Patients treated for long periods with metformin, a common drug for diabetes, are at risk of developing a deficiency of vitamin B12, which also can worsen over time, according to a study published on Friday.
Netherlands scientists said the results suggest that they should “seriously consider” regular monitoring of vitamin B12 levels during prolonged treatment with metformin to try to prevent deficiency and its effects.
Vitamin A is essential for maintaining nerve cells and red blood cells healthy. It is found in meat, dairy products, eggs, fish, seafood and fortified cereals, and can also be taken as a supplement.
Coen Stehouwer, Medical Center of Maastricht University in Holland, whose study was published in the British Medical Journal, said that the symptoms of B12 deficiency include fatigue, mental changes, anemia and brain damage called neuropathy.
All these symptoms can easily be misdiagnosed as arising from diabetes and its complications or aging, he said. But controlling the levels of the vitamin could help doctors evaluate and treat the real cause of the problem if it occurs.
“Our data strongly justify carrying out routine checks of vitamin B12 levels during prolonged treatment of metformin,” wrote Stehouwer.
Around 246 million people worldwide have diabetes, and rates are expected to grow along with the increase of obesity and overweight. Most have type 2 diabetes, which is linked with poor diet and lack of exercise.
Stehouwer’s team studied 390 patients with type 2 diabetes. A 194 metformin were given three times a day for more than four years and 194 showed them a placebo.
People who had taken metformin, reportedly had a 19 percent lower risk of reducing the levels of vitamin B12, compared with the other group, which almost remained unchanged.
The fall of B12 in the metformin group also persisted and became more evident over time, they added.
“Our study shows that it is reasonable to assume that some patients with low vitamin B12 levels induced by metformin suffer damage,” wrote Stehouwer.
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