybean consumption in women. Gynecol Obstet Invest. 2005;59(2):62-6.

18. Kreijkamp-Kaspers, S., Kok, L., Grobbee, D.E., de Haan, E.H.F., Aleman, A., Lampe, J.W., van der Schouw, Y.T. Effect of soy protein containing isoflavones on cognitive function, bone mineral density, and plasma lipids in postmenopausal women: A randomized controlled trial, JAMA. 2004;292:65-74.

19. Ho SC, Chan AS, Ho YP, So EK, Sham A, Zee B, Woo JL. Effects of soy isoflavone supplementation on cognitive function in Chinese postmenopausal women: a double-blind, randomized, controlled trial. Menopause. 2007 May-Jun;14(3 Pt 1):489-99.

20. Pilsáková L, Riecanský I, Ostatníková D, Jagla F. Missing evidence for the effect one-week phytoestrogen-rich diet on mental rotation in two dimensions. Neuro Endocrinol Lett. 2009 Mar;30(1):125-30.

21. Hogervorst E, Sadjimim T, Yesufu A, Kreager P, Rahardjo TB. High tofu intake is associated with worse memory in elderly Indonesian men and women. Dement Geriatr Cogn Disord. 2008;26(1):50-7. (Epub 2008 Jun 27)

22. White LR, Petrovitch H, Ross GW, Masaki K, Hardman J, Nelson J, Davis D, Markesbery W. Brain aging and midlife tofu consumption. J Am Coll Nutr. 2000 Apr;19(2):242-55.

23. Rice MM, Graves AN, McCurry SM, Larson EB. Tofu consumption and cognition in older Japanese American men and women. J Nutr 2000(Suppl):676S. (Published only as abstract)

24. Hogervorst E, Mursjid F, Priandini D, Setyawan H, Ismael RI, Bandelow S, Rahardjo TB. Borobudur revisited: Soy consumption may be associated with better recall in younger, but not in older, rural Indonesian elderly. Brain Res. 2010 Oct 28. (Epub ahead of print)

25. Strom BL, Schinnar R, Ziegler EE, Barnhart KT, Sammel MD, Macones GA, Stallings VA, Drulis JM, Nelson SE, Hanson SA. Exposure to soy-based formula in infancy and endocrinological and reproductive outcomes in young adulthood. JAMA. 2001 Aug 15;286(7):807-14.

26. Badger TM, Gilchrist JM, Pivik RT, Andres A, Shankar K, Chen JR, Ronis MJ. The health implications of soy infant formula. Am J Clin Nutr. 2009 May;89(5):1668S-1672S.

27. Martinez J, Lewi JE. An unusual case of gynecomastia associated with soy product consumption. Endocr Pract 2008;14:415–8. (Abstract)

28. Siepmann T, Roofeh J, Kiefer FW, Edelson DG. Hypogonadism and erectile dysfunction associated with soy product consumption. Nutrition. 2011 Feb 23.

29. Fischer L, Mahoney C, Jeffcoat AR, Koch MA, Thomas BE, Valentine JL, et al. Clinical characteristics and pharmacokinetics of purified soy isoflavones: multiple-dose administration to men with prostate neoplasia. Nutr Cancer 2004;48(2):160–70.

30. Chavarro JE, Toth TL, Sadio SM, Hauser R. Soy food and isoflavone intake in relation to semen quality parameters among men from an infertility clinic. Hum Reprod. 2008 Nov;23(11):2584-90.

31. Beaton LK, McVeigh BL, Dillingham BL, Lampe JW, Duncan AM. Soy protein isolates of varying isoflavone content do not adversely affect semen quality in healthy young men. Fertil Steril. 2010 Oct;94(5):1717-22.

32. Messina M, Watanabe S, Setchell KD. Report on the 8th International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment. J Nutr. 2009 Apr;139(4):796S-802S.

33. Sathyapalan T, Manuchehri AM, Thatcher NJ, Rigby AS, Chapman T, Kilpatrick ES, Atkin SL. The Effect of Soy Phytoestrogen Supplementation on Thyroid Status and Cardiovascular Risk Markers in Patients with Subclinical Hypothyroidism: A Randomized, Double-Blind, Crossover Study. J Clin Endocrinol Metab. 2011 Feb 16. (Epub ahead of print)

34. USDA Database for the Isoflavone Content of Selected Foods Release 2.0. 2008.

35. Bruce B, Messina M, Spiller GA. Isoflavone supplements do not affect thyroid function in iodine-replete postmenopausal women. J Med Food. 2003 Winter;6(4):309-16.

36. Tousen Y, Ezaki J, Fujii Y, Ueno T, Nishimuta M, Ishimi Y. Natural S-equol decreases bone resorption in postmenopausal, non-equol-producing Japanese women: a pilot randomized, placebo-controlled trial. Menopause. 2011 Jan 19. (Epub ahead of print)

37. Ham JO, Chapman KM, Essex-Sorlie D, Bakhit RM, Prabhudesai M, Winter L, Erdman JW, Potter S. Endocrinological response to soy protein and fiber in mildly hypercholesterolemic men. Nutr Res 1993; 13:873-884.

38. Zung A, Shachar S, Zadik Z, Kerem Z. Soy-derived isoflavones treatment in children with hypercholesterolemia: a pilot study. J Pediatr Endocrinol Metab. 2010 Jan-Feb;23(1-2):133-41.

39. Dillingham BL, McVeigh BL, Lampe JW, Duncan AM. Soy protein isolates of varied isoflavone content do not influence serum thyroid hormones in healthy young men. Thyroid. 2007 Feb;17(2):131-7.

40. Mackey R, Ekangaki A, Eden JA. The effects of soy protein in women and men with elevated plasma lipids. Biofactors. 2000;12(1-4):251-7.

41. Roughead ZK, Hunt JR, Johnson LK, Badger TM, Lykken GI. Controlled substitution of soy protein for meat protein: effects on calcium retention, bone, and cardiovascular health indices in postmenopausal women. J Clin Endocrinol Metab. 2005 Jan;90(1):181-9.

42. Lydeking-Olsen E, Beck-Jensen JE, Setchell KD, Holm-Jensen T. Soymilk or progesterone for prevention of bone loss–a 2 year randomized, placebo-controlled trial. Eur J Nutr. 2004 Aug;43(4):246-57.

43. Duncan AM, Merz BE, Xu X, Nagel TC, Phipps WR, Kurzer MS. Soy isoflavones exert modest hormonal effects in premenopausal women. J Clin Endocrinol Metab. 1999 Jan;84(1):192-7.

44. Hampl R, Ostatnikova D, Celec P, Putz Z, Lapcík O, Matucha P. Short-term effect of soy consumption on thyroid hormone levels and correlation with phytoestrogen level in healthy subjects. Endocr Regul. 2008 Jun;42(2-3):53-61.

45. Jayagopal V, Albertazzi P, Kilpatrick ES, Howarth EM, Jennings PE, Hepburn DA, Atkin SL. Beneficial effects of soy phytoestrogen intake in postmenopausal women with type 2 diabetes. Diabetes Care. 2002 Oct;25(10):1709-14.

46. Persky VW, Turyk ME, Wang L, Freels S, Chatterton R Jr, Barnes S, Erdman J Jr, Sepkovic DW, Bradlow HL, Potter S. Effect of soy protein on endogenous hormones in postmenopausal women. Am J Clin Nutr. 2002 Jan;75(1):145-53.

47. Watanabe S, Terashima K, Sato Y, Arai S, Eboshida A. Effects of isoflavone supplement on healthy women. Biofactors. 2000;12(1-4):233-41.

48. Nachvak SM, Moradi S, Anjom-Shoae J, Rahmani J, Nasiri M, Maleki V, Sadeghi O. Soy, Soy Isoflavones, and Protein Intake in Relation to Mortality from All Causes, Cancers, and Cardiovascular Diseases: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies. J Acad Nutr Diet. 2019 Sep;119(9):1483-1500.e17.

This article was first written by Jack Norris at veganhealth.org.

Contents

• Breast Cancer
• Dementia
• Infant Formulas
• Feminizing Characteristics
• Thyroid
• Soy Benefits
• References

Breast Cancer

Soy contains isoflavones, which have the ability to bind to estrogen receptors. There are about 25 mg of isoflavones in one serving of soy.

Case-control studies on soy and breast cancer have been generally encouraging to those with soy in their diets, with about half associating soy with a lower risk for breast cancer and the other half showing no effects.

Prospective studies, which are generally a higher level of evidence than case-control studies, have also been very positive. Of the six studies done on populations with higher soy intakes (about one to two servings per day is the typical upper intake amount), the Singapore Chinese Health Study (1), the Shanghai Women’s Study (2, 3), and the Japan Public Health Center study (4) all found that higher intakes of soy were associated with a reduced risk. The Japan Collaborative Cohort Study (5) and the Japan Life Span Study (6) found no association.

The European Prospective Investigation into Cancer-Oxford (7), which contained a large number of vegetarians, also found no association. Regarding the lack of association in the European study, some have speculated that in order to receive benefits from soy, exposure must occur during adolescence when breasts are developing, while Western vegetarians often add soy to their diets as adults.

As for women with breast cancer, including those with tumors that grow in response to contact with estrogen (known as estrogen receptor positive), the authors of the recently published Women’s Healthy Eating and Living Study (8) write:

Our study is the third epidemiological study to report no adverse effects of soy foods on breast cancer prognosis. These studies, taken together, which vary in ethnic composition (two from the US and one from China) and by level and type of soy consumption, provide the necessary epidemiological evidence that clinicians no longer need to advise against soy consumption for women diagnosed with breast cancer.

A 2019 dose-response meta-analysis of prospective cohort studies found that a 10 mg/day increase in soy isoflavone intake was associated with a 9% decreased risk of breast cancer mortality, and a 5 g/day increase in soy protein intake was associated with a 12% reduction in breast cancer death (48).

Also see Soy and Cancer Risk: Our Expert’s Advice from the American Cancer Society.

Dementia

The 2000 Honolulu-Asia Aging Study linked soy with lower cognitive function and brain shrinkage. Here’s a more thorough review of the research on soy and mental cognition.

There’ve been twelve short-term clinical trials lasting one week to a year. Nine show soy to be helpful (9, 10, 11, 12, 13, 14, 15, 16, 17), while three have shown soy to be neutral (18, 19, 20).

Epidemiological studies (unlike clinical trials) examine patterns of soy consumption and cognition in specific populations. One such study found tempeh (a fermented soy food) to be associated with improved cognition (21). Three reports from epidemiological studies have associated tofu with reduced cognition in some groups (21, 22, 23), but increased cognition in another group (24), and neutral in others (23, 24). The harmful findings for tofu in the epidemiological studies are likely due to confounding caused by the fact that people of lower economic status have traditionally eaten more tofu in Asian cultures as well as the fact that some Indonesian tofu has been prepared using formaldehyde.

The research as a whole provides little cause for concern.

Infant Formulas

The concern about infant formula is understandable giving that infants will be eating a large portion of their diet as soy.

The American Academy of Pediatrics and the National Toxicology Program considers soy formula safe.

The most important study to date, tracking adults who were fed soy formula as infants, provides assurance that there’s no reason to be concerned about thyroid or reproductive function (25).

The Beginnings Study is an ongoing study examining the effects of formula on child development (26). It’s in its early stages with findings from children only a year old, but to date, no negative effects of soy have been found on growth, sex organs, or neurological development compared to children on cow’s milk formula.

Some research shows that it’s best to choose a soy formula with DHA, and it’s important to note that soy formula isn’t intended for pre-term infants.

Feminizing Characteristics

Regarding the concern that soy could cause feminizing characteristics in men, there have been two case studies. In one, a man eating twelve servings per day of soymilk developed enlarged, sensitive breast tissue (27). In another, a man with type 1 diabetes was eating 14 servings per day of mostly processed soy foods for one year and developed erectile dysfunction (28), which normalized after ceasing the soy. While I would not recommend eating this much soy, one study used even much higher amounts of isoflavones and found no problems for most men (29).

As for sperm quantity and quality, while one epidemiological study raised concerns, albeit minor, about soy and sperm quantity (30), two clinical studies have shown no effects of soy (31, 32).

Thyroid

Isoflavones can affect thyroid hormone levels—especially if someone has iodine deficiency. A 2011 clinical trial found that 16 mg/day of isoflavones in people with mild hypothyroidism appeared to cause an increased rate of advancing to overt hypothyroidism (33).

Nine other clinical trials showed no effect of soy on the thyroid compared to placebo in people with presumably healthy thyroids (34, 35, 36, 37, 38, 39, 40, 41, 42), while the remaining five studies found small changes, all without physiological significance (43, 44, 45, 46, 47).

People without hypothyroidism should have no problems with soy as long as they get enough iodine, but until we know more, people with mild hypothyroidism might want to avoid soy just to be safe.

Soy Benefits

In addition to reducing the risk for breast cancer as mentioned above, soy also provides benefits for preventing prostate cancer, lowering LDL cholesterol, and improving menopausal symptoms. Please see Soy Part 2—Research for more details.

When you add up all the research on soy, there’s no reason to think that two servings per day are harmful to most people, and good reason to think soy provides some health benefits.

References

Last updated April 2011

1. Butler LM, Wu AH, Wang R, Koh WP, Yuan JM, Yu MC. A vegetable-fruit-soy dietary pattern protects against breast cancer among postmenopausal Singapore Chinese women. Am J Clin Nutr. 2010 Apr;91(4):1013-9.

2. Wu AH, Koh WP, Wang R, Lee HP, Yu MC (2008) Soy intake and breast cancer risk in Singapore Chinese health study. Br J Cancer 99(1):196–200.

3. Lee SA, Shu XO, Li H, Yang G, Cai H, Wen W, Ji BT, Gao J, Gao YT, Zheng W. Adolescent and adult soy food intake and breast cancer risk: results from the Shanghai Women’s Health Study. Am J Clin Nutr. 2009 Jun;89(6):1920-6.

4. Yamamoto S, Sobue T, Kobayashi M, Sasaki S, Tsugane S; Japan Public Health Center-Based Prospective Study on Cancer Cardiovascular Diseases Group. Soy, isoflavones, and breast cancer risk in Japan. J Natl Cancer Inst. 2003 Jun 18;95(12):906-13.

5. Nishio K, Niwa Y, Toyoshima H, Tamakoshi K, Kondo T, Yatsuya H, Yamamoto A, Suzuki S, Tokudome S, Lin Y, Wakai K, Hamajima N, Tamakoshi A. Consumption of soy foods and the risk of breast cancer: findings from the Japan Collaborative Cohort (JACC) Study. Cancer Causes Control. 2007 Oct;18(8):801-8.

6. Key TJ, Sharp GB, Appleby PN, Beral V, Goodman MT, Soda M, Mabuchi K. Soya foods and breast cancer risk: a prospective study in Hiroshima and Nagasaki, Japan. Br J Cancer. 1999 Dec;81(7):1248-56.

7. Travis RC, Allen NE, Appleby PN, Spencer EA, Roddam AW, Key TJ. A prospective study of vegetarianism and isoflavone intake in relation to breast cancer risk in British women. Int J Cancer. 2008 Feb 1;122(3):705-10.

8. Caan BJ, Natarajan L, Parker BA, Gold EB, Thomson CA, Newman VA, Rock CL, Pu M, Al-Delaimy WK, Pierce JP. Soy Food Consumption and Breast Cancer Prognosis. Cancer Epidemiol Biomarkers Prev. 2011 Feb 25.

9. File SE, Jarrett N, Fluck E, Duffy R, Casey K, Wiseman H. Eating soya improves human memory. Psychopharmacology (Berl) 2001; 157:430-6.

10. Duffy R, Wiseman H, File SE. Improved cognitive function in postmenopausal women after 12 weeks of consumption of a soya extract containing isoflavones. Pharmacol Biochem Behav. 2003 Jun;75(3):721-9.

11. Thorp AA, Sinn N, Buckley JD, Coates AM, Howe PR. Soya isoflavone supplementation enhances spatial working memory in men. Br J Nutr. 2009 Nov;102(9):1348-54.

12. Kritz-Silverstein D, Von Mühlen D, Barrett-Connor E, Bressel MA. Isoflavones and cognitive function in older women: the Soy and Postmenopausal Health In Aging (SOPHIA) Study. Menopause. 2003 May-Jun;10(3):196-202.

13. Fournier LR, Ryan Borchers TA, Robison LM, Wiediger M, Park JS, Chew BP, McGuire MK, Sclar DA, Skaer TL, Beerman KA. The effects of soy milk and isoflavone supplements on cognitive performance in healthy, postmenopausal women. J Nutr Health Aging. 2007 Mar-Apr;11(2):155-64.

14. Islam F, Sparkes C, Roodenrys S, Astheimer L. Short-term changes in endogenous estrogen levels and consumption of soy isoflavones affect working and verbal memory in young adult females. Nutr Neurosci. 2008 Dec;11(6):251-62.

15. Celec P, Ostatnikova D, Hodosy J, Putz Z, Kúdela M. Increased one week soybean consumption affects spatial abilities but not sex hormone status in men. Int J Food Sci Nutr. 2007 Sep;58(6):424-8.

16. Ostatníková D, Celec P, Hodosy J, Hampl R, Putz Z, Kúdela M. Short-term soybean intake and its effect on steroid sex hormones and cognitive abilities. Fertil Steril. 2007 Dec;88(6):1632-6.

17. Celec P, Ostatníková D, Cagánová M, Zuchová S, Hodosy J, Putz Z, Bernadic M, Kúdela M. Endocrine and cognitive effects of short-time soybean consumption in women. Gynecol Obstet Invest. 2005;59(2):62-6.

18. Kreijkamp-Kaspers, S., Kok, L., Grobbee, D.E., de Haan, E.H.F., Aleman, A., Lampe, J.W., van der Schouw, Y.T. Effect of soy protein containing isoflavones on cognitive function, bone mineral density, and plasma lipids in postmenopausal women: A randomized controlled trial, JAMA. 2004;292:65-74.

19. Ho SC, Chan AS, Ho YP, So EK, Sham A, Zee B, Woo JL. Effects of soy isoflavone supplementation on cognitive function in Chinese postmenopausal women: a double-blind, randomized, controlled trial. Menopause. 2007 May-Jun;14(3 Pt 1):489-99.

20. Pilsáková L, Riecanský I, Ostatníková D, Jagla F. Missing evidence for the effect one-week phytoestrogen-rich diet on mental rotation in two dimensions. Neuro Endocrinol Lett. 2009 Mar;30(1):125-30.

21. Hogervorst E, Sadjimim T, Yesufu A, Kreager P, Rahardjo TB. High tofu intake is associated with worse memory in elderly Indonesian men and women. Dement Geriatr Cogn Disord. 2008;26(1):50-7. (Epub 2008 Jun 27)

22. White LR, Petrovitch H, Ross GW, Masaki K, Hardman J, Nelson J, Davis D, Markesbery W. Brain aging and midlife tofu consumption. J Am Coll Nutr. 2000 Apr;19(2):242-55.

23. Rice MM, Graves AN, McCurry SM, Larson EB. Tofu consumption and cognition in older Japanese American men and women. J Nutr 2000(Suppl):676S. (Published only as abstract)

24. Hogervorst E, Mursjid F, Priandini D, Setyawan H, Ismael RI, Bandelow S, Rahardjo TB. Borobudur revisited: Soy consumption may be associated with better recall in younger, but not in older, rural Indonesian elderly. Brain Res. 2010 Oct 28. (Epub ahead of print)

25. Strom BL, Schinnar R, Ziegler EE, Barnhart KT, Sammel MD, Macones GA, Stallings VA, Drulis JM, Nelson SE, Hanson SA. Exposure to soy-based formula in infancy and endocrinological and reproductive outcomes in young adulthood. JAMA. 2001 Aug 15;286(7):807-14.

26. Badger TM, Gilchrist JM, Pivik RT, Andres A, Shankar K, Chen JR, Ronis MJ. The health implications of soy infant formula. Am J Clin Nutr. 2009 May;89(5):1668S-1672S.

27. Martinez J, Lewi JE. An unusual case of gynecomastia associated with soy product consumption. Endocr Pract 2008;14:415–8. (Abstract)

28. Siepmann T, Roofeh J, Kiefer FW, Edelson DG. Hypogonadism and erectile dysfunction associated with soy product consumption. Nutrition. 2011 Feb 23.

29. Fischer L, Mahoney C, Jeffcoat AR, Koch MA, Thomas BE, Valentine JL, et al. Clinical characteristics and pharmacokinetics of purified soy isoflavones: multiple-dose administration to men with prostate neoplasia. Nutr Cancer 2004;48(2):160–70.

30. Chavarro JE, Toth TL, Sadio SM, Hauser R. Soy food and isoflavone intake in relation to semen quality parameters among men from an infertility clinic. Hum Reprod. 2008 Nov;23(11):2584-90.

31. Beaton LK, McVeigh BL, Dillingham BL, Lampe JW, Duncan AM. Soy protein isolates of varying isoflavone content do not adversely affect semen quality in healthy young men. Fertil Steril. 2010 Oct;94(5):1717-22.

32. Messina M, Watanabe S, Setchell KD. Report on the 8th International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment. J Nutr. 2009 Apr;139(4):796S-802S.

33. Sathyapalan T, Manuchehri AM, Thatcher NJ, Rigby AS, Chapman T, Kilpatrick ES, Atkin SL. The Effect of Soy Phytoestrogen Supplementation on Thyroid Status and Cardiovascular Risk Markers in Patients with Subclinical Hypothyroidism: A Randomized, Double-Blind, Crossover Study. J Clin Endocrinol Metab. 2011 Feb 16. (Epub ahead of print)

34. USDA Database for the Isoflavone Content of Selected Foods Release 2.0. 2008.

35. Bruce B, Messina M, Spiller GA. Isoflavone supplements do not affect thyroid function in iodine-replete postmenopausal women. J Med Food. 2003 Winter;6(4):309-16.

36. Tousen Y, Ezaki J, Fujii Y, Ueno T, Nishimuta M, Ishimi Y. Natural S-equol decreases bone resorption in postmenopausal, non-equol-producing Japanese women: a pilot randomized, placebo-controlled trial. Menopause. 2011 Jan 19. (Epub ahead of print)

37. Ham JO, Chapman KM, Essex-Sorlie D, Bakhit RM, Prabhudesai M, Winter L, Erdman JW, Potter S. Endocrinological response to soy protein and fiber in mildly hypercholesterolemic men. Nutr Res 1993; 13:873-884.

38. Zung A, Shachar S, Zadik Z, Kerem Z. Soy-derived isoflavones treatment in children with hypercholesterolemia: a pilot study. J Pediatr Endocrinol Metab. 2010 Jan-Feb;23(1-2):133-41.

39. Dillingham BL, McVeigh BL, Lampe JW, Duncan AM. Soy protein isolates of varied isoflavone content do not influence serum thyroid hormones in healthy young men. Thyroid. 2007 Feb;17(2):131-7.

40. Mackey R, Ekangaki A, Eden JA. The effects of soy protein in women and men with elevated plasma lipids. Biofactors. 2000;12(1-4):251-7.

41. Roughead ZK, Hunt JR, Johnson LK, Badger TM, Lykken GI. Controlled substitution of soy protein for meat protein: effects on calcium retention, bone, and cardiovascular health indices in postmenopausal women. J Clin Endocrinol Metab. 2005 Jan;90(1):181-9.

42. Lydeking-Olsen E, Beck-Jensen JE, Setchell KD, Holm-Jensen T. Soymilk or progesterone for prevention of bone loss–a 2 year randomized, placebo-controlled trial. Eur J Nutr. 2004 Aug;43(4):246-57.

43. Duncan AM, Merz BE, Xu X, Nagel TC, Phipps WR, Kurzer MS. Soy isoflavones exert modest hormonal effects in premenopausal women. J Clin Endocrinol Metab. 1999 Jan;84(1):192-7.

44. Hampl R, Ostatnikova D, Celec P, Putz Z, Lapcík O, Matucha P. Short-term effect of soy consumption on thyroid hormone levels and correlation with phytoestrogen level in healthy subjects. Endocr Regul. 2008 Jun;42(2-3):53-61.

45. Jayagopal V, Albertazzi P, Kilpatrick ES, Howarth EM, Jennings PE, Hepburn DA, Atkin SL. Beneficial effects of soy phytoestrogen intake in postmenopausal women with type 2 diabetes. Diabetes Care. 2002 Oct;25(10):1709-14.

46. Persky VW, Turyk ME, Wang L, Freels S, Chatterton R Jr, Barnes S, Erdman J Jr, Sepkovic DW, Bradlow HL, Potter S. Effect of soy protein on endogenous hormones in postmenopausal women. Am J Clin Nutr. 2002 Jan;75(1):145-53.

47. Watanabe S, Terashima K, Sato Y, Arai S, Eboshida A. Effects of isoflavone supplement on healthy women. Biofactors. 2000;12(1-4):233-41.

48. Nachvak SM, Moradi S, Anjom-Shoae J, Rahmani J, Nasiri M, Maleki V, Sadeghi O. Soy, Soy Isoflavones, and Protein Intake in Relation to Mortality from All Causes, Cancers, and Cardiovascular Diseases: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies. J Acad Nutr Diet. 2019 Sep;119(9):1483-1500.e17.

This article was first written by Jack Norris at veganhealth.org.

Ingredients:

1. 1 medium-sized eggplant
2. 1 teaspoon salt
3. 1 tsp black pepper
4. 2 tsp ginger garlic paste
5. 3 green chilies chopped finely
6. 1 bunch fresh of coriander leaves
7. 2 tbsp fresh mint leaves
8. ½ tsp turmeric
9. 1 tbsp red chili powder
10. 2 tbsp oil
11. 2 tbsp grated fresh coconut
12. 2 ½ tbsp cumin seeds
13. 2 onions finely chopped
14. 4 tbsp peanut curd
15. 1 tsp garam masala
16. Salt to taste

Directions:

Chop off the top and bottom parts of the eggplant, then peel the skin off.    

Further, peel the eggplant into thin slices. In a pan, sprinkle the eggplant with salt and let it be there for 15-20 minutes.

Rinse the eggplant and squeeze as much water as you can.

Mash them thoroughly.

Add half of the chopped green chilies, half of the garam masala, salt, turmeric, 1 tsp ginger-garlic paste, half of the coriander leaves, and half of the mint leaves to the mashed eggplant.

Mix well. Apply oil on hands and prepare small balls 

Heat one tsp of oil in a pan for the gravy and add the fresh coconut. Saute for a few minutes. Add the cumin seeds and saute for another 2 minutes. Add sliced onions and saute till they turn golden brown. 

Turn off the heat and let it cool. Make a fine paste once it comes to room temperature. Add some water if needed while blending.

Heat 1 tbsp oil in a cooking vessel, add the ground paste, and cook for a few minutes until it turns brown. Add the remaining ginger garlic paste, green chilies, red chili powder, salt, and curd and stir. Add 2 cups of water and let it come to a boil. Cook for 3-4 mins on a medium-low flame.

Add the meatballs to the gravy, cover with a lid and cook them on low flame for 20 mins.

Add garam masala, the remaining chopped coriander, and mint leaves. Cook for another 10 minutes on low flame.

Turn off the heat, add lemon juice and combine.

Serve hot with rotis or white steamed rice for lunch or dinner.

Ingredients

• 1 cup soy chunks
• 2 cups warm water
• Salt – A pinch for soaking soya and 1 spoon for the gravy.
• 2 medium onions, finely chopped
• 1 tsp ginger garlic paste
• 2 tsp of coriander powder
• 4 cloves
• 1-inch piece of cinnamon
• Small piece of fresh coconut
• 4 cashews
• 2 cloves of garlic
• 2 tsp oil
• 2 green chillies, finely chopped
• 1/2 tsp red chili powder
• 1/2 tsp turmeric powder
• Coriander for garnish

Instructions

1. Put soy chunks in warm water, add salt and let it sit for a min. Squeeze out the water and keep it aside.
2. In a mixer, add coconut pieces and cashews, blend and keep aside.
3. For the masala, take a mortar pestle, add garlic, cinnamon, cloves, and coriander powder, make a coarse powder, and keep aside. Alternatively, you can also blend them in a mixer.
4. In a pan, heat oil and add the chopped onion and chillies.
5. Add salt and, once the onions turn brown, add turmeric powder, ginger garlic paste and fry for 2 mins.
6. Add soy chunks and let it cook for 5 mins.
7. Add the chilli powder, adjust the salt, add 1.5 cups water, close the lid, and cook it for 10 mins on medium flame.
8. Open the lid and, add the coconut & cashew paste and cook for 2 mins.
9. Add the masala, turn off the stove and garnish with coriander.

Serve warm with rice or rotis for lunch or dinner.

– By Bhavya Vatrapu, Senior Campaigns Manager at Vegan Outreach. Bhavya is also a conscious traveller writes travel blogs on FlamingoDiaries.com