The serum levels of vitamin A (retinol), vitamin E (alpha-tocopherol), cholesterol and triglycerides were studied in a group of 40 women who had been diagnosed as having breast cancer, and they were compared to the levels found in a group of 30 healthy women. Our results indicate that the only statistically significant differences found were those involving retinol, with the cancer group showing significantly lower levels (p < 0.05). These parameters have been examined in the context of the frequency of consumption of foods rich in these vitamins and lipids. A higher frequency of consumption of foods rich in the studied vitamins does not appear to cause significant differences in their blood levels. The differences in specific dietary habits have also been analyzed, with both groups showing a high percentage of people who consume skimmed milk and a majority who use olive oil. Nevertheless, the consumption of fruits and vegetables is lower in the cancer group than in the control group.