… Fuzzy mindedness could signal a vitamin or hormone deficiency, especially if you're also feeling unusually tired. For example, hypothyroidism – too-low levels of thyroid hormone – could be to blame, says Robert Orford, MD, consultant at the Mayo Clinic's Preventive Medicine Division in Scottsdale, AZ. "If there's a deficiency in thyroid hormone, metabolism slows, which reduces blood flow and cellular function in various parts of the brain," Dr. Orford says.
MSN.com, by Gini Kopecky, 12/11/11
Additional coverage: Yahoo! Shine