Methylxanthine, alcohol-free diet and fibrocystic breast disease: a factorial clinical trial.

A controlled clinical trial was conducted in Milan, Italy to analyze the effects of methylxanthine (MTX) and alcohol abstention on signs and symptoms of fibrocystic breast disease. A total of 192 women with a clinical and thermographic diagnosis of fibrocystic breast disease were randomly assigned to four groups on the basis of two-by-two factorial design: (1) abstention from MTX-containing beverages, (2) abstention from alcohol, (3) abstention from MTX and alcohol, and (4) no dietary advice. Of these, 162 (84.4%) were followed up at approximately 6 months. No statistically or clinically significant effect of a MTX- or alcohol-free diet was observed on signs and symptoms of fibrocystic breast disease. On the basis of the results of the present and previous randomized controlled studies, it thus appears possible to exclude that abstention from coffee and other MTX-containing beverages can substantially reduce signs and symptoms of fibrocystic breast disease within a few months.