A prominent Canadian researcher is facing claims that data in his widely reported study of a nutritional supplement's effects on thinking and memory in the elderly are so flawed as to have no real value. The scientist, Dr. Ranjit Kumar Chandra, is internationally known for his many contributions to the field of nutrition, and his work has been widely cited in professional and lay publications alike, including The New York Times. Scientific journals and three independent American scientists have raised questions about the validity of Dr. Chandra's findings, saying the study, published in September 2001 in the journal Nutrition, has...