Depression in Elderly Women Linked to Vitamin B-12 Deficiency
The other option is that people with vitamin B-12 deficiency are more likely to develop depression. Penninx feels there is no strong evidence for this link.
Jonathan E. Alpert, MD, PhD, of Harvard University, feels differently. "We know that severe B-12 deficiency can lead to neurological symptoms, so it's not implausible to think it can contribute to depression, even though that association hasn't been very strong in previous [studies]," says Alpert, who reviewed the study for WebMD. He notes, however, that the association between the women's actual levels of B-12 and their depression was not very strong in the current study.
Alpert says the study raises the awareness of both physicians and the public that there may be an association between vitamin B-12 levels and depression. "If one is severely depressed, you can have your B-12 levels checked," he says. "However, it won't tell you if taking B-12 would help or change your depression. It tells you that you have a nutritional deficiency that should be corrected."
Noting the 17% incidence of B-12 deficiency in the sample, Penninx agrees. "In this [elderly, disabled] population, depression is common and vitamin B-12 deficiency is common. If there's really a causal link between the two, we should be screening for vitamin B-12 deficiency because it is easily treatable."
Alpert says that the study leaves open some important questions: Would taking vitamin B-12 have prevented the depression, or could it treat the depression? "It's a reasonable speculation," Alpert says.
Says Lon S. Schneider, MD, of the University of Southern California Keck School of Medicine in Los Angeles: "There's absolutely no evidence from the way this study was done that taking vitamin B-12 would prevent depression." What the study does tend to show, he says, is something many physicians already know: that depression in the elderly is often accompanied by other medical problems.
Schneider says that normal doses of vitamins contain enough vitamin B-12 to prevent deficiency, as does a normal diet. People who are deficient in B-12 despite eating well and taking a multivitamin need further evaluation. "Treating B-12 deficiency isn't automatically giving vitamin B-12, because some people may not be able to absorb it," he says.
Alpert says he often recommends that depressed patients take a multivitamin: "One of the core symptoms of depression is that people eat poorly. Often I'll advise people both to try to improve their eating habits in general and take a multivitamin in the hope that will help, along with other treatments. ... It can't hurt."