Long-term Effects of Avocado Consumption on Health in Pre-diabetic Individuals

Overview

Primary aim of the study is to assess the effect of 12-week daily avocado consumption on cerebral blood flow and markers of cardio- and vascular health in both, the periphery and the brain, in pre-diabetic individuals with overweight or obesity. Secondary objective is to assess the effects of 12-week daily avocado consumption on brain insulin sensitivity after intranasal insulin delivery, vascular function, markers of metabolic health, cognition, and psychological well-being. For that purpose a total of 34 men and women between the ages of 40-75 years old, will participate in a randomised crossover intervention study.

Daily intake of avocado, a food rich in MUFA, PUFA and other essential nutrients such as folate and potassium, has previously been shown to lower systemic markers of cardiovascular risk as well as inflammation in overweight/obese individuals. Especially individuals with cardiovascular disease, or those at an increased risk for cardiovascular disease appear to benefit from regular avocado consumption. In addition to improvements in cardiovascular disease, large cross-sectional studies have linked avocado consumption to a lower risk for metabolic disease, including type 2 diabetes. Despite the beneficial systemic effects observed, the interaction of peripheral cardiovascular risk- and vascular function markers with brain vascular health remains unclear. Furthermore, the clinical implications of this interaction, especially in a population at risk, are unknown. A total of 34 men and women between the ages of 40-75 years old, with overweight/obesity (BMI: 26-40 kg/m2) will consume a daily avocado (intervention) or no avocado for 12 week in a crossover design. The primary outcome parameter of the intervention will be cerebral blood flow (CBF). Secondary outcomes include measures for endothelial function (brachial artery flow mediated vasodilation (FMD), carotid artery reactivity (CAR)) and arterial stiffness (pulse wave velocity (PWV), carotid artery distensibility). More cardiometabolic risk markers measured will include office blood pressure, serum lipids, lipoprotein and metabolite profiling, hemostatic factors and plasma biomarkers for low-grade systemic inflammation including IL-6, IL-8, TNF-α, CRP and SAA). Cognitive performance will be assessed in the domains of executive function, memory, psychomotor speed and attention with the Cambridge Neuropsychological Test Automated Battery (CANTAB) as well as the Erikson Flanker test.