Unravelling the Impact of Diet on Cardiovascular Health in Heterozygous Familial Hypercholesterolemia.

Study Overview
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Brief Summary
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The investigators will first conduct a fully controlled dietary randomized crossover trial (RCT) including 72 adults with HeFH to investigate the impact of a diet low in red and processed meats and high in plant foods, reflecting Canada's Food Guide, in place of a standard North-American diet on LDL-cholesterol (LDL-C) levels and the plasma metabolome. Such a robust design will also lead to the identification an objective proxy to healthy diet adherence: the metabolomic signature. Secondly, by leveraging the unique resources of the ECOGENE-21 cohort, which includes 963 adults with HeFH, the investigators will evaluate the relationship between the metabolomic signature of the healthy diet and cardiovascular disease risk to determine how objective adherence to a healthy diet is associated with cardiovascular disease outcomes in HeFH.

Detailed Description
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The research combines a dietary RCT (objectives 1, 2) and a cohort investigation (objective 3), both including adults with genetically-defined HeFH and free of lipid-lowering medication (i.e. untreated or withdrawn from medication). The dietary intervention will be undertaken as a crossover RCT at the Institute on nutrition and functional foods (INAF, Laval University) in Quebec City. Participants (men and women with genetically-defined HeFH) will consume in a random order a fully-controlled diet low in red and processed meats and high in plant foods, reflecting Canada's Food Guide principles (CFG diet in further sections), and a standard North American diet (NAD diet; i.e. control diet), reflecting current dietary intakes of French-Canadians, for 4 weeks each, and separated by a 4-week washout period. Once enrolled, participants will enter a 4-week run-in period at the beginning of which they will stop taking their lipid-lowering medication for the study duration (16 weeks). Other medications (e.g. anti-hypertensive drugs, oral contraceptives) will be allowed, but doses will have to remain constant during the study. At the end of the run-in, participants will provide a blood sample and complete a self-administered, validated web-based food-frequency questionnaire. Participants will be randomly assigned to either the CFG-NAD or NAD-CFG diet sequence, using a computer-assisted program. The randomization (1:1) will be stratified by sex and LDL-receptor (LDLR) genotype in 5 blocks of 16 subjects. The two diets will be consumed for 4 weeks and separated by a 4-week washout period. During diet phases, all meals and foods will be provided to ensure optimal diet control using a 7-day cyclic menu. The CFG diet emphasizes low intakes of red and processed meats and high intakes of minimally processed plant foods with water as the drink of choice, as per Canada's Food Guide. The NAD diet reflects current dietary intakes of the French-Canadian adult population in terms of foods, nutrients, and diet quality, as characterized in recent surveys conducted in an age- and a sex-representative sample of adults from the Province of Quebec. An experienced food technician will prepare the diets. Each food and ingredient will be weighed with a precision of ±0.1 g. On weekdays, subjects will visit INAF Clinical Research Unit to consume their lunch meal under the research coordinator's supervision. At that time, they will also be given their evening meals and the next day's packaged breakfast to take home. Weekend meals will be provided at the Friday visits. A checklist will be provided to all participants to identify the consumed foods.Alcohol, vitamin supplements, and natural health products will not be allowed. Tea and coffee (black) will be allowed (≤2 servings/day without daily fluctuations). Participants will be instructed to maintain their usual physical activity level. At the end of each diet, fasting plasma samples will be collected in ethylenediaminetetraacetic acid (EDTA) tubes. Parts of the samples will be stored at -80℃ for future ancillary analyses. Participants' anthropometry, body composition (DEXA scan), and blood pressure will be measured. To incorporate gender aspects associated with the intervention in knowledge transfer activities, subjects' appreciation of the diets will be assessed using visual analog scales filled after each meal on day 7 and 28 of each diet. Objective 1: To investigate the impact of a diet low in red and processed meats and high in plant foods in place of a standard North American diet on LDL-C concentrations - the primary treatment target in HeFH management. This objective will output a convincing demonstration of the cholesterol-lowering effects of diet in adults with HeFH, supporting the effectiveness of dietary interventions in HeFH management. Investigators will compare post-diet LDL-C levels (primary outcome) using mixed models for repeated measures. Objective 2: To assess the impact of a diet low in red and processed meats and high in plant foods in place of a standard North American diet on the plasma metabolome. This objective serves a dual purpose as it will: 1. inform on the dietary impact on systemic metabolism, beyond its impact on LDL-C levels, further supporting the importance of healthy dietary habits in HeFH; and 2. allow the identification of an unbiased HeFH-specific plasma metabolomic signature of a diet low in red and processed meats and high in plant foods to be used as an objective proxy of diet adherence. To document post-diet differences in plasma metabolome and identify the metabolomic signature of the CFG diet, investigators will derive a reproducible multi-metabolite model discriminating the post-CFG/post-NAD metabolomic profiles. Objective 3: To evaluate the association between the plasma metabolomic signature of a diet low in red and processed meats and high in plant foods and cardiovascular disease risk. The metabolomic signature will allow to infer how objective adherence to a healthy diet is associated with cardiovascular disease risk in a distinct, large cohort of free-living adults with HeFH. This will provide an innovative demonstration of the role of diet in long-term cardiovascular disease prevention in adults with HeFH, further supporting the importance of a healthy diet in this high-risk population. To evaluate the association between the plasma metabolomic signature of the healthy CFG diet and cardiovascular disease risk in adults with HeFH, investigators will leverage unique resources of the ECOGENE-21 FH cohort. Participants were recruited at the Chicoutimi Hospital Lipid Clinic. To be included, participants had to be a carrier of a mutation in the LDLR gene and aged 18 to 60 years. Upon recruitment, participants underwent a complete clinical assessment and fasting blood samples were collected in EDTA tubes. Investigators will include the 963 untreated (i.e., never used lipid-lowering medication) adults with HeFH at the moment of plasma sampling. Of those, 295 had a personal history of cardiovascular disease. Investigators will fit and standardize the CFG multi-metabolite model (signature) to the ECOGENE-21 metabolomic data. The relationship between the CFG multi-metabolite model (independent variable) and cardiovascular disease risk will be assessed using logistic regressions. Results will fill key gaps on the short- and long-term influence of diet on cardiovascular health in HeFH.

Official Title
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Unravelling the Impact of Diet on Cardiovascular Health in Heterozygous Familial Hypercholesterolemia: a Metabolomic Approach.

Conditions
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Familial Hypercholesterolemia, Nutrition, Healthy, Cholesterol, Elevated, Cholesterol; Metabolic Disorder, Cardiovascular Diseases

Intervention / Treatment
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* Other: Canada's Food Guide principles (CFG diet)
* Other: Standard North American diet (NAD diet)


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Genetically-defined HeFH Premenopausal women with a regular menstrual cycle for >3 months Postmenopausal women (without hormone replacement) Exclusion criteria: Any cardiovascular disease-risk exacerbating conditions (age >60 years, homozygous FH, personal history of cardiovascular disease, diabetes/anti-diabetic drug use, severe obesity, unstable body weight for >3 months, uncontrolled hypertension, genetic hypertriglyceridemia), Allergies/aversions to components of the experimental diets Any condition that would interfere with optimal participation in the intervention.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: The proposed research will combine a dietary RCT (objectives 1, 2) and a cohort investigation (objective 3). The dietary intervention will be undertaken as a crossover RCT at the INAF (Université Laval) in Quebec City. Men and women with genetically-defined HeFH will consume in a random order a fully-controlled diet low in red and processed meats and high in plant foods, reflecting Canada's Food Guide principles (CFG diet in further sections), and a standard North American diet (NAD diet; i.e. control diet), reflecting current dietary intakes of French-Canadians, for 4 weeks each, and separated by a 4-week washout period. The first and second objective consist respectively to investigate the impact of a CFG diet in place of a standard NAD on LDL-C concentrations and plasma metabolome. The third objective consist to evaluate the association between the plasma metabolomic signature of a diet low in red and processed meats and high in plant foods and cardiovascular disease risk.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Canada's Food Guide principles (CFG diet)<br>During 28 days, participants will receive de CFG diet. The CFG diet emphasizes low intakes of red and processed meats and high intakes of minimally processed plant foods with water as the drink of choice, as per Canada's Food Guide. The number of portions of protein foods, whole-grains, fruits and vegetables to be served daily reflects the recommended ¼-¼-½ proportions. Regarding protein quality, vegetable proteins are served more often than animal proteins as stated in Canada's Food Guide. Weekly, red meat is served once, two days are meatless, and one day is free of animal products. | Other: Canada's Food Guide principles (CFG diet)<br>* 28-day fully controlled dietary intervention during which participants will receive a diet that reflects the recommendations of Canada's Food Guide.<br>|
| Experimental: Standard North American diet (NAD diet)<br>During 28 days, participants will receive de NAD diet. The NAD diet reflects current dietary intakes of the French-Canadian adult population in terms of foods, nutrients, and diet quality, as characterized in recent surveys conducted in an age- and a sex-representative sample of adults from the Province of Quebec. Intakes of minimally processed fruits and vegetables will be low; animal proteins, mostly red and processed meats, will be consumed more often than vegetable proteins; grains will be mostly refined; and ready-to-eat/ready-to-heat foods and sugary beverages will be served daily. | Other: Standard North American diet (NAD diet)<br>* 28-day fully controlled dietary intervention during which participants will receive a diet that reflects the eating habits of Canadians.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Post-diet differences in LDL-C levels. | Investigators will investigate the impact of a diet low in red and processed meats and high in plant foods in place of a standard North American diet on LDL-C concentrations among adults with HeFH. | This analysis will compare LDL-C levels from plasma samples collected at the end (day 28) of each diet. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Post-diet differences in plasma metabolomics profiles. | Investigators will assess the impact of a diet low in red and processed meats and high in plant foods in place of a standard North American diet on the plasma metabolomics profiles to identify the metabolomic signature of the CFG diet. Plasma metabolites will be measured using 3 complementary liquid chromatography-tandem mass spectroscopy methods for 1) polar metabolites (e.g. amino acids), 2) lipids, and 3) free fatty acids. | This analysis will compare metabolomic profiles from plasma samples collected at the end (day 28) of each diet. | 
| Association between the plasma metabolomic signature of the healthy CFG diet and cardiovascular disease prevalence. | Investigators will evaluate the association between the plasma metabolomic signature of the CFG diet (outcome 2) and the prevalence of cardiovascular disease (defined as a composite of myocardial infarction, coronary artery bypass graft, coronary angioplasty, and/or stroke) in the ECOGENE-21 cohort of 963 adults with HeFH using logistic regressions. The main independent variable will be the CFG multi-metabolite signature. In the logistic regressions, the CFG multi-metabolite signature will be modeled as a continuous variable using a z-score. The z-score reflects adherence to the CFG diet (higher z-scores indicate higher adherence to the CFG diet. Prevalent cardiovascular disease (dichotomic variable; yes/no) will be treated as the dependent variable in the logistic regressions. | This analysis will leverage metabolomic profiles from plasma samples collected at the end (day 28) of each diet, but it is not part of the intervention time frame per se. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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familial hypercholesterolemia, diet, LDL-cholesterol, metabolome, cardiovascular disease