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

Hypertension Clinical Trial

— GABA2  

Official 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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02763930
• Other study ID #: INAF-2015-268
• Status: Completed
• Phase: N/A
• First received: May 3, 2016
• Last updated: February 21, 2018
• Start date: February 2016
• Est. completion date: December 2017

Study information

• Verified date: February 2018
• Source: Laval University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

Description:

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 60
• Est. completion date: December 2017
• Est. primary completion date: July 2017
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 75 Years

Eligibility

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)

Related Conditions & MeSH terms

• Hypertension

Intervention

Other:
• Control diet

• Milk diet

• GABA-rich cheese diet

Locations

Country	Name	City	State
Canada	Institute of Nutrition and Fonctional Foods	Quebec

Sponsors (3)

Lead Sponsor	Collaborator
Laval University	Agriculture and Agri-Food Canada, Dairy Farmers of Canada

Country where clinical trial is conducted

Canada, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Variation in daytime ambulatory systolic blood pressure after dairy product consumption (Milk or GABA-rich cheese) compared with the control dairy-free diet.		6 weeks (end-point value)
Secondary	Variation in lipid concentrations (LDL-C, HDL-C, TG)		6 weeks (end-point value)
Secondary	Variation in apolipoprotein B (ApoB) concentration		6 weeks (end-point value)
Secondary	Variation in Low Density Lipoproteins (LDL) particle size	Post-diet values will be compared	6 weeks (end-point value)
Secondary	Variation in High Density Lipoproteins (HDL) particle size		6 weeks (end-point value)
Secondary	Variation in C-Reactive Protein (CRP) concentration		6 weeks (end-point value)
Secondary	Variation in Adiponectin concentration		6 weeks (end-point value)