The Sense of Smell

     Altered sense of smell is one of the first symptoms found in patients who later go on to develop Alzheimer's disease. Researchers in 2011 found a deficiency of vitamin D to be associated with a loss of the sense of smell. Vitamin D is synthesized from cholesterol and long term deficiency of this nutrient has been suggested as causative in Alzheimer's. Magnesium deficiency has also been associated with loss of the sense of smell.
References:
Lorin, Henry, Alzheimer's Solved, www.booksurge.com, 2005, 63.
Kruse, Ralph and Cambron, Jerrilyn, A possible correlation between vitamin D deficiency and loss of smell: 2 case reports, J. Chiropr Med, Dec. 2011; 10(4):310-315.