The Neuroscience of Fasting

By Mishaa Khan, First Year Behavioural Neuroscience

Ramadan is a holy month of the Islamic calendar in which Muslims all around the world abstain from eating, drinking, and engaging in sexual intercourse from the early morning prayer (before dawn) to around sunset. In many Muslim societies, there are changes in work and school timings but the same cannot be said for Western societies. This leads to Muslims fasting while trying to keep up with their busy school and/or work lives and because of this, many do not look forward to this month as much as their counterparts in majority-Muslim societies do. In this short essay, the implications of fasting on neurological and psychological functions are discussed.

Since there is limited data on the specific neurological changes observed when a person undergoes a traditional Ramadan fast, this essay will primarily discuss research findings of intermittent fasting (IF); IF is when a person limits their calorie intake to a small window of time of their day. Unlike Ramadan fasting, those who take part in IF will consume water and possibly other liquids throughout the day, and it is often done for health reasons instead of religious reasons. IF has shown to improve learning and memory in animals (Li, Wang, & Zuo, 2013; Anson et al., 2003). These conclusions were made based on studies in which mice were put through IF and tested using a maze and fear-based conditioning (Li,Wang, & Zuo, 2013). Imaging technologies also showed an increase in thickness in the CA1 pyramidal layer (Li,Wang, & Zuo, 2013), which is a part of the brain (hippocampus) responsible for learning and memory. The thickening of this layer could potentially indicate neurogenesis, or the formation of new neurons, taking place in the CA1 pyramidal layer. Alternatively, the thickening may be a result of the prevention of “chemically induced” degeneration of neurons in the hippocampus (Qiu et al., 2012) or a combination of both. IF has also proven to reduce brain aging in mice by reducing oxidative stress (Li,Wang, & Zuo, 2013) which happens as a result of an imbalance in free radicals (oxygen with uneven electrons) and antioxidants. Reduced oxidative stress results in an improvement of brain functions and structures (Li,Wang, & Zuo, 2013) due to an increase in the brain’s plasticity, the ability of the brain to “shape” itself according to the owner’s experience. (Murphy, Dias, & Thuret, 2014). The major distinction between intermittent fasting and Ramadan fasting is that IF includes drinking liquids (usually water) throughout the day while the latter does not. Dehydration negatively affects cognition, since dehydrated individuals have been observed to have to work harder to complete a task compared to hydrated individuals (Kempton et al., 2010). The study only focused on adolescents, but similar conclusions can be drawn about other age groups too. It is important for Muslims to ensure that they are consuming enough liquids during the period when they are not fasting.

A study found that 32 Malaysian men who underwent IF for religious reasons showed a decrease in tension, anger, confusion, and depression (Hussin, Shahar, Teng, Ngah, & Das, 2013). One might think that remaining hungry and thirsty for long hours of the day while working can result in the average person being “hangry” or irritated. Despite this, the study showed that the Malaysian men experienced the complete opposite effect. The reason for this may be due to a transformation of their spiritual state; Ramadan is meant to be a month where Muslims become closer to their Creator and if done correctly, it can improve their psychological state as well. Indeed, this effect may be a manifestation of Allah’s wisdom in prescribing fasting as an act of worship.

This makes sense since people who are more spiritual happen to have a lower risk of depression according to a study conducted in China, India, and the United States (Portnoff, Mcclintock, Lau, Choi, & Miller, 2017). The fact that the results were consistent in three different countries with three different predominant religions shows that this is a universal trait. One of the reasons for this may be having a sense of purpose.

Even though the lack of glucose in your brain might make you think you will perform poorly in a given task, research studies have shown that fasting in mice has a positive effect on learning and memory; because of genetic similarities between mice and humans, the same could apply to humans. So, don’t let the next test, project, presentation or any major assessment scare you during Ramadan.  With the blessings of Allah (SWT) and the effect of intermittent fasting on the hippocampus (part of the brain responsible for learning and memory), you will do well insha Allah. As Muslims, we often get caught up in our everyday lives and forget to remember our Creator as much as we should. We should use Ramadan to get into the habit of relying only on Allah (SWT) because He is the best of planners. And Allah knows best.

 

Misha’a Khan is a Behavioural Neuroscience student at SFU. She is an international student who who was born and raised in Saudi Arabia, but is originally from Pakistan. Her interests include public policy, mental health, criminal rehabilitation, neuroplasticity and neurogenesis.

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References

Anson, R. M., Guo, Z., de Cabo, R., Iyun, T., Rios, M., Hagepanos, A., … Mattson, M. P.

(2003). Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake. Proceedings of the National Academy of Sciences of the United States of America, 100(10), 6216–6220. http://doi.org/10.1073/pnas.1035720100

Hussin, N. M., Shahar, S., Teng, N. I., Ngah, W. Z., & Das, S. K. (2013). Efficacy of Fasting and Calorie Restriction (FCR) on mood and depression among ageing men. The Journal of Nutrition, Health & Aging,17(8), 674-680. doi:10.1007/s12603-013-0344-9

Kempton, M. J., Ettinger, U., Foster, R., Williams, S. C., Calvert, G. A., Hampshire, A., . . .

Smith, M. S. (2010). Dehydration affects brain structure and function in healthy adolescents. Human Brain Mapping,32(1), 71-79. doi:10.1002/hbm.20999

Li, L., Wang, Z., & Zuo, Z. (2013). Chronic Intermittent Fasting Improves Cognitive Functions and Brain Structures in Mice. PLoS ONE, 8(6), e66069. http://doi.org/10.1371/journal.pone.0066069

Murphy, T., Dias, G. P., & Thuret, S. (2014). Effects of Diet on Brain Plasticity in Animal and

Human Studies: Mind the Gap. Neural Plasticity,2014, 1-32. doi:10.1155/2014/563160

Portnoff, L., Mcclintock, C., Lau, E., Choi, S., & Miller, L. (2017). Spirituality cuts in half the relative risk for depression: Findings from the United States, China, and India. Spirituality in Clinical Practice,4(1), 22-31. doi:10.1037/scp0000127

Qiu, G., Spangler, E. L., Wan, R., Miller, M., Mattson, M. P., So, K., . . . Ingram, D. K. (2012). Neuroprotection provided by dietary restriction in rats is further enhanced by reducing glucocorticoids. Neurobiology of Aging,33(10), 2398-2410. doi:10.1016/j.neurobiolaging.2011.11.025

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