Abstract
In 2002, we found zinc(Zn)deficiencies in many of the patients visiting our small public clinic in Kitamimaki, a village in Central Japan's Nagano Prefecture. To learn more about the extent of this potential public health problem, we conducted three surveys to study the Zn levels of residents living in the area. These studies were the Kitamimaki Study(n=1431 participants)at Kitamimaki Village in 2003, the Tomi Study(n=1773)at Tomi City in 2005, and the Nagano Study(n=851)at seven clinics widely scattered throughout Nagano Prefecture from November 2005 through March 2006. All these surveys showed that mean Zn levels of the residents were lower than the prevailing, commonly accepted "normal" value for people in Japan. Residents' Zn levels were also lower than those of subjects studied in the 1985 Center for Disease Control NHANES II health survey, in which serum Zn levels were examined from 1976 through 1980 in the United States of America. These findings suggest that we must pay greater attention to Zn deficiency, especially among Nagano Prefecture's elderly, and lead us to speculate that this health threatening tendency may be found on a larger scale nationwide. We discuss possible causes of Zn deficiency, including zinc content in various types of food, eating habits, local soil composition, food additives, medicines, and other factors that may lower the serum zinc level of subjects.
