Will a dietary intervention affect markers of inflammation and gene expression among breast cancer survivors?

Abstract

Background: Breast cancer (BC) ranks as the most commonly diagnosed cancer amongst New Zealand females. The mortality rate for BC in New Zealand was calculated at 14.4% in 2012. The high mortality rate was reported among women over 45, which reveals an elevated risk among postmenopausal women. Additionally, women previously diagnosed with BC are at high risk of disease recurrence. Weight, inflammation, and genetic biomarkers are commonly prone to adverse changes after BC diagnosis, as reported in many BC research studies. The beneficial consequences of diet and lifestyle changes on the BC prognosis have been detected through several nutritional interventions, which contribute to increasing BC patients’ motivations to adapt their dietary intakes and lifestyles. Extensive focus has been given to a low-fat diet, and current recommendations have considered this dietary pattern the most beneficial. Recent studies have shown the role of the Mediterranean diet on health and chronic diseases, including cancer. Aim: The aim of this research is to identify whether a Mediterranean–style or low-fat diet is a beneficial dietary intervention improving health biomarkers among women with breast cancer in the New Zealand population. Methods: Postmenopausal women following treatment for BC aged 45-76 years, were enrolled in a randomised control clinical trial for six months (n=40). Participants were randomised into three dietary arms, the Mediterranean diet (BC-MED) n=15, the New Zealand low-fat healthy diet (BC-LF) n=12, and the Control diet with their usual diet (n=13). Dietary counselling, education, and electronic recipe books were provided, the former two through monthly face-to-face group sessions with participants in the BC-MED and BC-LF groups. PREDIMED questionnaires and blood samples were collected at baseline and postintervention. Outcome measures included weight, body mass index (BMI), waist circumference, DNA damage, FAMEs levels, and differential gene expression for ATM, BRIP-1, COX-2, and BCL-2 genes. Three-day diaries were collected to assess dietary intakes. Results: Both dietary intervention arms showed a notable decrease in BMI and waist circumference measurements between pre- and post-intervention periods, and the decrease was more pronounced among BC-MED group members (p=0.04 and 0.044, respectively). DNA damage increased amongst all three groups over the course of the study. However, the increase was notably significant in the control group, p=0.02. Gene expression experiments revealed a positive role of the two dietary patterns on the expression of ATM (BC- LF p=0.03) and BRIP-1 (BC-MED p=0.04). Both genes increased over the course of the study among BC-MED and BC-LF arms. The three study groups showed a similar trend in COX-2 gene expression with significant reductions over the course of the study. No change was observed in the expression of BCL-2 among the three groups between baseline and postintervention. Positive trends were observed following the dietary interventions, with significant differences between the two intervention arms and control. There were significant differences in BC-LF group intakes of energy, total fat, MUFAs, PUFAs and fructose (p= 0.013, 0, 014, 0.05, and 0.023, respectively). Cholesterol, protein, and iron intakes were significantly lower among BC-MED, compared with the control group. A significant difference was observed between the two intervention arms and the control group in sugar intake. Conclusion: Both dietary patterns showed a similar beneficial effect improving the biomarkers of inflammation and gene expression. It is apparent that nutritional education and group support play an important role in improving the outcomes of BC survivors.