Title: Flavanols and Cardiovascular Disease Prevention
Date Posted: September 28, 2010
Authors: Heiss C, Keen CL, Kelm M.
Citation: Eur Heart J 2010;Sep 18:[Epub ahead of print].
Perspective:
Diet plays a major role in the primary and secondary prevention of numerous chronic diseases, including cardiovascular conditions and diabetes. Epidemiological studies suggest that the beneficial cardiovascular health effects of diets rich in fruits and vegetables are in part mediated by their flavonoid content, with particular benefits provided by one member of this family, the flavanols. This concept is supported by findings from small-scale intervention studies with surrogate endpoints including endothelium-dependent vasodilation, blood pressure, platelet function, and glucose tolerance. Mechanistically, effects on endothelium-dependent vasodilation following the consumption of flavanol-rich foods, as well as purified flavanols, have been linked to an increased nitric oxide bioactivity in healthy humans, and those with increased cardiovascular risk.
While flavanols represent a promising class of food components that are associated with lower cardiovascular risk and may positively affect cardiovascular surrogate parameters in the short term, epidemiological studies are prone to confounding, and no long-term randomized controlled dietary intervention trials with hard clinical endpoints are available to date. More clinical and experimental studies are needed before flavanols can be considered as a feasible and effective therapeutic option for the prevention or treatment of cardiovascular diseases.
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Title: Long-Term Effects of a Lifestyle Intervention on Weight and Cardiovascular Risk Factors in Individuals With Type 2 Diabetes Mellitus: Four-Year Results of the Look AHEAD Trial
Date Posted: September 30, 2010
Authors: The Look AHEAD Research Group.
Citation: Arch Intern Med 2010;170:1566-1575.
Study Question:
Does a lifestyle modification intervention result in long-term changes in weight and cardiovascular disease risk factors among patients with type 2 diabetes?
Methods:
The Look Ahead Study is a multicenter randomized clinical trial comparing the effects of an intensive lifestyle intervention versus diabetes support and education. Patients all had type 2 diabetes and were between the ages of 45 and 76 years. Additional inclusion criteria included a body mass index (BMI) of 25 or greater. The intensive intervention included diet modification for a goal weight loss of 7% over the first year, with weight loss maintenance over the following years. Participants met with study members weekly in the first 6 months, then three times per month for the next 6 months, followed by once per month for the following study follow-up period. The control group had three group sessions each year.
Results:
A total of 5,145 overweight or obese patients with diabetes (mean age 58.7 years, 59.5% female) were included in the study. Over the 4-year follow-up, patients in the intensive lifestyle modification group had greater weight loss compared to the control group (-6.15% vs. -0.88%, p < 0.001) and greater improvement in treadmill fitness (12.74% vs. 1.96%, p < 0.001). The intensive intervention also resulted in lower glycated hemoglobin levels, and lower systolic and diastolic blood pressure compared to the control group. Lipid profiles among those in the intensive group also improved with great increases in high-density lipoprotein (HDL) cholesterol (3.67 vs. 1.97, p < 0.001) and reductions in triglyceride levels (-25.56 vs. 19.75 mg/dl, p < 0.001). Reductions in low-density lipoprotein cholesterol were greater in the control group, as compared to the intensive lifestyle group (-11.27 vs. 12.84 mg/dl, p = 0.009); however, lipid-lowering medication use was higher in the control group, which may explain this finding. At 4 years, those patients in the intensive intervention group had greater improvements in weight, fitness, glycated hemoglobin, systolic blood pressure, and HDL cholesterol compared to those in the control group.
Conclusions:
The investigators concluded that an intensive lifestyle modification program can result in reductions in weight and improvements in cardiovascular disease risk factors and fitness over several years.
Perspective:
Lifestyle modification can result in significant improvements of risk factors, including blood pressure and lipids. These findings are encouraging in that the intervention resulted in long-term improvements, which have the potential to result in reductions in cardiovascular disease events. However, the ability to implement such intensive programs in the community remains unclear.
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