The American Council for Science and Health (ACSH) has struck another blow for science and sanity. ACSH president Elizabeth Whelan's column yesterday, "Are Foods 'Addictive' ?" laments the tactic of critics of "Big Food" who try to make customers the victim of a conspiracy -- unable to protect their interests (in this case, their health) and, unstated but implied, requiring protection through more government intervention. Not so fast, Whelan says.
The word "addiction" is used very loosely today -- as when people claim they are "addicted" to exercise, chocolate, or the Internet. But addiction is a medical term referring to compulsive, habitual use of a substance that has physiological effects but is not necessary for survival. Addictive substances produce tolerance (meaning that it takes an increasing amount of the substance to produce the desired effect) and physical dependence -- and unpleasant symptoms of withdrawal if use is discontinued. The nicotine in cigarettes fits all these criteria. Food does not.
There have been claims that eating high-fat or high-sugar foods overactivates drug-like substances in the brain called endogenous opioid peptides, leading to food cravings, overeating, and obesity. Food, it is argued, causes an increase in neurotransmitter levels just as addicting drugs do. Some animal experiments may support this idea, but other animal data and human observations do not. If overeating were induced through an opioid-like mechanism, one might expect that opioid-antagonists would be useful in treating overeating, but they are not.
If this sounds familiar to salt-interested readers, it should. More than 20 years ago the Center for Science in the Public Interest (CSPI) conflated salt with cocaine -- "another white powder we snort" -- and labeled salt addictive. This past summer, critics accused "Big Salt" of heading a "conspiracy" as we tried to mobilize resources for a definitive controlled trial of the question of whether the amount of salt in a person's diet is related to their health outcomes, particularly to cardiovascular mortality. We have only observational studies addressing this question to date and they tend to suggest just the opposite of our current policy. Existing studies show no health benefits for reducing dietary sodium and several have identified heightened risk.
Fortunately, over these past 20 years, we've seen serious scientists express revulsion and reject this fear-mongering. The Cochrane Collaboration grew from a core of concerned research scientists at Oxford University to become first the inventor and then a worldwide force for "evidence-based" medicine (now everybody claims their product is "evidence-based" even when they stray from the Cochrane Collaboration's evidentiary rules). Now groups like ACSH and blogs like JunkScience and Junkfoodscience have taken up the watchdog role protecting the public against those who would pervert science to advance their policy objectives.
