Nutrition and Cognitive Function


Have you been in a situation where you weren’t able to concentrate because you were hungry? Maybe there was a week when you didn’t eat properly due
to the number of assignments that were nearing deadlines. Ever wonder why you just couldn’t focus on anything? This is because your brain sends signals to your body which gets you distracted. Imagine a part of your brain (the hypothalamus) shouting out because it realizes that your body needs food! It releases chemicals to tell your body to eat, and since this is much more important for your body than your assignment, you aren’t able to give in your 100%. But here’s something you should know – you will be able to improve your cognitive functioning by eating right and ensuring proper nutrition.

In the book, Teaching with the Brain in Mind, Jensen has beautifully summarized best-designed studies on food/nutrition and cognitive function (Jensen, 2005, p.35). Here are the key points along with an explanation of each of them:


Hypoglycemia means low levels of blood sugar. As glucose is virtually the sole source of energy for the human brain (Berg, J. M., Tymoczko, J. L., & Stryer, L., 2002), this condition negatively impacts the hippocampus, which is the part of the brain responsible mainly for learning and memory. Our human brain consumes about 120g of glucose daily, which is approximately 420 Kcal of energy input! Complex carbohydrates, from the name, are evident that they are longer chains of sugar molecules. These carbohydrates (example: cereal, rice, pasta) take a longer time to breakdown in the body and hence are more efcient in maintaining blood sugar levels and preventing hypoglycemia. Therefore, consuming simple carbohydrates tend to release energy immediately, hampering concentrations over longer periods of time. Consuming complex carbohydrates can provide energy for sustained periods of time, due to which you can concentrate without getting irritated due to distractions such as hunger.


The rapid growth of the body during childhood requires sufcient protein. This is because, besides water, the body is made of more protein than any other substance. Also, protein is essential for the optimal functioning of the Central Nervous System (CNS) (Liberman, 1999). In short, the CNS consists of the brain and spinal cord. This system is responsible for most of our bodily functions ranging from awareness, movements, memory, thought process, and speech. Since our Central Nervous System plays a big role in processing and transmitting information, consuming amino acids in protein foods are required to keep the system working well. Proteins are synthesized into dopamine and norepinephrine, which are both neurotransmitters (chemical messengers in the body), essential for quick reactions, thinking and memory.


Vitamins A, B, C, and E are required for brain maintenance, protective efects, and memory. Studies have been successful in showing that adequate levels of these vitamins can boost cognitive function.

Essential Fatty Acids

Essential fatty acids (EFA) are fatty acids that are required to be taken through the diet because our body cannot synthesize them. Two especially important classes are omega 3 and omega 6. They help to improve attention and reduce fatigue. To understand better, imagine your brain with more than billions of cells. Essential fatty acids are like the building blocks of these cells, and by binding to the cells – they help improve fuidity, which is essential for rotation, difusion, and other such functions of the cell.

Figure 1: Schematic depiction of how nutrition infuences cognition and emotion
(Spencer et al., 2017)

The white arrows depict that those factors send “negative signals” to the brain, thereby hampering cognitive functioning. The blue arrows on the other hand, represents inhibition to these negative signals. That is, they suppress negative signals which could negatively afect our cognitive functioning. Simply put, “signals” in this case are messages sent by consumption of foods to the brain. A positive message could potentially promote biological reactions to keep you awake and focused whereas a negative message could signal prioritization away from better concentration.

Overeating, high-fat diet, poor early-life diet, or early life adversity can produce an infammatory response in our immune cells. In addition, they might also play havoc on the blood-brain barrier (which is a barrier that regulates what enters from the blood to the Central Nervous System where the neurons reside) and factors that regulate satiety.

These infammatory signals that arise due to the factors mentioned above can activate specialized cells, which are microglial cells in the CNS which impairs cognition, memory impairments, and leads to depression-like symptoms. However, Polyunsaturated fatty acids (such as those found in walnuts, sunfower seeds, faxseeds, and plant-oils), polyphenolics (which are plant-derived compounds rich in antioxidants found in cocoa, berries, nuts, vegetables, etc.), and an early-life positive environment can prevent negative signals which harm the functioning of the CNS.

Also, it is evident from fgure 1 that when the microglia are activated, they may lead to severe consequences such as fever, anorexia, and lethargy, which results in contextual and spatial memory impairments. Consuming the positive-signaling foods as mentioned above can help keep the microglia young and healthy.
In the next section, let us have a look at 5 foods which boost cognition, learning and memory, and how they do so:


We all love cofee for how it helps us stay awake. It’s the cafeine in cofee that performs this role by interacting with adenosine (Ribeiro, J. A., & Sebastião, A. M., 2010). Adenosine is a neurotransmitter that makes you sleepy over time by slowing neuron activity. However, the cafeine present in cofee inhibits adenosine’s function in the brain, thereby delaying the slowing down of neuron activity. This helps you to stay more alert and concentrate better. Cofee also has been shown to improve mood, learning, attention, and general mental function.

Green Leafy Vegetables

These include kale, broccoli, spinach, lettuce. They contain large amounts of brainhealthy nutrients such as vitamin K, antioxidants such as lutein, alpha-tocopherol and folate (Morris, M. C., Wang, Y., Barnes, L. L., Bennett, D. A., Dawson-Hughes, B., & Booth, S. L., 2018). Aim to consume at least 1 serving of green leafy vegetables a day!


Some nuts were found to stimulate brain frequencies more than others. From fgure 2, it can be understood that gamma waves are required for concentration and problem solving, beta waves for busy and active minds, delta for sleep and dreaming, and so on. Peanuts produced the greatest delta response which is associated with natural healing and sleep. Pecan nuts, walnuts and cashews were also found to have high stimulation of gamma and delta waves in the brain (Berk, L. et al., 2017). The researchers stated that more research needs to be carried out to fnd a defnitive relation between frequency patterns produced in the brain and nut consumption. However, it does not hurt to grab some nuts in between meals and carry some in your bag!

Figure 2: Brain wave samples depicting dominant frequencies for each activity
(Abhang, P. A., Gawali, B. W., & Mehrotra, S. C., 2016)


Green tea Green tea

One part of green tea’s ability to boost cognitive function is cafeine, as in cofee (fun fact: green tea has 60x more cafeine than cofee!). However, what green tea has, and cofee does not is L-theanine, an amino acid. The combination of cafeine and L-Theanine helps to release the cafeine into the blood over prolonged periods so that there is no cafeine crash or jitters. Another reason is the presence of antioxidants such as epigallocatechin gallate (EGCG), which is known to make you feel calm and improve memory and attention (Scholey et al., 2012). Keep some green tea bags in your backpack so you can brew them with some hot water at any time!

Dark chocolate Dark chocolate

Yes, it is chocolate! However, not the processed chocolate on the market shelves, whichare mostly made of fat and sugar rather than chocolate. Pure cacao or cocoa contains favanols (naturally occurring plant- based compounds) thatimprove cognitive function. They can cross the blood-brain barrier and be present in locations of the brain associated crucial for learning and memory such as the hippocampus and cerebral cortex (Socci, V., Tempesta, D., Desideri, G., De Gennaro, L., & Ferrara, M., 2017). By doing so, they can take part in important signaling pathways that regulate cognition. Chocolate can also boost your mood, needless to say. Consume good quality chocolate in moderation often! Any better health advice than asking you to have chocolate?!

In conclusion, it is important to always keep in mind the crucial role that food and nutrition play in our cognitive performance. Eat right, get adequate nutrients for the day, and avoid foods that impair cognitive function and cause cognitive decline. The studies discussed above have put in an efort to establish a possible connection between a particular group of foods and better cognitive functioning. Although they do not directly defne a relationship, consuming these nutritive foods are benefcial because the downsides are minimal. Happy learning, and of course, eating!


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Berg,J.M.,Tymoczko,J.L.,&Stryer,L.(2002).Eachorganhasaunique metabolic profle. Biochemistry. 5th Edition.

Berk,L.,Lohman,E.,Bains,G.,Bruhjell,K.,Bradburn,J.,Vijayan,N.,More,S., Patel, K., Dhuri, S., Mourya, S., Park, G., Gujaran, A., & Nikam, S. (2017). Nuts and brain health: Nuts increase eeg power spectral density (μV&[sup2]) for delta frequency (1–3Hz) and gamma frequency (31–40 Hz) associated with deep meditation, empathy, healing, as well as neural synchronization, enhanced cognitive processing, recall, and memory all benefcial for brain health. The FASEB Journal, 31(S1), 636.24- 636.24. c

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Morris,M.C.,Wang,Y.,Barnes,L.L.,Bennett,D.A.,Dawson-Hughes,B.,& Booth, S. L. (2018). Nutrients and bioactives in green leafy vegetables and cognitive decline: Prospective study. Neurology, 90(3), e214–e222.

Ribeiro,J.A.,&Sebastião,A.M.(2010).Cafeineandadenosine.Journalof Alzheimer’s Disease: JAD, 20 Suppl 1, S3-15. 1379

Scholey,A.,Downey,L.A.,Ciorciari,J.,Pipingas,A.,Nolidin,K.,Finn,M., Wines, M., Catchlove, S., Terrens, A., Barlow, E., Gordon, L., & Stough, C. (2012). Acute neurocognitive efects of epigallocatechin gallate (Egcg). Appetite, 58(2), 767–770.

Socci, V., Tempesta, D., Desideri, G., De Gennaro, L., & Ferrara, M. (2017). Enhancing human cognition with cocoa favonoids. Frontiers in Nutrition, 4.

Spencer, S. J., Korosi, A., Layé, S., Shukitt-Hale, B., & Barrientos, R. M. (2017). Food for thought: how nutrition impacts cognition and emotion. Npj Science of Food, 1(1).

Wikimedia Foundation. (2020, August 30). Chocolate. Wikipedia.



About the Author


Yukta Tanvi Mahendran

Yukta is a sophomore at NUS, majoring in Food Science and Technology and aims to revolutionize the way people eat healthy.

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