In times gone by, the human diet was dictated by the complex forces that were mostly outside an individual’s control. Nowadays, for many people, their diet certainly is an individual choice, with a balanced diet being the ideal one should strive for as a pre-requisite for success in other avenues of modern life. All that it takes is a degree of self-discipline, as material constraints are a thing of the past, at least for those residing in developed countries.
Scientific endeavors into the complex relationship between eating habits and cognitive performance are still in their infancy, nevertheless, progress is steady. This is an area of research that is bound to attract significant attention from the media and the public as a whole. Moreover, that should not be surprising as it is a feasible method of increasing one’s quality of life, truly a concept that should stand in the center of an individual’s personal ambitions.
For a better understanding of terminology, we should mention that “cognition” (and cognitive) are not to be understood in a mechanical way, as something needed to achieve a technical end, but stress related to cognitive health also has consequences on the emotional aspect of the personality, having a profound influence on psychiatric manifestations such as moods.
The aim of this article is to provide a global perspective on the relationships between dietary patterns and an optimal functioning of the brain, followed by a review of foods that have proven beneficial effects on the cognitive process and the maintenance of its long-term health. In passing, we will mention the chief culinary culprits responsible for placing strains the intellectual well-being.
Brain Function and Nutrients – A Complicated Relationship
For more than a few decades now, food has stopped being considered as a mere provider of energy for the human body, with its far wider implications just starting to be fathomed and analyzed by scientists. An adequate diet is not just a tool in the management of diseases, but an imperative for all those who wish to improve their abilities, be they physical or intellectual.
The current morphology and functionality of the human brain is the result of an evolution shaped by a specific diet, and other (lesser) factors like physical activity and weather. The current (modern) problem with this state of facts is that feeding habits are determined by a much higher degree by cultural and economic factors than by the emerging precepts of nutrition.
The interdependence that exists between the areas of the brain responsible for the cognitive process and those that facilitate them have been long recognized, with the simplest evidence being the pleasant or unpleasant memories that are created when ingesting pleasurable or disagreeable foods.
A few essential effects that gastrointestinal processes have on the properties of cognition (and vice-versa) are an ongoing object of study:
- Gut Hormones and Cognition – the influence that gut hormones (like insulin, ghrelin or leptin) have on the cognitive processes are just beginning to be established. For example, the levels of leptin are an indicator that the brain interprets to assess appetite, and control further food intake. Obese rodents in lab tests exhibit highly dysfunctional neural receptors of leptin, a condition that has been associated with the impairment of spatial memory. This is a new development, however, it has long been known that the increase of insulin production by the pancreas happens with in connection with a mental anticipation of a meal.
- Stimulation of the Vagal Nerve – the central nervous system monitors the critical features of digestion through the vagal nerve (absorption of food and enzyme release). Laboratory tests on rats show that anomalies in vagal nerve stimulation influence the overall moods of the subjects. Other promising research considers the treatment of chronic depression with the aid of vagal nerve stimulation therapy. The balance of hormones in the prefrontal cortex in this type of therapy alters in a way that mimics the effects of antidepressant drugs.
If this could seem like a matter of detail, imagine that cognitive functions can be severely influenced by the metabolic process as a whole, due to the disproportionate amount of energy the brain requires just to sustain the survival mechanisms, not to mention its “higher” functions. Metabolic dysfunctions can thus translate into rational ones. At the micro level, this is a consequence of the problems that neurons have in the distribution of energy, leading to affections in synaptic plasticity, which starts the vicious circle all over again. To relieve the strain, omega-3 acids are a known stimulant of the said plasticity.
Furthermore, numerous patients with mental illnesses (ranging from epilepsy to Alzheimer’s) exhibit modifications in energy homeostasis, therefore at least a better management of these disorders may become a reality shortly with the aid of correct dietary provisions.
Primarily through the regulation of neurotransmitter pathways and cell membrane fluidity, dietary components can positively influence cognitive processes. Many of these influences were thought in the past to be indirect, however, in recent times an increasing number of studies have shown that they perform direct actions upon nervous cells and tissues.
The most famous of these substances are unsaturated fatty omega-3 acids, which not only aid in the correct functioning of the mental mechanisms in healthy persons, but there are also strong indications that a chronic deficiency of omega-3 acids in the metabolism may be responsible for learning and memory disabilities, recurring depression and even schizophrenia. The continued presence of high levels of saturated and trans-saturated fat acids, on the other hand, seems to have a pernicious effect on the cognitive process.
The other undoubted “star” of cognitive enhancing/preservation substances is folic acid, which is naturally created in the liver for the intestine to be able to absorb vitamins from the B group. A healthy intake of foods containing folic acid is crucial for the fetus’ development during pregnancy and a healthy progress during childhood and adolescence. Several trials for patients with age-related cognitive disorders show strong correlations between rich folic acid diets and later onset of the symptoms.
A preliminary list of compounds that facilitate a better functioning of the cognitive processes, with the main food sources from which they are obtained between parentheses:
- Omega-3 acids (fish, walnuts, kiwi fruit)
- Flavonoids (red wine, Ginkgo biloba, green tea, cocoa)
- Curcumin (the curry spice)
- Saturated Fat (various oils, meat, dairy products)
- Vitamin D (fatty fish, cereal grains)
- Choline (egg yolks, lettuce, veal)
- Selenium (nuts, fish)
- Vitamin E (avocado, spinach, vegetable oils)
- Copper (oysters, black pepper, blackstrap molasses)
A high intake of calories without the according lifestyle changes in exercise and/or sleep patterns has harmful repercussions on the cognitive function, due to a possible reduction in synaptic plasticity which, in turn, has its origin in an evolutionary adaptation mechanism developed by the body to ensure survival despite a minimal caloric intake. Such an increase facilitates the formation of free radicals and leaves proteins at the cellular level vulnerable to oxidation damage. Such risks are particularly more pronounced after a certain age.
Antioxidant foods are another instance of a ubiquitous presence, at least when nutritional pamphlets are concerned. Because of the brain’s sheer necessary levels of energy, the rate of the chemical processes involved poses a high risk of oxidation, a feature that has been known for decades now. This is the reason that diets claiming to be rich in antioxidants have garnered such popularity over the years. Inroads into deciphering the mechanisms through which antioxidants perform their role are being made, and there is solid data that points to their properties in maintaining metabolic homeostasis.
The implications of designing and increasing the popularity of possible cognitive-enhancing diets are truly intriguing due to signs that changes in diet can echo in perpetuity by virtue of it getting embedded in DNA. To illustrate this, a multigenerational study was performed on more than 300 unrelated families across Sweden concerned with the incidence of diabetes. The results showed that a grandchild is much more likely to develop the disease if his grandparents (and particularly the grandfather) had lived an abundant life, strictly from a dietary point of view, than if the grandparents had experienced times of hardship. The idea that changes that result from lifestyle choices have the potential to modify and shape cognitive functions across generations is truly a fascinating one.
Established Foods that Maintain and Promote Brain Functions
Ascertaining the benefits or risks of every edible thing on this planet would be a walloping task. It would remain true even if we consider food staples from all cultures. Therefore, some differentiations is required. The presentation is focused on examples that are relevant to our world of mass consumption, shaped by the Western tradition with episodic inputs from Eastern traditions. Having said that, it should be added that these indications should be followed in the larger context of a general balanced diet coupled with the adequate amounts of exercise.
Mediterranean & Low Carbohydrate Diet
It seems to be no accident that individuals living in Mediterranean countries always come on top in lists regarding average life span, given the fact that they also score very well when it comes to mental problems among the elderly. Individuals relying on the staples of Mediterranea cuisine – fresh fruit, fish, saturated fats coming mostly from vegetable oil, vegetables – are more than 60 percent less likely to develop cognitive deficiencies in their adult life than the rest of the population.
Regular consumption of leafy vegetables such as spinach, collard greens or kale (at least three times a week) acts as a mental aging deterrent, due to their containing many nutrients (like flavonoids or carotenoids, as well as a source of folic acid) in a surprisingly low-calorie package. That sounds tempting, however, one must make sure of their freshness, as they begin to deteriorate rapidly after more than 72 hours from harvesting time.
A diet that is low in carbs helps maintain adequate levels of insulin in the brain because, in addition to the argument presented in the previous section, there is a clear relationship between the incidence of Alzheimer’s and high levels of insulin in individuals that have passed the 50-year old mark. A low carb diet is one that features less than 20 grams a day.
The A-C-E Complex Fosters Better Oxygenation
Foods rich in Vitamin C, in addition to being an inhibitor in the creation of free radicals in the neurotransmitting tissues, are also adept at the protection of the walls of arteries thus preventing their premature degradation and providing a better oxygenation to all tissues including nervous ones.
Everybody knows that fresh fruit and vegetables are an adequate source of assimilating vitamin C but amongst them berries are the true thoroughbreds, having the uncanny ability to help the process of cell regeneration. There are speculations that diets which feature a recurring intake of berries (particularly blueberries) may have positive effects on the overall health of the cerebellum, the part of the brain that oversees coordination and balance.
The other vitamins of the complex may be harvested from a wide variety of sources, the most renowned among them being carrots, vegetables in the vein of cabbage (Brussels sprouts, broccoli), ray-finned fish like salmon or trout, cereal germ, sunflower seeds or walnuts.
B and D Vitamins to Reduce the Wear and Tear
If you suffer from a constant feeling of burnout, maybe you are not including sources of B and D vitamins in your regimen. At the cellular levels, B vitamins are involved in promoting cell division because they are an integral part of the making of RNA and DNA, the building blocks of every living organism. They are therefore essential in reducing the stress placed on the neurotransmitters that aid in the higher functions of the central nervous system. Vitamin D, on the other hand, seems to be involved in the release of serotonin and other monoamines, substances whose actions in the development of mood swings and even depression (and other more severe mental disorders) are critical and yet to be fully understood.
Chickpeas and related vegetables are excellent sources of B6 vitamin, folic acid is best assimilated from leafy vegetables while meat of all kinds (but especially fish) account for vitamin B12. For an intake of vitamin D, something as simple as sun exposure (in moderate amounts) is known to be beneficial, however, you can supplement that from fatty fish like mackerel and sardines.
Natural Memory Boosters
We explored the important role that the acetylcholine neurotransmitter has in the “higher” functions the brain performs, especially those involving the memory process. It is also crucial in muscle control. The caveat with acetylcholine is that it is manufactured using its precursor, choline – a phospholipid which is also fundamental to cell membranes. Choline cannot be produced independently in the body so it has to be harvested from nutrients. To provide the body with the necessary intake of choline make sure to do not pass on eggs (particularly the yolks), brewing yeasts or soybeans (that have undergone a minimal thermal treatment).
Magnesium is an element that is indispensable to life, and likewise to nervous processes – nerve functions through the synthesis of proteins, controlling the levels of sugar in the bloodstream, the release of neurotransmitters – in addition to other significant roles such as and agent in the production of antioxidants. Renowned sources of magnesium are bananas, dark chocolate, avocado, almonds, pumpkin seeds, chard or spinach (cited in the ascending order of concentration).
As is the case with any great landscape, things would not be complete if we had not have added the elements that create the contrast. There are many substances, we are talking about the legal ones, that pose a significant threat to the optimal activities of the nervous system, some of them widely consumed and whose reputations are not widely tarnished. As “enemies of brain functions” was not the subject of this article, this is a radically incomplete list, but one that reviews the truly dangerous:
- trans-unsaturated fats;
- added sugars, especially corn syrup;
- enriched or refined flour;
- grains that are not 100 percent whole grain.
The first part of this article has touched on the surface of the (still mostly mysterious) way that nutrients affect the brain’s complex functions and processes, revealing a budding area of research that can evolve ( in a few decades’ time) into precepts for a healthier cerebral life. Still, most scientists admit that we are talking only about favorizing factors and not certainties, cautiously optimistic hypotheses.
When it comes to forging a diet that has the potential of stimulating brain activity, the foods above should be considered in the wider aspect of what one desires to achieve, as some of them are in contradiction with weight management to name just one of the purposes of a diet. What the best piece of advice anyone can give in this matter is to take balance and moderation as the chief beacons and always double-check these kinds of information from reliable sources.
There are undergoing trials regarding connections between certain diets and their respective impact on emotional well-being, however, the road towards a scientific designation of clear links is still a long one.
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