The sunshine vitamin could offer women with Type 2 diabetes a brighter outlook on life and help them better manage their often-trying disease, according to a recent pilot study by Loyola University researchers.
The study, which followed 46 women, found that vitamin D significantly improved their moderate depression. The researchers are starting a larger study on the findings.
In the pilot study, the women, who were an average age of 55 and had an eight-year history of diabetes, were given 50,000 International Units of vitamin D weekly over six months. Before they started taking the study's doses of vitamin D, the women had only 18 nanograms per milliliter (ng/ml) of the vitamin in their blood, which is considered insufficient. A vitamin D level of less than 20 ng/ml is considered deficient, 21-29 insufficient, greater than 30 sufficient and target levels are now 40 to 50 ng/ml, Penckofer said.
Sue M. Penckofer, lead author of the study, said the women in the study showed about the same rate of mood improvement as patients who took part in her eight-week behavioral modification therapy program.
"The sad thing about mental health in this country is a lot of people don't get coverage for it or don't have access to it," said Penckofer, a professor at Loyola's Niehoff School of Nursing. "Maybe it [vitamin D supplementation] could prevent relapses with depression."
The pilot was funded by the Chicago Center for Diabetes Translation Research at the University of Chicago and the results presented at a recent conference of the American Diabetes Association. The study's co-authors are Todd Doyle, Patricia Mumby, Mary Byrn, Dr. Mary Ann Emanuele and Dr. Diane Wallis.
People with diabetes are twice as likely to be depressed as those without, according to the Centers for Disease Control and Prevention. Penckofer noted that more than 25 percent of women with diabetes are depressed and have worse health outcomes than other diabetics.
The new study will follow 180 women with Type 2 diabetes who have insufficient levels of vitamin D and a placebo group. Patients will receive vitamin D supplementation weekly, and their blood will be checked for vitamin D levels at regular intervals. They will be evaluated for depression symptoms, blood pressure and their ability to manage their disease.
This $1.49 million study is being funded by the National Institute of Nursing Research at the National Institutes of Health. Working with Penckofer as co-investigators are Dr. Angelos Halaris, Ramon Durazo, Dr. Pauline Camacho and Joanne Kouba.
Dr. E. Sherwood Brown, an expert on depression at the University of Texas Southwestern Medical Center at Dallas, said the study showed promise and was a "particularly interesting twist on combining depression and diabetes."
Brown was senior author of a study published in Mayo Clinic Proceedings in 2012 that found a link between insufficient levels of vitamin D and depression.
"I think they're doing a great study that will advance the field, but we don't really understand all the mechanisms," said Brown, a professor of psychiatry. "The idea of increasing the levels of vitamin D and improving depression to then lead to the secondary effect on diabetes control and other health-related outcomes is certainly interesting."
Brown said one challenge would be to discover whether vitamin D actually improved depression or whether participation in the study boosted mood. He also said the study would need to show that the supplement was actually helping depression rather than diabetes.
"It is possible that depression won't improve, but diabetes outcomes may improve due to a direct effect of vitamin D on diabetes," he said.