The B vitamin niacin may protect people against Alzheimer's disease and other forms of mental decline, new research suggests. Lean meats, legumes, milk, coffee, and tea are some natural sources of niacin, and flour and cereals are fortified with the nutrient. Earlier studies had suggested that several other B vitamins counter dementia (SN: 3/2/02, p. 141: Available to subscribers at High homocysteine tied to Alzheimer's).
A severe dietary shortage of niacin, or vitamin B3, can lead to pellagra, a potentially fatal illness marked by rashes, diarrhea, confusion, and psychosis. Now rare, pellagra was epidemic in the southern United States in the early 20th century.