Table 1.
Current clinical studies evaluating the effects of phytochemicals in breast cancer prevention
| Phytochemical | Study design | Year | Study participants (number) | Results | Reference |
|---|---|---|---|---|---|
| dTAC | Hospital-based case–control study | 2021 | Women with pathologically confirmed BC (n = 412) and healthy controls (n = 456) | Inverse association between dTAC and odds of BC (whole population); highest quartile of dTAC → 0.39 times less probability of BC vs. the lowest quartile; postmenopausal women with greatest dTAC had lower odds for BC vs. those with the lowest dTAC | [53] |
| Legumes and nuts | Population-based case–control study | 2021 | New BC cases (n = 350) and controls (n = 700) | Inverse association between the consumption of legumes and nuts and odds of BC | [54] |
| Plant-based diet | Population-based case–control study | 2021 | Newly diagnosed BC (n = 350) and healthy controls (n = 700) | Inverse association between adherence to plant-based diet index and hypothesized healthy plant-based diet index with breast cancer risk | [55] |
| HEI | Case–control study | 2020 | BC cases (n = 134) and cancer-free controls (n = 265) | HEI associated with decreased BC risk | [56] |
| PVG | Prospective cohort study | 2020 | Women in the Seguimiento Universidad de Navarra cohort (n = 10,812) | Inverse association with BC for a modest overall PVG, but not for hPVG and uPVG separately | [57] |
| Fruits and vegetables | Data from prospective cohort study – NHS | 2019 | NHS (n = 88,301) and NHSII (n = 93,844) | Fruits and vegetables (especially cruciferous and yellow or orange vegetables) associated with lower risk of BC, total vegetables with lower risk of oestrogen receptor negative BC, total fruits and vegetables with lower risk of HER2-enriched, basal-like, and luminal A BC | [58] |
| 24 months of dietary or physical intervention | Randomized intervention trial | 2019 | Healthy postmenopausal women (n = 226) | Reduced mammographic breast density | [59] |
| Healthier diet | Case–control study | 2018 | BC cases (n = 145) and controls (n = 148) | Healthier diet (vitamin A, β-carotene, vitamin C, and folate) associated with decreased risk of BC vs. high fat and lamb meat | [60] |
| Bean fiber, beans, grains | Food frequency data from population-based case–control study | 2018 | BC cases (n = 2135) and controls (n = 2571) | Greater intake of bean fiber, beans, grains may lower the risk of ER- and PR- BC | [61] |
| Cruciferous vegetables, glucosinolates, and isothiocyanate | Case–control study | 2018 | BC cases (n = 1485) and controls (n = 1506) | Indicated association between higher intake of cruciferous vegetable, glucosinolates, and isothiocyanates and BC risk in Chinese women | [62] |
| Green tea extract | Randomized, double-blinded, placebo-controlled phase II clinical trial | 2017 | Healthy postmenopausal women (n = 1075) | Reduced PMD in younger women when compared with placebo group | [63] |
| MD | Multivariate case–control analyses | 2017 | Incident BC cases (n = 2321) and subcohort members (n = 1665) | Moderately strong inverse associations with risk of ER- (40% reduction), and ER- PR- (39% reduction) breast cancers | [64] |
BC; breast cancer, dTAC; dietary total antioxidant capacity, ER-; oestrogen receptor negative, HEI; Healthy Eating Index, HER2; human epidermal growth factors receptor 2, hPVG; healthful pro-vegetarian dietary pattern, MD; Mediterranean diet, NHS; Nurses’ Health Study, PMD; percent mammographic density, PR-; progesterone receptor negative, PVG; pro-vegetarian dietary pattern, uPVG; unhealthful pro-vegetarian dietary pattern