A randomized, double-blind dietary intervention trial examines the impact of consuming an açaí-rich meal on various disease markers.
The açaí berry (Euterpeoleracea) is a small grape-like fruit grown in South America. It is known for its high concentration of flavonoids, a type of polyphenol. In recent years, the berry has found its way into the global health market. Many hoped that consuming açai would yield health benefits, but to date, few human studies have been conducted. Açaí is usually available as a powdered supplement or as a minor constituent in food items such as berry drinks or yogurts.
A recently published American Journal of Clinical Nutrition trial examined the effect of consuming an açaí smoothie on vascular function, oxidative stress, blood pressure, heart rate and glucose.
In this randomized, controlled, double-blind, crossover, acute dietary intervention, açaí puree was mixed with a banana, as it is typically prepared in Brazil, and was consumed after eating a high-fat breakfast. The authors sought to evaluate the mitigating effect of the flavonoid-rich fruit on the negative vascular impact caused by the fat-laden meal.
Twenty-three British male volunteers were given a high fat breakfast followed by either an açaí smoothie containing 694 mg polyphenols or a micronutrient-matched control smoothie containing less that 10 mg polyphenols. The volunteers were healthy men aged 30-65 with a body mass index between 25-30. Assessments were performed at 2, 4 and 6 hours after the meal.
The primary endpoint was the assessment of endothelial function of the brachial artery by flow-mediated dilatation (FMD). FMD is a measure of vascular function and a well-established marker of cardiovascular disease risk. Other disease markers assessed, each indicative of cardiovascular disease risk, included oxidative stress, blood pressure, heart rate and glucose response.
Researchers found that men who consumed the açaí smoothie experienced an increase in FMD of 1.4% at 2 h and 0.8% at 6 h. Volunteers who consumed the control smoothie experienced an increase in FMD of 0.4% and a decrease of -0.3% at the respective assessment times. Results also indicated a significant reduction in oxidative stress after açaí consumption relative to the control group. There were no significant changes in blood pressure, heart rate, or glucose response in either the high-polyphenol or the control group. However, the insulin peak at 2 h was more elevated for the men who consumed the açaí -rich meal relative to the control group.
Any intervention that reduces the burden of cardiovascular diseases is desirable, particularly when determining public health programs. Previous studies have indicated that a diet high in fruit and vegetables may protect against cardiovascular disease. However, the need to identify particular plant foods offering a strong protective effect and to understand the mechanisms involved in how they prevent disease remains.
Previous research demonstrated that consuming polyphenol-rich blueberries improved risk factors associated with metabolic syndrome, diabetes, and cardiovascular disease and may also have a beneficial effect on flow-mediated dilatation (FMD). Other studies demonstrated that polyphenol-rich foods such as cocoa, green tea and grapes may also improve FMD.
This study was the first controlled dietary intervention in humans that demonstrated the benefits of consuming açaí with a well-validated assessment of cardiovascular disease risk as an endpoint.
Authors suggest future research should examine the long-term effects of açaí consumption rather than a short-term dietary intervention and should assess the benefits of açaí consumption on groups other than healthy overweight men.
Written By: Lynn Kim