RESUMEN
We investigated the effect of fish oil (FO) supplementation, at 4 g/day, on the respiratory performance and blood lipid profile of 32 patients with breast cancer at the beginning of chemotherapy. They were randomized into two groups: control (C) and FO supplemented (S). Both groups underwent three respiratory evaluations and blood harvest (before chemotherapy-Day 0, and 30 and 60 days after supplementation). The S group showed a significant increase in the maximal inspiratory and expiratory pressure (P ≤ 0.05 vs. Day 0) and in the maximum voluntary ventilation (P ≤ 0.05). In the treadmill 6-min-walk test, the S group had a significant increase in the walked distance (P ≤ 0.05). Blood lactate concentration was significantly lower in the S group after 60 days, at rest, when compared to C (P ≤ 0.05). Plasma high-density lipoprotein (HDL) cholesterol concentration remained the same after 60 days of supplementation, while in the C group, it decreased significantly (P ≤ 0.05 Day 0 vs. Day 60). Triacylglycerol (TAG) plasma concentration in the S group was lower when compared to the C group (P ≤ 0.05 Day 60S vs. Day 60). Supplementation with FO caused improvement in the respiratory muscle strength and endurance, ameliorated functional performance, and kept TAG, HDL cholesterol, and lactate plasma concentration at normal levels.