September 4, 2019; Vol. 366; l4897
Tammy Y N Tong, Paul N Appleby, Kathryn E Bradbury, Aurora Perez-Cornago, Ruth C Travis, Robert Clarke, Timothy J Key: From the University of Oxford, UK.
Vegetarianism, embraced by many for its purported health benefits, has long been associated with a reduced risk of cardiovascular diseases. However, a recent in-depth examination, known as the EPIC-Oxford cohort study, challenges some prevailing assumptions. The study investigates the associations between vegetarian diets and the risks of ischemic heart disease and stroke, unraveling a nuanced relationship that considers various diet groups and an array of confounding variables.
Key Points from the Study:
- Diverse Diet Groups and Comprehensive Analysis:
- The study encompassed meat eaters, fish eaters, vegetarians, and vegans, with a focus on individuals with no history of cardiovascular diseases. A meticulous analysis considered socio-demographic characteristics, lifestyle factors, medical history, and nutritional levels.
- Risk of Acute Myocardial Infarction and Ischemic Stroke:
- Surprisingly, the study found no significant differences between diet groups for the risk of acute myocardial infarction or ischemic stroke.
- Lower Risks of Ischemic Heart Disease for Fish Eaters and Vegetarians:
- Fish eaters and vegetarians demonstrated lower risks of ischemic heart disease compared to meat eaters, suggesting a potential cardiovascular benefit associated with these diets.
- Higher Rates of Haemorrhagic Stroke for Vegetarians:
- Vegetarians exhibited significantly higher rates of haemorrhagic stroke than meat eaters and a higher risk of total stroke. This contradicts conventional wisdom and raises questions about the protective factors associated with animal food consumption.
- Nutrient Levels and Stroke Risks:
- The study observed that vegetarians and vegans in the EPIC-Oxford cohort had lower circulating levels of essential nutrients, such as vitamin B12, vitamin D, essential amino acids, and long-chain n-3 polyunsaturated fatty acids. These nutritional differences may contribute to the observed associations with stroke risks.
- Intriguing Connection Between LDL-C and Haemorrhagic Stroke:
- The study explored an inverse association between LDL-C (low-density lipoprotein cholesterol) and haemorrhagic stroke, suggesting a counterintuitive relationship where reduced LDL-C levels might increase the risk of stroke.
- Blood Pressure and Cardiovascular Risks:
- High blood pressure emerged as a significant risk factor for both ischemic heart disease and stroke, reinforcing the importance of considering this factor in cardiovascular risk assessments.
- Quantifying the Impact:
- Adjusting for socio-demographic and lifestyle factors, fish eaters and vegetarians exhibited 13% and 22% lower rates of ischemic heart disease than meat eaters, respectively. However, vegetarians had 20% higher rates of total stroke, primarily due to an increased risk of haemorrhagic stroke.
The EPIC-Oxford cohort study adds a layer of complexity to our understanding of the cardiovascular implications of vegetarian diets. While fish eaters and vegetarians show a reduced risk of ischemic heart disease, the study unveils a higher risk of haemorrhagic and total stroke for vegetarians. The intricate interplay of nutritional factors, lifestyle choices, and the unexpected connection between LDL-C and stroke risk emphasizes the need for continued research in the realm of dietary patterns and cardiovascular health. As individuals navigate dietary choices, these findings underscore the importance of a well-balanced and informed approach to promote heart health and minimize stroke risks.