Soy intake and breast cancer risk: a prospective study of 300,000 Chinese women and a dose–response meta-analysis

Abstract

Epidemiological evidence on the association of soy intake with breast cancer risk is still inconsistent due to different soy intake levels across previous studies and small number of breast cancer cases. We aimed to investigate this issue by analyzing data from the China Kadoorie Biobank (CKB) study and conducting a dose-response meta-analysis to integrate existing evidence. The CKB study included over 300,000 women aged 30-79 from 10 regions across China enrolled between 2004 and 2008, and followed-up for breast cancer events until 31 December 2016. Information on soy intake was collected from baseline, two resurveys and twelve 24-h dietary recalls. We also searched for relevant prospective cohort studies to do a dose-response meta-analysis. The mean (SD) soy intake was 9.4 (5.4) mg/day soy isoflavones among CKB women. During 10 years of follow-up, 2289 women developed breast cancers. The multivariable-adjusted relative risk was 1.00 (95% confidence interval [CI] 0.81-1.22) for the fourth (19.1 mg/day) versus the first (4.5 mg/day) soy isoflavone intake quartile. Meta-analysis of prospective studies found that each 10 mg/day increment in soy isoflavone intake was associated with a 3% (95% CI 1-5%) reduced risk of breast cancer. The CKB study demonstrated that moderate soy intake was not associated with breast cancer risk among Chinese women. Higher amount of soy intake might provide reasonable benefits for the prevention of breast cancer.

A Korean-Style Balanced Diet Has a Potential Connection with Ruminococcaceae Enterotype and Reduction of Metabolic Syndrome Incidence in Korean Adults

“…Mucin contents influence the host’s signal transduction pathway to maintain intestinal morphological integrity [ 46 ]. It is known that Bifidobacterium adolescentis have anti-obesity and anti-inflammatory activities [ 47 ], and Faecalibterium prausnitzii is an excellent butyric acid-producer [ 42 ]. Butyrate can stimulate colon mucin and enhance the barrier capacity of the intestine [ 41 ].…”

A Narrative Review of the Role of Diet and Lifestyle Factors in the Development and Prevention of Endometrial Cancer

“…The reason why some studies have shown an increased risk of developing breast cancer through ingestion of isoflavones [ 281 , 287 ], whilst other studies have not confirmed such associations or have shown the opposite [ 179 , 180 , 277 , 279 , 283 , 285 , 286 , 288 , 289 ], is probably due to the presence of the oestrogen receptors in the starting neoplasm [ 281 ], the population under study [ 290 ] or the physical form that the isoflavone that is consumed [ 288 , 291 ]. Meta-analyses of different studies in various populations generally support the idea that moderate to high consumption of a diet that contains isoflavones prevents EC, ovarian and breast cancer and its recurrence [ 283 , 292 , 293 , 294 ]. These data suggest that a diet rich in isoflavones or that concentrated soy supplements, which contain much higher isoflavone concentrations will be beneficial, but until more research is done with pre- and peri- and postmenopausal cohorts, a definitive conclusion cannot be met.…”

Flavonoids and Other Polyphenols Act as Epigenetic Modifiers in Breast Cancer

“…Recently, a large meta-analysis indicated that the dose of isoflavone is a critical factor for its effect in reducing breast cancer risk. This study showed that a higher amount of daily soy consumption, approximately 10 mg/day, decreased breast cancer risk by 3% (95% CI 1-5%) [37].…”