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Completed

NCT Number: NCT03376555

Cheese Consumption and Human Microvascular Function

Increased dairy intake is associated with improved measures of blood vessel health. Dairy cheese, however, is often high in sodium. Dietary sodium can impair blood vessel function. The researchers examine if and how natural cheese may protect against impairments in blood vessel function caused by sodium. For this study, participants complete four 8-day controlled feeding periods in which they eat cheese (6 oz/day) or no cheese during a low-sodium or high-sodium base-diet. The participants complete baseline experiments while on their normal personal diet and then repeat experiments at the end of each controlled feeding period. In some of our experiments, the researchers use a technique called "microdialysis" (MD). With MD, the researchers perfuse some research drugs into the skin on the forearm through tiny tubing that mimics capillaries. These MD drugs mimic or block substances the body naturally makes to control the small blood vessels in the skin. The drugs remain in nickel-sized areas around the tubing and do not go into the rest of the body. The researchers also use a standard technique called "flow mediated dilation" (FMD) that uses blood pressure cuffs and ultrasound to look at the health of larger blood vessels in the body. FMD includes placing a small tablet of nitroglycerin under the tongue during part of the test.

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Key information

Conditions

Microvascular Dysfunction Cardiovascular Diseases Hypertension Vascular Diseases

Age range

55 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1 / Phase 2

Primary location

Pennsylvania State University

University Park, Pennsylvania, 16802, United States

About this study

Subject screening will be performed by the Penn State Clinical Translational Research Center (CTRC) medical staff and will include a physical exam by a clinician, anthropometry, and a chemical and lipid profile, liver and renal function. Participants meet with a registered dietitian to determine their caloric energy requirements and identify food preferences. The interview includes surveying the subject's physical activity over the previous 7 days.

Subjects will undergo baseline microdialysis experiments to examine the function of the blood vessels in the skin microcirculation. Subjects will also go through a baseline assessment of conduit vessel endothelial and vascular smooth muscle function with brachial artery flow-mediated vasodilation (FMD), and sublingual nitroglycerin. Following baseline experiments, subjects participate in 4 controlled feeding periods, each 8 days in duration. The controlled feeding periods are assigned in a randomized order. At the end of each 8-day controlled dietary period, subjects will repeat microdialysis experiments, brachial artery FMD, and responsiveness to sublingual nitroglycerin.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Seated systolic pressure 120-140 mmHg
  • Seated diastolic pressure 70-90 mmHg.
  • Normoglycemic (HbA1C <5.7%)

Exclusion criteria

  • Taking pharmacotherapy that alters peripheral vascular control
  • Pregnancy
  • Breastfeeding
  • Females taking contraceptives (pills, patches, shots, etc.) or hormone replacement therapy
  • Taking illicit and/or recreational drugs
  • Use of nicotine containing-products (e.g. smoking, chewing tobacco, etc.)
  • Known allergy to latex or investigative substances

Treatment and study plan

Low sodium no cheese

Dietary Supplement

Diet contains 1,500 mg sodium per day Diet does not contain dairy cheese 8 days

Low sodium cheese

Dietary Supplement

Diet contains 1,500 mg sodium per day Diet contains 6 oz dairy cheese per day 8 days

High sodium no cheese

Dietary Supplement

Diet contains 5,500 mg sodium per day Diet does not contain dairy cheese 8 days

High sodium cheese

Dietary Supplement

Diet contains 5,500 mg sodium per day Diet contains 6 oz dairy cheese per day 8 days

Primary outcomes

  1. Microvascular Reactivity to Acetylcholine

    Time frame: 1 hour

    Skin blood flow is measured with laser Doppler flowmetry (flux units) and normalized to cutaneous vascular conductance by dividing by mean arterial pressure. Log molar increasing concentrations of acetylcholine are perfused and dose response curves are generated. Dose response curves were analyzed to determine the logEC50 (log Molar)

Secondary outcomes

  1. Systolic Blood Pressure

    Time frame: 8 days

    Blood pressure is measured via brachial auscultation manually or with a critical care monitor. The peak blood pressure during a cardiac cycle when the heart contracts.

  2. Diastolic Blood Pressure

    Time frame: 8 days

    Blood pressure is measured via brachial auscultation manually or with a critical care monitor. The lowest blood pressure during a cardiac cycle when the heart is between beats.

  3. Flow Mediated Dilation

    Time frame: 8 days

    Flow mediated dilation is measured through Doppler ultrasound probe placed at brachial artery.

Sponsors and collaborators

Lead sponsor

Lacy Alexander

Other

Collaborators

  • National Dairy Council

Registry information

Important dates

Study start
2017
Primary completion
2021
Study completion
2021
First posted
Dec 18, 2017
Registry last updated
May 4, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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