Diabetes and obesity are growing health concerns worldwide.
A type of medication called GLP-1 receptor agonists, commonly used to treat type 2 diabetes, has gained attention for its ability to lower blood sugar levels and help people lose weight.
However, some experts have worried that these drugs might cause too much muscle loss, which could lead to weakness or frailty.
To better understand how these medications work, researchers from the University of Hong Kong (HKUMed) studied genetic data from over 800,000 people. Their goal was to see whether GLP-1 receptor agonists cause weight loss by reducing fat or muscle.
The study, published in Diabetes, Obesity and Metabolism, found that these drugs lead to more fat loss than muscle loss, making them a useful option for managing weight.
How Do GLP-1 Receptor Agonists Work?
GLP-1 receptor agonists are medications originally developed for type 2 diabetes. They work by mimicking a natural hormone called GLP-1, which helps the body control blood sugar. These drugs:
- Help the body release more insulin to lower blood sugar levels.
- Reduce the amount of another hormone, glucagon, which raises blood sugar.
- Slow down digestion, making people feel full for longer and reducing appetite.
Because of their ability to promote weight loss, these medications have become popular for treating obesity. However, researchers wanted to know whether they mainly reduce body fat or if they also cause too much muscle loss, which could be harmful.
What the Study Found
The research team analyzed genetic data from over 800,000 European individuals using a method called genome-wide association studies (GWAS).
They focused on a specific genetic marker (rs877446) that naturally lowers body mass index (BMI) in a way similar to GLP-1 receptor agonists. By looking at how this genetic variation affects muscle and fat, they could estimate how these medications impact body composition.
The findings showed that people with this genetic variation lost both muscle and fat, but they lost more fat than muscle. Specifically, for every unit of BMI lost:
- Body fat decreased by about 7.9 kg (17.4 lbs)
- Muscle mass decreased by about 6.4 kg (14.1 lbs)
This means that while GLP-1 receptor agonists do lead to some muscle loss, they mainly reduce fat, leading to an overall drop in body fat percentage by around 4.5%.
Why This Matters
Some doctors were concerned that GLP-1 receptor agonists might cause too much muscle loss, which could lead to weakness over time. However, this study suggests that these medications primarily target fat, making them a safe and effective option for weight management.
The study also highlights how genetics can help researchers understand how medications work without requiring large clinical trials. According to Professor Ryan Au Yeung Shiu-lun from HKUMed, this approach helps scientists predict the effects of drugs more quickly and at a lower cost.
Dr. Dipender Gill from Imperial College London also noted that using genetic data can provide valuable insights into how medications impact the body.
What’s Next?
While this study provides strong evidence that GLP-1 receptor agonists are effective for reducing fat, more research is needed to fully understand their long-term effects.
Future clinical studies could explore how to balance fat loss with maintaining muscle strength, ensuring the best outcomes for people using these medications for diabetes or obesity.
For now, these findings support the growing use of GLP-1 receptor agonists as a tool for safe and effective weight loss.
The research findings can be found in Diabetes, Obesity and Metabolism.
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