January 3rd, 2012 

National Health and Nutrition Examination Survey

written by Michael O’Leary

People with type 2 diabetes who control their blood glucose with metformin are more likely to be deficient in vitamin B12 than those who don’t use metformin.

That’s the finding of a survey of more than 8,000 adults, 6,867 of whom have type 2 diabetes conducted by the National Health and Nutrition Examination Survey. The survey results appear online Dec. 16 in the journalDiabetes Care.

The survey involved U.S. adults 50 years or older, and included 1,621 people without diabetes and 6,867 people with type 2 diabetes. Participants had to have been diagnosed with type 2 diabetes after age 30 and had not started insulin therapy within a year of being diagnosed. Vitamin B12 deficiency was defined as concentrations of the vitamin in the blood below 148 pmol/L, and borderline deficiency was between 148 and 221 pmol/L. (Published site)

Vitamin B12 is one of a family of vitamins essential for good health. Vitamin B12 is important for brain and nervous system function, and is involved in the formation of blood.

When the researchers, led by Lael Reinstatler of the Rollins School of Public Health, Emory University, Atlanta, Georgia, analyzed the survey data, they found that 5.8 percent of those with diabetes who were using metformin had a vitamin B12 deficiency. That compared to 2.4 percent of those who were not using metformin, and 3.3 percent of those without diabetes.

The bad news is that they also found that taking vitamin B12 supplements did not overcome the deficiency in those with type 2 diabetes while taking the vitamin supplements among those without diabetes resulted in a two-thirds reduction in deficiency. The good news is that apparently 94.2 percent of type 2 diabetes patients did not have the vitamin B12 deficiency.