Principal investigator Sue M. Penckofer, PhD, RN, and colleagues hypothesize that women who have low levels of vitamin D and receive weekly doses of 50,000 IUs of vitamin D3 will report a better mood than those who receive weekly doses of 5,000 IUs.

"Using a higher dose of vitamin D is potentially an easy and cost-effective way to improve mood," Dr. Penckofer said. "Improving mood may make these women more likely to eat properly, take their medication, get enough exercise and better manage their disease overall."