Nutrition for the prevention of Cognitive decline
We well understand the importance of feeding a young brain for optimal development, and it’s a natural instinct to want to give your child the greatest opportunity for growth and development that you can. But what about yourself? What about maintaining and optimising your own brain function and making sure you stay bright and vital throughout your while life. Some research using MRI scans have shown that grey matter of the brain continues to grow well into adulthood showing growth into the mid to late 40’s and you make new neurons throughout your life in response to mental activity. Your brain is not only found within your skull, researchers are finding white and grey matter in tissue throughout the body and there is growing evidence of the influence of the digestive tract, bacteria and hormones on brain health and cognitive function. So, maintaining a healthy diet, exercise, social networks and reducing exposure to toxins, helps ensure your whole system supports a healthy brain and cognitive functioning.
When we think about cognitive decline we automatically think of the brain, so what is it made of and how do we support it.
Firstly, the mass of your brain is around 75% water so it’s important for your brain, and overall health to ensure you are well hydrated. In a relatively brief period of time, failure to consume sufficient waterwill lead to deteriorating cognitive and neurologic function.
There are more than 160 000 km of blood vessels and it uses around 20% or your total oxygen supply, making it the organ with the highest energy needs. There are strong links between optimal blood flow and energy metabolism with optimal neural function.
The tissue of your brain is made of around 60% fat, making it the fattiest organ of your body, being made mainly of fatty tissue it is critical to protect it against situations that break down and destroy fats. One of the main sources of damage to fatty tissue is what we call oxidative stress and so the brain is particularly vulnerable. Oxidative stress occurs naturally in our body as a consequence of many functions, most notably in the production of cellular energy and we naturally combat this by producing antioxidants to neutralise these molecules and we also enhance this defence by consuming antioxidant rich foods in our diet.
Dietary antioxidants are found in richly coloured fresh fruits and vegetables, some vitamins also have strong antioxidant properties, Vitamin E is particularly effective because it is fat soluble and supports high fat tissue like brain cells, some good sources of vitamin E are plant oils, wheat germ, avocado, almonds, peanuts and sunflower seeds, and tahini. In addition, supplementing with Vitamin C enhances the protective effect of vitamin E.
Other sources of antioxidants are in fresh brightly coloured fruits and vegetables, the rich reds, orange and yellow pigments (carotenoids) that give these fruits and vegetables their colour have antioxidant properties and an added benefit from blue coloured pigments (anthocyanins) in blue and purple vegetables and berries protect the thousands of kilometres of small blood vessels and capillaries of the brain, strengthening them from breaking down and making sure oxygen gets where it is needed.
Alpha-lipoic Acid(ALA) found in good amounts in spinach, broccoli and organ meats (kidney, heart and liver) helps as an antioxidant. It also regenerates other antioxidants and acts as an essential ingredient in the production of energy in the brain.
Some minerals also play a role in the antioxidant defence system and support and spare other antioxidants from depletion.
Selenium, found in brazil nuts, seafood, organ and muscle meats, cereals and grains broccoli, mushrooms, cabbage and celery support the body’s key antioxidant enzymes. Copper and Zinc are other important minerals needed for body’s most potent free radical scavenger, superoxide dismutase(SOD), lean dark meats and fish are a good source of zinc and liver, shellfish, crab, nuts, sunflower seeds, lentils, soy products, dark chocolate, broccoli and mushrooms are a good source of copper.
Heavy metals, lead, mercury, cadmium and aluminium are all toxic to brain cells and avoiding exposure is critical to brain health.
Environmental exposure to Lead is the main source of lead toxicity with lead-based paint being the main culprit, but exposure to lead can also be from rustproofing and soldering. Older lead pipes and soldered joints also contaminate water in a household. Burning coloured paper or painted wood can release lead into the air and lead is present in tobacco, cigarette smoke and ash. Occupational exposure to lead should be taken seriously, follow all safety guidelines provided, and use good quality protective masks and clothing when doing home renovations. Consuming foods high in iron, calcium and vitamin C can help reduce the amount of ingested lead absorbed into the body.
Mercury has the capacity to cross the blood brain barrier in the form of methylmercury, accumulating in the central nervous system it is responsible for a raft of neurological disturbances. Two of the main sources of methylmercury are in amalgam tooth fillings and large, long living warm water fish including Shark (flake), large tuna, swordfish, broadbill and marlin. Opting for fish such as salmon, mackerel, tuna, herring, and sardines reduces your risk of mercury toxicity and also provides the brain with beneficial fats and proteins. Grinding your teeth with amalgam fillings and dental drilling of those fillings also release methyl mercury vapours.
Exposure to Cadmium also has neurotoxic effects and causes oxidative damage within the brain. Cadmium also increases the permeability of the blood brain barrier weakening the brains natural defence against other toxins including other heavy metals. Exposure can be from industrial processing, fertilisers, cigarette smoke, incineration of waste containing plastics and cadmium batteries. Our body lacks an effective pathway to eliminate cadmium and it is reabsorbed by the kidney, so best avoiding exposure.
Aluminium toxicity has been linked to impaired mental ability and forgetfulness, the onset of Alzheimer’s and dementia in the elderly and delayed mental development on the young. Aluminium cooking pots, Teflon, buffered analgesics and antacids are the main sources of ingested aluminium but may also be contained in intravenous injections. Occupations that involve exposure to aluminium welding fumes and the production/use of aluminium powders, aluminium welding, as well as plasma cutting, grinding, polishing and thermal spraying of aluminiumall involve increased risk of toxicity, inhaled particles are deposited in the lungs and then released to blood brain and bones.
Inflammation is the natural enemy of the brain, so reducing inflammatory foods, ie, saturated fats and trans fats, highly processed foods and foods high in simple carbohydrates and sugars. Healthy fats for the brain have an anti-inflammatory effect, help to build the structure of brain cell walls and promote good communication between brain cells, the best sources are Omega 3 fats are found in cold water fish such as salmon, mackerel, tuna, herring, and sardines, other sources include nuts and seeds (such as flaxseed, chia seeds, and walnuts) and some plant oils such as flaxseed and extra virgin olive oil.
Conversely fats that promote inflammation also promote cognitive decline so reducing the amount of saturated fats found in fatty cuts of beef, pork and lamb, processed meats like salami, sausages and the skin on chicken and dairy cream butter and cheese. Oils that are modified to be like fats, AKA trans fats found in manufactured foods and margarines are also inflammatory and detrimental to the health of your brain.
Having adequate protein from both animal and vegetable sources are also important for the brain. The production of neurotransmitters is dependent on adequate clean protein.
Foods that are high in fibre have a dual effect, firstly they feed and promote the gut bacteria play a crucial role in our neurotransmitter balance and secondly, they slow the release of sugars into the blood stream, reducing insulin spikes and maintaining blood sugar balance. Both actions are important for brain function. Diets rich in foods that spike your blood sugar, white breads, pastas, sweet drinks and cereals have been associated with poorer cognitive test results. A diet rich in fibre also benefits by generally being higher in B group vitamins which are protective to the brain and a fibre rich diet is known to be protective against high blood pressure, a major factor in cognitive decline and also in the balance of cholesterol in the blood stream protecting against the risk of stroke.
Limit Coffee to one cup per day, coffee has been shown to increase blood levels of homocysteine and promote the excretion of protective B vitamins. Homocysteine occurs naturally as part of a metabolic process called methylation, when this process is impaired or influenced by diet levels of homocysteine increase in the blood and it is known to be a risk factor for both the development of Alzheimer’s and heart disease, its effect on the brain may be due to the depleting effect homocysteine has on protective vitamins B6, B12 and Folate.
A good alternative is green tea, it is a good source of protective antioxidants and also a contains good levels of an amino acid L-theanine. This amino acid benefits the brain by inducing calming alpha waves, increasing feel good and calming neurotransmitters dopamine, serotonin and GABA.
An even better alternative to coffee is good old clean water. Adding some lemon juice to the water increases your antioxidant intake and helps to improve digestion and supports the function of the liver by stimulating bile, which in term helps support a healthy microbiome for neurotransmitter production and healthy colon function for clearing toxins that can affect he brain.
Heavy use of alcohol is known to be toxic for the brain and is a major risk factor for cognitive decline.
Your brain uses a lot of energy and needs to have a steady supply of fuel and oxygen. Maintaining a steady blood sugar balance, adequate iron to deliver the oxygen to the brain cells. Once received in the brain cells the fuel and oxygen need to be then converted into a form that the body can use, that comes down to the mitochondria of the brain cell. The highest concentration of mitochondria is in the heart, brain and muscles and this concentration declines as we age, so supporting the function of mitochondria is critical for cognitive function especially as we get older. Ubiquinol or CoQ10 is used by the mitochondria to produce energy and acts as an antioxidant in the cellular environment. It is produced from an amino acid tyrosine using eight vitamins, six are B group vitamins emphasising their importance, and also both vitamin C and Vitamin E play crucial roles in the production of ubiquinol and the protection of blood vessels carrying oxygen to the brain cells using the energy.
Avoiding artificial food additives and flavour enhancers is a good idea when considering the health of your brain. Glutamates used in flavour enhancers like MSG can literally irritate the nerve ending in the brain and effect excitatory neuro transmitter and can lead to irritability and anxiety etc. Some classes of food colour similarly effect the brain in an adverse way and artificial sweeteners can also be neurodegenerative, for example aspartame can separate to phenylalanine and aspartate in the brain effecting neurons and the balance of serotonin and dopamine with people suffering mood disorders most at risk. People with mood disorders may be at higher risk of cognitive decline so avoiding these additives will help.
Hormones throughout your life interact with the brain, changes in hormones associated with aging effect the function of the brain, especially with the onset of menopause for women. The parts of your brain that are responsible for learning and memory have receptors for oestrogen and progesterone and these hormones have been found to be protective for the brain, a decline of these hormones during menopause has been associated with forgetfulness and changes in mood. Suboptimal clearing of hormones can also increase the risk of cognitive decline by precipitating disordered mood. Other hormones produced through stress, adrenaline and cortisol also impact on brain function and increase the risk of cognitive decline as we age. Practicing mindfulness and learning to relax are important here. The good news is that the nutrients that we have highlighted here also support the balance and clearance of hormones and increase tolerance to stress.
Some lifestyle activities also help with cognitive function. Exercise is known to cause nerve cells to multiply and strengthen connections. Sleeping well allows the brain to restore energy and clear toxins via the glymphatic system, a chronic lack of sleep can cause the brain to stop producing new cells. Getting sunlight optimises vitamin D levels and recent research has found that vitamin D improves the brains detoxification processes and sunlight helps in the production of serotonin to bring that sense of wellbeing. Your brain is like a muscle and responds to stimulation, learning new tasks, languages, skills or simply solving puzzles stimulates growth and protection of brain cells.
This information that I’ve presented her is by no means comprehensive and as we are all individuals with individual circumstances it’s advisable to consult with your health professional if you have any concerns about your current cognitive status.
If you wish to test your memory or check your cognitive function a free online test and recourses are available at
Food for the Brain Cognitive Function Test.
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