The Effects of Alkalised Cocoa on Human Vascular Function

A randomised, triple blind, cross-over design human intervention studies will be conducted in 10 healthy human volunteers to test the impact of alkalisation on the absorption, metabolism and vascular reactivity of cocoa flavanols. Participants will be requested to consume a standardised high flavanol-rich cocoa, non-alkalised (1745 mg of flavanols), a low-flavanol cocoa, heavily alkalised (1.3 mg of flavanols) and a flavanol-rich cocoa, medium alkalisation (410 mg of flavanols). The three intervention diets are otherwise matched for macro- and micronutrient content. Vascular measurements will be performed by using Flow Mediated Dilation (FMD), Laser Doppler imaging (LDI) and Digital Volume Pulse (DVP). Blood and urine samples will be taken to measure the concentration of flavonoids from the cocoa drinks and markers of blood vessel function. A number of other biochemical and physiological measures will be recorded including blood glucose, lipoproteins, cytokine levels and blood pressure.

Inclusion criteria

• Male
• signed consent form
• age of 18-35 years inclusive
• BMI between 18.5-30

Exclusion criteria

• Blood pressure > 150/90 mmHg
• Haemoglobin (anaemia marker) < 125 g/l
• Gamma GT (liver enzymes) > 80 IU/l
• Cholesterol > 6.5 mmol/l
• Had suffered a myocardial infarction or stroke in the previous 12 months
• Suffers from any reproductive disorder
• Suffers from any blood-clotting disorder
• Suffers from any metabolic disorders (e.g. diabetes or any other endocrine or liver diseases)
• Any dietary restrictions or on a weight reducing diet
• Drinking more than 21 units per week
• On any lipid-modifying medication
• On any blood pressure lowering medication
• On any medication affecting blood clotting
• Planning on altering consumption of vitamin supplements/fish oil capsules during the course of the study
• Regular or vigorous exercise (3 times/week, 20 minutes each session)
• Smoking