This summary table contains detailed information about research studies. Summary tables offer an informative look at the science behind many breast cancer guidelines and recommendations. However, they should be viewed with some caution. In order to read and interpret research tables successfully, it is important to understand some key concepts. Learn how to read a research table.
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Introduction: Although postmenopausal hormones containing estrogen and progestin may ease menopausal symptoms, long-term use increases the risk of breast cancer (see Table 8) [1]. For this reason, many women seek other ways to reduce hot flashes and other symptoms.
Soy foods and soy supplements have been suggested as way of relieving menopausal symptoms. Findings from randomized controlled trials are mixed. Some show soy can reduce hot flashes, while others do not.
Learn more about soy.
Read our perspective on the role of soy in breast cancer recurrence and survival.
Learn about the strengths and weaknesses of different types of studies.
Study selection criteria: Randomized controlled trials with at least 60 participants and meta-analyses.
Table note: Relative risk above 1 indicates increased risk. Relative risk below 1 indicates decreased risk.
Study
|
Study Population
(number of participants)
|
Treatment Duration
|
Menopausal Symptoms
Studied
|
Type of Soy
|
Menopausal Symptoms Reduced among
Women Taking Soy
versus Placebo?
|
Randomized controlled trials
|
Levis et al. [2]
|
182
cancer-free women
|
2 years
|
Hot flashes
|
Soy tablet
|
No
|
Quella et al. [3]
|
175
breast cancer survivors
|
4 weeks
|
Hot flashes
|
Soy tablet
|
No
|
Van Patten et al. [4]
|
123
breast cancer survivors
|
12 weeks
|
Hot flashes
|
Soy beverage
|
No
|
Ferrari et al. [5]
|
121
cancer-free
women
|
12 weeks
|
Hot flashes
|
Soy tablet
|
Yes
|
Nahas et al. [6]
|
80
cancer-free
women
|
10 months
|
Hot flashes
|
Soy capsule
|
Yes
|
Faure et al. [7]
|
75
cancer-free
women
|
16 weeks
|
Hot flashes
|
Soy capsule
|
Yes
|
Lewis et al. [8]
|
66
cancer-free
women
|
16 weeks
|
Hot flashes
|
Soy flour muffin
|
No
|
Penotti et al. [9]
|
62
cancer-free
women
|
6 months
|
Hot flashes
|
Soy tablet
|
No
|
Welty et al. [10]
|
60
cancer-free
women
|
8 weeks
|
Hot flashes
|
Soy nuts
|
Yes
|
Carmignani et al. [11]
|
60
cancer-free
women
|
16 weeks
|
Hot flashes
and vaginal dryness
|
Soy powder
|
Yes
|
Meta-analyses
|
Bolaños et al. [12]
|
17 studies
|
12 weeks
|
Hot flashes
|
Various
|
Yes
|
Nelson et al. [13]
|
5 studies
|
4-6 weeks
|
Hot flashes
|
Various
|
No
|
| |
4 studies
|
12-16 weeks
|
Hot flashes
|
Various
|
Yes
|
| |
2 studies
|
6 months
|
Hot flashes
|
Various
|
Yes
|
References
1. Rossouw JE, Anderson GL, Prentice RL, et al. for the Writing Group for the Women’s Health Initiative Investigators. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women's Health Initiative randomized controlled trial. JAMA. 288(3):321-33, 2002.
2. Levis S, Strickman-Stein N, Ganjei-Azar P, Xu P, Doerge DR, Krischer J. Soy isoflavones in the prevention of menopausal bone loss and menopausal symptoms: a randomized, double-blind trial. Arch Intern Med. 171(15):1363-9, 2011.
3. Quella SK, Loprinzi CL, Barton DL, et al. Evaluation of soy phytoestrogens for the treatment of hot flashes in breast cancer survivors: A North Central Cancer Treatment Group Trial. J Clin Oncol. 18(5):1068-74, 2000.
4. Van Patten CL, Olivotto IA, Chambers GK, et al. Effect of soy phytoestrogens on hot flashes in postmenopausal women with breast cancer: a randomized, controlled clinical trial. J Clin Oncol. 20(6):1449-55, 2002.
5. Ferrari A. Soy extract phytoestrogens with high dose of isoflavones for menopausal symptoms. J Obstet Gynaecol Res. 35(6):1083-90, 2009.
6. Nahas EAP, Nahas-Neto J, Orsatti FL, Carvalho EP, Oliveira MLCS, Dias R. Efficacy and safety of a soy isoflavone extract in postmenopausal women: a randomized, double-blind, and placebo-controlled study. Maturitas. 58(3):249-58, 2007.
7. Faure ED, Chantre P, Mares P. Effects of a standardized soy extract on hot flushes: a multicenter, double-blind, randomized, placebo-controlled study. Menopause. 9(5):329-34, 2002.
8. Lewis JE, Nickell LA, Thompson LU, Szalai JP, Kiss A, Hilditch JR. A randomized controlled trial of the effect of dietary soy and flaxseed muffins on quality of life and hot flashes during menopause. Menopause. 13(4):631-42, 2006.
9. Penotti M, Fabio E, Modena AB, Rinaldi M, Omodei U, Vigano. Effect of soy-derived isoflavones on hot flushes, endometrial thickness, and the pulsatility index of the uterine and cerebral arteries. Fertil Steril. 79(5):1112-7, 2003.
10. Welty FK, Lee KS, Lew NS, Nasca M, Zhou JR. The association between soy nut consumption and decreased menopausal symptoms. J Womens Health (Larchmt). 16(3):361-9, 2007.
11. Carmignani LO, Pedro AO, Costa-Paiva LH, Pinto-Neto AM. The effect of dietary soy supplementation compared to estrogen and placebo on menopausal symptoms: a randomized controlled trial. Maturitas. 67(3):262-9, 2010.
12. Bolaños R, Del Castillo A, Francia J. Soy isoflavones versus placebo in the treatment of climacteric vasomotor symptoms: systematic review and meta-analysis. Menopause. 17(3):660-6, 2010.
13. Nelson HD, Vesco KK, Haney E, et al. Nonhormonal therapies for menopausal hot flashes: systematic review and meta-analysis. JAMA. 295(17):2057-71, 2006.
Updated 02/10/12
