The effect of blueberries on blood vessel function, inflammation and oxidative stress in older people

INTERVENTION: Based on a computer randomization plan, participants are randomized to receive the two study products in a random order. The trial is divided into two phases. For the first phase of the trial, participants will be asked to consume a portion of blueberry products obtained from a specific cultivar of blueberry, rich in polyphenols, or a control product. Before the ingestion and after 1 h, 1,5 h, 2 h and 4 h, blood samples will be collected by all participants to evaluate the kinetics of absorption of main blueberry polyphenols, salicylates, glycaemic and insulinemic response, markers of inflammation (e.g. IL‐6, IL‐8, TNF‐alpha), oxidative stress (e.g. cell resistance against H2O2‐induced DNA damage) and vascular function (e.g. nitric oxide, endotelin‐1). Following a 2‐week wash out period the participants will be asked to undergo the intervention again, since the trial has a cross over design. For the second phase of the trial, participants will be asked to consume the same blueberry product or control product of the first phase. Then, they will undergo the measurement of peripheral arterial function markers (i.e. Reactive Hyperaemia Index (RHI) and Framingham RHI (FRHI)), arterial stiffness markers (dAix and dAix@75), systolic blood pressure and heart rate before the ingestion and after 2 h from the consumption of blueberry or control product, which correspond to the peak of main blueberry polyphenols absorption. Participants will also provide urine samples 24 and 48 h after the consumption of blueberry or control product. In both phases participants will be informed about dietary habits that they should follow. They will also receive a list of food that they should avoid before and after the interventio CONDITION: Vascular function in older people ; Circulatory System PRIMARY OUTCOME: ; Phase I: polyphenols and salicylates measured through high‐performance liquid chromatography (HPLC) and liquid chromatography–mass spectrometry (LC‐MS) analysis before and after intake at 1 h, 1,5 h, 2 h and 4 h; Phase II: reactive hyperaemia markers (i.e. Reactive Hyperaemia Index (RHI) and Framingham RHI) and arterial stiffness markers (Augmentation Index (AI) and AI@75) measured through non‐invasive EndoPAT 2000 device before and after intake at 2 h; SECONDARY OUTCOME: ; 1. Systolic and diastolic blood pressure measured through a sphygmomanometer following standard procedure before and after intake at 2 h; 2. Plasma levels of glucose and insulin evaluated through routine laboratory clinical assessment before and after intake at 1 h, 1,5 h, 2 h and 4 h; 3. DNA damage evaluated through the comet assay before and after intake at 1 h, 1,5 h, 2 h and 4 h; 4. Vascular function markers (e.g. nitric oxide, endothelin‐1, VEGF, VCAM‐1, ICAM‐1) and inflammation markers (e.g. IL‐6, IL‐8, TNF‐alpha) evaluated using an enzyme‐linked immunosorbent assay (ELISA) kit before and after intake at 1 h, 1,5 h, 2 h and 4 h; INCLUSION CRITERIA: 1. Age =60 years old 2. Absence of major diseases