Fried potatoes and human cancer

As Beer et al.1 mention in their letter, our case-control studies started before the issue of acrylamide and cancer was first raised.2 Consequently, no information was collected on the browning degree of fried and baked potatoes, as well as on their cooking temperature and duration, that have been related to the concentration of acrylamide in foods.3 In any case, the reliability and validity of any such information would be undefined. Beer et al.1 also indicate that other foods or beverages, particularly coffee, contain smaller amounts of acrylamide but are widely consumed. Consequently, they may be responsible of an important proportion of acrylamide intake. In fact, according to Swiss data, coffee consumption contribute for about a third to a fifth of total acrylamide intake (Swiss Federal Office of Public Health assessment of acrylamide intake by duplicate diet study; www.bag.admin.ch). To provide further information on the issue, we include in Table I published data4, 5, 6, 7, 8, 9, 10 from the same network of case-control studies,2 as well as from other Italian and Swiss case-control studies of breast and colorectal cancers,6, 7, 8, 9 on the role of coffee consumption on the risk of selected cancers. The number of cases and controls included in the studies, odds ratios (ORs) and 95% confidence intervals for selected cancers according to consumption of coffee are given in Table I. As compared to the lowest level of coffee consumption, the ORs for the highest one were 0.6 for oral/pharyngeal and esophageal cancers, 0.8 for laryngeal cancer, 0.8 (in Italy) and 0.4 (in Switzerland) for colorectal cancer and around unity for breast and ovarian cancers. Coffee has been widely studied in relation to cancer risk, and our findings are in broad agreement with most studies on the issue.11 Although coffee is considered as a possible carcinogenic agent to the urinary bladder, an excess risk of other cancers considered has been excluded.11, 12 The inverse relation between coffee drinking and colorectal cancer has also been reported.11, 12 No noticeable differences were observed between Italian and Swiss median values of coffee consumption (about 2 cups/day), computed on the control groups. These values were similar to those reported in the Swiss assessment of acrylamide intake (mean, 2.4 servings/day; www.bag.admin.ch). Coffee is prepared in different ways in Italy and Switzerland, and its acrylamide contents may be different, too. Nevertheless, the ORs computed from the two countries were comparable. The present data confirm therefore that in the populations investigated, coffee drinking was not related to excess risk of selected cancers. Finally, a Swedish case-control study found no considerable impact of various measures of acrylamide intake on risk of large bowel, bladder and kidney cancers.13 Yours sincerely, Conducted with the financial support of the Italian Association for Cancer Research and the Italian and Swiss Leagues Against Cancer. The authors thank Mrs. M.P. Bonifacino for editorial assistance. Claudio Pelucchi, Carlo La Vecchia, Silvia Franceschi, Fabio Levi