How to eat for a happy and healthy brain
When you hear the word diet – do you think about your body or your brain?
You probably know that sugar is bad for your teeth, that you need protein to build muscle and that vitamins are essential for keeping your body healthy. But do you also know what to eat for your mental health?
The human brain functions under a high metabolic rate which means that it uses a large quantity of the energy supplied to the body in form of vitamins, fats, amino-acids, minerals and trace elements. From this point of view, it might seem quite evident that our nutrition modulates brain function and mental health. However, it wasn’t until the past decade that clinical research really started to investigate the differentiated effects of certain nutrients or diets on the brain.
Best vs Worst Diet
The two types of diets that mark the bottom and top of the brain (and body) health food scale are the Western and the Mediterranean diet. The former is characterized by a high intake of saturated fats (found in animal fats such as meat), omega-6 fatty acids (found in corn, safflower, sunflower and soybean oil), sugar and highly processed foods.
The Mediterranean diet, often regarded as the gold standard of diets, comprises a great consumption of vegetables, fruits, fish, whole grains, legumes and olive oil and is associated with some of the most important nutrients for healthy brain function. These nutrients include omega-3 polyunsaturated fatty acids, B vitamins, vitamin D and antioxidants (including vitamin A, C and E) as well as the minerals iodine, magnesium, zinc, selenium, potassium and iron.
Why your Brain loves Omega-3 Fatty Acids
When looking at specific nutrients that are essential for mental health and cognitive function across the lifespan, omega-3 polyunsaturated fatty acids are given special importance. As our bodies cannot synthesize them in adequate amounts, it is important that we obtain them through our diet where high amounts can be found in fish, walnuts, flax and chia seeds. Additionally, the ratio of omega-6 to omega-3 polyunsaturated fatty acids (olive and canola oil score high in this) is important for healthy brain function.
DHA, a particular omega-3 polyunsaturated fatty acid that is found preliminarily in fatty fish, is needed for the synthesis of new neuronal cells as well as the formation of synapses in the adult brain. DHA supplementation has been shown helpful in increasing cognitive function as well as preventing cognitive impairment and neurodegenerative processes, so be sure to fill up your and your grandmother’s plate with these healthy fats!
The Common Factor of Sunlight and Fish: Vitamin D
Another nutrient that seems to play a major role for neuronal development and maintenance of healthy brain function is Vitamin D. Low Vitamin D levels have been associated with various severe outcomes such as dementia or autism as well as increased risks of depression or schizophrenia. Although fatty fish contains low amounts of Vitamin D3 (the one that our body and brain need) we need to cover the most substantial part of our daily demand from direct sunlight. If you live in countries where sunlight is scarce a Vitamin D supplement is recommended especially during the winter months.
How Vitamin B12 and Folate disappeared from our Plates (and how to bring them back)
Moving on to Vitamin B12 and folate which are essential for healthy functioning of the central nervous system, cognitive function and mental health. Severe deficiencies cause mental dysfunction, fatigue, memory loss and even depression. Sub-clinical deficiencies are common nowadays caused by insufficient intake of the two indispensable vitamins through nutrition. This can be explained by the shift from a traditional diet to a modern Western diet: vitamin B12 is found mainly in animal products and unprocessed foods, such as beans, whole grains and nuts, while folate (found in cruciferous vegetables, leafy greens and legumes) is often depleted from our food through refinement of grains, cooking and harvesting.
B vitamins are also required for the effective production of some neurotransmitters such as serotonin, dopamine and epinephrine. Hence a vitamin B12 and folate deficiency causes a decrease in neurotransmitter production which can lead to depression, neuropsychiatric illness and even epilepsy. Sound scary? If you are following a plant-based diet or simply loving your refined flour a little too much (eyeing you, baguette) you might want to consider popping a supplement to keep your brain happy and healthy.
What are Antioxidants and why do I need them?
You have probably already heard about antioxidants at some point. The nutrients fight off free radicals in the body that are evoked by exposure to pollution, radiation, tobacco smoke, drugs and pesticides. Free radicals cause chemical chain processes in the cells leading to chronic degenerative diseases like cancer and cardiovascular disease.
Unfortunately, the brain is highly vulnerable to this oxidative stress which in combination with inflammatory processes has been linked to various psychiatric disorders (depression, anxiety disorder, schizophrenia and autism to name a few), cognitive impairment and neurodegeneration. Luckily, vitamin A, C and E are potent dietary sources of antioxidants of which high amounts can be found in fruits and vegetables. Vitamin E prevents neurological damage and together with Vitamin A it aids the preservation of cell membranes while vitamin C helps vitamin E to fight off those free radicals. Is that enough of a reason yet for you to pile your plate high with your (minimum) five a day?
These vitamins also have a non-nutrient backup: phytochemicals, phenolic and polyphenolic compounds (found in tea, red wine, nuts, herbs, spices, grains, legumes, fruits and vegetables) that have antioxidant properties. The largest polyphenol group are flavonoids that can often traverse the blood-brain barrier and help scavenge free radicals there. Good news: next to apples, beetroot and red cabbage cacao is a great source of flavonoids, so you can enjoy a glass of red wine and that piece of dark chocolate by doing something good for your brain – just everything in moderation.
What is all the Fuss about Fermentation about?
Another food group in the spotlight of mental health are fermented foods – once a substantial part of traditional diets they have disappeared from the menu of the modern Western diet. As a result of an increased intake of sugar and saturated fats, intestinal linings become more porous causing elevated amounts of environmental toxins and endotoxins such as lipopolysaccharide (LPS). LPS has been linked to decreased neurotransmission, elevated levels of inflammation, oxidative stress and depression. Reversely, oral administration of probiotics has been shown to decrease stress and anxiety while improving mood.
If you thus want to do your gut and brain a favor you should incorporate fermented food and drinks such as sauerkraut, kimchi, kombucha and kefir into your diet.
Are Carbohydrates evil?
We need carbohydrates for a healthy brain. While most people would agree that pizza and ice cream are great sources of happiness, there is actually a scientific reason behind it. Foods rich in carbhohydrates trigger the production of serotonin and tryptophan, neurotransmitters that influence our mood. This effect has been found to be more sustainable with foods that have a lower glycemic index such as whole grains, vegetables and some fruits opposed to refined sugar and grains.
What to expect from the Future of Brain Food
The research field investigating the link between diet and mental health might be a young one, but it has been growing tremendously over the past years leading to a vast variety of studies investigating the effects of specific diets and nutrients on various outcomes. The brain food winner is with no doubt the Mediterranean diet which is associated with the prevention of brain diseases such as depression, Parkinson’s and Alzheimer’s and improved cognitive function due to its richness in essential vitamins and minerals. However, results should be treated with caution due to two common limitations: on the one hand it is difficult to isolate the effects of single nutrients that naturally always occur in combination with various other nutrients. On the other hand, there is a lack of properly controlled longitudinal studies investigating the effects of certain nutrients on mental health.
So, while we are waiting for outcomes of the latter: eat your veggies, grab your healthy fats, take your supplements if you need them and roll up your sleeves to get that vitamin D in your body!