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Home > Trending on TAP > June 2018 > Soy and Cruciferous Vegetables in Breast Cancer Survivors

Soy and Cruciferous Vegetables in Breast Cancer Survivors

6/13/2018 11:41:48 AM
Survivors of breast cancer often experience cancer-related or treatment-related symptoms months or years after treatment. These symptoms commonly include menopausal symptoms, fatigue, cognitive changes, and hair thinning or hair loss. There is reason to believe that consumption of some phytochemicals in foods might mitigate these late effects of breast cancer treatment. Isoflavones in soy bind to estrogen receptors and exert weak estrogenic effects. Glucosinolates in cruciferous vegetables influence estrogen-metabolizing enzymes in phase I and phase II liver pathways and reduce inflammation. In this cross-sectional study, researchers evaluated the associations between soy and cruciferous vegetable consumption and late effects of breast cancer treatment.
 
The study population included 192 Chinese American and 173 non-Hispanic white women who had been diagnosed and treated for stage 0-III breast cancer in California. The majority of women were menopausal (48%) or perimenopausal (22%). The length of time since diagnosis was < 2 years in 30% of women, 2-3 years in 30% of women, and ≥ 3 years in 40% of women. Most women were diagnosed with stage 0 (30%) or stage I (45%), and hormone-receptor positive subtypes were most common. Approximately 25% received chemotherapy, 46% received radiation, and 59% received endocrine therapy (tamoxifen or aromatase inhibitors).
 
Data were collected through a telephone interview and a food frequency questionnaire. The variables assessed were soy and cruciferous vegetable consumption. The outcomes evaluated were menopausal symptoms (hot flashes, night sweats, vaginal dryness, vaginal discharge), joint problems, fatigue, and hair thinning or loss.
 
Cruciferous vegetable intake was associated with fewer menopausal symptoms in the overall population. Women consuming more than 71 grams per day of cruciferous vegetables had an adjusted odds ratio for menopausal symptoms of 0.50 (95% CI, 0.25-0.97) when compared with those consuming less than 33 grams per day. Higher soy intake was associated with fewer menopausal symptoms and less fatigue in the overall population, but in models stratified by race, these associations were only significant in non-Hispanic white women.
 
The associations between soy and cruciferous intake and symptoms varied by treatments received. For example, higher soy intake was associated with less fatigue in women who had not received endocrine therapy and less joint pain in women who had received aromatase inhibitors. Soy intake was not associated with symptoms in tamoxifen users. Higher cruciferous vegetable intake was associated with fewer menopausal symptoms in aromatase inhibitor users but not in tamoxifen users or those who had not received endocrine therapy.
 
This study concludes that higher consumption of soy and cruciferous vegetables may be associated with fewer menopausal symptoms and less fatigue in breast cancer survivors. This conclusion may not be generalizable to all breast cancer survivors, however, because the interactions appear to vary, depending on factors such as race and treatments received.
 
Reference
Nomura SJO, Hwang YT, Gomez SL et al. Dietary intake of soy and cruciferous vegetables and treatment-related symptoms in Chinese-American and non-Hispanic White breast cancer survivors. Breast Cancer Res Treat. 2018; 168: 467-479.

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