Effects of High Fruit, Vegetable, and Dairy Intake on Plasma Lipids and Blood Pressure in Healthy Individuals

Study Overview
=================
Brief Summary
-----------------
The Dietary Approaches to Stop Hypertension (DASH) trial has been shown to reduce blood pressure and plasma total and LDL-cholesterol (C) compared to a Western diet, but shows no benefit on other blood lipid variables associated with cardiovascular disease (CVD) risk, namely HDL-cholesterol and triglycerides. The overall objective of this study is to determine whether modification of the DASH diet by substituting carbohydrate with fat will result in improvements in multiple biomarkers of CVD risk. Specifically, the investigators will test the hypotheses that modification of the DASH diet by reducing carbohydrate, primarily in the form of simple sugars and glycemic starches, and allowing for a more liberal intake of total and saturated fat, primarily from dairy foods, will: (1) improve lipoprotein markers of CVD risk (reduced total/HDL-C ratio, apolipoprotein B, small LDL particles, and increased HDL-C, apoAI, and large HDL particles); and (2) result in comparable reductions of systolic and diastolic blood pressure to those achieved with the standard DASH diet. The investigators will also assess the effects of the modified DASH diet on markers of insulin resistance and inflammation. Our main hypotheses will be tested by a controlled dietary intervention conducted in 40 healthy men and women who will be randomly allocated to consume, for 3 weeks each, a control Western diet, a standard DASH diet, and a modified low-carbohydrate DASH diet, separated by 2-week washout periods.

Official Title
-----------------
Effects of a Modified Lower Carbohydrate, Higher Fat DASH Diet Plan on Plasma Lipids, Lipoprotein Particle Size, and Blood Pressure in Healthy Adults

Conditions
-----------------
Cardiovascular Disease, Dyslipidemia, Blood Pressure

Intervention / Treatment
-----------------
* Other: Dietary Intervention
* Other: Dietary Intervention
* Other: Dietary Intervention


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age 22 years and older Average systolic blood pressure <160 mm Hg and diastolic blood pressure 80 - 95 mm Hg measured on 2 separate days Non-smoking Agrees to abstain from alcohol and dietary supplements during the study Willing to consume all study foods as instructed Exclusion Criteria: History of coronary heart disease, cerebrovascular disease, peripheral vascular disease, bleeding disorder, liver or renal disease, diabetes, lung disease, HIV, or cancer (other than skin cancer) in the last 5 years. Taking hormones or drugs known to affect lipid metabolism or blood pressure. Body Mass Index (BMI) > 35 Total- and LDL-cholesterol > 95th percentile for sex and age. Fasting triglycerides > 500 mg/dl. Fasting blood sugar (FBS) > 126 mg/dl. Abnormal thyroid stimulating hormone Not weight stable Pregnant or breast-feeding

Ages Eligible for Study
-----------------
Minimum Age: 22 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dietary Intervention: Control Diet<br> | Other: Dietary Intervention<br>* 3 weeks of a typical Western diet pattern. 48% carbohydrate, 15% protein, 37% fat.<br>|
| Experimental: Dietary Intervention: DASH-based diet<br> | Other: Dietary Intervention<br>* 3 weeks of a diet based on the Dietary Approaches to Stop Hypertension (DASH) diet plan. 57% carbohydrate, 18% protein, 25% fat.<br>|
| Experimental: Dietary Intervention: Modified DASH diet<br> | Other: Dietary Intervention<br>* 3 weeks of a reduced carbohydrate, higher fat modification of the DASH diet plan. 42% carbohydrate, 18% protein, 40% fat.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total:HDL-cholesterol ratio |  | 4 weeks | 
| HDL-cholesterol |  | 4 weeks | 
| Apolipoprotein B |  | 4 weeks | 
| Apolipoprotein AI |  | 4 weeks | 
| Small LDL particles |  | 4 weeks | 
| Large HDL particles |  | 4 weeks | 
| Total:HDL-cholesterol ratio |  | 9 weeks | 
| Total:HDL-cholesterol ratio |  | 14 weeks | 
| HDL-cholesterol |  | 9 weeks | 
| HDL-cholesterol |  | 14 weeks | 
| Apolipoprotein B |  | 9 weeks | 
| Apolipoprotein B |  | 14 weeks | 
| Apolipoprotein AI |  | 9 weeks | 
| Apolipoprotein AI |  | 14 weeks | 
| Small LDL particles |  | 9 weeks | 
| Small LDL particles |  | 14 weeks | 
| Large HDL particles |  | 9 weeks | 
| Large HDL particles |  | 14 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood Pressure |  | End of each experimental diet (4 wks, 9 wks, and 14 wks) | 
| Triglycerides |  | End of each experimental diet (4 wks, 9 wks, and 14 wks) | 
| Total Cholesterol |  | End of each experimental diet (4 wks, 9 wks, and 14 wks) | 
| LDL-Cholesterol |  | End of each experimental diet (4 wks, 9 wks, and 14 wks) | 
| Lipoprotein Subclasses (HDL, LDL, IDL, VLDL) |  | End of each experimental diet (4 wks, 9 wks, and 14 wks) | 
| HOMA-IR |  | End of each experimental diet (4 wks, 9 wks, and 14 wks) | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
carbohydrate, DASH diet, blood pressure, cholesterol