New meta-analysis below [1].
The flavonoid family (Anthocyanidins, Anthoxanthins, Flavanones, Flavanonols, Flavans, & Isoflavonoids) include members that have hormone-like properties. "This meta-analysis was aimed to explore the association between flavonoids intake and {hormone-related cancer} HRC risk among observational studies."
Wikipedia [2]:
"Clinical studies investigating the relationship between flavonoid consumption and cancer prevention or development are conflicting for most types of cancer, probably because most human studies have weak designs, such as a small sample size. There is little evidence to indicate that dietary flavonoids affect human cancer risk in general, but observational studies and clinical trials on hormone-dependent cancers (breast and prostate) have shown benefits. A recent review has suggested that dietary intake of flavonoids is associated with a reduced risk of different types of cancer, including gastric, breast, prostate, and colorectal cancer"
From the new paper:
"The present study suggests evidence that intake of total flavonoids, flavonols, flavones, flavanones, flavan-3-ols and isoflavones would be associated with a lower or higher risk of HRCs, which perhaps provides guidance for diet guidelines to a certain extent."
"All included studies were rated as medium or high quality. Higher consumption of flavonols (OR = 0.85 ...), flavones (OR = 0.85 ...) and isoflavones (OR = 0.87 ...) was associated with a decreased risk of women-specific cancers (breast, ovarian and endometrial cancer), while the higher intake of total flavonoids was linked to a significantly elevated risk of prostate cancer (OR = 1.11 ...)"
Note that soy products would account for a significant intake of isoflavones. Genistein (a phytoestrogen) has been shown to have a biphasic effect on PCa cells - being growth-promoting at physiological levels & growth-inhibiting at pharmaceutical levels.
i.e. perhaps prudent to avoid dietary soy. If using supplements, go big.
-Patrick
[1] pubmed.ncbi.nlm.nih.gov/355...
(90 papers are referenced)
Nutr J
. 2022 May 11;21(1):27. doi: 10.1186/s12937-022-00778-w.
Consumption of flavonoids and risk of hormone-related cancers: a systematic review and meta-analysis of observational studies
Fubin Liu 1 2 3 , Yu Peng 1 2 3 , Yating Qiao 1 2 3 , Yubei Huang 1 2 3 , Fengju Song 1 2 3 , Ming Zhang 4 , Fangfang Song 5 6 7
Affiliations collapse
Affiliations
1 Department of Epidemiology and Biostatistics, Key Laboratory of Molecular Cancer Epidemiology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, 300060, China.
2 Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin, 300060, China.
3 Key Laboratory of Breast Cancer Prevention and Therapy, Ministry of Education, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, 300060, China.
4 Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, 518020, Guangdong, China. mingle1981@163.com.
5 Department of Epidemiology and Biostatistics, Key Laboratory of Molecular Cancer Epidemiology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, 300060, China. double1980@163.com.
6 Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin, 300060, China. double1980@163.com.
7 Key Laboratory of Breast Cancer Prevention and Therapy, Ministry of Education, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, 300060, China. double1980@163.com.
PMID: 35545772 DOI: 10.1186/s12937-022-00778-w
Abstract
Background: Flavonoids seem to have hormone-like and anti-hormone properties so that the consumption of flavonoids may have potential effects on hormone-related cancers (HRCs), but the findings have been inconsistent so far. This meta-analysis was aimed to explore the association between flavonoids intake and HRCs risk among observational studies.
Methods: Qualified articles, published on PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI) from January 1999 to March 2022 and focused on relationships between flavonoids (total, subclass of and individual flavonoids) and HRCs (breast, ovarian, endometrial, thyroid, prostate and testicular cancer), were retrieved for pooled analysis. Random effects models were performed to calculate the pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs). Funnel plots and Begg's/Egger's test were used to evaluate the publication bias. Subgroup analyses and sensitivity analyses were conducted to explore the origins of heterogeneity.
Results: All included studies were rated as medium or high quality. Higher consumption of flavonols (OR = 0.85, 95% CI: 0.76-0.94), flavones (OR = 0.85, 95% CI: 0.77-0.95) and isoflavones (OR = 0.87, 95% CI: 0.82-0.92) was associated with a decreased risk of women-specific cancers (breast, ovarian and endometrial cancer), while the higher intake of total flavonoids was linked to a significantly elevated risk of prostate cancer (OR = 1.11, 95% CI: 1.02-1.21). A little evidence implied that thyroid cancer risk was augmented with the higher intake of flavones (OR = 1.24, 95% CI: 1.03-1.50) and flavanones (OR = 1.31, 95% CI: 1.09-1.57).
Conclusions: The present study suggests evidence that intake of total flavonoids, flavonols, flavones, flavanones, flavan-3-ols and isoflavones would be associated with a lower or higher risk of HRCs, which perhaps provides guidance for diet guidelines to a certain extent.
Trial registration: This protocol has been registered on PROSPERO with registration number CRD42020200720 .
Keywords: Flavonoid subclasses; Flavonoids; Hormone-related cancers; Meta-analysis; Observational studies.
© 2022. The Author(s).
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