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People who are on the anti-diabetes drug metformin may be piling up some unconnected health benefits. Studies carried out by medical scientists on metformin, a drug that three out of Indian four diabetics take regularly, have been springing many surprises of late. Apart from helping maintain blood sugar levels, the drug has been protecting our hearts and livers as well as shielding us from many cancers, studies by different research groups reveal.
The latest study, reported early last month, has gone a step ahead and shown that the drug may even help people to live longer.
The study, by a team of researchers led by Craig Currie of Cardiff University in the UK, tried to compare the survival rates of diabetics who take metformin with those who take sulphonyurea, another common anti-diabetic drug.
Surprisingly, the study reported in the journal Diabetes, Obesity and Metabolism, showed that people who take metformin may even live longer than non-diabetics who do not take the drug.
According to the scientists, patients treated with metformin have a small but statistically significant improvement in survival rates compared to controls who are non-diabetic. Those treated with sulphonylurea had a consistently reduced survival rate compared with healthy volunteers. While metformin works by reducing the production of glucose in the liver, sulphonylurea, an equally effective drug, enhances the production of insulin, the hormone that helps muscles and cells to take up more glucose.
Currie, a researcher with the university’s School of Medicine, says the findings actually surprised them because it is capable of giving prophylactic benefits to people who do not suffer from type 2 diabetes. “It opens up many potential opportunities in both non-diabetics and in those with type I (or juvenile) diabetes,” Currie told KnowHow.
But this result should be taken with a pinch of salt because there are certain inherent limitations in the study despite the fact that it involved data from 1,80,000 people, says Dr Nihal Thomas, head of internal medicine at the Christian Medical College (CMC), Vellore.
Dr Thomas too agrees that scientists have been of late stumbling upon several additional benefits of metformin, a drug which has been in use for more than half a century.
“Many benefits of metformin have been known for the last three-four years,” says Dr Thomas. They are due to different actions of the molecule, he says. “In certain cancers, metformin reduces the rate of mitosis (division of cells) and thus prevents the production of extra cells. In myocardial cases it accelerates the production of an enzyme called AMP kinase, which offers cardiovascular protection,” says the CMC doctor.
Nowadays, metformin is also a first-line drug for treating obesity. It has become the drug of choice after the withdrawal of two other anti-obesity drugs, says Dr Thomas. “It is not only cheap but also effective in treating obesity. Many doctors are now prescribing it.”
In another important study by a team of Belgian scientists in June this year unravelled the cellular mechanisms that help metformin to delay ageing and increase lifespan.
Working with roundworms, which have remarkably similar yet simpler genome than humans, scientists from the KU Leuven showed that metformin increases the production of a number of toxic oxygen molecules called reactive oxygen species (ROS) in the cells, and this, surprisingly, increases cell robustness and longevity in the long term.
ROS is actually a byproduct of the energy production process within cells. They are produced when mitochondria — producers of power in cells — convert energy into forms that can be used by cells.
While these molecules are harmful because they can damage proteins and DNA and disrupt normal cell functioning, a small dose can actually do the cell good. “As long as the amount of harmful oxygen molecules released in the cell remains small, it has a positive long-term effect on the cell. Cells use reactive oxygen particles to their advantage before they can do any damage,” says Wouter De Haes, postdoctoral researcher at KU Leuven, who is the first author of the paper that appeared in the journal Proceedings of the National Academy of Sciences in June.
“Metformin causes a slight increase in the number of harmful oxygen molecules. We found that this makes cells stronger and extends their healthy lifespan,” he says in a statement.
Another recent experiment in people suffering from liver cirrhosis has questioned the on-going practice of discontinuing metformin once diagnosis is done.
Metformin is usually discontinued once cirrhosis is diagnosed owing to concerns about the increased risk of adverse effects associated with this treatment in patients with liver impairment.
Cirrhosis is scarring of the liver caused by liver diseases such as chronic viral hepatitis, chronic alcohol abuse and non-alcoholic fatty liver. This condition is the consequence of damage done to the liver over many years. As cirrhosis progresses, more and more scar tissue forms, impeding proper liver functions.
The study — reported in the journal Hepatology in June by researchers at Mayo Clinic in Rochester, in Minnesota — showed that patients who continued taking metformin after cirrhosis diagnosis had a significantly longer survival rate than those who stopped taking the drug.
“Our study suggests that metformin can be used safely in cirrhotic patients. Diabetic patients who take metformin to control their blood sugar levels can continue taking metformin after cirrhosis diagnosis, if there is no specific contradiction,” says Mayo Clinic gastroenterologist Dr Lewis Roberts, a senior author of the study.
Is metformin a wonder drug? The jury is still out.