Animal studies suggest that ketogenic diets improve cognitive function during sleep deprivation. Military cadets who consumed a ketogenic diet had greater cognitive scores, mood, and less sleepiness compared to the high carbohydrate group.
SUMMARY OF THE KETO DIET COGNITION EFFECT
- The study examined the keto diet cognition effect of sleep deprived cadets.
- Military cadets who consumed a ketogenic diet had greater cognitive scores, mood, and less sleepiness compared to the high carbohydrate group.
- Animal studies suggest that ketogenic diets improve cognitive function during sleep deprivation.
A low-carb diet was established as a treatment for epilepsy; however is now often used for weight loss and fat loss but has other benefits, such as lowering the risk of diabetes and other metabolic disorders. Furthermore, using exogenous ketone supplements has been found to result in better mood states (i.e., lower depression) while dieting. New research also finds that keto diets may be useful for improving cognition, especially when sleep deprived.
THE KETOGENIC DIET COGNITION CONNECTION
A very low-carbohydrate diet (KD) increases blood ketones. There are three ketones: beta-hydroxybutyrate (BHB), acetoacetate (AcAc), and acetone (ACE). The main ketone is D-β hydroxybutyrate (βHB). The brain normally uses glucose as the primary fuel source, but during starvation/fasting or a low carbohydrate diet, the brain switches from glucose to ketones as an energy source.
Ketone bodies yield ATP (i.e., energy for the body) more efficiently than glucose, and some studies have demonstrated that KDs increase brain ATP. (DeVivo et al., 1978; Pan et al., 1999) Thus, ketones have been described as the body’s alternative fuel. (Williams & Turos, 2021)
KETONES AND THE BRAIN
Researchers suggest that ketones serve not just as a backup fuel but perhaps even as a preferred fuel for the brain. Brain imaging scans show that the brain takes in ketones at a rate directly proportional to their concentration in the blood. The brain draws glucose at a rate dependent on the cell’s metabolic requirement.
Courchesne-Loyer et al. (2017) found evidence of delayed glucose uptake in the brain with aging, but no data indicates this happens with ketones. Researchers suggest that the brain might prefer ketones as fuel because metabolically, it’s much easier to push them into a cell than to pull them.
When studying older adults, two diets have been found to have distinctly long-term protective effects in delaying cognitive impairment: a ketogenic diet and a Mediterranean diet. A Mediterranean diet is based on high consumption of olive oil, legumes, whole grains, fruit, vegetables, nuts, poultry, fish, low-fat milk derivatives, moderate consumption of wine, and reduced consumption of red meat, sausages, and refined cereal products.
KD is a very high-fat and low-carbohydrate diet, which forces the system to shift from glucose metabolism toward the metabolism of fatty acids with the production of ketone bodies.(Vinciguerra et al., 2020) Researchers are actively studying the keto diet cognition effect.
KETONES MAY ENHANCE COGNITION
At the molecular level, ketosis has been found to demonstrate antioxidative effects. It can also drive anti-inflammatory processes and promote mitochondrial biogenesis (i.e., the creation of more powerhouses of the cell), which may be beneficial for cognition, especially for those with cognitive impairments. (Williams & Turos, 2021)
THE KETO DIET COGNITION EFFECT
The other improved anthropometric (i.e., weight loss/fat loss) and biochemical factors (i.e., lower glucose) did not relate to improvements in cognitive performance. (Krikorian et al., 2012) Researchers are unsure if the lower insulin levels or ketones have cognitive benefits. It is noteworthy that a recent trial involving 12 weeks’ calorie restriction in a sample of 50 middle-aged and older adults demonstrated improvement in memory function related to the change in fasting insulin. (Witte et al., 2009)
A similar study in adults with mild cognitive impairment was found to have improved mental function when switching to a low-carb diet for six weeks. (Sheffler et al., 2022) Others have found that giving adults with cognitive impairment a ketone beverage (i.e., ketogenic medium-chain triglyceride, 15 grams twice a day) improved memory, executive function, and language. (Fortier et al., 2021)
The role of ketones in improving brain function and cognitive abilities stems from the ability to reduce oxidative stress (i.e., free radicals) in the brain. (Veech, 2004)
KETONES AND SLEEP DEPRIVATION
A study earlier last year interested the scientific community in how keto diets prevent sleep-induced cognitive declines. It was a mice study that found that when older mice (i.e., equivalent to 58-year-old humans) were either fed a standard diet or a ketogenic diet. These mice were kept awake for 21 days straight!
They found that the sleep-deprived mice on the ketogenic diet prevented cognitive decline. (Yang et al., 2022) Another interesting finding was that the mice had higher levels of a protein called BDNF (brain-derived neurotrophic factor), which protects against cognitive decline.
THE STUDY ON THE KETO DIET COGNITION EFFECT
A new study compared the cognitive effects of a high carbohydrate or a ketogenic diet followed by 36 hours of sleep deprivation. The study design was designed to study the keto diet cognition effect during the following dietary conditions:
Group A: 2 weeks of a ketogenic diet consisting of <5% energy intake from carbohydrates (i.e., < 40 grams a day), 15%–20% energy intake from protein, and > 75% energy intake from fat.
Group B: 2 weeks of a carbohydrate-rich diet consisting of >45% energy intake from carbohydrates, 15%–20% energy intake from protein, and < 40% energy intake from fat.
At the end of the 2 week diet period, cadets were exposed to 36 hours of wakefulness and not allowed to sleep. A series of cognitive tests were performed while the subjects remained awake.
The researchers found that the military cadets who consumed a ketogenic diet had greater cognitive scores, mood, and less sleepiness compared to the high carbohydrate group. Similar studies have found that lower carbohydrates (40%) resulted in less sleepiness than a higher carbohydrate diet (65%) during sleep deprivation. (Lowden et al., 2004)
This suggests that being in ketosis may be beneficial for sleep-deprived people. More research needs to be conducted on the keto diet cognition effect during sleep deprivation.
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Sheffler, J. L., Arjmandi, B., Quinn, J., Hajcak, G., Vied, C., Akhavan, N., & Naar, S. (2022). Feasibility of an MI-CBT ketogenic adherence program for older adults with mild cognitive impairment. Pilot Feasibility Stud, 8(1), 16. https://doi.org/10.1186/s40814-022-00970-z
Veech, R. L. (2004). The therapeutic implications of ketone bodies: the effects of ketone bodies in pathological conditions: ketosis, ketogenic diet, redox states, insulin resistance, and mitochondrial metabolism. Prostaglandins Leukot Essent Fatty Acids, 70(3), 309-319. https://doi.org/10.1016/j.plefa.2003.09.007
Vinciguerra, F., Graziano, M., Hagnäs, M., Frittitta, L., & Tumminia, A. (2020). Influence of the Mediterranean and Ketogenic Diets on Cognitive Status and Decline: A Narrative Review. Nutrients, 12(4). https://doi.org/10.3390/nu12041019
Williams, M. S., & Turos, E. (2021). The Chemistry of the Ketogenic Diet: Updates and Opportunities in Organic Synthesis. Int J Mol Sci, 22(10). https://doi.org/10.3390/ijms22105230
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Yang, Y., Wang, X., Xiao, A., Han, J., Wang, Z., & Wen, M. (2022). Ketogenic diet prevents chronic sleep deprivation-induced Alzheimer’s disease by inhibiting iron dyshomeostasis and promoting repair via Sirt1/Nrf2 pathway [Original Research]. Frontiers in Aging Neuroscience, 14. https://doi.org/10.3389/fnagi.2022.998292