Posted by the NCSF on April 25th, 2011
Diet High in Fiber Associated with Decreased Disease
According to Northwestern School of Medicine high fiber content in the diet may be even more important than once thought. Certainly the association between fiber content in the diet and reduced risk for cardio-metabolic disease and some cancers speaks to its importance. In the new study presented at the American Heart Association’s - Nutrition, Physical Activity and Metabolism/Cardiovascular Disease Epidemiology and Prevention Conference, authors demonstrated that fiber intake was associated with lifetime risk for cardiovascular disease. The study found that for adults between the ages of 20 and 59 years old those with the highest fiber intake had a significantly lower estimated lifetime risk of cardiovascular disease (America’s top killer) compared to those with the lowest fiber intake. According to Donald M. Lloyd-Jones, MD, chair of the department of preventive medicine at Northwestern University Feinberg School of Medicine, it has been know that “high-fiber diets can help people lose weight, lower cholesterol and improve hypertension. The results of this study make sense because weight, cholesterol, and hypertension are major determinants of your long term risk for cardiovascular disease.” According to the American Heart Association, a high fiber diet is one that is made up of at least 25 grams of fiber per day. A caveat to the recommendation is the fiber should be from naturally occurring whole food sources like those found in fruits and vegetables, not from supplements, processed fiber bars, and drink mixtures. The lead author Hongyan Ning, MD examined the data provided from a recent NHANES providing a sample of 11,000 adults. To determine lifetime risk for CVD, Ning included diet, blood pressure, total cholesterol, smoking status, and history of diabetes in his analysis. Interestingly, it was the younger populations that demonstrated the greatest effects from the high fiber diet as those individuals over 60 did not experience the same reduction in risk as those between 20 and 59. “It’s possible that the beneficial effect of dietary fiber may require a long period of time to achieve, and older adults may have developed significant risk for heart disease before starting a high fiber diet” said Ning. This certainly suggests the sooner one starts a healthy lifestyle the greater the impact on lifetime health. (Northwestern University News Center, March 2011)
It is well known that daily exercise is important for preventing cardiovascular disease and recent studies further support the need for routine exercise in children and adolescents. The term exercise though is fairly encompassing and therefore the type of exercise is necessary to consider based on the desired outcomes. New research published in the American Journal of Human Biology demonstrated that if reduced risk for heart disease is the primary emphasis of the training, high intensity exercise seems to be more beneficial than traditional steady state endurance training. Lead author Duncan Buchan from the University of West Scotland stated that "cardiovascular disease (CVD) is a leading cause of mortality throughout the world and its risk factors have their origins in childhood. Our research examines the effects of brief, intense exercise when compared to traditional endurance exercise on the markers of CVD in young people." Researchers recruited forty-seven boys and ten girls and randomly divided them into either a moderate or high intensity exercise group. Both groups performed exercise three times per week for seven weeks. The high intensity exercise group engaged in a series of 20 meter sprints over 30 seconds. In contrast, the moderate intensity group performed a steady pace for a period of 20 minutes. Total volume completed by the respective groups over the seven weeks equaled 420 minutes of exercise for the moderate intensity group while the high intensity group trained for a total of 63 minutes. The estimated energy expenditure for the high intensity group was 907.2 kcal compared to 4,410 kcal for the moderate intensity group. When analyzed for CVD risk factors both groups demonstrated significant improvements. Researchers were quick to cite that the moderate intensity group spent more time (6x more) exercising compared to the high intensity group who also demonstrated significant improvements in CVD risk factors but in only 15% of the total exercise time of the moderate group. These findings demonstrate that brief, intense exercise is a time efficient means for improving CVD risk factors in adolescents. Although limited to relatively small samples, the findings demonstrate significant improvements in cardiorespiratory fitness, blood pressure, body composition and insulin resistance in healthy adolescent youth after a 7 week intervention of different exercise intensities. According to Buchan, this study is the first “to demonstrate the effects of a novel interval training program on both traditional and novel CVD risk factors in adolescents,” and added “larger scale and extended interventions must be undertaken so that the long term impact and effects of intermittent training programs on unfavorable metabolic profiles may be investigated further." (American Journal of Human Biology, 2011)
