Time for Ozempic to walk the plank? 

Top dietitians in Australia this week are waving a red flag about an unforeseen impact of the GLP-1 class of weight-loss drugs, including Ozempic, Wegovy and Mounjaro. 

In a new systematic review of existing research, led by professor Clare Collins of the Newcastle School of Health Sciences in New South Wales, Australia, it appears that very few global trials of the drugs have taken into consideration what and how much patients are eating while using them. 

This, experts have said, means many patients have been functionally malnourished — sometimes developing serious vitamin deficiencies like scurvy.

Part of what makes these drugs so effective for weight loss and diabetes management is their ability to suppress appetite. But not eating, or not eating enough of the right stuff, is simply not a sustainable path forward for anyone, regardless of whether or not they’re using a GLP-1. And dietitians are calling for more oversight.

“A reduction in body weight does not automatically mean the person is well-nourished or healthy,” Collins told the Australian Financial Review. “Nutrition plays a critical role in health and right now it’s largely missing from the evidence.”

One high-profile case of scurvy arose last year, when British pop singer Robbie Williams was diagnosed with what he called a “17th century pirate disease.” He had been open about his use of injectable weight loss medication for years, and has also spoken anecdotally about its potential connection to his degrading eyesight.

While scurvy — a vitamin C deficiency that can be deadly if untreated — posed a regular threat to sea-farers of yore, these days, it’s quite rare, especially in the US, UK and Australia, where nutrient-dense diets are common.

But now, Collins told the AFP that she’s heard of several doctors reporting cases of scurvy. “Let’s not wait for every GP to see a case of scurvy, let’s get on the front foot and link these GP chronic management plans to a dietitian referral,” she said.

According to the AFP, use of a GLP-1 has also in rare cases been linked to thiamine deficiency, which can cause neurological and cardiovascular disease.

Only two of the more than 40 studies Collins and her team analyzed for this report — spanning controlled trials of weight-loss drugs that involved more than 50,000 participants over the course of 17 years — actually measured patients’ diets. This concerned her.

“Only one [trial] had published what people ate. We wrote to all the authors, and got data from one more trial. This is being missed,” she said. “It does not give you an opportunity on how it might impact their dietary intake. We know there are a lot of side effects. For such an expense it is a marked miss.”

In addition to common side effects like nausea and dizziness, other potentially serious GLP-1 side effects have come to light in recent months, from eating disorders to certain rare cancers. 

Don’t toss all weight-loss drugs overboard just yet, though. Ozempic and Wegovy, brand names for semaglutide, still have their benefits on a case-by-case basis, and more research is regularly coming out about the best applications for the drugs.

Some longevity doctors are even pointing to microdoses of semaglutide as a potential anti-aging tool, citing decreased risk of heart attack, stroke and metabolic complications.

In 2024, the National Institute of Health released a poll showing that 12% of US adults had used a GLP-1. Among adults with diabetes, the number more than doubled, according to the CDC. 

With stats like that, these drugs aren’t going anywhere soon. But without strong dietary guidance and support, more patients will feel marooned by their providers.

Dietitians Australia chief executive Magriet Raxworthy told the AFP that personalized medical nutrition therapy from a dietitian is essential for GLP-1-users to prevent more cases of scurvy and other severe complications.

Without it, “people may struggle to meet their nutritional needs and can be placed at risk of significant muscle loss, bone density loss, micronutrient deficiencies and disordered eating behaviors,” she said.

“In this case, it’s clear — medication alone does not deliver sustainable health outcomes.”

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