A Plant Called Thunder God Vine Could Give Us a Miracle Weight-Loss Drug
If there were a magic weight loss pill, Oprah is fond of saying, she would have taken it by now. This coming from a woman who famously wheeled 67 pounds of fat onstage while triumphantly wearing her size 10 Calvin Klein jeans.
If hopeful Harvard Medical School researchers have their way, Harpo Productions might soon be giving out diet pills in place of cars. In a study published last week in Cell, researchers found that after three weeks of treatment with an extract made from the peeled root of the Chinese herb called thunder god vine, obese mice lost nearly half their body weight. The mice in the control group did not lose any weight.
Thunder god vine (Tripterygium wilfordii) has been used in traditional Chinese medicine to treat inflammation and autoimmune diseases for more than 400 years, but researchers have rebranded it with a pharmaceutical-appropriate name: Celastrol. The effect this study suggests the plant may have, however, is related to the far more recent discovery of the appetite-suppressing hormone leptin. Oprah acolytes (and drug companies) freaked out at its weight-loss potential when it was first discovered—but in the last two decades, no one has figured out how to make it work. The authors of the Cell study believe Celastrol can do the trick.
“The message from this study is that there is still hope for making leptin work, and there is still hope for treating obesity,” the senior author, Umut Ozcan, an endocrinologist at Boston Children’s Hospital and Harvard Medical School, said in a statement. If the drug works in humans as it does in mice, he went on, it could be a powerful treatment for “patients suffering from obesity and associated complications, such as heart disease, fatty liver, and type 2 diabetes."
That’s a big if, said Christy Harrison, a registered dietitian with a master’s of public health. “In science, there’s a lot of history of something working in a mouse model and then not working in human trials,” she pointed out.
The study looked at Celastrol’s effects on a few strains of mice. In two of the mice models used in the trials—one of which, Harrison noted, is one of the standard models used in obesity studies—the drug proved ineffective.
“If this mouse model that we consistently use to study obesity doesn’t show improvement on this drug, that’s sort of a red flag that this drug doesn’t work or might not work for humans,” she said.
Even if it does prove effective in humans, would a miracle weight-loss drug have significant public health benefits? Getting healthy isn’t always as straightforward as just losing weight. The Mayo Clinic, after all, advises that drug treatments for obesity and weight problems only work when used in conjunction with diet and exercise, adding that “when you stop taking a weight-loss medication, you may regain much or all of the weight you lost.”
By “may,” they mean you almost most definitely will. Harriet Brown, the author of Body of Truth: How Science, History, and Culture Drive Our Obsession With Weight—and What We Can Do About It reports that 97 percent of dieters regain everything they lost and then some within three years.
“Obesity research fails to reflect this truth because it rarely follows people for more than 18 months,” she wrote recently in Salon. “This makes most weight-loss studies disingenuous at best and downright deceptive at worst.”
This process of losing and gaining, or weight cycling, is linked to heart disease, insulin resistance, higher blood pressure, and inflammation.
“The conventional wisdom is ‘Lose weight and your risk factors will decrease or disappear,’ ” Harrison said. “When in reality, if you lose weight and then put it back on, that’s actually increasing your risk factors.”
The areas of concern are the statistical extremes of the spectrum, which encompass those who are underweight or morbidly obese—the groups with the highest and second-highest mortality risks, respectively. “The quote-unquote overweight category has a lower mortality risk than ‘normal’ weight,” Harrison said.
When new research shows that weight loss is not correlated with health improvements, are we even asking the right questions? Not “Does this diet pill work?” but “Is our nationwide obsession with weight loss about health or aesthetics?” Or, as Brown asks, “Does obesity cause ill health or result from it?”
“There are associations between obesity and chronic diseases,” Harrison said, “but there’s no causation that’s been proved.”
“People can improve their health outcomes without decreasing their weight,” she continued. “The push to get people into the normal weight range is maybe somewhat misguided or doesn’t have a real basis. In many measures, what we consider overweight is actually optimal.”