In an editorial aptly entitled “Snake Oil in the Supermarket,” the editors of Scientific American argue in their September issue that it’s time Congress gave the U.S. Food and Drug Administration the regulatory authority to make sure that all health claims on packaged foods and beverages are truthful before the products go on grocery shelves.

As it is now, the FDA can only play catch-up, as it did earlier this year when it issued warning letters to 17 food and beverage manufacturers about false or misleading health claims. But meanwhile, the Scientific American editors note, “the snake oil sits on supermarket shelves.”

It’s not this way in Europe, as the editors point out:

Differences between the lenient U.S. system and the more restrictive European system are easily apparent. For instance, visitors to the Web site for Activia (www.activia.com) — a yogurt product from Dannon — will have a very different experience depending on which country they indicate they are from. The U.S. version prominently displays the product’s putative health benefits, asserting that it can “help regulate your digestive system by helping reduce long intestinal transit time.” (It does not say explicitly that the yogurt helps to alleviate constipation, which would be a clear violation of the FDA prohibition of unauthorized claims about specific medical conditions.) The U.K. version, on the other hand, says only that the yogurt contains an exclusive bacterial culture and, like other yogurts, is a source of calcium and vitamin B12.

The European Food Safety Authority has rejected 80 percent of the more than 900 health claims made by food manufacturers since 2006, the year it began requiring rigorous scientific evidence for such claims. Among the rejections were claims about probiotics (the marketing ploy that has made Activia a best-seller in the U.S.) and omega-3 fatty acids. (Food manufacturers love to add omega-3 fatty acids to foods so they can suggest, without any scientific evidence, that their product helps promote brain development.)

These actions — and the publicity around them — may explain why Europeans have begun to turn a deaf ear to the claims of “functional foods,” the term used to describe products manufacturers have altered to provide supposed health benefits.

FDA officials have gotten tougher about functional food claims under the Obama administration, but whether they’ll stay tough remains to be seen. There’s a lot of money involved. As the Scientific American editors point out, functional foods generated $31 billion in the U.S. in 2008 — a 14 percent increase over 2006.

“Industry representatives complain that having to prove claims about the health benefits of food would cost too much and take too long. It’s a lame argument,” write the editors.

“The nation is currently engaged in a struggle against skyrocketing rates of obesity and other diet-related diseases that are among the leading causes of death in the U.S. In this context, unsubstantiated health claims on processed foods are a harmful abuse of science that we should not tolerate.”