Mechanism of the Blood Pressure Lowering Effect of the DASH Dietary Pattern

This study has been completed.
Sponsor:
Collaborator:
American Heart Association
Information provided by (Responsible Party):
Duke University
ClinicalTrials.gov Identifier:
NCT01017484
First received: November 19, 2009
Last updated: April 9, 2013
Last verified: November 2009
  Purpose

Understanding the possible mechanism(s) by which the DASH dietary pattern lowers blood pressure will potentially enhance the value of this dietary intervention by elucidating the conditions under which it will be most effective, identifying target populations, examining its impact on vascular health beyond blood pressure, and enhancing the investigators' understanding of the interactions among diet, blood pressure and vascular function. In addition, results of this study may help to identify additional therapeutic targets. Therefore, the overall goal of the proposed study is to determine the mechanism(s) by which the DASH dietary pattern lowers blood pressure by using a controlled feeding design.


Condition Intervention
Blood Pressure
Other: DASH, Control

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Outcomes Assessor)
Official Title: Mechanism of the Blood Pressure Lowering Effect of the DASH Dietary Pattern

Resource links provided by NLM:


Further study details as provided by Duke University:

Primary Outcome Measures:
  • urinary sodium [ Time Frame: 2 weeks ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • blood pressure [ Time Frame: 2 weeks ] [ Designated as safety issue: Yes ]

Enrollment: 20
Study Start Date: July 2007
Study Completion Date: June 2009
Primary Completion Date: June 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: DASH
The Dietary Approaches to Stop Hypertension Dietary pattern.
Other: DASH, Control
controlled feeding of either the DASH dietary pattern or a typical American diet at isocaloric level.
Experimental: Control
The typical American diet as estimated from the NHANES survey.
Other: DASH, Control
controlled feeding of either the DASH dietary pattern or a typical American diet at isocaloric level.

Detailed Description:

Randomized, controlled feeding trials have established the BP lowering effects of the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, which emphasizes fruits, vegetables and low fat dairy and is low in saturated and total fat. The DASH studies were designed to establish efficacy, not to determine mechanism of action. Other studies suggest that the DASH diet may have effects on the renin-angiotensin-aldosterone system (RAAS). These effects have not been directly evaluated, nor have other potential mechanisms of action such as effects on adrenergic tone, vascular function and inflammation. The BP-lowering effect of the DASH dietary pattern was maximal after two weeks of controlled feeding, and was comparable in magnitude to antihypertensive medication among participants with stage 1 hypertension. Understanding the possible mechanism(s) by which the DASH diet lowers BP will potentially enhance the value of this intervention by elucidating the conditions under which it will be most effective, identifying target populations, examining its impact on vascular health beyond BP, and enhancing our understanding of the interactions among diet, BP and vascular function. In addition, results of this study may help to identify additional therapeutic targets. Therefore, the overall goal of the proposed study is to determine the mechanism(s) by which the DASH diet lowers BP. Our unifying hypothesis is that DASH diet lowers BP through effects on vascular function and sodium excretion, mediated through the effects on RAAS.

  Eligibility

Ages Eligible for Study:   22 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  1. SBP 140-159 mm Hg and DBP 90-99 mm Hg based on mean values over two screening visits,
  2. Age ≥22 years, and
  3. Willing to eat at least one on-site meal/day, five days/week, and willing to eat study diets and nothing else for the 3 weeks of controlled feeding.

Exclusion Criteria:

  1. Any serious illness that would interfere with participation or make DASH diet unsafe to the participants,
  2. Currently on cancer chemotherapy or with evidence of active malignancy or radiation therapy within past six months,
  3. History of CVD event (MI, CABG, angioplasty, symptomatic ischemic heart disease, or stroke),
  4. Clinical diagnosis of congestive heart failure,
  5. Current diagnosis of diabetes and treatment for diabetes with oral medication or insulin,
  6. Body mass index > 45 Kg/m2,
  7. DASH MECHANISM staff or household member of DASH MECHANISM staff,
  8. Using Medications including BP lowering drugs within the last three months, using lithium,insulin or oral diabetes medications, oral corticosteroids, unstable doses of psychotropics or phenothiazines, antacids or nutritional supplements unless they can be discontinued, or weight reducing medications;
  9. Consumption of more than 14 alcoholic drinks per week;
  10. Investigator discretion for safety or compliance reasons;
  11. Inability to provide reliable BP & vascular functions measurements;
  12. Planning to leave the area prior to the anticipated end of the intervention period;
  13. Pregnant, planning a pregnancy prior to the end of intervention, or breast feeding;
  14. Significant food allergies, preferences, or dietary requirements that would interfere with diet adherence; and
  15. Subjects taking medications for erectile dysfunction.
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT01017484

Sponsors and Collaborators
Duke University
American Heart Association
Investigators
Principal Investigator: Pao-Hwa Lin, PhD Duke University
  More Information

No publications provided

Responsible Party: Duke University
ClinicalTrials.gov Identifier: NCT01017484     History of Changes
Other Study ID Numbers: Pro00001236, AHA 0755460U
Study First Received: November 19, 2009
Last Updated: April 9, 2013
Health Authority: United States: Institutional Review Board

Keywords provided by Duke University:
blood pressure
DASH diet
hypertension

ClinicalTrials.gov processed this record on September 18, 2014