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NCT Number: NCT02763930

Study of the Impact of Low Fat Dairy and High Fat Dairy Consumption on Daytime Ambulatory Blood Pressure

Market trends depicted by Agriculture and Agri-Food Canada suggest stagnation in cheese consumption, with potentially important impact on this key industry in Canada. This is in part due to the commonly accepted notion that saturated fat in the diet, of which cheese contributes significantly, increases the risk of heart disease. Yet, a rather large body of recent evidence suggests that saturated fat may have been unfairly demonized and that its impact on the risk of heart disease may in fact be less important than originally thought. This concept that dairy fat increases the risk of heart attacks therefore needs to be revisited.

The proposed research is designed to investigate which risk factors for heart disease (e.g. cholesterol, blood pressure) are beneficially modified when low fat (milk) and high fat (cheese) dairy products are consumed.

Our hypotheses are : (1) Consumption of low fat dairy (milk 1% fat) compared with a dairy-free control diet reduces daytime ambulatory systolic blood pressure and reduces inflammation; (2) Consumption of a high fat dairy (GABA-rich cheese) compared with a dairy-free control diet reduces daytime ambulatory systolic blood pressure and has favorable effects on LDL particle size, inflammation and HDL-C concentration.

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Key information

Conditions

Hypertension Cardiovascular Diseases Vascular Diseases

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Institute of Nutrition and Fonctional Foods

Québec, G1V 0A6, Canada

About this study

This is a single-center randomized crossover controlled feeding study. Briefly, adult men and women will be recruited based primarily on blood pressure criteria in the Quebec City metropolitan area through the media (newspaper, radio) and mailing lists (n=60).

Participants will be randomized to 3 experimental diets of 6 weeks each: 1- CONTROL dairy-free diet, 2- low fat dairy (MILK, 1% fat, 3 servings/d), 3- high-fat dairy (GABA-rich cheddar cheese, approximately 32% fat, 1 serving (50g)/d). Usual energy intake will be estimated at the beginning of the study using validated tools. Experimental diets will be provided as part of a full feeding protocol under carefully controlled isocaloric conditions to maintain body weight constant. All meals and foods will be provided to participants so that control for energy and macronutrient intake will be optimized. The breakfast meal will represent approximately 30% of the daily energy intake whereas the lunch and dinner meals each will provide 35% of daily energy intake. Participants will be instructed to consume their entire meals. A seven-day cyclic menu will be used. We have opted to test the impact of dairy intake over a 6-week period (as opposed to 4 or 5 weeks) to maximize the chance to observe clinically meaningful changes in blood pressure. Diets will be separated by a 4 to 8 week washout period. Randomization will be stratified by sex. Blood samples will be collected the day before each dietary phase and on 2 consecutive days after each dietary phase. The mean of the 2 consecutive measurements will be used in the analyses.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Men and women age between 18 and 75 years
  • Average daytime systolic blood pressure ≥ 125 mmHg (blood pressure medication must be stopped 2 weeks before the start of the study).
  • Stable weight for 3 months before the start of the study (+/- 5lbs)

Exclusion criteria

  • Men or women aged under 18 years or over 75 years
  • Average daytime systolic blood pressure ≥ 160 mmHg
  • Average daytime diastolic blood pressure ≥ 110 mmHg
  • History of cardiovascular disease, type 2 diabetes or dyslipidaemia monogenic
  • Endocrine disorders
  • Regular smoker
  • Lipid lowering medications or diabetes medications
  • Food allergies and aversions to any food in the composition of experimental menus
  • Subjects with special dietary habits (e.g. vegetarianism)

Treatment and study plan

Control diet

Other

Milk diet

Other

GABA-rich cheese diet

Other

Primary outcomes

  1. Variation in daytime ambulatory systolic blood pressure after dairy product consumption (Milk or GABA-rich cheese) compared with the control dairy-free diet.

    Time frame: 6 weeks (end-point value)

Secondary outcomes

  1. Variation in lipid concentrations (LDL-C, HDL-C, TG)

    Time frame: 6 weeks (end-point value)

  2. Variation in apolipoprotein B (ApoB) concentration

    Time frame: 6 weeks (end-point value)

  3. Variation in Low Density Lipoproteins (LDL) particle size

    Time frame: 6 weeks (end-point value)

    Post-diet values will be compared

  4. Variation in High Density Lipoproteins (HDL) particle size

    Time frame: 6 weeks (end-point value)

  5. Variation in C-Reactive Protein (CRP) concentration

    Time frame: 6 weeks (end-point value)

  6. Variation in Adiponectin concentration

    Time frame: 6 weeks (end-point value)

Sponsors and collaborators

Lead sponsor

Laval University

Other

Collaborators

  • Agriculture and Agri-Food Canada
  • Dairy Farmers of Canada

Registry information

Official study title

Study of the Impact of Low Fat Dairy (Milk) and High Fat Dairy (Cheese) Consumption on Daytime Ambulatory Blood Pressure and Other Cardiometabolic Risk Factors

Acronym: GABA2

Important dates

Study start
2016
Primary completion
2017
Study completion
2017
First posted
May 5, 2016
Registry last updated
Feb 22, 2018

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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