I noticed my husband started to walk like a drunken sailor without a drop to drink. A visit to the doctor revealed a vitamin B12 deficiency. With supplementation, he's back to normal. Can you explain this to me?

The way your husband was walking is a gait pattern called ataxia. The person has enough strength to walk normally but is unsteady because he is unaware of limb position. It appears to be related to loss of position sensation from the feet.

In older adults this type of ataxia is linked with vitamin B12 deficiency needed for normal neurologic function. Degeneration of the spinal cord can occur with subsequent ataxia and other symptoms.

A loss of gastric acid or other gastrointestinal problems that impair the release of B12 from food can result in vitamin B12 deficiency. B12 comes from animal sources so strict vegetarians are also at greater risk for deficiency.

Symptoms can be irreversible unless treated early. Treatment is with Vitamin B12 supplementation. Monthly injections of B12 are the standard form of administration. Vitamin B12 is also available orally in pill form or by nasal spray. Periodic follow-up with your physician is important.