I want to commend Bette Hileman on her excellent summary of acrylamide in food (C&EN, Aug. 14, page 43). She has ably captured the major points of scientific and policy debate attending acrylamide's surprise discovery in food in April 2002. I have been deeply involved in these scientific and regulatory issues since then and wish to add some important points of clarification.
While I agree with her that "no one knows for sure whether the levels in food are dangerous for humans," she omitted that six dietary epidemiologic studies on acrylamide have been published, and none shows any increased risk of cancer. There has even been a reported suggestion in a few of these studies of a reduced risk for colorectal cancer at higher acrylamide intake levels. Additionally, those studies that looked at the risk of specific foods have shown no demonstration of increased risk for foods known to contain higher acrylamide levels. It is ironic that the same authorities that dismiss negative epidemiology studies are often the first ones to raise alarms when even one study shows an apparent positive cancer association with some dietary intake factor.
The included Food & Drug Administration table of the "Top 20 Sources" of acrylamide in the U.S. diet does not capture the important fact that acrylamide has been detected in foods making up almost 40% of the total daily caloric intake of adults. These same foods account for significant portions of the acceptable daily intakes of many nutrients, including essential vitamins and minerals. Thus, nutrient requirements would be expected to be compromised if consumers decided to simply avoid acrylamide-containing foods, including nutritious breads, cereals, and other rich sources of essential nutrients. Consequently, FDA continues to advise consumers to eat a balanced diet and to choose a variety of foods.
Turning to California Proposition 65, current Proposition 65 regulations require that a cancer warning be given when the average consumption of a food product exceeds 0.2 µg of acrylamide per day. This warning level would be triggered for almost all foods with even barely detectable acrylamide levels (the 40% of our foods noted above), not just those snacks targeted by the California attorney general's suit. Surely something must be wrong with Proposition 65's science and regulations if California wants its consuming public to be warned away from this many foods.
Two critically important toxicological considerations about acrylamide have received little attention to date: First, the relevance of the observed rodent tumors (seen in two high-dose drinking water bioassays) to humans; and second, the metabolic and toxicologic consequences of very low human acrylamide intakes. Consequently, the determination of dietary acrylamide's real risk to humans must await the completion of important ongoing studies and the subsequent evaluation of the entire health effects database using a scientifically defensible risk assessment approach, not just the knee-jerk employment of linear extrapolations based on extremely high dose rodent studies.
Laguna Niguel, Calif.