Effects of Exercise and Nutrition on Memory in Japanese Americans With Impaired Glucose Tolerance
- G. Stennis Watson, PHD12,
- Mark A. Reger, PHD12,
- Laura D. Baker, PHD12,
- Marguerite J. McNeely, MD, MPH3,
- Wilfred Y. Fujimoto, MD3,
- Steven E. Kahn, MB, CHB34,
- Edward J. Boyko, MD, MPH35,
- Donna L. Leonetti, PHD6 and
- Suzanne Craft, PHD12
- 1Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, Washington
- 2Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington
- 3Department of Medicine, University of Washington, Seattle, Washington
- 4Research and Development Service, VA Puget Sound Health Care System, Seattle, Washington
- 5Epidemiologic Research and Information Center, VA Puget Sound Health Care System, Seattle, Washington
- 6Department of Anthropology, University of Washington, Seattle, Washington
- Address correspondence and reprint requests to G. Stennis Watson, PhD, VAPSHCS, S-182-GRECC, 1660 S. Columbian Way, Seattle, Washington 98108. E-mail: gswatson{at}u.washington.edu
Type 2 diabetes, impaired glucose tolerance (IGT), and associated hyperinsulinemia increase the risk for impaired verbal memory (1–3). In rodents, insulin resistance adversely affects brain structures that support memory (4). In humans, pharmacologic management of diabetes improves cognitive functioning (5,6). Weight loss and exercise decrease the incidence of diabetes (7,8). This study examined whether endurance exercise and dietary fat restriction would improve cognition in Japanese American adults who have a high risk for IGT and type 2 diabetes (9).
RESEARCH DESIGN AND METHODS
Adults with IGT were recruited from the Japanese American Community Diabetes Study. Screening and diagnostic procedures have been described previously (10). Participants (15 active and 13 control) completed cognitive testing at baseline and at 6 and 12 months. Treatment was randomly assigned, and groups were equivalent with respect to baseline age ([mean ± SD] active 58.0 ± 9.7 and control 60.6 ± 9.0 years), BMI (active 24.7 ± 3.2 and control 26.7 ± 4.3 kg/m2), Vo2max (active 29.5 ± 7.1 and control 27.4 ± 5.6 ml · kg−1 · min−1), and 2-h oral glucose tolerance test (OGTT) glucose levels (active 9.4 ± 1.1 and control 9.4 ± 0.9 mmol/l).
Active participants followed an American Heart Association step 2 eucaloric diet (total calories <30% fat, <7% saturated fat, 55% carbohydrate, and 15% protein). An exercise physiologist supervised walking or jogging on a treadmill three times weekly for 1 h. …
