Is it possible to boost academic and tactical performance with what you eat?
As we all focus on appearance and look for the next miracle diet to make us thin and toned, the food manufacturers are looking to make as much money out of our obsessions as possible. We all seem to have forgotten that brain development and function is way and far more important than anything else, particularly during childhood and adolescence.
BRAIN DEVELOPMENT & FOOD
“It’s a very odd thing
As odd as can be
That whatever Miss T. eats
Turns into Miss T.”
Walter de la Mare
As suggested by Walter de la Mare (and more recently in various popular TV programs), we are made out of what we eat. Our brains develop most rapidly in the last third of pregnancy and in the first two years of our life. The brain of a newborn baby makes up about 10% of its body weight (vs 2% in adults), by 2 yrs old it is ~80% the size of an adult brain and is ‘full grown’ at around 14-16yrs, which means for brain development early childhood nutrition may be key.
For a long time it was thought that was it, ‘job done’, the brain you had as you reached puberty, was what you had, but we now know that brain development (brain plasticity) continues right through adolescence and adulthood into old age. Adolescence maybe particularly important (see previous posts The Mysterious Workings of the Adolescent Brain & The Amazing Teenage Brain), as just before puberty, there is a large increase in the amount of grey matter and then a ‘pruning’ back of neural pathways, leaving a brain that is more ‘adult’ in structure and has more adult ways of thinking, with the ability to develop abstract thought, deductive reasoning and problem solving. What you do and what you eat during adolescence may have lasting impact on your brain through adulthood and into old-age. Brain plasticity, cognitive function, improved deductive reasoning and better problem solving have been linked to diet as well as to exercise and physical fitness (see post Does Exercise boost Academic Performance).
The solid matter of the brain is approximately 60% fat and fat makes up 80% of nerve cells. The vast majority of brain fats are polyunsaturated, the most common being the omega3 fat docosahexaenoic acid (DHA) and the omega6 arachidonic acid (AA). Being polyunsaturated means their structure contains few or no double bonds between atoms. As they are incorporated in the brain during growth spurts they create dynamic flexible membranes that are able to transmit and receive information. Omega3 and Omega6 fatty acids are essential. The body is not able to make them and the must be supplied by in the diet. A lot of research has been done on the effects of diet on the developing brain. Poor diet during childhood has been widely demonstrated to have life long consequences on IQ, learning, memory, anxiety and mental health. Research is on-going and is not yet conclusive but it has been shown that if there is deficiency in the ‘right’ fats, the brain will build itself with the ‘wrong’ fats, which would lead to stiffer less flexible membrane structure and causes subtle changes that effect cell communication. Saturated and Trans-fats from the diet are found to accumulate in the brain and may impede the flow of oxygen and impact brain communication. Animal studies have shown a diets high in trans-fats can causes learning difficulties, animals performing five times worse at learning tasks than those on a more balanced diet. Studies have also shown that correcting an omega3s deficiency ameliorates the effects of a high sugar diet.
Good quality protein in vital to the structure of the brain. Amino acids provide the building blocks for both the neurones (brain cells) and neurotransmitters (substances that transmit nerve impulses across synapses/junctions in the nerves or to muscle fibres and other structures). The amino acid tryptophan is vital for the production of serotonin and tyrosine forms part of the structure of dopamine. Proteins are also vital in the formation of receptors, structures embedded in membranes that aid in cell communication.
~75% of your brain is water and water is essential for optimal brain health and function. Water maintains the tone of membranes for neurotransmission and improves circulation, aiding oxygen delivery and waste removal. Neurons store water in tiny balloon-like structures. Even low level dehydration has been conclusively shown to effect cognition, a loss of body weight of 2% from water loss, common during exercise or in hot weather, causes an approximately 10% decline in cognitive. After an overnight fast, adolescents given a plain breakfast bar, and registering possible thirst, performed 14% worse in simple tests than matched children who were given a bottle of water with their breakfast bar. Dehydration also leads to fatigue and poor concentration. Even mild levels of dehydration can impact school performance.
BRAIN FUNCTION : What to eat for optimal brain function…..
Except during starvation glucose is virtually the only fuel used by the human brain. The brain has no fuel stores and requires a continuous supply. An average adult brain consumes about 120 g of glucose a day (about 420 kcal (1760 kJ)) which is about 60% of glucose used by the whole body (in the resting state). Glucose is used to power transport mechanisms that maintain the Na+-K+ balance required for impulse transmission and to synthesise neurotransmitters and neuroreceptors. Very low carbohydrate diets have been shown to reduce cognitive agility and skipping breakfast to lower academic performance and concentration. Very little research has been done on the best source of glucose but the limited evidence that there is suggests that a low-glycemic (slow release) sugar is best. High levels of blood sugar have been found to be bad for brain function and also associated with cognitive decline in old age. The use of sweets as an ‘exam aid’ does not appear to have any scientific basis and is likely to cause blood sugar peaks and troughs negatively affecting performance later in the day.
Fatty acids are never used as fuel for the brain and do not traverse the blood-brain barrier. In starvation, ketone bodies generated by the liver from protein partly replace glucose as fuel for the brain.
Ive included a table of all the different types of food that have been linked to the brain and brain performance at the end of this piece but as a summary :-
ADVICE FOR OPTIMAL PERFORMANCE
1. EAT – Your brain needs the energy from food to work efficiently. Skipping meals and failing to drink will lower performance. The brain uses about 20% of the total energy required for the body and this can be as high as 44% in children.
2. HEALTHY BRAIN BOOSTING FOODS – Carbohydrates are important but low glycemic carbohydrates are best and wholegrain is a good source of B-vitamins. Protein-rich foods may lead to greater mental alertness and contain helpful amino acids and minerals. Foods high in omega3 fats are vital for brain development and plasticity (we get plenty of Omega6 as they are in all processed foods) and eating fish / shellfish will also give a good source of minerals. Omega 3s and 6s share the same digestive pathways and lowering your intake of 6s (maize/corn oil, sunflower oil, grape seed oil) maybe necessary to absorb more 3s. Eating fruit and vegetables may have huge benefits – there is growing evidence that phyto-nutrients from plants may have a hugely beneficial effect on brain function and memory particularly during ageing.
3. AVOID BRAIN BLOCKING FOODS – there is not a huge amount of strong evidence but increasingly it is suggested that processed foods and highly refined carbohydrates can clog brain function and trans-fats are known to effect brain processing. Try wherever possible to eat food that is as unprocessed as possible. Many chemical additives are now know to cross the blood-brain barrier. Some preservatives and colourings are known to affect behaviour, others we just don’t know about. I have written about additives in a piece on E Numbers and give details on which ones might be worth avoiding.
4. AVOID SUGAR – I wrote about sugar in my post ‘Sugar what you need to know‘. Sugars relationship with the brain and cognition is complicated but in general it is better only to consume sugar as part of a food, rather than as a food. Although the mechanism is not yet certain, high sugar diets have been shown to negatively effect attention, mood, anxiety and learning. Eating adequate omega3 fats has been shown to ameliorate some of the negative effects of sugar. New research on artificial sweeteners shows they have many of the same effects as sugar. Aspartame intake has been linked to brain cell death, poor learning and increased mental health risks.
5. MAKE SURE YOUR DIET IS HIGH IN VITAMINS AND MINERALS – The table below shows the benefits of having good levels of Vitamin A, B Vitamins, Vitamin C, Vitamin E, Vitamin K, Vitamin D, Iron, Zinc, Selenium, Calcium, Magnesium, Chromium, Copper and Iodine in your diet for optimal brain function. Vitamin D, B Vitamins, Selenium, Magnesium, Zinc and Iodine are often found to be deficient in UK teenagers, particularly if they play a lot of sport.
|NUTRIENT||EFFECT ON COGNITION, EMOTION AND MEMORY||FOOD SOURCES|
|VITAMIN A (retinol)||Role poorly understood. Retinoids control neuronal differentiation. Role in memory, sleep, depression, Parkinson disease and Alzheimer’s (1). Deficiency disrupts memory (2).||Cheese, eggs, oily fish, milk, fortified margarine and yoghurt (3)|
|VITAMIN B COMPLEX
||Deficiency causes wide variety of mental conditions including dementia, inability to concentrate, nervousness, loss of memory, schizophenia and depression (4,5,11). Supplementation B6 & B12 & folate had been thought to have positive effects on memory (51) but Cochrane review concluded no benefit on mood or cognition (7,8,12). B12 Improves cognitive impairment in rats fed a choline-deficient diet (52). Some evidence of benefit of supplementation in Alzheimers (4).||Various. Pork, chicken, fish, veg, dairy products, nuts dried/fresh fruit, eggs, wholegrain, Soya mushrooms (3). For vegetarians B12 in algae, seaweed, yeast extract and fortified cereals (3).|
|CHOLINE||Precursor for neurotransmitter acetylcholine (17). Reduction of seizure-induced memory impairment in rodents (54). Evidence of a relationship between dietary choline and cognition in animal studies (55). Supplementation during development results in improved cognitive performance (56).||Egg yokes, soy beef, chicken, veal, turkey, liver, dairy products, lettuce, basil, many spices, turmeric (3)|
|VITAMIN C||Deficiency reduces IQ score/memory/non-verbal intelligence and alters behaviour (11). High intake may delay cognitive decline (10). Essential for synthesis of neurotransmitters (11).||Citrus fruits, fruit and vegetables.|
|VITAMIN E (tocopherols)||Deficiency causes poor memory and attention. Increased risk of Alzheimers disease. Improved cognitive repair after brain trauma in rodents (44), reduces cognitive decay in the elderly (45, 10). Constituent of supplements in many successful trials (13).||Asparagus, avocado, nuts, peanuts, olives, red palm oil, seeds, spinach, vegetable oils, wheatgerm.|
|VITAMIN D||Deficiency linked to schizophrenia and depression (14). Vital for brain development (15) Important for preserving cognition in the elderly (53).||Fish, liver , milk, soy, fortified products, Eggs (3)|
|VITAMIN K||Associated with cognitive decline in aging. Supplementation may have beneficial effect on preventing or treating Alzheimer’s disease (16).||Green leafy veg, vegetable oils and cereals. Small amount found in meat and dairy products (3)|
|IODINE||Critical in early brain development. Deficiency can cause cretinism or substantial reduction in IQ (17,18). Supplementation results in improved information processing and fine motor skills (19).||Sea fish and shellfish. Also some plant foods if soil is rich in iodine. In UK cows milk (3).|
|IRON||Deficiency effects mood and memory (17). Iron treatment normalizes cognitive function in young women (60)||Red meat, fish, poultry, lentils, beans. Dried fruit/nuts, dark green leafy vegetables (3).|
|COPPER||Cognitive decline in patients with Alzheimer’s disease correlates with low plasma concentrations of copper (59)||Oysters, beef/lamb liver, brazil nuts, Mushrooms|
|ZINC||Deficiency causes neuropsychological impairment (11). Supplementation beneficial to infants but less effective in older children (17).||Oysters a small amount in beans, nuts, almonds, whole grains, sunflower seeds. Mushrooms|
|SELENIUM||Selenium status linked to mood (20). Lifelong low selenium associated with lower cognitive function in humans (58)||Nuts, cereal, meat, fish, eggs. Mushrooms|
|CALCIUM||High serum calcium is associated with faster cognitive decline in the elderly (56). Calcium plays vital role in nerve excitability (11).||Milk, Cheese, green leafy veg, soya beans, tofu, nuts, bread, sardines (3).|
|MAGNESIUM||Vital for activity of enzymes and for neurochemical transmission (11). Deficiency leads to neurological symptoms and psychiatric disturbances (11).||Green leafy veg, nuts, bread, fish and meat (3)|
|CHROMIUM||May have protective function (21). and supplementation may improve memory (22).||Meat, wholegrains, lentils and spices (3)|
|LONG CHAIN OMEGA-3 FATTY ACIDS
||Amelioration of cognitive decline in the elderly (47), basis for treatment in patients with mood disorders (40), improvements of cognition in traumatic brain injury in rodents (41), amelioration of cognitive decay in mouse model of Alzheimer’s disease (48,49). Supplementation beneficial in children with behaviour or learning disorders (23). Very strong evidence that high intakes are beneficial to brain function.||Oily Fish, krill, flax seeds, chai, kiwi fruit, butternuts, walnuts. Supplements.|
||FLAVONOIDS Cognitive enhancement in combination with exercise in rodents (43), improvement of cognitive function in the elderly (50)CURCUMIN Amelioration of cognitive decay in mouse model of Alzheimer’s disease (46) and in traumatic brain injury (42)||Cocoa, green tea, ginkgo tree, citrus, wine (higher in red), dark chocolate. Herbs SAGE – significantly improves memory in humans (24)Turmeric (curry spice)|
|LIPOIC ACIDL-CARNITINE||Studies in animals show L-carnitine and liponic acid supplementation results in improved memory performance and delayed structural decay (25). Use in Parkinsons and Alzheimers (26)||Offal, dark leafy vegetables, potatoesRed meat and dairy products.|
||B-CAROTENE – may delay cognitive decline in the elderly (10), particularly over the long-term (29). Low plasma levels of lycopene and zeaxanthin linked to higher risk of cognitive decline (30) Antioxidant vitamin intake delays cognitive decline in the elderly (54)||Fruit and vegetables.|
|AMINO ACIDS||Branched chain amino acid supplementation enhances cognitive recovery of patients with severe traumatic brain injury. Tyrosine and tryptophan are vital precursors of neurotransmitters) (27). Tryptophan is essential in the diet. Some evidence that taurine, (put in energy drinks) improves cognitive function and mood (28).||Meat, meat products, fish, shellfish. Soya.(energy drinks)|
|GLUCOSE||Energy requirement of the brain almost exclusively met by aerobic glucose degradation (31). Glucose drinks enhance memory in elderly (32), improves attention (33) reaction times (34) and mood (32). Beneficial cognitive effects in AD (30) and Downs syndrome (35).||Carbohydrate/sugarPotatoes, pasta, bread, fruit.|
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If you are interested in reading more about the effects of drinking and water on the brain interesting research has been done by Dr Caroline Edmonds, a psychologist at the University of East London and can be accessed from her website http://www.carolineedmonds.com