Effect of major dietary modifications on immune system in patients with breast cancer: a pilot study

A pilot study was conducted to evaluate the effect of diet on immune function in nine premenopausal, post-therapy patients with breast cancer. The patients were instructed on following the American Cancer Society dietary guidelines and were told to do so from day 0 to day 28. These guidelines recommend a high-fiber, low-fat diet. On day 29, the patients continued the diet but included fish high in omega-3 fatty acids until day 56. Twenty-four-hour urine and blood samples, and 3-day diet records were obtained on days 0, 28, and 56. The following parameters were monitored: lymphocyte subsets, T-cell function (proliferation and cytolytic response), and urinary prostaglandin E2 (PGE2). Results throughout the study suggested a benefit from decreasing dietary fat intake, and increasing fish intake. Helper T-cell (CD4) percentage increased from day 0 to days 28 and 56 (P = 0.048). Cytotoxic/suppressor T-cell (CD8) percentage decreased from day 0 to days 28 and 56 (P = 0.002). The CD4/CD8 cell ratio increased by days 28 and 56 (P = 0.0004). The proliferation of CD4 cells increased from day 0 to days 28 and 56 (P = 0.005). Significant changes were not found in the cytolytic activity of T cells, natural killer cells, total T and B cells, or urinary prostaglandin E2. Results suggest that patients with breast cancer may benefit from following American Cancer Society dietary guidelines and consuming cold-water ocean fish.