Diet, Neurotoxicants and Brain Function
It is well known that the food we eat has an impact on our health, but most importantly, it affects the most complex organ in our body: the brain. Research highlights that an unhealthy diet causes inflammation of neurons and glial cells, such as microglia and astrocytes and inhibits the process of neurogenesis and affects the synaptic plasticity of the brain. Synaptic plasticity is simply a measure of the number of connections between neurons. The more connections between neurons, the better they can communicate and the better we can learn, think and memorise.
The hippocampus is one of the most important structures of the brain. It helps to regulate memory and neurogenesis. Neurons, including those in the hippocampus, produce and use many molecules to send and receive messages. Brain-derived neurotrophic factor (BDNF) is one such molecule. BDNF can protect neurons from death, increase neurogenesis and improve our cognitive abilities. A healthy diet can increase the levels of BDNF and improve neurogenesis in the hippocampus. This increased neurogenesis in the hippocampus can improve our learning, memory, mood, attention and mental health.
On the other hand, the gut and the brain are connected by neurons that transmit messages back and forth between them. The food we eat is sensed by the neurons of the gut, which then send signals to alert the brain. This connection and the resulting communication are called the gut-brain axis. Because of the gut-brain axis, it is not surprising that an unhealthy diet can cause problems with cognitive functions as it causes inflammation in certain parts of the brain, including the hippocampus. This inflammation is related to anxiety or depression and can even lead to neurodevelopmental disabilities, including autism, attention-deficit hyperactivity disorder, dyslexia and other cognitive impairments, which affect millions of children worldwide and some diagnoses seem to be increasing in frequency. Industrial chemicals that injure the brain are among the known causes for this rise in prevalence. Some of those neurotoxicants that are used in some of the products we consume are: lead, methylmercury in fish, polychlorinated biphenyls, arsenic (commonly found in rice), toluene, manganese in whole grains or fluoride in toothpaste, among many others. Also, pesticides, organic solvents, phthalates and bisphenol A which are added to many different types of plastics, cosmetics and other consumer products act as neurotoxicans too and might lead to neurobehavioural deficits, psychiatric diagnoses and other scary illnesses such as cancer.
Therefore, when it comes to health and proper brain functions, knowing which foods to avoid is just as important as knowing which foods to eat. For example, drinking sodas or energy drinks containing the artificial sweetener aspartame can cause irritability, anxiety and sleep difficulties such as insomnia. Eating trans-fats can increase the risk of cognitive problems and Alzheimer’s disease. Too much sugar in the diet can affect the brain’s memory and learning abilities and a high-fat diet is also unhealthy because it can lead to oxidative stress in the brain. Oxidative stress is a harmful process that can disrupt several structures inside cells such as lipids, proteins and DNA.
It is worth mentioning that DHA can lower the amount of inflammation that happens in the brain following brain injury. It increases neurogenesis and decreases the death of neurons that are injured. Studies have also indicated that taking DHA during pregnancy can improve the development of the neurons of the unborn baby.
To conclude, carefully watch what you eat, since your diet can make or break it when it comes to your brain health!
Carmen María Álvarez Martínez
Escuela Oficial de Idiomas de Murcia