Impact of Dairy Consumption on Inflammation: a Clinical Study (PLI)

Study Overview
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Brief Summary
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Inflammation and endothelial dysfunction are being increasingly recognized as key etiological factors in the development of atherosclerosis and subsequent cardiovascular disease (CVD). These pro-atherogenic states are strongly correlated and often found co-segregating among individuals with obesity and the metabolic syndrome. There is increasing evidence to support the use in clinical practice of these novel markers of atherosclerosis and CVD risk. Recent data from the JUPITER study (Justification for the Use of Statins in Primary Prevention: An Intervention Trial Evaluating Rosuvastatin) has provided undisputable evidence that treating patients with elevated plasma CRP concentrations, a marker of systemic subclinical inflammation, leads to marked reduction in the risk of CHD even in patients with highly desirable LDL-C levels. There is also accumulating evidence associating endothelial dysfunction, which is defined as incapacity of the arteries to vasodilate when required, to an increased risk of CVD. While there are more and more studies on how diet affects inflammation and endothelial function, the impact of dairy consumption per se on these novel risk factors for CVD has not been well characterized. The purpose of this study was to investigate the impact of dairy consumption on markers of inflammation and other risk factors in men and women with low grade systemic inflammation.

Detailed Description
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This research will be undertaken as a multicenter randomized cross-over controlled study. A total of 140 men and women with subclinical inflammation (plasma CRP 2-10 mg/l) but otherwise healthy will consume two diets, one rich in dairy and one without dairy, while consuming a diet low in saturated fat (<10% energy), in trans fat (<1% energy) and in cholesterol (<200 mg/day). During the DAIRY diet, subjects will be asked to incorporate 3 servings of dairy (milk, yogurt, cheese) into their every day diet. During the CONTROL arm of the study, participants will be asked to consume energy equivalent replacement products. Each diet will be undertaken consecutively in random order and will have duration of approximately 28 days each (4 weeks).The primary analysis consists in comparing inflammation markers and related risk factors between the two treatments. The study is designed to detect a 12-16% difference in plasma CRP concentrations (the primary endpoint) between the control and the dairy diet. A 2-week stabilization run-in period will precede the randomization of participants. During this run-in period, participants will be asked and instructed to adapt their diet to a prudent dietary pattern low in saturated fat (<10% energy), in trans fat (<1% energy) and in cholesterol (<200 mg/day). The total amount of fat in the diet will not be restricted, with recommendations ranging from 25-35% of energy. However, substitution of saturated for unsaturated fat will be advocated. Sodium intake <2300 mg/d will also be recommended. Recommendations will also include advice on how to restrict the consumption of processed and energy dense foods. The run-in diet will not include specific recommendation on dairy products. Participants will have the choice to include/exclude dairy from their prudent diet, as long as they comply with the main dietary recommendations. This 2-week run-in period will allow participants to familiarize themselves with the dietary recommendations used during the intervention per se. The two diets will be separated by a 4-week wash out period and will also consist to the prudent dietary pattern recommended. It must be stressed that foods will not be provided during the run-in and wash-out periods. These periods are imposed to minimize the inter- and intra-individual variability before and between the experimental phases.

Official Title
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Impact of Dairy Consumption on Inflammation: a Clinical Study

Conditions
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Cardiovascular Disease

Intervention / Treatment
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* Other: Dairy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women aged between 18 and 70 years Presenting a subclinical inflammation (Plasma CRP >2 and <10 mg/l) Abdominal obesity, waist girth >94 cm in men and >80 cm in women Consumption of dairy products fewer than 2 servings per day Pre-menopausal women with regular menstrual cycle for the last 3 months Exclusion Criteria: Plasma CRP <2 or >10 mg/l Smokers (>1 cigarette/day) Body weight variation >10% for the last 6 months prior to the study baseline BMI >35 kg/m2 Previous history of CVD, type 2 diabetes and monogenic dyslipidemia Subjects taking medications for hyperlipidemia, hypertension Post menopausal women who have initiated hormone replacement therapy within 6 months of study onset Endocrine or gastrointestinal disorders Smoking Food allergies, milk aversion or intolerant to lactose Clinical use of vitamin D or calcium supplements Vegetarianism

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dairy diet<br> | Other: Dairy<br>* During the DAIRY diet, subjects will be asked to incorporate 3 servings of dairy (375 ml of milk, 175 g of yogurt, 30 g of cheese) into their every day diet. During the CONTROL arm of the study, participants will be asked to consume energy equivalent replacement products (375 ml of fruit juice, 1 homemade cookie, 20 g of cashew).<br>* Other names: Dairy products, milk, cheese, yogourt;|
| Placebo Comparator: Control diet<br> | Other: Dairy<br>* During the DAIRY diet, subjects will be asked to incorporate 3 servings of dairy (375 ml of milk, 175 g of yogurt, 30 g of cheese) into their every day diet. During the CONTROL arm of the study, participants will be asked to consume energy equivalent replacement products (375 ml of fruit juice, 1 homemade cookie, 20 g of cashew).<br>* Other names: Dairy products, milk, cheese, yogourt;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in plasma CRP concentrations |  | At the beginning of the study and the end of the two 4-week diets | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in endothelial function |  | At the end of the two 4-week diets | 
| Change in plasma lipid concentrations (LDL-Cholesterol, HDL-C, triglycerides) |  | At the beginning of the study and the end of the two 4-week diets | 
| Change in insulin levels |  | At the beginning of the study and the end of the two 4-week diets | 
| Change in anthropometric measures (waist and hip circumferences) |  | At the beginning of the study and the end of the two 4-week diets | 
| Change in blood pressure |  | At the begining of the study and the end of the two 4-week diets | 
| Change in CRP intravascular kinetics (in a subsample of the entire study population) |  | At the end of the two 4-week diets | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Keywords;, Cardiovascular disease, Dairy, Inflammation, Blood lipids