Mediterranean dietary pattern is associated with lower incidence of premenopausal breast cancer in the Seguimiento Universidad de Navarra (SUN) Project

Abstract

Objective: Due to the growing interest in the role of dietary patterns (DPs) on chronic diseases, we assessed the association between a posteriori identified DPs in the Seguimiento Universidad de Navarra (SUN) Project – a prospective cohort study in a Mediterranean country – and breast cancer (BC) risk. Design: DPs were ascertained through a principal component analysis based on 31 predefined food groups. BC cases were initially identified through self-report or, if deceased, from death certificates or by notification by the next kin. Women reporting BC were asked to provide a copy of their medical report and diagnoses for confirmation purposes. We fitted Cox regression models to assess the association between adherence to the identified DPs and BC risk. Setting: Spanish university graduates. Participants: We included 10 713 young and middle-aged – mainly premenopausal – women. Results: After a median follow-up of 10·3 years, we identified 100 confirmed and 168 probable incident BC cases. We described two major DPs: ‘Western dietary pattern’ (WDP) and ‘Mediterranean dietary pattern’ (MDP). A higher adherence to a WDP was associated with an increased risk of overall BC (multivariable-adjusted HR for confirmed BC Q4 v. Q1 1·70; 95 % CI 0·93, 3·12; P for trend = 0·045). Contrarily, adherence to a MDP was inversely associated with premenopausal BC (multivariable-adjusted HR Q4 v. Q1 0·33; 95 % CI 0·12, 0·91). No significant associations were observed for postmenopausal BC. Conclusions: Whereas a higher adherence to the WDP may increase the risk of BC, a higher adherence to the MDP may decrease the risk of premenopausal BC.

An updated systematic review and meta-analysis on adherence to mediterranean diet and risk of cancer

“…Alcohol predominately in the form of red wine represents the most controversial ´food group´ within the context of the associations of the MedDiet on cancer. Increased ROS synthesis, suppressed anti-tumour immune response as well as metabolization of ethanol into DNA-damaging acetaldehyde may all explain the positive association between alcohol intake and cancer [125,126]. The 3rd WCRF report indicated that there is a "convincing" grade of evidence for a positive association between alcohol intake and risk of upper aerodigestive, breast, colorectal or liver cancers, irrespective of the type of drink [10].…”

“…Differences between scores concerned mostly cut-off points for moderate alcohol consumption and a way of handling healthy fat intake. Five added studies derived MedDiet scores from principal component analysis [113,114,116,122,125].…”

Dietary patterns and breast cancer risk, prognosis, and quality of life: A systematic review

“…Studies on the effects of a Mediterranean diet, characterized by high intakes of fish, vegetables, beans, boiled potatoes, fruit, olives and vegetable oils, and a low intake of fruit juice, were carried out in the United States (n = 3), China (n = 2), Spain (n = 1), and Italy and Switzerland (n = 1), while studies of 'prudent' dietary patterns similar to a Mediterranean-style diet (34) have been carried out in China (n = 1), Spain (n = 1), and Poland (n = 2). A higher score for a Mediterranean diet was negatively related to BC in some studies (21-23, 28, 35, 36), especially after the menopause (37)(38)(39), while the Spanish study and two studies in the United States showed only a weak or no correlation (31,33,39). Prudent dietary patterns were associated with a lower risk of BC in one study (34), but had no observable effect on BC in the Spanish study (37)(38)(39).…”

“…A higher score for a Mediterranean diet was negatively related to BC in some studies (21-23, 28, 35, 36), especially after the menopause (37)(38)(39), while the Spanish study and two studies in the United States showed only a weak or no correlation (31,33,39). Prudent dietary patterns were associated with a lower risk of BC in one study (34), but had no observable effect on BC in the Spanish study (37)(38)(39).…”

“…The effects of a Western dietary pattern were investigated in Iran (n = 1), Spain (n = 2), and Mexico (n = 1). This pattern (high intakes of fat, sugar products, and red and processed meat) increased women's risk of BC in some studies (24,29,(37)(38)(39). However, some studies found a positive correlation between a Western diet and the risk of invasive ductal carcinoma of the breast, but no significant correlation with the risk of invasive lobular carcinoma (55,56).…”