What is an ischemic stroke?

Ischemic Stroke by definition refers to a sudden interruption of blood flow to a specific area or some areas of the brain. This can lead to subsequent declines in neurological functions. According to a study published in 2020, it is the second leading cause of death and disability in the world. The American Stroke Association recognises ischemic strokes as 87% of all strokes. 

This article focuses on the fact that ischemic strokes are preventable by addressing some key risk factors like managing cardiovascular diseases, smoking cessation, optimising physical activity, and improvements in one's diet.¹

Understanding Ischemic strokes 

For the brain to function efficiently, it requires a continuous supply of oxygen from arteries, a type of blood vessel. But when there's a blockage in the arteries supplying blood to the brain, the oxygen flow to the brain gradually reduces, causing the death of brain cells. Typically, a blood clot forms, reducing the lumen diameter of the artery in an area of the brain. This results in ischemia, which is a lack of oxygen and nutrients in cells. Another common cause of blockages is the accumulation of fatty deposits, known as plaques, within the blood vessels. These plaques narrow blood vessels and prevent optimal blood circulation.² 

Conversely, a hemorrhagic stroke occurs when an artery in the brain leaks blood or ruptures, leading to excessive pressure on brain cells, which could result in brain damage.²

Additionally, there is another type of stroke called the Transient Ischaemic Stroke (TIA), also known as “mini-stroke” or “warning stroke”. These terms are used because these types of strokes are often warning signs of a future stroke. TIA denotes a brief disruption in blood flow to the brain. Generally, the clot responsible either dissolves spontaneously or becomes dislodged, resulting in symptoms that last for less than five minutes.³  Recent definitions of TIA describe focal symptoms that last less than 1 hour and do not reveal evidence of infarction.⁴

Someone experiencing an ischemic stroke might have:

• Loss of balance
• Trouble seeing
• Face drooping
• Arm or legs weakness
• Slurred speech
• Time is critical 

Call (999 in the UK or 911 in the US) if you think someone is having a stroke.

People at risk or who have experienced an ischemic stroke typically have underlying conditions, with the most common being diabetes, hypertension, and high blood cholesterol. Individuals with conditions like sickle cell disease and atrial fibrillation are also at risk of ischemic strokes.⁵ Managing these conditions helps prevent the occurrence of an ischemic stroke and other types of strokes in general.

Role of diet in ischemic stroke 

In addition to doctor-prescribed medications, researchers suggest that adopting a healthy diet can significantly reduce the risk of developing an ischemic stroke.

Various studies from these researchers recommend following dietary patterns rather than suggesting specific foods.^6,7 The Mediterranean and Dietary Approaches to Stop Hypertension (DASH) are extensively documented dietary patterns.⁷ The traditional Mediterranean diet consists of a high use of olive oil, nuts, fruits, vegetables and cereals; moderate intake of fish and poultry; low consumption of dairy products, red meat and processed meat; low intake of sweets and moderate alcohol intake. These dietary plans incorporate high levels of fibre, vitamins, minerals, phenolics, and unsaturated fatty acids while maintaining low levels of sodium and saturated and trans fatty acids.⁷

Consumption of fruits and vegetables can moderately decrease the risk for both ischemic and hemorrhagic strokes. In particular, higher consumption of apples and/or pears, citrus fruits as well as green leafy vegetables are associated with significantly reduced stroke risk. A fruit-vegetable-rich diet can modestly lower blood pressure, partly through its magnesium-potassium contents, carotenoids and phenolic compounds which have an inverse relationship with associated stroke risks.

Fruits and vegetables serve as excellent sources of vitamin C. This vitamin acts as an antioxidant, which may limit low-density lipoprotein cholesterol oxidation, reduce smooth muscle growth, and decrease blood pressure and systemic inflammation. Green leafy vegetables like cabbages, beans, and lentils are rich in folate which also contributes to stroke prevention.⁶

Dietary factors linked to ischemic stroke

Diet plays a role in the risk of developing a stroke through several mechanisms including blood pressure, lipids, cholesterol levels, oxidative stress, inflammation, vascular health, blood sugar levels, gut microbiome and body weight.⁷

Certain factors can increase the odds of developing an ischemic stroke:

Dyslipidemia

When we consume foods containing fatty acids, the body converts them into cholesterol and triglycerides. High levels of “bad” cholesterol and triglycerides in the bloodstream can lead to the formation of atherosclerotic plaque inside arteries, thereby making them narrow and more prone to ischemic strokes.⁸

The effect of sodium and potassium intake

Too much sodium is associated with high blood pressure, a major cause of strokes. Conversely, potassium-rich foods such as bananas, spinach, and sweet potatoes help to regulate blood pressure, thus reducing the chances of experiencing a stroke.⁹ The National Health Service (NHS) recommends the consumption of no more than 6g (0.20z) of salt, the equivalent of one teaspoon of salt, per day.

Hyperglycemia

Increased levels of glucose in the blood have been linked to a higher likelihood of developing a stroke, especially for diabetics. Stabilizing blood sugar with a diet containing complex carbohydrates, lean protein and healthy fats is fundamental in preventing strokes.

Effects of alcohol and substance use

Light and moderate alcohol consumption have been reported, by a meta-analysis study, to decrease the risk of ischemic strokes. However, excessive alcohol consumption can increase the risk of strokes by raising blood pressure and promoting the formation of blood clots.¹⁰ The NHS advised not to regularly drink more than 14 units a week and to spread drinking over 3 days or more. Also, individuals who haven’t fully recovered from a stroke could be more sensitive to alcohol. Furthermore, recreational drugs such as amphetamines, heroin, and cannabis are known to increase blood pressure. so they are associated with a higher risk of both ischemic and Hemorrhagic strokes.¹¹

Importance of adequate hydration

It is highly recommended to ensure adequate hydration for conditions such as hypertension, anaemia and diabetes. Hydration is imperative for maintaining good blood flow within the body and preventing the increased chances of having a stroke.

Dietary strategies for recovery after an ischemic stroke

When it comes to recovering from an ischemic stroke, dietary choices play a critical role alongside physiotherapist rehabilitation methods. Neuroplasticity, i.e., the growth of new brain cells and the enhancement of connections between neurons, can be activated through consistent practice and targeted exercises. This process heavily relies on a protein called BDNF.¹² Therefore, incorporating BDNF-promoting foods like fruits, vegetables, whole grains, and lean protein in the diet of someone who has suffered from an ischaemic stroke would greatly complement rehabilitation, leading to more successful recovery. It is also important to consult with a healthcare professional or a registered dietitian if you have odynophagia or experience difficulty swallowing. They can help develop a personalized diet plan that meets specific nutritional needs and supports recovery. 

Practical tips for a stroke-friendly diet

Read food labels and make informed choices

Carefully read labels when purchasing food. Focus on products that are low in sodium, saturated fats, and added sugars; choose whole and unprocessed foods whenever possible.

Stay hydrated

Drink plenty of water throughout the day to maintain hydration and support optimal blood flow. Avoid sugary drinks and excessive caffeine consumption, as they can contribute to dehydration.

Seek guidance from a specialist

Consult with your healthcare provider or a registered dietitian to develop a personalized diet plan that meets your specific nutritional needs and supports your overall health goals, including ischemic stroke prevention and recovery.

Here is an example of a dietary recommendation plan from Professor J David Spence, an internationally renowned neurologist who worked at the London Health Center: 

• Avoid egg yolks: use egg whites, egg beaters, egg creations or similar substitutes
• The flesh of any animal: a serving the size of a hand palm or less, every other day (or half that daily)
• Seldom red meat, mainly fish and chicken
• Get a high intake of olive oil and canola oil
• Only consume whole grains
• High intake of vegetables, fruits and legumes
• Avoid deep-fried foods and hydrogenated oils (trans fats)
• Cut back on sugar and refined grains, and limit potatoes

Lastly, there is currently limited data on specific diets concerning ischemic stroke subtypes (eg, large-vessel, small-vessel, and cardioembolic stroke). The various subtypes of ischaemic strokes have different underlying disease mechanisms so they may need different dietary approaches. This is why guidance from a professional is very important in the case of ischaemic strokes.

FAQ’s 

Can a stroke patient eat eggs?

Eggs are a valuable protein source for individuals recovering from a stroke. They are soft and versatile, making them suitable for consumption by those experiencing swallowing difficulties (dysphagia) post-stroke. While egg yolks are high in cholesterol, opting for egg whites is recommended.

What heals the brain after a stroke?

Neuroplasticity, the brain's ability to form new connections and regenerate cells, is crucial for post-stroke recovery. This process is supported by a protein called BDNF, which plays a key role in facilitating brain cell repair and growth. To enhance neuroplasticity and promote recovery, it is recommended to include BDNF-rich foods in your diet.

How are ischemic strokes classified?

Depending on the mechanism of the ischemia there are 3 main ischemic strokes subtypes:

thrombosis, embolism, and hypoperfusion.

• Thrombosis refers to the formation of a blood clot directly in an artery of the brain 
• An embolism occurs when a fragment of a clot formed elsewhere in the body breaks free and travels through the bloodstream until it becomes lodged in the brain
• Hypoperfusion or inadequate blood flow, occurs when there is a decrease in the delivery of blood to a particular area of the body. In the context of the brain, hypoperfusion can result from various factors, such as reduced blood volume or constriction of blood vessels

Summary

To conclude, it is possible to reduce the chances of developing an ischemic stroke by embracing good eating habits and adopting a healthy lifestyle. This means consuming fruits, vegetables, whole grains as well as lean proteins and beneficial fats, while avoiding processed foods and excessive sodium intake. Additionally, it is important to drink enough water and avoid alcohol and substance abuse. It is highly advisable to consult medical practitioners who will offer advice on proper nutrition plans that suit specific needs.