Dietary changes in the first 3 years after breast cancer diagnosis: a prospective Chinese breast cancer cohort study

BACKGROUND: The diagnosis of cancer can motivate patients to change their dietary habits. Evidence on changes in dietary intake before and after breast cancer diagnosis in Chinese women has been limited. PATIENTS AND METHODS: In an ongoing prospective cohort study which involved 1,462 Chinese women with early-stage breast cancer, validated food frequency questionnaire was used to assess prediagnostic dietary intake (using questionnaire to recall dietary intake before diagnosis, which completed at baseline, ie, 0–12 months after diagnosis) and postdiagnostic dietary intake at 18-month and 36-month follow-ups after diagnosis. This study quantitatively compared dietary intake across three time points before and after breast cancer diagnosis. RESULTS: Breast cancer patients significantly and continuously increased vegetables and fruits consumption, from 4.54 servings/day at prediagnosis to 5.19 and 5.59 servings/day at 18-month and 36-month follow-ups postdiagnosis, respectively (each compared to baseline, P<0.001). At 18-month follow-up postdiagnosis, the intake of whole grains, refined grains, eggs, and nuts increased significantly (P<0.001, each). Conversely, the consumption of red meat (P<0.001), processed meat (P<0.001), poultry (P<0.001), dairy products (P<0.001), soy foods (P=0.024), sugar drinks (P<0.001), and coffee (P<0.001) decreased significantly. Compared with prediagnosis diet, the assessment at 36-month follow-up postdiagnosis observed similar dietary changes. The magnitude of changes between two postdiagnosis dietary assessments was much smaller than comparisons made between each of these time points with that of prediagnosis intakes. Postdiagnosis changes in dietary intake occurred in parallel with changes in macronutrients, vitamins, and minerals. CONCLUSION: Chinese breast cancer patients reported significant and long-term changes in dietary intake after cancer diagnosis, which was in line with current dietary recommendation. The present findings suggested that a cancer diagnosis might be a stimulus for patients to take up health-protective changes; health care professionals should consider this as a window of opportunity to educate patients on healthy lifestyle. Further follow-up of this cohort would enable clinicians to determine whether such dietary changes could improve long-term outcomes.