Bioavailability and Vascular Effects of Apple Polyphenols

Bioavailability and Vascular Effects of Apple Polyphenols

The main purpose of this study is to determine the oral bioavailability of flavanols (polyphenolic compounds) from apple granules and an apple extract delivered in a water based beverage at two different doses. We will also investigate the effects of apple flavanols on nitric oxide production.

This study is a randomized four phase crossover trial investigating the bioavailability of apple flavanols and the effects on nitric oxide products, a surrogate marker for changes in endothelial function. Each test phase will comprise a 3 day period of intervention which will be identical in nature (except for the test product consumed) and separated by a minimum of 1 week. On days 1-3 of each test phase volunteers will consume a low flavanol diet. After consumption of the test product on the morning of day 2, blood and urine samples will be collected at regular intervals for the next 24h.

Inclusion Criteria:

• Men and women aged 45-70 years

Exclusion Criteria:

• Smokers (or have quit smoking less than 1 year ago)
• Regular prescribed medication (excluding some eye and skin medication that is judged not to affect study outcome)
• Non-prescribed medication that may affect the study data, e.g. aspirin. The use of non prescribed medications will be assessed on an individual basis.
• Dietary supplements or herbal remedies which may affect the study data unless the volunteer is willing to discontinue them for 1 month prior to starting study. (Please note that some supplements may not affect the study and this will be assessed on an individual basis).
• Gastro-intestinal diseases (excluding hiatus hernia unless symptomatic or study intervention/procedure is contra-indicated).
• Diabetics
• Known cardiovascular disease
• Asthmatics (unless no medication taken for 1 year)
• Lactose Intolerance
• Pregnancy or have been pregnant within the last 12 months
• Parallel participation in another research project which involves dietary intervention
• Participation in another research project which has involved blood sampling within the last four months unless the total amount of combined blood from both studies does not exceed 470 mls.
• Has donated or intends to donate blood within 16 weeks prior to or during the study period.
• Depressed or elevated blood pressure measurements (<90/50 or 95/55 if symptomatic or >160/100)
• Any person related to or living with any member of the study team
• Results of the clinical screening which indicate or are judged by the HNU Medical Advisor to be indicative of a health problem which could compromise the well-being of the volunteer if they participated or which could affect the study data.
• Alcohol consumption > approximately 20 g alcohol/day (2.5 units/day)
• BMI <19.5 or > 35