Stroke is a leading cause of morbidity and mortality worldwide. According to the Stroke Association, there are 100,000 people who have strokes each year, and there are 1.3 million strokes survivors in the UK. Recovery from stroke involves complex rehabilitation processes that are influenced by various factors, including nutrition. Recent research suggests that diets high in protein and fat may offer specific benefits for stroke patients. This article explores the potential advantages of a high protein and fat diet for individuals recovering from stroke, focusing on muscle preservation, gut and brain health, and overall recovery.

Gut-brain axis

Discovery of the enteric nervous system (ENS), which is also considered the third branch of the autonomic nervous system (ANS), in the middle of the nineteenth century, has led to an understanding of the interaction between the nervous system and the digestive system. The ENS is often referred to as the ‘second brain’ due to likenesses with the brain such as complexity, size, and similarity in neurotransmitters and signalling molecules.

There is two-way communication between the brain and the viscera, which includes the gastrointestinal tract. This occurs through multiple parallel pathways, including two branches of the ANS, namely the sympatho-adrenal axis, which modulates gut-associated lymphoid tissue, and the hypothalamic-pituitary-adrenal (HPA) axis, as well as descending monoaminergic pathways, which modulate gain of dorsal horn excitability and spinal reflexes. The two key subcortical structures that generate these outputs are the hypothalamus and the amygdala. Findings from recent studies suggest that there are various forms of subliminal ineroceptive inputs from the gut, which include signals generated by intestinal microbes. The evidence suggests that this may influence emotional arousal, memory formation, and affective behaviours.

Brain health and cognitive recovery

The brain's health is intricately linked to its nutritional environment. Diets high in healthy fats, particularly omega-3 fatty acids, and adequate protein are beneficial for brain function and recovery post-stroke.

Omega-3 fatty acids, found in fatty fish, have anti-inflammatory and neuroprotective properties. These fatty acids are crucial for maintaining the integrity of neuronal membranes and promoting synaptic plasticity, which is vital for cognitive recovery after a stroke. Research indicates that omega-3 supplementation can reduce inflammation, protect against neuronal damage, and support brain repair mechanisms.

In addition to healthy fats, proteins are essential for the production of neurotransmitters, the chemicals that facilitate communication between neurons. Amino acids derived from dietary proteins, such as tryptophan and tyrosine, are precursors to neurotransmitters like serotonin and dopamine, which play roles in mood regulation, motivation, and cognitive function. Choline, derived from eggs, is also crucial as it is involved in acetylcholine, which is associated with higher cognitive functions, and phosphatidylcholine (PtdCho), which is a crucial component of cellular membranes and plays a role in cell signalling. Ensuring adequate protein intake can thus support mental health and cognitive recovery in stroke patients.

Inflammation and immune response

Inflammation plays a significant role in the pathophysiology of stroke. Diets rich in anti-inflammatory nutrients can modulate the immune response and aid recovery. Evidence suggests that Inflammatory Bowel Disease (IBD) increases the risk of acute ischemic stroke highlighting the effect of gut-inflammation, which leads to neuroinflammation.

Healthy fats, particularly monounsaturated and polyunsaturated fats, have anti-inflammatory properties. Foods like olive oil, avocados, nuts, and seeds can reduce systemic inflammation, which is beneficial for stroke recovery. Lower inflammation levels can improve endothelial function, reduce the risk of secondary strokes, and support overall cardiovascular health. There are mixed studies regarding the effects of a high protein diet on cardiovascular morbidity and mortality, but a recent meta-analysis suggested that there is no association between high protein diets and cardiovascular morbidity and mortality. This being said, more research is needed regarding the matter.

Proteins are vital for the immune system. Amino acids are required for the synthesis of antibodies and other immune-related molecules. Adequate protein intake ensures that the body can mount an effective immune response, which is essential for recovery and preventing infections, a common complication in stroke patients.

Energy provision and metabolic health

A diet high in fats and proteins can provide a stable and efficient energy source which is crucial for stroke recovery.

The ketogenic diet, characterised by high fat, moderate protein, and low carbohydrate intake, has shown promise in neurological recovery. By inducing a state of ketosis, where the body utilizes fats as its primary energy source, the ketogenic diet can enhance mitochondrial function and reduce oxidative stress. This metabolic shift can be particularly beneficial for brain health, potentially improving outcomes in stroke rehabilitation.

High-fat and high-protein diets have a lower glycemic impact and can improve several metabolic parameters, such as glucose metabolism and insulin sensitivity, in comparison to high-carbohydrate diets. The release of incretin hormones like GLP-1 and GIP in response to protein intake helps in regulating blood sugar levels and may contribute to improved metabolic health, which helps in maintaining stable blood sugar levels, reducing the risk of insulin resistance and type 2 diabetes, which are common comorbidities in stroke and dementia patients. Stable blood sugar levels are crucial for preventing further vascular damage and inflammation, including supporting overall metabolic health during recovery.

Muscle preservation and recovery

One of the critical challenges faced by stroke patients is muscle atrophy and weakness, often resulting from prolonged immobility. High protein intake is essential for muscle repair and maintenance. Proteins are the building blocks of muscle tissue, and adequate protein consumption helps to mitigate muscle loss and promote muscle protein synthesis.

Protein consumption stimulates muscle protein synthesis (MPS), which is crucial for muscle repair and growth. Amino acids, particularly leucine, play a significant role in this process. High-protein diets ensure a steady supply of these essential amino acids, which can enhance the recovery of muscle strength and function in stroke patients. Studies have shown that patients receiving higher protein intake have better outcomes in terms of muscle mass retention and rehabilitation progress.

Sarcopenia, the loss of muscle mass and strength associated with aging and inactivity, is a common issue among stroke survivors. A high-protein diet can combat sarcopenia by providing the necessary nutrients to preserve lean body mass. This is especially important for older stroke patients, who are at a higher risk of muscle deterioration. Evidence has shown that high protein diets can support muscle growth and improve body composition, especially when combined with resistance training. For instance, resistance-trained men consuming high protein diets (greater than 2 g/kg/day) have shown favourable changes in body composition, such as increased lean mass and reduced fat mass. However, the effects can vary based on individual differences and training regimens.

Practical considerations and dietary recommendations

Implementing a high protein and fat diet in stroke patients requires careful planning to ensure it meets all nutritional needs and supports overall health and can be vital to successful rehabilitation.

Meat-based high-protein diets provide essential amino acids and other nutrients like iron, selenium, and vitamins B12 and A, which are crucial for overall health. It is important to include high-quality protein sources such as red meats, fish, eggs, and full-fat dairy products in stroke patients’ diet plans. Eggs contain many beneficial nutrients, among them choline, which plays an integral part in brain, muscle, and liver function, and lipid metabolism. It is essential to distribute protein intake evenly throughout the day to maximize muscle protein synthesis.

Incorporating healthy fats from sources like fatty fish, avocados, and animal fats such as butter, ghee, and beef or goose fat/dripping is crucial. These fats not only provide energy but also contribute to brain health and anti-inflammatory benefits. Fats such as butter provide Vitamins A, D, E, K2 and B12 which play a vital role in bone health, immune support, vision, and mental health. Animal fats are a great source of cholesterol which is crucial for brain cell survival.

Dietary plans should be individualized based on the patient’s specific needs, preferences, and medical conditions. Regular monitoring by healthcare professionals, including dietitians, is necessary to ensure the diet is balanced and effective in supporting recovery.

Conclusion

A high protein and fat diet such as the carnivore and keto carnivore diet offers numerous benefits for stroke patients, from preserving muscle mass and supporting cognitive recovery to providing stable energy and reducing inflammation. While promising, it is essential to tailor these dietary interventions to individual needs and monitor their effects closely. Further research is needed to optimise dietary strategies for stroke recovery, but current evidence suggests that high protein and fat intake can play a crucial role in enhancing rehabilitation outcomes.

Notes

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10 Stroke statistics | Stroke Association.