In this proposed human trial, the investigators aim to establish whether 4 weeks of daily consumption of beta-glucan matched meals providing either a high dose or a moderate dose of oat avenanthramides and phenolic acids leads to dose-dependent chronic improvements in markers of CVD risk and gut health relative to an energy matched control intervention in healthy adults with above average blood pressure.

• To investigate the chronic effects of daily intake of oat products on flow mediated dilatation of the brachial artery (FMD; primary endpoint), microvascular endothelial function (measured by laser Doppler iontophoresis), pulse wave analysis, gut microbiota diversity, 24h blood pressure, activity of the renin angiotensin system, markers related to cellular production of nitric oxide and reactive oxygen species, inflammatory cytokines, and further potentially emerging biochemical markers of CVD risk.
• To establish if phenolic acids and avenanthramides from oat products exert cardiovascular and microbial effects in a dose dependent manner.
• To measure urinary and fecal excretion of avenanthramide and phenolic acid metabolites.

To explore correlations between bacterial population changes and CVD risk markers.

Inclusion Criteria:

• Above average blood pressure (i.e. systolic 120-159 mmHg and diastolic 75-99 mmHg)

Exclusion Criteria:

• Abnormal biochemical, haematological results as assessed at health screening
• Hypertension (i.e. SBP/DBP ≥160/100 mm Hg)
• BMI >35
• Current smoker or ex-smoker ceasing <3 months ago
• Past or existing medical history of vascular disease, diabetes, hepatic, renal, haematological, neurological, thyroidal disease or cancer
• Prescribed or taking lipid lowering, antihypertensive, vasoactive (e.g. Viagra), anti-inflammatory, antibiotic or antidepressant medication
• Allergies to whole grains
• Parallel participation in another research project
• Having flu vaccination or antibiotics within 3 months of trial start
• Chronic constipation, diarrhea or other chronic gastrointestinal complaint
• On a weight reduction regime or taking food, probiotics or prebiotics supplements or laxative within 3 months of trial start
• Performing high level of physical activity (i.e. ≥150min aerobic exercise/week)
• Consumption of ≥21 units of alcohol/week
• Females who are breast-feeding, may be pregnant, lactating or, if of reproductive age and not using a reliable form of contraception (including abstinence)

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