Recent Blog Articles

Taking up adaptive sports

Cutting and self-harm: Why it happens and what to do

Discrimination at work is linked to high blood pressure

Pouring from an empty cup? Three ways to refill emotionally

Give praise to the elbow: A bending, twisting marvel

Sneezy and dopey? Seasonal allergies and your brain

The FDA relaxes restrictions on blood donation

Apps to accelerometers: Can technology improve mental health in older adults?

Swimming and skin: What to know if a child has eczema

A muscle-building obsession in boys: What to know and do
Heart Beat: Diabetes drug interferes with vitamin B12
Metformin (Glucophage, generic) is a first-line drug for treating type 2 diabetes. It limits the amount of sugar the body absorbs from food, cuts down on the amount of sugar the liver produces, and makes muscles and other tissues more sensitive to insulin, the hormone that ushers blood sugar into cells. Although metformin is very safe, one-third of those who take it develop low levels of circulating vitamin B12. The body needs this vitamin to make new red blood cells and to keep nerve cells healthy. In a Canadian study, diabetics taking metformin had half the blood levels of vitamin B12 of those who weren't taking metformin; 31% of the metformin takers had levels significantly below normal. They also had more advanced neuropathy, the degeneration of nerves that often accompanies diabetes (Diabetes Care, January 2010).
Older people are prone to vitamin B12 deficiency because aging reduces the body's ability to absorb this vitamin from food; adding metformin can worsen the problem. A severe deficiency can lead to anemia and confusion, and sometimes masquerades as dementia or Alzheimer's disease.
To continue reading this article, you must log in.
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.
- Research health conditions
- Check your symptoms
- Prepare for a doctor's visit or test
- Find the best treatments and procedures for you
- Explore options for better nutrition and exercise
I'd like to receive access to Harvard Health Online for only $4.99 a month.
Sign Me UpAlready a member? Login ».
Disclaimer:
As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
Free Healthbeat Signup
Get the latest in health news delivered to your inbox!