Vegetarian Diet in Patients With Ischemic Heart Disease
Keywords
Abstract
Description
Background
Cardiovascular disease is the leading cause of death globally. Ischemic heart disease (IHD) contributes the most to this statistic and since 1990 the global burden of IHD has increased. It is estimated that 50 000 Swedish patients are hospitalized every year due to IHD. The risk of developing IHD is to a large extent determined by the existence and state of several modifiable risk factors including dietary habits, smoking, hypertension, diabetes mellitus, hyperlipidemia, high apolipoprotein B/ apolipoprotein A1-ratio, abdominal obesity, physical inactivity, alcohol consumption and psychosocial factors. High levels of oxidative stress, oxidized LDL cholesterol and the microbial metabolite trimethylamine N-oxide TMAO have been suggested to be associated with development of IHD.
A plant-based (vegetarian) diet may provide cardiovascular health benefits through various mechanisms. Clinical studies suggest that a vegetarian diet has positive effects on low-density lipoprotein (LDL) cholesterol, oxidized LDL cholesterol, total cholesterol, triglycerides, apolipoprotein B, body mass index (BMI), inflammatory markers, blood pressure, arterial intima-media thickness, insulin sensitivity, glycated hemoglobin, (HbA1c) and fasting glucose levels. Through positive impacts on risk factors that a vegetarian diet is associated with a lowered incidence and mortality of IHD and an overall reduced mortality.
A weakness of several prior long-term controlled studies comparing vegetarian and meat-containing diets is the lack of well-defined control diets leading to study heterogeneity. For example, some of the subjects on meat-containing diets consume great quantities of red meat, others eat substantial amounts of processed meat products and some eat mostly white meat and fish complicating interpretation of outcome. In cross-sectional or observational cohort studies comparing long-term vegetarians to long-term omnivores, results may be influenced by other lifestyle choices besides the studied diet, such as smoking and exercise.Furthermore, the participants in many previous studies were often healthy volunteers and not patients with overt cardiovascular disease.
Purpose
The objective is to perform an open label, 4 week randomized, cross-over study to compare the effect of a vegetarian diet to a conventional (meat containing) diet based on the Swedish average meat consumption on a range of parameters with prognostic importance for cardiovascular disease: lipids, inflammation, oxidative stress, BMI, HbA1c, apolipoprotein B/apolipoprotein A1-ratio, gut microbiota, endothelial function and quality of life. The study will be conducted in patients diagnosed with STEMI (ST-segment elevation myocardial infarction), non-STEMI (non-ST-segment elevation myocardial infarction) or angina pectoris and treated by percutaneous coronary intervention (PCI).
Hypothesis
The study hypothesis is that patients diagnosed with IHD can benefit from a vegetarian diet as assessed by multiple risk markers for this type of disease with a primary focus on changes in oxidized LDL cholesterol.
Clinical relevance
During the last decades the global mortality from IHD has remained unchanged regardless of development of new invasive and pharmacological treatments. Despite the fact that the prevalence and mortality from IHD have decreased in this country since 1990 and that the decrease most likely is due to lifestyle changes, IHD remains the leading cause of death in Sweden.
Dates
Last Verified: | 01/31/2020 |
First Submitted: | 10/19/2016 |
Estimated Enrollment Submitted: | 10/20/2016 |
First Posted: | 10/23/2016 |
Last Update Submitted: | 02/11/2020 |
Last Update Posted: | 02/16/2020 |
Actual Study Start Date: | 09/30/2017 |
Estimated Primary Completion Date: | 09/30/2018 |
Estimated Study Completion Date: | 05/31/2019 |
Condition or disease
Intervention/treatment
Other: Vegetarian diet followed by meat diet or vice versa
Phase
Arm Groups
Arm | Intervention/treatment |
---|---|
Experimental: Vegetarian - Meat 4 weeks of vegetarian diet followed by 4 weeks of 'wash out' (no intervention) and 4 weeks of meat-containing diet | |
Active Comparator: Meat - Vegetarian 4 weeks of meat-containing diet followed by 4 weeks of 'wash out' (no intervention) and 4 weeks of vegetarian diet |
Eligibility Criteria
Ages Eligible for Study | 18 Years To 18 Years |
Sexes Eligible for Study | All |
Accepts Healthy Volunteers | Yes |
Criteria | Inclusion Criteria: - Stable ischemic heart disease and previous percutaneous coronary intervention (PCI. - Under optimal medical treatment including aspirin and cholesterol lowering drugs (statins) Exclusion Criteria: - PCI treatment during the last 30 days - Inability to provide informed consent - Already following a vegetarian or a vegan diet - Known vitamin B deficiency - Known food allergy - Previous obesity surgery or gastric bypass surgery - Life expectancy <1 year |
Outcome
Primary Outcome Measures
1. Change in oxidative stress evaluated by oxidized LDL cholesterol changes [4 weeks]
Secondary Outcome Measures
1. Changes in cardiovascular risk profile according to the Framingham Risk Score [4 weeks]
2. Changes in biomarkers of inflammation [4 weeks]
3. Changes in biomarkers of lipid status [4 weeks]
4. Changes in HbA1c [4 weeks]
5. Changes in TMAO levels in plasma [4 weeks]
6. Changes in gut microbiota [4 weeks]