Food is not only essential for our bodily functions, but also for our brain functioning and associated behavioural performance. Some studies have shown that eating more of a certain nutritional compound can enhance your performance. But is it really that simple? Can food supplements support our performance? While performing studies on the micronutrient tyrosine, I found out that it is not that simple, and I will tell you why.

Your food contains a range of nutrients that your body uses amongst others as energy sources and as building blocks for cells. For example, protein-rich food such as dairy, grains and seeds are made up of compounds called amino acids. Amino acids are used for different purposes in your body. Muscles use amino acids from your diet to grow. Some people take advantage of this process to increase muscle growth by eating extra protein in combination with exercise.

But amino acids also have a very important role for brain functioning; specific amino acids such as tryptophan, phenylalanine and tyrosine are precursors for neurotransmitters. Specifically tyrosine is a precursor for the neurotransmitter dopamine, which is crucially involved in cognitive processes such as short-term memory, briefly memorizing a phone number or grocery list. Ingested tyrosine from a bowl of yoghurt or a supplement is digested in your intestines, taken up into the bloodstream and then passes through the barrier between the blood stream and the brain (the blood-brain-barrier). In neurons in the brain, tyrosine is further processed and converted into dopamine. Here, dopamine influences the strength and pattern of neuronal activity and hereby contributes to cognitive performance such as short-term memory.

Short-term memory functions optimally most of the time, but can also be challenged. For example during stressful events like an exam or when faced with many tasks on a busy day, many people experience trouble remembering items. Another example is advancing age; elderly people often experience a decrease in their short-term memory capacity. These decrements in short-term memory have been shown to be caused by suboptimal levels of brain dopamine.

The intriguing idea arises to preserve or restore optimal levels of dopamine in the brain with a pharmacological tweak, or even better, using a freely available nutritional compound. Could it be that simple? Yes and no. Yes, if you eat high amounts of tyrosine, there will be more dopamine precursors going to your brain. But the effects on short-term memory vary between individuals and experiments.

Various experiments have been conducted using tyrosine supplementation to see if cognitive performance can be preserved, with mixed success.

In groups of military personnel, negative effects of stress or sleep deprivation on short-term memory were successfully countered. Subjects were asked to take an ice-cold water bath, known to induce stress, and to perform a short-term memory task [1]. In other experiments subjects remained awake during the night or performed challenging tasks on a computer in a noisy room, mimicking a cockpit [2,3].

The group that took tyrosine before or during these stressful interventions showed less decline in their short-term memory than the group that ingested a placebo compound. Tyrosine supplementation also benefitted performance on a cognitive challenge without a physical stressor, compared with performing a simpler task. Other experiments, without a physical or cognitive stressor didn’t show any differences in performance compared with a control group.

These results show that tyrosine supplementation can benefit performance on cognitive processes, such as short-term memory, but only during challenging or stressful situations that induce a shortage of brain dopamine (for review see 4,5).

However, results have also been shown to vary with age. Experiments in elderly people showed that tyrosine also influences the most challenging task compared with simple processes, but contrary to observations in younger adults, in many older adults tyrosine decreased rather than improved performance [6,7]! It seems that the effects seen in young(er) adults no longer hold in healthy aging adults. This can be due to changes in the dopamine system in the brain with aging, as well as changes in other bodily functions, such as the processing of protein and insulin. This doesn’t mean that tyrosine supplementation should be avoided all together for older adults. The results so far suggest that dosages should be adjusted downwards for the elderly body. Further testing is needed to conclude on the potential of tyrosine to support short-term memory in the elderly.

We can conclude that nutrients affect behavior, but importantly, these effects vary between individuals. So, unfortunately, one size does not fit all. To assure benefits from nutrient supplementation or diet rather than wasteful use or unintended effects, dosages should be carefully checked and circumstances of use should be considered.

REFERENCES
O’Brien, C., Mahoney, C., Tharion, W. J., Sils, I. V., & Castellani, J. W. (2007). Dietary tyrosine benefits cognitive and psychomotor performance during body cooling. Physiology and Behavior, 90(2–3), 301–307

Magill, R., Waters, W., Bray, G., Volaufova, J., Smith, S., Lieberman, H. R., … Ryan, D. (2003). Effects of tyrosine, phentermine, caffeine D-amphetamine, and placebo on cognitive and motor performance deficits during sleep deprivation. Nutritional Neuroscience, 6(4), 237–246.

Deijen, J. B., & Orlebeke, J. F. (1994). Effect of tyrosine on cognitive function and blood pressure under stress. Brain Research Bulletin, 33(3), 319–323.

van de Rest, O., van der Zwaluw, N. L., & de Groot, L. C. P. G. M. (2013). Literature review on the role of dietary protein and amino acids in cognitive functioning and cognitive decline. Amino Acids, 45(5), 1035–1045.

Jongkees, B. J., Hommel, B., Kuhn, S., & Colzato, L. S. (2015). Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands-A review. Journal of Psychiatric Research, 70, 50–57.

Bloemendaal, M., Froböse, M. I., Wegman, J., Zandbelt, B. B., van de Rest, O., Cools, R., & Aarts, E. (2018). Neuro-cognitive effects of acute tyrosine administration on reactive and proactive response inhibition in healthy older adults. ENeuro, 5(2).

van de Rest, O.& Bloemendaal, M., De Heus, R., & Aarts, E. (2017). Dose-dependent effects of oral tyrosine administration on plasma tyrosine levels and cognition in aging. Nutrients, 9(12).

Please follow and like us:

Nutrition as part of the solution to the mental health crisis!

Mental illness affects one in five people globally and, despite the wide availability of solid empirically supported therapies, these statistics are not getting any better. We appear to have reached an impasse improving outcomes, despite improvements in other areas of medicine.

We need to explore new avenues.

There has been a small explosion in research using nutrients for the treatment of mental illness over the last decade. The general premise is that our brains need nutrients to function and chemicals that are essential for good mental health, like dopamine and serotonin, require micronutrients, like vitamins and minerals.

Preliminary clinical trials are putting micronutrients and good nutrition on the map as essential for optimal brain health. These trials show that giving more nutrients than what is obtained through diet alone can have a positive impact on serious conditions, like Attention-Deficit/Hyperactivity Disorder (ADHD)(1), autism(2) or anxiety(3). Along a similar vein, other studies are highlighting that improving diet alone can also improve mental health. By showing that manipulation of the amount of nutrients one consumes can influence mental health, the research demonstrates that the nutrients these participants were receiving prior to these interventions were not adequate to meet their mental health needs.

Beyond a ‘sledge hammer’ solution

Nutrition and mental healthAt the moment though, in the area of nutrient supplementation research, we are taking a sledge hammer to the problem. We give everyone a broad array of nutrients and see who gets better. That’s been a good start in that significant changes in many areas of functioning have been observed in many people, but the problem is that we each have unique nutrient requirements.

This approach of “one size fits all” will only go so far. Some people don’t respond. Some people only get marginally better. Why? Can we use genetic and nutrient testing to determine the optimal dose and nutrients that someone may require to get better based on their individualized profile? Can we use microbiome analyses to determine what microbial strains are required to best heal the gut to optimize absorption of nutrients? Current and future technologies should allow us to greatly expand the number of people who benefit from a nutritional approach.

Can this research also be used to target our food choices? To date, nutritional value is not the primary motivator in food processing. Agricultural practices tend to prioritize food storage, growth rates, transportability, shelf life, colour, shape and size above nutrient content. Could scanning of nutrient levels of fruits and vegetables using your mobile phone bring focus to the importance of the nutrient quality of our food such that this becomes the priority of consumers over aesthetic qualities or price?

Food or medicine?

Some challenges lie ahead in access to nutrients. As soon as nutrients are proven to have therapeutic benefit, legislation in some countries requires that they be treated as medicines. In other cases, dose alone can affect classification as a supplement or medication. This means as the evidence for efficacy increases, accessibility to the general public will be reduced as the ministry may insist that nutrients be accessible only by prescription.

Based on the medical model, there is a belief that pills that improve health comes with side effects that must be carefully monitored and controlled. To date, our research has shown minimal to non-existent side effects from the nutrient combinations we have studied. Moreover, physicians are currently not well placed to prescribe nutrients because so few have training in nutrition.

Government has the power to ensure legislation allows easy access to nutrients and permits health claims to be made based on good science. Such legislation could ensure that nutrients are easily available due to the very low risk associated with consuming nutrients as compared with pharmaceutical drugs.

Further challenges

Some companies sell nutrient products that optimize profit over health benefit. This may result in cutting corners, not using minerals that have been well chelated, not using the most bioavailable forms of vitamins. This will impact efficacy. It will be a challenge to ensure that nutrients designed for improving mental health are not compromised. Snake oil salesmen are never too far away.

Ensuring good access to nourishing food will also be a challenge. The prevailing mindset is that good food is expensive. However, this is true only if one doesn’t count the costs associated with eating poorly. We need attitudes towards food to change from providing calories to providing the essentials of health. Perhaps one day we will all come to realize that so many packaged and highly processed foods are nutritionally depleted. Ideally, if consumers would stop buying these products, changes would follow.

It is encouraging that some people can have better mental health and more fulfilling lives simply by ensuring their brains receive adequate nutrients and that they will not have to experience the side effects associated with so many medications. Perhaps mental illness will be viewed as being at least partially caused by improper nutrition, as our ancestors knew. Could such a shift influence the stigma associated with mental illness?

Valuing the role of nutrition as part of addressing our mental health statistics is part of our future. How well we can ensure that access is optimized and price is affordable will depend on good legislation, a re-evaluation of our current health care model and ensuring competing market forces don’t compromise the acceptability and efficacy of this solution.

(1) Rucklidge JJ1, Frampton CM, Gorman B, Boggis A. Vitamin-mineral treatment of attention-deficit hyperactivity disorder in adults: double-blind randomised placebo-controlled trial. Br J Psychiatry.2014;204:306-15. doi: 10.1192/bjp.bp.113.132126. Epub 2014 Jan 30.

(2) Adams JB, Audhya T, McDonough-Means S, et al. Effect of a vitamin/mineral supplement on children and adults with autism. BMC Pediatrics. 2011;11:111. doi:10.1186/1471-2431-11-111.

(3) Rucklidge JJ1, Andridge R, Gorman B, Blampied N, Gordon H, Boggis A. Shaken but unstirred? Effects of micronutrients on stress and trauma after an earthquake: RCT evidence comparing formulas and doses. Hum Psychopharmacol. 2012 Sep;27(5):440-54. doi: 10.1002/hup.2246. Epub 2012 Jul 11.

Please follow and like us: