Millions of weight loss drug users could end up facing silent health issue, warns Cambridge professor

Nearly one in 10 adults in the UK - around 1.6 million people - are currently using weight loss drugs.

And over three million people are interested in starting treatment, as patients typically lose between 14 percent and 16 percent of their body weight in the first year.

Despite clear results, many users will put the weight back on if they stop taking the Glucagon-like peptide-1 (GLP-1) drugs, sold under names such as Ozempic, Wegovy and Mounjaro.

Science Focus reports that a Cleveland Clinic study of 460,000 adults taking a GLP-1 drug showed that one in five developed a nutrient deficiency within a year.

Another study by researchers in Mexico showed that 13.6 percent of 480,000 GLP-1 users developed a significant vitamin D deficiency within a year, and around 60 percent weren’t getting enough iron or calcium.

'You might end up with nutritional deficiencies'

Nutrient deficiencies can directly and indirectly cause various heart issues (Getty Stock Images)

Prof Giles Yeo, a neuroendocrinology and obesity expert at the University of Cambridge, told the outlet that 'if you just take the drugs and don’t make any behavioural changes, then you’re going to eat less of a not-great diet'.

“Unless you improve your diet, you might end up with nutritional deficiencies,” Yeo said, noting that a diet full of ultra-processed foods lacks essential nutrients.

The American-British biologist went on to say that deficiencies in vitamin D, vitamin B12, and iron are very common in the UK and that weight loss drugs might only make matters worse.

Long-term nutrient deficiencies can lead to a compromised immune system, organ damage and cognitive decline.

Shortages of specific vitamins and minerals can also result in chronic diseases like heart failure, anemia and permanent neurological issues.

“Those are the deficiencies we already see relatively commonly,” adds Yeo. “Those are only going to be worse [with GLP-1s].

“For many people on these drugs, their diets may not have been great to begin with.”

'Gastrointestinal symptoms, like vomiting or diarrhoea'

Yeo warns that the many weight loss drug users might not be eating healthy enough to begin with (Getty Stock Images)

Dr Steven Heymsfield, director of the Metabolism and Body Composition Laboratory at Louisiana State University, also suggested that your 'doctor should assess you with nutrient blood tests – just like they do for other diseases'.

“When people are treated with GLP-1s, they reduce their food intake – but they also get gastrointestinal symptoms, like vomiting or diarrhoea,” Heymsfield adds.

“If you have diarrhoea, you’re going to lose nutrients through that pathway.

“I think this will become very important. I’ve been telling people, don’t write off GLP-1s as completely safe. You’ve got to wait and see how the deficiencies play into long-term impacts.”

While Yeo says 'we don’t want to overstate and scaremonger, because these drugs are still powerful tools', he notes that a lack of micronutrient intake 'will only become worse when people eat less'.

LADbible Group has reached out to Novo Nordisk (manufacturers of Ozempic and Wegovy) and Eli Lilly (manufacturers of Mounjaro) for comment.