Freeze a Nerve for Weight Loss? Not So Fast!

Here’s a bit of hype that crossed many screens this week. The Society of Interventional Radiology wants you to know that an experimental procedure to freeze a nerve may “ignite weight loss.” Ignite sounds good, right?

Naturally, health reporters had fun hyping this one. Our favorite: “Freezing the ‘hunger nerve’ could be key to more permanent weight loss.” Never mind that the study was only 90 days. This is catnip for cable news and websites.

Targeting the Posterior Vagal Trunk

This concept is not a terrible idea. Nor is it completely novel. It targets the posterior vagal trunk and freezes that nerve to block hunger signals to the brain.

Three years ago, FDA approved a medical device that works in a related way. The implantable vBloc device can regulate hunger signals on the vagus nerve. Instead of freezing the nerve, it uses electrical signals to block it. The result with that device is an average of about seven percent total weight loss, maintained for at least two years with continued therapy.

But the study of this nerve freezing therapy is so small that, honestly, any conclusions about effectiveness are simply not valid. The study included only ten patients, no controls, and followup for only 90 days. Those 10 patients lost an average of 3.6% of their starting weight. We have no evidence that the effect will last over time. Nor do we know if this procedure has anything more than a placebo effect.

A Pilot Study

The present study is nothing but a pilot study. It was just a limited trial to see if the procedure is safe enough to study further. It wasn’t intended to provide any effectiveness data and it doesn’t. A press release about “igniting weight loss” is pretty hard to defend in light of these facts.

Health reporters should know better. And so should the Society of Interventional Radiology.

Click here for the study abstract and here for the offending press press release.

Developing Nerve Cells, photograph © ZEISS Microscopy / flickr

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March 25, 2018