It is common knowledge that food influences your health. But the fact that food is also able to influence your cognitive functions might be new to you. Even more surprising is that the compound with the worst reputation, fat, might actually be able to improve and protect your cognitive functions: It has been shown that verbal learning, episodic memory, processing speed and overall cognition could benefit from fatty acids [1,2]. Furthermore, the risk of cognitive impairment can be reduced by consuming fatty acids [2].

Types of fat
However, this does not mean you can deep-fry all your food and get smarter while you eat. This is because there are only certain variants of fat that might cause an improvement of cognitive functions: Omega-6 and Omega-3 fatty acids. Omega-6 is abundantly present in the Western diet because meat is produced from animals that are fed grains high in Omega-6 [3]. Another major source of Omega-6 is vegetable oil, which is not only used for cooking but also present in snacks [3]. In contrast to Omega-6, there are limited levels of Omega-3 present in the Western diet [3]. This forms a problem, because cognitive functions might only improve when the ratio between Omega-6 and Omega-3 is 4:1 or less [4]. The current ratio is estimated to be 20:1, meaning our diets are deficient. A deficient diet could decrease learning ability and memory function, according to studies on rodents [5]. Thus, it could be that we do not live up to our full potential yet.

Proposed mechanism
But how do these Omega fatty acids actually alter our cognitive functioning? This is an indirect process. Omega-3 and Omega-6 are used for structuring the cell membrane of neurons [6]. This structure changes the communication between neurons by increasing binding abilities for neurotransmitters such as serotonin [7]. Altered levels of serotonin will affect brain areas that have many serotonin receptors, such as the hippocampus. This structure is known to be involved in memory and learning [8], so Omega fatty acids can indirectly influence these cognitive abilities by altering serotonin levels.

How to benefit?
If you want to live up to your full potential, you should change your typical Western diet, by substituting food rich in Omega-6 for food rich in Omega-3. How can this be realized? Become a ‘hipster flexitarian’: Decrease your meat consumption and substitute this meat for fatty fish. Join the hype and start frying your vegetables in flaxseed oil, substitute your snacks with chia, and your brain will live happily ever after.

References:
[1] Giles, G. E., Mahoney, C. R., Urry, H. L., Brunyé, T. T., Taylor, H. A., Kanarek, R. B. (2015). Omega-3 fatty acids and stress-induced changed to mood and cognition in healthy individuals. Pharmacology, Biochemistry and Behavior, 132, 10-19.
[2] Kalmijn, S., van Boxtel, M. P. J., Ocké, M., Verschuren, W. M. M., Kromhout, D., & Launer, L. J. (2004). Dietary intake of fatty acids and fish in relation to cognitive performance at middle age. Neurology, 62, 275-280.
[3] Bailey, N. (2009). Current choices in Omega 3 supplementation. Nutrition Bulletin, 34, 85- 91.
[4] Yehuda, S., Rabinovitz, S., & Mostofsky, D.I. (1998). Modulation of learning and neuronal membrane composition in the rat by essential fatty acid preparation: Time-course analysis. Neurochemical research, 5, 627-634.
[5] Denis, I., Potier, B., Vancassel, S., Heberden, C., & Lavialle, M. (2013). Omega-3 fatty acids and brain resistance to ageing and stress: Body of evidence and possible mechanisms. Ageing Research Reviews, 12, 579-594.
[6] Schipper, P., Killiaan, A., & Homberg, J.R. (2011). A mixed polyunsaturated fatty acid diet normalizes hippocampal neurogenesis and reduces anxiety in serotonin transporter knockout rats. Behavioural Pharmacology, 22, 324-334.
[7] Simopoulos, A. P. (2011). Evolutionary aspects of diet: The Omega-6/Omega-3 ratio and the brain. Molecular Neurobiology, 44, 203-215.
[8] Haahr, M. E., Fisher, P., Holst, K., Madsen, K., Jensen, C. G., Marner, L., …, & Hasselbalch, S. (2013). The 5-HT4 receptor levels in hippocampus correlates inversely with memory test performance in humans. Human Brain Mapping, 34, 3066-3074.