Nutritional cognitive neuroscience - nutrition and rehabilitation
From hospital bed to rehabilitation: can our meals really help us heal after brain injury? With the Paralympic GB team doing us proud in Tokyo, we thought we would look back at the importance of nutrition following brain injury; after all, if you want to be an elite athlete in your discipline, nutrition must be high on the agenda! Here we look to the new school of science, trying to find the best recipes for brain health.
Nutritional cognitive neuroscience is one of the newest kids on the research block, an arrival merited by mounting evidence linking specific nutrients and diets to the brain’s structure and function.
It is already widely accepted that our mood, behaviour and brain function are all influenced by our diet.
But scientists are now discovering that diet can make a big difference to rehabilitation outcomes for brain injury survivors.
TBI (traumatic brain injury) is associated with profound nutritional alterations. 
Scientists already know (1) damage to the brain can cause profound nutritional changes in the body, such as:
- Hypermetabolism: an increase in our metabolic rate (the rate at which we process energy from food to stay alive) which may lead to sudden weight loss
- Protein loss: protein lost through the digestive tract can potentially cause fluid retention, food intolerance and diarrhoea.
- Changes in nitrogen metabolism: we need nitrogen to make amino acids, which make proteins, and nucleic acids, which form our DNA and RNA.
- Gastrointestinal disorders, such as nausea, stomach pain and incontinence.
And these changes can lead to further complications (2), including:
- Secondary brain injury, triggered by the initial injury, such as hypoxia (low oxygen in the body tissues) or cerebral oedema, when fluid builds up around the brain.
- Prolonged need for assisted ventilation.
- Increased risk from infections.
Research is ongoing to pinpoint exactly which nutrients and processes of the brain are linked and how damage to the brain affects those links.
But studies are already showing better rates of survival recovery and clinical outcome in brain-injured patients who receive prompt, sustained nutrition (4) compared to those who do not.
Indeed, assessing ‘nutritional risk’ as soon as possible after a brain injury was, only recently, flagged as ‘necessary’ by researchers.(3)
It seems essential, then, to place nutrition at the top of brain injury rehabilitation priorities.
What are the basics of a healthy brain diet?
Water!
Water accounts for 75 per cent of brain mass and 60 – 70 per cent of body weight and is lost from our bodies through sweating, urinating and breathing.
It is defined as an essential nutrient since, without it, none of the body’s biochemical reactions could occur, including:
- Digestion.
- Regulating body temperature.
- Absorbing and distributing nutrients.
- Disposing of waste products.
Fluid therapy management’ post-brain injury is a key concern for health professionals in order to:
- Restore or maintain normal bodily functions.
- Ensure blood and other fluids can still reach the damaged tissue.
- Avoid further complications caused by the wrong level of hydration.
Long-standing advice in the UK has been to drink up to 8 glasses of water (or 1.9 litres) a day to stay hydrated - despite a lack of evidence proving this to be true.
More recent guidance suggests we rely more on our thirst ‘instinct’ or craving to self-assess hydration.
But this may not help brain injury survivors if their injury has affected the neural networks linked to the thirst triggers or if their thirst is affected by medication.
It is important, then, to be aware of dehydration symptoms other than ‘feeling thirsty’, including:
- Dry mouth, lips and eyes.
- Headaches.
- Feeling light-headed.
- Dizziness.
- Dark yellow and strong-smelling urine.
- Urinating less than four times a day.
Food!
Evidence is growing that standard nutritional approaches following a brain injury are flawed in that they fail to address patient-specific nutritional needs.
More research is needed but, for now, the consensus among medical experts and brain injury survivors is as follows:
- Stick to small meals, evenly spaced through the day, as over-eating can cause sleepiness.
- Set a reminder/alert if you need help remembering to eat.
- Carry healthy snacks with you for an energy boost when fatigue strikes.
- Aim for nutritionally balanced meals.
What is the nutritional balance?
A combination of carbohydrates, fats, protein, fibre, vitamins and minerals is the accepted UK health leaders’ advice, with recommendations as follows:
Starchy foods(carbohydrates) should make up just over a third of the food we eat as they provide energy, iron, calcium, fibre, and B vitamins.
Think:
- Rice
- Pasta
- Bread
- Cereals (wholemeal varieties are even better)
- Potatoes (skin on for more fibre).
Fats - Divided into saturated and non-saturated, these are also high in energy, provide essential fatty acids and help to absorb vitamins A, D and E.
Saturated fats: Research suggests too many of these can raise cholesterol levels, increasing heart disease and stroke risks.
Think:
- Meat and meat products.
- Butter, lard, cheese and cream.
- Chocolate.
- Biscuits, crackers, cakes and pastries.
- Palm and coconut oil.
Non-saturated fats: Current advice is that it is healthier to try to swap saturated with unsaturated fats
Think:
- Avocados.
- Olive, corn, sunflower and rapeseed oils, and their spreads.
- Some nuts, including peanuts, almonds and brazils.
- Oily fish such as sardines, herring and salmon.
Protein is essential for the body’s growth and good health and, intrinsically for brain injury, cell repair.
Think:
- Meat.
- Fish.
- Eggs.
- Cheese.
- Cereals and products, such as bread.
- Nuts.
- Pulses (beans, lentils, chickpeas).
Fibre: eating lots of this, research suggests, reduces the risk of heart disease, stroke, bowel cancer and type-2 diabetes.
Think:
- Whole wheat/grain/meal cereals, oats, pasta and rice.
- Skin-on boiled new or baked potatoes.
- Pulses.
- Vegetables.
- Fresh, dried or canned fruit.
- Nuts and seeds.
Vitamins and Minerals: these are the essential nutrients in the food we need to maintain health.
Vitamin A: to help immunity, vision and skin.
Thinkmilk; cheese; yoghurt; low-fat spreads, oily fish, and eggs.
Vitamin B1: for a healthy nervous system and to help release energy from food.
Think vegetables; meat and fish; eggs; wholegrain bread; dried and fresh fruit; some fortified cereals.
Vitamin B2: another energy releaser; this also helps towards healthy skin, eyes and nervous system.
Think milk, rice, eggs, and some fortified cereals.
Vitamin B3: this also releases energy from food and helps keep the skin and nervous system in good health.
Think meat and fish; wheat flour; milk; and eggs.
Vitamin B6: essential in forming haemoglobin, which carries oxygen in the blood around the body; this is also needed to use and store energy in the body.
Think fish, lean meat, whole cereals, vegetables, peanuts, milk, eggs, and soya beans.
Vitamin B12: essential to make red blood cells, keep the nervous system healthy and release energy from food.
Think eggs, dairy foods, meat, fish, shellfish, and some fortified cereals.
Vitamin C helps to heal wounds and keep cells and connective tissue healthy.
Thinkgreen, leafy vegetables; citrus fruit such as oranges; peppers; blueberries, blackberries and strawberries; and potatoes.
Vitamin D: made by our skin from sunlight; for strong bones, teeth and muscle health. People who are seldom outdoors may need Vitamin D supplements.
Thinkred meat; oily fish; egg yolks, cereal, and soy products.
Vitamin E: an immunity booster that helps to repair damaged cells and keeps eyes and skin healthy.
ThinkCereals and cereal products; seeds and nuts; olive and rapeseed oil.
Vitamin K: vital for healing, blood clotting and bone health.
Thinkmeat; plant oils; nuts and seeds; green, leafy vegetables; dairy products; and soya beans.
Pantothenic acid: to help release energy from food.
Thinkporridge, wholemeal bread; brown rice; potatoes; broccoli; tomatoes, eggs, chicken, beef, and kidney.
Folic acid: working with vitamin B12, this also helps to form red blood cells.
Think brussels sprouts; spinach; broccoli; asparagus, chickpeas, peas, fortified cereals, and liver.
Calcium: to help healing and regulate heartbeat, this also contributes to strong bones and teeth and is important in blood clotting.
Thinkbony fish; dairy foods; green, leafy vegetables; and fortified cereal and soy products.
Iron: vital to make red blood cells that carry oxygen around the body.
Thinkred meat; liver; dark green, leafy vegetables; dried fruit; beans; whole grains; nuts; and fortified cereals.
Potassium: for healthy heart function and controlling fluid balance in the body.
Thinkbroccoli, parsnips; brussels sprouts; bananas; pulses, seeds and nuts, meat, shellfish, and fish.
This article was originally created to support the UK malnutrition awareness week that is generally held each October and more details can be found here.
In our next look at nutrition following brain injury, we explore the body’s need for other minerals found in foods, including magnesium and sodium, and the role of ‘trace elements’, such as zinc and iodine.
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References
- Charrueau, C., et al. Metabolic Response and Nutritional Support in Traumatic Brain Injury: Evidence for Resistance to Renutrition. s.l.: Journal of Neurotrauma, 2009.
- Badjatia, N., Patel, N. and Tavarez, T. Nutrition and the Neurologic Patient. Ali Z. Prabhakar H. Textbook of Neuroanesthesiaand Neurocritical Care. [book auth.] 2019.
- Early Enteral Nutrition and Clinical Outcomes of Severe Traumatic Brain Injury Patients in Acute Stage: A Multi-Center Cohort Study. Chiang, Y-H., et al. s.l.: Journal of Neurotrauma, 2012.
- Shirai, K. Nutritional Support in Neurocritical Care. [book auth.] K. Kinoshita. s.l.: Neurocritical Care, 2019.