Fibre, Barley and Cholesterol Study: Can eating barley containing higher levels of beta-glucan (a type of dietary fibre) reduce cholesterol levels in the blood?

INTERVENTION: 74 men and women with elevated blood cholesterol will be recruited. There will be an initial visit during which volunteers will be screened for blood cholesterol to make sure they are suitable to take part to the study. Then blood and urine collections, blood vessel stiffness and blood pressure measurements will be performed six times during the study (at first visit, after two 2‐week periods on a refined (no wholegrain) diet (run‐in before intervention and after wash‐out period between interventions), after 6‐week interventions (week 8 and 16) and after a 4‐week follow‐up period. Blood vessel stiffness and central blood pressure will be also determined at these time points. Dietary assessment will be carried out four times during the study (at baseline, during both intervention periods and during the 4‐week follow‐up period). Blood and urinary markers of chemicals involved in cholesterol regulation and other markers for heart disease risk will be measured as required. Compliance to the interventions will be assessed by analysing food diaries and as well as by measuring plasma and urine alkylresorcinols (chemical compounds found in wholegrains). If the volunteers are willing, they will be asked to provide stool samples seven times during the study at weeks 2, 4, 8, 10, 12, 16 and 20. Our primary outcome is blood cholesterol (adjusted for baseline) after 6 weeks intervention, which will be compared between the two groups. After 2 weeks on a wholegrain‐free diet, half of the participants will eat 75 g of barley daily for 6 weeks while the other half will eat 65 g wholewheat‐based diet. All will then eat a wholegrain free diet for 2 weeks. Then they will all switch to the other arm of the intervention (barley or wheat‐based diet depending on which they started with). Volunteers will be asked to provide optional stool samples several times during the study to assess changes in gut microbiota composition. The subjects will be followed up CONDITION: Untreated borderline hypercholesterolaemia ; Nutritional, Metabolic, Endocrine PRIMARY OUTCOME: ; 1. Plasma total cholesterol; 2. Plasma HDL‐cholesterol; 3. ApoA1; 4. ApoB100; 5. Triacyclglycerol (TAG, triglycerides); 6. Glucose; All blood tests will be performed using standard laboratory analysis using blood samples taken at weeks 2, 8, 10, 16 and 20.; ; SECONDARY OUTCOME: ; 1. Participant‐reported compliance to the intervention assessed by examining food diaries; 2. Alkylresorcinol levels assessed by HPLC analysis of plaasma and urine samples taken at weeks 2, 8, 10, 16 and 20.; 3. Markers of inflammation (GlycA, hsCRP, IL6, serum amyloid A, oxidised LDL) will be measured by immunoassays using blood samples taken at weeks 2, 8, 10, 16 and 20; 3. Gut microbiota activity assessed using markers such as plasma trimethylamine oxide measured by by liquid chromatography/mass spectrometry using blood samples taken at weeks 2, 8, 10, 16 and 20; INCLUSION CRITERIA: 1. Aged 30‐65 years 2. Borderline/untreated high cholesterol levels