The relationship between breast cancer and polyunsaturated fatty acids
The article entitled ''Fatty acid composition of phospholipids in erythrocyte membranes and risk of breast cancer" by Zaridze et al. (1990) was of interest to all the scientists involved in the study of fat and breast cancer (BC) and especially of lipid peroxidation, anti-oxidants and BC. This study showed that low levels of polyunsaturated fatty acids (PUFA) in erythrocyte membranes are associated with breast cancer. However, the analysis would have been more persuasive if mean values and relative risk had been adjusted for age. Also, the relevance to the analysis of seasonal changes is not clear.
In the first part of the "Discussion", the authors consider the relationship of diet and BC. They state that the fatty acid (FA) composition of erythrocyte membrane is a fairly good marker of recent fat intake; consequently, the assumption that high fat intake is associated with decreased cancer risk cannot be warranted by this cross-sectional study. The authors, indeed, quoted a prospective study to support their explanation. Moreover, contrarily to what is alleged, most epidemiological case-control studies investigating the relationship of diet and BC used retrospective data on long-term nutritional habits collected by a diet history questionnaire (