A Human In Vivo Feeding Study Of The Blood Monocyte Response To Dietary Lipid Intake (Lipophage14)

The aim of the present study is to identify the effects of different dietary fats on the body's immune system and how different types of cells respond. There will be two rounds of recruitment in order to satisfy different aims of the study. In the first round, volunteers will be asked to undergo five separate 1-day assessments where you will be given diets in the form of milkshakes differing in amounts of fats. Volunteers recruited for this round will also be given the opportunity to participate in the second round of recruitment and feeding. A second round of recruitment will then take place to complete recruitment, if required. In the second round, volunteers will be asked to undergo two separate 1-day assessments in the form of milkshakes with differing fats, one of which will contain a tracking label added to the food during preparation. This label is in the form of is a 'stable isotope' and safe to consume (used commonly in some medical tests - see below for further information) and will allow the researchers to later find the food particles within blood cells. During these 1-day assessments blood samples will be collected to identify the impact different diets have on the immune system, specifically monocyte cells thought to play an important role in the development of atherosclerosis, a primary cause of cardiovascular disease.

For feeding of 5 different fatty acid meals in order to assess the monocyte response ex vivo Mixed high fat diet Low fat diet Saturated fat diet Monounsaturated fat diet Polyunsaturated fat diet

For feeding of 2 different fatty meals, in order to assess the molecular monocyte response and track the fate of fats. Saturated fat Triolein 13C

ICAM-1 is a marker of monocyte activation (inflammation). ICAM-1 expression can be measured using flow cytometry techniques to quantify expression and therefore inflammation.

Lipid uptake by monocyte subsets will be measured as a % of cell volume by staining monocytes with Oil-red-O for neutral intracellular lipid. The % of cell volume with lipid will be compared between the 5 interventional arms of the trial (mixed high fat, low fat, saturated fat, monounsaturated fat and polyunsaturated fat meals).

The quantity of dietary fat incorporated into a monocyte will be measured through the use of isotope labelled dietary fat that will be tracked using gas chromatography to provide an exact quantity of how much intracellular lipid within the monocyte originated from the dietary intervention.

Inclusion Criteria: healthy men aged between 18-65 years (inclusive) body mass index of between 18.5-25kg/m2 Exclusion Criteria: Female Undiagnosed metabolic syndrome (assessed at initial screening) Current smokers Substance abuse Excess alcohol intake Significant medical illness including: diabetes, established cardiovascular disease, cancer, gastrointestinal disease (e.g. inflammatory bowel disease or irritable bowel syndrome), kidney, liver or pancreatic disease or autoimmune or inflammatory disease processes. Taking regular medications Major surgery in last 6 months