Biomarkers of dietary fatty acid intake and the risk of breast cancer: A meta‐analysis

Abstract

The use of the fatty acid composition of adipose tissue, erythrocyte membranes, serum and plasma as biological markers of fatty acid intake was recently introduced in epidemiological studies. The biomarkers of fatty acid intake have the advantage of providing quantitative measurement independent of energy intake and of the subject's memory. We performed a meta-analysis of published results of epidemiological studies of the composition of fatty acids in biological samples and breast cancer risk. The analysis was based on 3 cohort and 7 case-control studies including 2,031 cases and 2,334 controls. The summary statistic used was the average of the relative risk estimated for each level of the fatty acid on study, weighted by the inverse of its variance. Random effect models were assumed when the test for heterogeneity was significant. Overall relative risks were estimated for studies including pre-and post-menopausal breast cancer and separately for post-menopausal women. In cohort studies, a significant protective effect was found for total n-3 polyunsaturated fatty acids, while total monounsaturated fatty acids, oleic acid (C18:1 n-9c) and palmitic acid (C16:0) were significantly associated with an increase of breast cancer risk. Total saturated fatty acids were significantly associated with breast cancer risk in cohort studies only in postmenopausal women. For case-control studies, the only finding was for alpha linolenic acid (C18:3, n-3), which showed an inverse association bordering on statistical significance. The findings of cohort studies fit well with hypotheses derived from experimental animal studies. More epidemiological cohort studies that integrate biological markers of dietary fatty acid intake are needed in order to determine the contribution of different types of fatty acids in the etiology of breast cancer.

Adherence to the mediterranean diet and risk of breast cancer in the European prospective investigation into cancer and nutrition cohort study

“…Finally, the MD's favorable fatty acid profile, with a high MUFA to SFA ratio, may be relevant owing to its influence on hormone metabolism and insulin resistance. [41][42][43] However, the combination of the MD components is probably most biologically relevant as when individual components of the arMED score were analyzed separately, few components were significantly associated with BC, consistent with the previous MD-dietary pattern studies. 9,10 The strengths of our study include its prospective design and its large size which allowed us to carry out analyses by menopausal and hormone receptor status.…”

Breast cancer risk and erythrocyte compositions of n‐3 highly unsaturated fatty acids in Japanese

“…46 Using erythrocyte membranes, serum phospholipids or adipose tissue (in the breast or subcutaneous) as biomaterials, risk has consistently been found to be inversely linked with n-3 PUFAs, EPA and DHA, but not 18:3n-3 in both cohort and case-control studies. 27,47,48 In postmenopausal women in cohort studies, decreased risk was associated with higher compositions of n-6 PUFAs and 18:2n-6, but not AA. 26,48 The AA cascade is suggested to play critical roles in tumor development from laboratory studies, [1][2][3]6 but an inverse association with breast cancer risk was unexpectedly here found for erythrocyte composition of AA.…”

Diet and breast cancer

“…[65][66][67][68][69][70][71][72] We also included 1 metaanalysis for milk, biomarkers of fat composition, and green tea. [73][74][75] We also identified 7 nested case-control studies that examined gene-environment interactions.…”

“…[61][62][63][64] Only the ORDET Study conducted in Italy found a statistically significant association between monounsaturated fatty acids measured in erythrocyte membranes and breast cancer (odds ratio [OR] ¼ 5.21; 95% CI, 1.95-13.9) and polyunsaturated fat (OR ¼ 0.34; 95% CI, 0.15-0.79). 63 In a pooled analysis of these studies including 268 postmenopausal cases, high levels of monounsaturated fatty acids were associated with an elevated RR, in particular among postmenopausal women (RR ¼ 2.20; 95% CI, 1.93-2.52) 75 ; this association was restricted to cohort studies and not seen in case-control studies. High levels of n3-polyunsaturated fatty acids (OR ¼ 0.58; 95% CI, 0.52-0.64), n6-polyunsaturated fatty acid (RR ¼ 0.67;95% CI, 0.59-0.75), and linoleic acid (RR ¼ 0.88; 95% CI, 0.78-0.98) were associated with a decreased RR of breast cancer, again, particularly among postmenopausal women (Table 4).…”