The first study to assess how weight-loss drugs affect overall human health has found an “eye-opening” effect on the body, researchers say.

An analysis involving nearly two million people linked the drugs to better heart health, fewer infections, a lower risk of drug abuse and fewer cases of dementia.

US researchers also warned that the drugs were “not without risks” and appeared to cause increased joint pain and potentially fatal inflammation of the pancreas.

However, very careful interpretation of the results is required.

Weight loss drugs have exploded in popularity—but a full understanding of what they do to the body is still coming.

“This is new territory,” said Dr. Ziad Al-Ali, a clinical epidemiologist and lead researcher at the University of Washington.

Initially, they were a proven treatment for type 2 diabetes. Then, weight loss was seen as a significant side effect – and Ozempic and Vegovy became household names.

The study used data from 175 US veterans with type 2 diabetes, some of whom were given Ozempic or Vegovy and some more standard drugs, to measure their effect on other diseases.

The new weight loss drugs appear to be a significant boon for heart health, with lower levels of heart attacks, strokes, heart failure and high blood pressure in those who take them.

They also reduce the risk of substance abuse (including alcohol, opioids, and cannabis) as well as schizophrenia, suicidal thoughts, and seizures.

Despite the study being small, and people only taking the drugs for 3.5 years because they are new, it found a 12% reduction in Alzheimer’s disease.

There were also reductions in liver cancer, muscle pain and chronic kidney disease, as well as reductions in bacterial infections and fevers.

On the other hand, people were more likely to have problems with the digestive system. Feeling sick, stomach pain, abdominal swelling, diverticulitis (bulges in the intestines that can be painful) and hemorrhoids were more common on Ozempic or Vegovy.

figure, Published in the journal Nature MedicineLow blood pressure including fainting, headache, disturbed sleep, kidney stones, kidney swelling and pain in bones or joints including arthritis were also seen more frequently.

“It was definitely eye-opening for me to see all these different effects in different organ systems,” Dr. Ally told BBC News.

The explanations for the drugs’ widespread effects are both obvious and mysterious.

Losing excess weight will improve health. For example, low levels of sleep apnea – when breathing stops and starts while sleeping – are thought to be caused by weight gain around the tongue and throat, which can block the airway.

But the drugs appear to be directly changing the behavior of cells and tissues in the body.

Dr. Ally said: “Obesity is bad for the brain. Obesity is bad for mental health. Obesity is bad for the heart. Obesity may be the mother of all diseases.”

Ozempic and Vegovy contain the same active ingredient, semaglutide, in different doses, and mimics the hormone glucagon-like peptide-1.

Released by the gut after eating, GLP-1 travels through the blood and sticks to tiny receptors on the surface of brain cells.

This tells the brain that there is food in the stomach and is why people feel less hungry after eating.

However, receptors that respond to GLP-1 are found throughout the body, including the heart and parts of the immune system.

Dr. Ely said, “It’s very clear that this class of drugs suppresses the reward mechanism (so it’s in the brain), inhibiting the desire to seek alcohol, to seek tobacco, to seek gambling.”

Meanwhile, low levels of inflammation, a red flag for the immune system, can have wide-ranging effects on health.

Dr. Ely said the range of health benefits could strengthen the case for some people using the drugs.

“When you add more benefits for people who are really at risk for these conditions, it’s an added plus,” he said.

But for those whose weight isn’t impacting their health, “perhaps the risk they’re buying themselves really outweighs the benefit”.

However, the study has shortcomings that limit its conclusions.

Most of the veterans were white men, so there were no female-specific effects included, such as improved fertility and the anecdotal phenomenon of unexpected “Ozempic babies”.

And there may be reasons why some were prescribed Ozempic or Vegovy rather than other drugs, which may provide alternative explanations for some of the findings.

Intensive clinical trials have already proven benefits for heart health – and nausea is a known side effect – but other findings need to undergo similarly rigorous testing.

Alzheimer’s disease begins more than a decade before symptoms appear – but this study shows that semaglutide has a protective effect after only a few years.

tests are already running To find out if this effect is real.

Professor Navid Sattar, of the University of Glasgow, said: “Such tests will take us much closer to the truth.”

“Fortunately … many will report over the next one to four years.”

And while “interesting,” he said the findings of this latest study were not strong enough to influence the way the drugs are prescribed.

Professor Sir Stephen O’Rahilly, of Cambridge University, said the study needed to be interpreted “with caution”, but that it provided “useful reassurance” about the safety of the drugs in people with diabetes.

And further studies on other patients were “awaited with interest”.

The “most surprising finding” was an increase in joint pain, as weight loss should reduce pressure on the joints.

But the fact that some cells in the immune system had GLP-1 receptors meant that the effects of these drugs were “somewhat unpredictable” and that while some inflammatory disorders could be reduced, “others could potentially be aggravated.” Were”, Professor O’Rahilly said.