The Effects of Diet and Exercise on Endogenous Estrogens and Subsequent Breast Cancer Risk in Postmenopausal Women

Abstract

Endogenous estrogens have been associated with overall breast cancer risk, particularly for postmenopausal women, and ways to reduce these estrogens have served as a primary means to decrease overall risk. This narrative review of clinical studies details how various nutritional and exercise lifestyle interventions have been used to modify estrogen levels and metabolism to provide a protective impact against breast cancer incidence. We also summarized the evidence supporting the efficacy of interventions, outcomes of interest and identified emerging research themes. A systematic PubMed MEDLINE search identified scholarly articles or reviews published between 2000-2020 that contained either a cohort, cross-sectional, or interventional study design and focused on the relationships between diet and/or exercise and overall levels of different forms of estrogen and breast cancer risk and occurrence. Screening and data extraction was undertaken by two researchers. Data synthesis was narrative due to the heterogeneous nature of studies. A total of 1625 titles/abstracts were screened, 198 full texts reviewed; and 43 met eligibility criteria. Of the 43 studies, 28 were randomized controlled trials, and 15 were observational studies. Overall, studies that incorporated both diet and exercise interventions demonstrated better control of detrimental estrogen forms and levels and thus likely represent the best strategies for preventing breast cancer development for postmenopausal women. Some of the strongest associations included weight loss via diet and diet + exercise interventions, reducing alcohol consumption, and consuming a varied dietary pattern, similar to the Mediterranean diet. More research should be done on the effects of specific nutritional components on endogenous estrogen levels to understand the effect that the components have on their own and in combination within the diet.

Associations between abdominal adipose tissue, reproductive span, and brain characteristics in post-menopausal women

“…However, it is unclear how individual variation in oestrogen exposure pre-menopause may influence associations between adipose tissue and brain health post-menopause, and how this may relate to circulating oestrogen levels, which were not available at the time of the brain and body MRI scans. Although oestradiol measures were available from baseline in a smaller subsample, it can take several years for oestradiol levels to stabilise following menopause ( Randolph Jr et al, 2011 ), and these measurements may be influenced by certain types of hormone replacement therapy ( Waaseth et al, 2008 ) as well as lifestyle factors ( Wiggs et al, 2021 ). Due to the time window between assessments, changes in both oestradiol and adipose tissue levels could occur, limiting any firm conclusions based on these measures.…”

Associations of increasing breast cancer incidence with the current drinking habits and the past smoking habits among Japanese women

“…Clinical and experimental studies have demonstrated that estrogen is involved in each phase of the carcinogenesis through complex mechanisms. 6 Concerning the modifiable cancer risk factors shown in the present study, blood estrogen levels can be elevated in postmenopausal women with obesity 7 and in pre-and postmenopausal women with drinking habits, 8,9 but cannot be elevated in women with smoking habits. 10 The age-specific incidence and mortality rates of uterine body cancer, another estrogen-related cancer, also increased from 2005 to 2015, despite smaller rates compared with those of breast cancer.…”

Counseling in menopausal women: How to address the benefits and risks of menopause hormone therapy. A FIGO position paper

“…150 Healthy eating, such as that of the Mediterranean diet, and physical activity are pivotal in containing cardiovascular and cancer risks at mid-life and beyond. [151][152][153][154][155] Maintaining alcohol consumption that meets public health recommendations and avoiding smoking are also key to reducing such risks. 156,157 Last but not least, engaging in leisure activities, such as visiting art exhibitions, reading, listening to music, singing, and painting, is positively associated with a lower risk of depression, dementia, and death by any cause.…”

“…Healthy eating, such as that of the Mediterranean diet, and physical activity are pivotal in containing cardiovascular and cancer risks at mid‐life and beyond 151–155 …”