1. Your numbers are low: 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.
Prevention, by Gini Kopecky Wallace, 02/20/2012