As a generation, we have grown up knowing what the effects of fats, carbs and proteins are on our bodies. However, how aware are we of the effect that our dietary habits have on the way we think? Although an ideal diet is always different depending on each person, there are a few components that can help increase motivation, productivity and overall feelings of wellness.
L-tryptophan is an essential amino acid (EAA), therefore our bodies are not able to synthesise it. We can only acquire it through our diet. It is the sole precursor of serotonin, a neurotransmitter (NT) crucial for feelings of relaxation and impulse control, and even more crucial in the production of melatonin. Melatonin is a hormone which regulates diurnal rhythms (sleep/wake cycle), reproductive and immune systems, and even digestive processes and motility. Unsurprisingly, low plasma levels of L-tryptophan are linked to depression, insomnia and aggression. Supplementation with tryptophan has been shown to be effective in the treatment of seasonal affective disorder (winter blues).
Dietary sources: Bananas, oats, dried fruit, milk, tuna, chicken, peanuts, turkey.
Precursor for dopamine, adrenaline and thyroid hormones.
Dopamine (a.k.a. feel-good NT) is responsible for feelings of optimism and enthusiasm. It facilitates normal nervous system function and helps reduce fatigue. It also works to keep energy levels constant by sustaining blood sugar. Our brains are solely dependent on glucose (sugar) for metabolic functions, therefore sugar rushes – which are always followed by sugar crashes – not only cause emotional disturbances, but also decrease productivity, cognitive performance and memory recollection.
Adrenaline is the fight-or-flight hormone. It contributes to feelings of alertness and focus and regulates our response to stressful situations. Without appropriate amounts (and sources!) of adrenaline, we end up feeling overwhelmed and chaotic when we most need to remain
Thyroid hormones are produced and released by the thyroid gland, triiodothyronine (T3) and thyroxine (T4) are crucially important for metabolic functions. These (along with B vitamins) aid in the breakdown of food for energy and increase the body’s basal metabolic rate (the amount of energy we spend at rest).
Dietary sources: Soy products, Eggs, Seafood, Chicken, Turkey.
How often do we forget to drink even half the amount of water that we should? Coffee and black tea don’t count. Although moderate levels of caffeine are known to improve focus and even physical performance, caffeine is also a diuretic. Diuretics increase the rate at which we excrete water, decreasing the amount of water we have available and contributing to dehydration. Encephalic (brain) dehydration decreases nervous transmission and cerebral blood flow and has been linked to lower IQ scores and cognitive performance. Research has shown that even minor dehydration (1–2% from optimal hydration levels) decreases attention, memory and psychomotor functions.
A note on carbohydrates
Carbs are our main source of glucose and therefore provide immediate energy for our brains (as opposed to eating proteins or fats, which require several more biochemical processes). The problem with simple carbohydrates (processed sugars, sweets, white bread/pasta/rice) is that since they are processed so quickly (there is no fibre involved), their consumption produces massive increases in our blood sugar level. The body then responds by releasing huge amounts of insulin (hormone) to bind the sugar molecules so our cells can use them for energy, which creates the infamous ‘sugar crash’. A sugar crash can be felt particularly as drowsiness, laziness or overall demotivation as our brains rely especially on glucose. From a more somatic perspective, insulin is an anabolic hormone responsible for the storage of carbohydrates in the form of adipose tissue (fat). When we consume complex carbohydrates, the fibre in them delays the breakdown of glucose which is then released slowly into the bloodstream so there is no need for it to be stored in adipose tissue. Just as well, the more moderate pace of consumption keeps us full for longer amounts of time.
Complex carbohydrates dietary sources: More-or-less everything that contains fibre; vegetables, fruits, whole wheat pasta/bread/rice.
For many years, the focus of changing our diets has been the effect that it can have on our physical appearance and health. As important as these are, our experiences are almost entirely based on our psychological status, so making the correct dietary choices daily can provide the framework for more productive, constructive and positive days. What are you eating today?
Andrea E. Vasconez (Trainee Medical Writer, HealthCare21)
- Fernstrom JD. Dietary Amino Acids and Brain Function. J Am Diet Assoc. 1994;94(1): 71–7.
- Martínez García RM, et al. ‘[Nutrition strategies that improve cognitive function].’ Nutr Hosp. 2018; 35(Spec No6): 16–19. [Article in Spanish; Abstract available in English from the publisher].
- Richard DM, et al. L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications. Int J Tryptophan Res. 2009;2:45–60.
- Simopoulos AP. Evolutionary Aspects of Diet, the Omega-6/Omega-3 Ratio and Genetic Variation: Nutritional Implications for Chronic Diseases. Biomed Pharmacother. 20016;60(9):502–7.
- St-Onge MP, et al. Effects of Diet on Sleep Quality. Adv Nutr. 2016;7(5): 938–49.
- Carvalho DP and Dupuy C. Thyroid hormone biosynthesis and release. Mol Cell Endocrinol. 2017;458: 6–15.