HOW SWEET IT ISN’T

The August article “Hitting the Sweet Spot” [The Chemistry of . . . Artificial Sweeteners] supports the safety of aspartame and gives credence to the half-truths often espoused by the diet-food industry. While it is true that both aspartame and fruit yield small amounts of methanol, in fruit the methanol is accompanied by ethanol, a natural antidote, and bound to pectin, which renders it unavailable to humans. In aspartame the methanol is unopposed, readily available, and ultimately metabolized to formaldehyde, which cannot be eliminated and hence accumulates in the body. It is not accurate to claim, as does your article, that aspartame “has consistently been declared safe” or that “no concerns have held up under scrutiny.” My own double-blind study on adverse reactions to aspartame, published in Biological Psychiatry, should raise legitimate questions about the safety of this product.

Ralph G. Walton

Professor of clinical psychiatry  Northeastern Ohio Universities

College of Medicine

Rootstown, Ohio

Researchers continue to raise questions about aspartame’s safety. Their concern partly reflects the fact that many studies of sugar substitutes have been funded by companies with a direct interest in the outcome. A 2003 report by Lexchin et al. ( British Medical Journal) found that company-funded drug studies were up to four times more likely to report favorable outcomes than those conducted independently. More than two-thirds of the trials published in major journals are industry funded. We asked D. Eric Walters, professor of biochemistry and molecular biology at Rosalind Franklin University of Medicine and Science, to respond to Walton’s letter. Over the past 14 years he has occasionally served as a consultant to companies in the food industry, including the NutraSweet Company.

—The editors

Walton’s assertion that methanol is “metabolized to formaldehyde, which cannot be eliminated” is incorrect. The methanol formed is converted first to formaldehyde and then rapidly to formic acid. Formic acid is the metabolite primarily responsible for the toxicity of large doses of methanol via acidosis (Jacobsen and McMartin, Medical Toxicology, 1986); at levels encountered in the diet, neither fruit juice nor aspartame produces acidosis. Concerns with Walton’s 1993 study have been pointed out by others (Butchko, Biological Psychology, 1994). Aspartame has been approved by the FDA and other regulatory agencies worldwide. It is considered safe by numerous independent organizations, such as the American Dietetic Association and the American Diabetes Association. Aspartame’s metabolic fate in the body is extremely well understood, and all three products of aspartame metabolism were part of the human diet for thousands of years before aspartame’s discovery.       

  —D. Eric Walters

THE CULTURE RACE

Robert Sapolsky’s article “Are the Desert People Winning?” [August] is an excellent illustration of  why most anthropologists have shied away from overarching generalizations about culture: They fall into the fallacy of dualistic thinking. There are far more ecological possibilities than deserts and forests (coasts, plains, mountains). Moreover, we do not always have good information as to where a culture was “born.” The !Kung appear to have lived in southwestern Africa for at least 20,000 years, but most peoples have migrated from one ecological zone to another over the course of their history. Any theoretical overview worth its salt must account for the dramatic exceptions as well as the statistical means. Buddhism, a classic example of a forest-based religion, has spread successfully and peacefully into desert Mongolia. The relatively peaceful desert-dwelling peoples of central Australia succumbed rapidly to conquest by immigrants from England. Even the spread of Christianity and Islam out of the Near East across Europe and North Africa would hardly have been so successful had not the Romans, originally a forest-dwelling people, literally paved the way for it.

Curtiss Hoffman

Chairman, Department of Anthropology

Bridgewater State College

Bridgewater, Massachusetts

There is virtually no realm of science where a simplistic dichotomy is the final word on a subject, and it is virtually never the case that some pattern comes with no exceptions. Thus, Curtiss Hoffman and I are in complete agreement, a view I tried to make clear in the piece when writing, “Obvious exceptions exist, some quite dramatic.” Hoffman is also correct in believing that one should also be interested in the exceptions. That task, however, tends to be more involved than can be encompassed in a single magazine article—witness the length of Jared Diamond’s landmark Guns, Germs, and Steel in analyzing the related issue of why our planet is dominated by Eurasian culture, an analysis that considers both that overall pattern and the exceptions.  

      —Robert Sapolsky

CREATIONISM, DARWINISM, AND BEYOND

Your August R&D “23 Years Ago in Discover: Creationism” reminds me of Neil Postman’s suggestion (in Building a Bridge to the Eighteenth Century: How the Past Can Improve Our Future) that creationism should be taught in schools—but in a different way than proponents suggest. Postman proposes that students should first be taught about what science is and how it is done and how competing theories are evaluated. Then, and only then, are Darwin and the creationists discussed and the students asked to judge between them as theories. That’s the way to educate students about science. If we merely tell them what to think, we are not teaching; we are indoctrinating.  

Doug Olsen

Oakland, California

STOP THAT PANTHER

A slight error was made in one of the photo captions for “Dr. Mushroom” [July]. The features of the mushroom identified on page 53 as a destroying angel—the white patches of tissue on the cap and the cap’s slight tan-green tinge—are more indicative of the rarely deadly but highly toxic Amanita pantherina, or panther mushroom. Destroying angels, while sometimes darkening with age, don’t display a speckled cap. 

Jonathan LaTour

Salem, Oregon