Vegan Diets: Stroke Risk Or Healthier Choice?

A vegan diet may put you at risk for stroke, according to a study published in the British Medical Journal. The research followed 48,000 people for up to 18 years and found that those on plant-based diets had a 20% higher risk of stroke. However, the study could not prove whether this was due to their diet or other lifestyle factors. Experts suggest that the association may be linked to low vitamin B12 levels, which are commonly found in meat, dairy, and fish. While more studies are needed to confirm the connection, it is important for vegans and vegetarians to ensure they are consuming enough specific nutrients like vitamin B12 and iron to maintain their health.

Plant-based diets may lower stroke risk

Stroke is a leading cause of death and disability in the United States and worldwide. Each year, approximately 795,000 Americans experience a stroke, costing the country $33 billion annually. While high-income countries have seen substantial declines in stroke incidence and mortality, low-income countries continue to experience significant increases.

Risk Factors

There are numerous risk factors for stroke, including advanced age, hypertension, diabetes, dyslipidemia, atrial fibrillation, smoking, physical inactivity, poor nutrition, family history, chronic kidney disease, obesity, coronary heart disease, sleep apnea, and depression. Many of these risk factors are modifiable through lifestyle changes, suggesting that certain lifestyle choices may significantly impact stroke risk.

Plant-Based Diets and Stroke Risk

Plant-based diets have been associated with a reduced risk of diabetes and cardiovascular disease. However, the relationship between plant-based diets and stroke risk is less clear, with few studies examining this association.

A recent study by Baden et al. (2021) analyzed the association between plant-based diet quality and stroke risk in three large US cohorts: the Nurses' Health Study, the Health Professionals Follow-Up Study, and the NHSII. They found that participants who adhered to a healthful plant-based diet had a lower risk of total stroke, with a 10% reduction in risk compared to those with the lowest-quality diets.

The study also examined the association between plant-based diet quality and specific types of stroke, finding a marginally lower risk of ischemic stroke (the most common type of stroke) among those with the highest-quality plant-based diets. However, no association was found between plant-based diet quality and hemorrhagic stroke risk.

In contrast, a previous study by Tong et al. (2019) suggested that vegetarian and vegan diets may increase stroke risk. This study, based on the EPIC-Oxford Study, found that vegetarians and vegans had a 20% higher risk of stroke compared to meat-eaters. The researchers proposed that this could be due to low vitamin B12 levels, which are commonly associated with plant-based diets.

The Importance of Diet Quality

The discrepancies between studies may be due to differences in the quality of plant-based foods consumed. A vegetarian or vegan diet high in unhealthy plant-based foods, such as refined grains and added sugars, may not provide the same health benefits as a diet rich in whole foods. Baden et al. (2021) emphasized the importance of considering plant-based dietary quality, highlighting the need to increase the consumption of healthy plant foods while decreasing the intake of unhealthy plant-based options.

While more research is needed, current evidence suggests that plant-based diets may lower stroke risk, particularly when these diets are rich in healthy plant-based foods. However, it is important to note that a well-planned and varied diet is essential, regardless of whether it is plant-based or includes meat.

Vegetarian diets may increase stroke risk

Vegetarian and vegan diets have been associated with a reduced risk of heart disease, but recent research has linked them to an increased risk of stroke. While the research is not yet conclusive, the findings highlight the importance of considering the quality of plant-based diets and ensuring adequate nutrient intake.

Study Findings

A study published in the British Medical Journal (BMJ) found that vegetarians and vegans had a 22% lower risk of heart disease compared to meat-eaters, but a 20% higher risk of stroke. This suggests that while plant-based diets can offer some health benefits, they may also carry certain risks. Another study published in Neurology found that a healthful plant-based diet was associated with a 10% lower risk of total stroke and a marginally lower risk of ischemic stroke, but no association was found with hemorrhagic stroke.

Potential Explanations

The increased risk of stroke among vegetarians and vegans may be due to low levels of certain essential nutrients, such as vitamin B12, vitamin D, and cholesterol. These nutrients are primarily found in animal products, and their deficiency can increase the risk of stroke. Additionally, plant-based diets may be higher in processed foods, added sugars, and refined grains, which can contribute to an increased risk of stroke.

Recommendations

To reduce the risk of stroke, it is important to focus on the quality of plant-based foods and ensure a well-planned diet that includes a variety of nutrients. This includes consuming whole grains, fruits, nuts, vegetables, and legumes, while limiting refined grains, added sugars, and processed foods. It is also crucial for vegetarians and vegans to monitor their nutrient intake and consider taking supplements, especially for vitamin B12, to prevent deficiencies that can increase stroke risk.

Hemorrhagic strokes are linked to vegan diets

Vegan diets have been linked to an increased risk of hemorrhagic strokes, a type of stroke caused by a ruptured blood vessel in the brain. This is surprising, given that plant-based diets are associated with a reduced risk of heart disease. However, research suggests that this may be due to deficiencies in certain essential nutrients that are more commonly found in animal products.

The increased risk of hemorrhagic stroke

Vegetarians and vegans were found to have a 20% higher risk of stroke than meat-eaters, and this was mostly due to a higher rate of hemorrhagic stroke. Hemorrhagic strokes are caused by the rupture of a weakened blood vessel, which causes bleeding into the brain. They can often be more damaging and deadly than ischemic strokes, which are caused by blood clots.

The potential causes

The increased risk of hemorrhagic stroke among vegetarians and vegans may be due to deficiencies in certain essential nutrients. For example, very low cholesterol levels have been linked to a higher risk of hemorrhagic stroke, although low cholesterol is protective against heart disease.

In addition, vitamin B-12, vitamin D, and other nutrient deficiencies are more common among vegetarians and vegans, and these deficiencies could contribute to an increased risk of hemorrhagic stroke. Vitamin B-12, in particular, is mostly found in animal products, so people who follow vegan or vegetarian diets may not be getting enough. Other nutrients that can be lacking in plant-based diets include vitamin B-6, folic acid, and omega-3 fatty acids, all of which are important for brain health.

The importance of a well-planned diet

While vegan and vegetarian diets can be healthy, it is important to ensure that they are well-planned and include a variety of nutrient-dense foods. This may involve supplementing with certain vitamins or minerals to prevent deficiencies. Including plenty of fruits, vegetables, whole grains, and plant-based sources of protein and healthy fats can also help to ensure a balanced and nutritious diet.

Overall, while vegan diets may be linked to an increased risk of hemorrhagic stroke, this risk can potentially be mitigated by ensuring adequate intake of essential nutrients.

Plant-based diets may lack certain nutrients

Plant-based diets have gained popularity in recent years due to their perceived health benefits, as well as environmental and ethical concerns. However, it is important to note that these diets may lack certain essential nutrients, which could potentially increase the risk of stroke and other health issues.

Nutrients Lacking in Plant-Based Diets

• Vitamin B12: Vitamin B12 is essential for developing red blood cells, maintaining nerves, and supporting normal brain function. It is almost exclusively found in animal-sourced foods, and vegans are at a higher risk of deficiency than vegetarians.
• Creatine: Creatine is important for muscle and brain function and is found in animal foods. While it is not essential as it can be produced by the liver, vegetarians tend to have lower levels of creatine in their muscles.
• Carnosine: Carnosine is an antioxidant that is important for muscle function and is only found in animal-derived foods.
• Vitamin D3: Vitamin D3 is essential for various functions in the body and is found in animal-sourced foods, especially fatty fish. Those following a plant-based diet may be at a higher risk of deficiency, especially in winter and in countries far from the equator.
• Docosahexaenoic Acid (DHA): DHA is an essential omega-3 fatty acid that is important for normal brain development and function. It is mainly found in fatty fish, fish oil, and certain types of microalgae. While it can also be made from the omega-3 fatty acid ALA found in plant foods like flaxseeds, chia seeds, and walnuts, the conversion process is very inefficient.
• Heme Iron: Heme iron, found only in meat, is much better absorbed than non-heme iron, which is commonly found in plant foods.
• Taurine: Taurine is a sulfur compound found in various body tissues, and its function is not entirely clear. It is naturally found in animal-based foods but is also available in synthetic supplement form.

Addressing Nutrient Deficiencies in Plant-Based Diets

To ensure adequate nutrient intake, those following a plant-based diet may need to supplement their diet with specific nutrients. For example:

• Vitamin B12 can be obtained through supplements or by including fortified foods such as enriched yeast extracts, nori seaweed, and tempeh in the diet.
• Creatine and carnosine supplements are available for vegetarians and vegans.
• Vitamin D3 supplements made from lichen are available for vegans.
• DHA supplements in the form of algal oil can be taken by vegans and vegetarians.
• Pairing different plant-based protein sources, such as rice and beans, can help ensure a complete amino acid profile.
• Including algae or algae oil in the diet can help address potential omega-3 fatty acid deficiencies.
• Iron supplements can be taken if blood levels are low, and including vitamin C-rich foods with plant-based iron sources can enhance absorption.

While plant-based diets offer many health benefits, it is important to be mindful of potential nutrient deficiencies. By supplementing the diet with specific nutrients and carefully planning meals, individuals can ensure they are getting all the essential nutrients their bodies need.

Meat-eaters are at higher risk of heart disease

While a vegan diet may increase the risk of stroke, meat-eaters are at a higher risk of heart disease. A study published in the UK-based BMJ found that fish eaters and vegetarians had 13% and 22% lower rates of heart disease, respectively, compared to meat eaters.

A larger, more recent study by the University of Oxford's Nuffield Department of Population Health supports this finding. It was the largest systematic review of prospective evidence to date, including 13 cohort studies and over 1.4 million participants. The study found that each 50g/day increase in the consumption of processed meat (e.g. bacon, ham, sausages) and unprocessed red meat (e.g. beef, lamb, pork) increased the risk of coronary heart disease by 18% and 9%, respectively. The high content of saturated fat in red meat and sodium (salt) in processed meat are likely contributors to this increased risk.

The INTERSTROKE study, an international case-control study with approximately 27,000 participants, found that plant-based diets may reduce the likelihood of several risk factors linked to heart disease, including hypertension, waist-to-hip ratio, diet quality, diabetes, cardiac causes, and lipid profile. Additionally, very low-fat, high-fibre plant-based diets have been shown to reverse atherosclerotic lesions in clinical interventions involving patients with ischemic heart disease.

Furthermore, meat consumption has been positively correlated with total stroke risk in multiple meta-analyses. In one such analysis, for every additional meat serving (100g) consumed per day, there was a 24% increased risk of ischemic stroke.

In summary, while a vegan diet may increase the risk of stroke, meat-eaters are at a significantly higher risk of heart disease due to the high content of saturated fat in red meat and sodium in processed meat, as well as the positive correlation between meat consumption and stroke risk. Plant-based diets have been shown to reduce multiple risk factors for heart disease and may even reverse atherosclerotic lesions.

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