Note to reporters/editors:
The October 27, 1999, issue of the Journal of the American Medical Association (JAMA) spotlights the health risks of obesity, a major risk factor for heart disease. About 97 million American adults --55 percent of the population-- are now overweight or obese.
The JAMA issue includes three articles on research supported by the National Heart, Lung, and Blood Institute (NHLBI):
"Dietary Fiber, Weight Gain, and Cardiovascular Disease Risk Factors in Young Adults." This report examines the association of fiber consumption to insulin levels and the risk of cardiovascular disease (CVD). The researchers reviewed data from the multicenter NHLBI Coronary Artery Risk Development in Young Adults (CARDIA) Study. The attached statement describes the study of nearly 3,000 black and white young adults in more detail. The authors conclude that high-fiber diets may protect against obesity and CVD by lowering insulin levels. Catherine Loria, Ph.D., Epidemiologist, NHLBI, is available for comment on this study.
"Effects of Intermittent Exercise and Use of Home Exercise Equipment on Adherence, Weight Loss, and Fitness in Overweight Women." The researchers from Brown University and the University of Pittsburgh conducted an 18-month trial with overweight women. They found that, contrary to expectation, advice to exercise in short bouts rather than long bouts did not increase sustained adherence or long-term weight loss. However, the provision of home exercise equipment improved weight loss for those advised to exercise in short bouts compared with those advised to exercise in short bouts but were not provided equipment. Eva Obarzanek, Ph.D., Research Nutritionist, NHLBI, is available for comment on this study.
"Reducing Children's Television Viewing to Prevent Obesity." Dr. Thomas N. Robinson of Stanford University gives results of a trial that involved about 190 elementary school children. Children who received an 18-lesson, 6-month curriculum reduced their body mass index and their TV, videotape, and video game use. They also ate fewer meals in front of the TV. Elaine Stone, Ph.D., Health Scientist Administrator, NHLBI, is available for comment on this study.
Statement from Dr. Claude Lenfant, director, National Heart, Lung, and Blood Institute
High fiber diets may protect against obesity and cardiovascular disease (CVD) in healthy young adults by lowering insulin levels. This is one of the findings of an analysis of participants in the CARDIA Study (Coronary Artery Risk Development in Young Adults), sponsored by the National Heart, Lung, and Blood Institute (NHLBI). CARDIA is a long-term study examining the evolution of CVD risk factors in young adults. The new analysis indicates that fiber consumption is independently and inversely associated with insulin levels, weight gain and other CVD risk factors among healthy, young black and white adults. A report of this analysis, "Dietary Fiber, Weight Gain, and Cardiovascular Disease Risk Factors in Young Adults," appears in the October 27, 1999 edition of the Journal of the American Medical Association (JAMA).
The CARDIA Study, a multi-center, population-based study, is following young black and white adults in four US areas: Birmingham, AL, Chicago, IL, Minneapolis, MN, and Oakland, CA. The new analysis looked at 2,909 of the CARDIA participants over the 10 years between 1985-1986 to 1995-1996. Its purpose was to examine the role of fiber compared to fat and other major dietary components in the development of hyperinsulinemia (an abnormally high level of insulin in the blood), obesity and other CVD risk factors (e.g. hypertension, high blood cholesterol). Insulin resistance and hyperinsulinemia are associated with many of these risk factors.
The health benefits of dietary fiber have been the subject of research interest for some time. Findings from this new study support the positive effects of diets high in fiber. The authors discuss how fiber may affect the risk of CVD. They note that dietary fiber slows the rate of nutrient absorption following a meal, and may reduce insulin secretion. This study's findings need to be confirmed in long-term interventional studies which more fully examine the relationship between dietary fiber, insulin levels, and CVD risk factors.
For more information on CVD risk factors and heart health, visit the NHLBI Web site at www.nhlbi.nih.gov.
To arrange an interview with any of the NHLBI spokespersons listed, contact the NHLBI Communications Office at 301-496-4236.