Olive oil and risk of breast cancer: a systematic review and dose–response meta-analysis of observational studies

Abstract

Olive oil consumption has been suggested to be inversely associated with breast cancer risk, likely due to its high monounsaturated fatty acid and polyphenol content. The purpose of this meta-analysis was to assess the association between olive oil and breast cancer risk, including assessing the potential for a dose-response association. We performed a systematic search of PubMed, Web of Science, CINAHL, and Cochrane Central Register of Controlled Trials (CENTRAL) through June 2020, identifying 10 observational studies (two prospective studies and 8 case-control studies) for inclusion in the present meta-analysis. We estimated summary odds ratios (OR) and 95% confidence intervals (CI) for the highest versus lowest olive oil intake category across studies using random effect models, and assessed the dose-response relationship between olive oil and breast cancer risk using restricted cubic splines. The summary OR comparing women with the highest intake to those with the lowest category of olive oil intake was 0.48 (95% CI = 0.09-2.70) in prospective studies and 0.76 (95% CI=0.54-1.06) in case-control studies, with evidence of substantial study heterogeneity (prospective: I2 = 89%, case-control: I2 = 82%). There was no significant dose-response relationship for olive oil and breast cancer risk; the OR for a 14 g/day increment was 0.93 (95% CI=0.83 - 1.04). There may be a potential inverse association between olive oil intake and breast cancer; however, since the estimates are non-significant and the certainty level is very low, additional prospective studies with better assessment of olive oil intake are needed.

Saturated fat, the estimated absolute risk and certainty of risk for mortality and major cancer and cardiometabolic outcomes: an overview of systematic reviews

“…The included SRMAs were published between 2014 and 2021. Among them, 13 were reviews of observational studies (e.g., cohorts, case-controls) [ 25 – 37 , 42 ] and 4 were reviews of RCTs [ 38 – 41 ]. The characteristics of the included SRMAs are reported in Table 1 .…”

Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on sustainable dietary and physical activity recommendations for the Spanish population

“…This study did not evaluate the minimum intake necessary to produce this beneficial effect. In this same line, another meta-analysis that specifically evaluated the effect of olive oil on breast cancer risk observed a non-significant inverse relationship, with heterogeneity of the studies (Sealy et al, 2021).…”

Arbeitsgemeinschaft Gynäkologische Onkologie Recommendations for the Diagnosis and Treatment of Patients with Early Breast Cancer: Update 2023

“…Adherence to normal body weight (BMI 18.5-25 kg/m 2 ), particularly for postmenopausal women (LoE 2a/B/++), as well as the prevention/screening and treatment of diabetes mellitus type II (LoE2b/B/AGO++) has an effect on the reduction of BC incidence and mortality [2]. A balanced Mediterranean diet including extra virgin olive oil (LoE2b/B/ AGO+) [7,8], nuts (>10 g/die) (LoE 2b/B/AGO+), reduced consumption of fat (LoE2a/B/AGO+), and red meat (LoE2b/C/AGO+) may decrease the incidence of BC [2]. With regard to medical primary prevention, Acetylsalicylsäure, COX2-inhibitors (LoE2a/B/AGO+/−), bisphosphonates, vitamin D (LoE2b/B/AGO+/−), might reduce BC risk, whereas statins rated (LoE2b/B/ AGO−).…”