Intermittent Fasting & Cognitive Function

I am often asked about Intermittent Fasting (IF) and weight loss. However, IF has gained significant attention in recent years for its potential benefits in promoting cognitive health and mitigating the effects of cognitive impairment. This makes it an even more interesting dietary intervention.

For those of you who don’t know, the IF approach alternates periods of eating and fasting, inducing a metabolic switch from glucose to ketone bodies, which has been shown to trigger various beneficial physiological responses.  There are many different types of IF, but some of the most popular and well-studied include 16:8 (16 hours of fasting and 8 hours of eating) and 18:6 (18 hours of fasting and 6 hours of eating). There is also the 5:2 diet, this regimen involves eating normally for five days a week and fasting or severely restricting calories on the remaining two days. (Please note this list is incomplete.)

Intermittent Fasting and Cognitive Function

Research indicates that IF can enhance cognitive function and protect against neurodegenerative diseases. Studies on animal models have demonstrated that IF can improve motor coordination, learning, and memory consolidation. These improvements are associated with increased neurogenesis and the expression of brain-derived neurotrophic factor (BDNF), a key molecule involved in brain plasticity and cognitive function​.

Human studies also support the cognitive benefits of IF. For instance, a longitudinal study following older adults with mild cognitive impairment found that those who practiced IF exhibited better cognitive outcomes and higher rates of successful aging compared to those who did not fast​. These findings suggest that IF could be an effective non-pharmacological intervention to support cognitive health in aging populations.

The Gut-Brain Axis

The gut-brain axis plays a crucial role in mediating the cognitive benefits of IF. The gut microbiota significantly influences brain function and overall health. IF has been shown to alter the composition of the gut microbiota, promoting the growth of beneficial bacteria while reducing harmful ones​.

These changes in gut microbiota composition are associated with the production of microbial metabolites that positively impact brain health. For example, short-chain fatty acids (SCFAs) produced by gut bacteria during fasting periods can cross the blood-brain barrier and exert neuroprotective effects. SCFAs have been implicated in reducing neuroinflammation, enhancing synaptic plasticity, and promoting the expression of neurotrophic factors​.

Furthermore, IF has been linked to improved gut barrier function, which helps prevent the translocation of harmful bacteria and their endotoxins into the bloodstream. This reduction in systemic inflammation can alleviate neuroinflammatory processes that contribute to cognitive decline and neurodegenerative diseases​.

Mechanisms of Neuroprotection

The neuroprotective effects of IF are mediated through several mechanisms:

1. 1. Reduction of Oxidative Stress and Inflammation: Fasting triggers the production of ketone bodies, which serve as an alternative energy source for neurons. This metabolic switch reduces oxidative stress and inflammation, two key contributors to neurodegenerative diseases.
   2. Enhancement of Autophagy: IF promotes autophagy, a cellular process that removes damaged proteins and organelles. Enhanced autophagy helps maintain cellular homeostasis and prevents the accumulation of toxic protein aggregates associated with conditions like Alzheimer’s disease​.
   3. Improvement of Mitochondrial Function: Mitochondria are essential for cellular energy production, and their dysfunction is a hallmark of many neurodegenerative diseases. IF has been shown to improve mitochondrial biogenesis and function, thereby supporting neuronal health and cognitive function​.
   4. Synaptic Plasticity and Neurogenesis: The promotion of BDNF and other neurotrophic factors through intermittent fasting enhances synaptic plasticity and neurogenesis, crucial processes for learning, memory, and overall cognitive resilience​.

I find this area of research extremely exciting. It is amazing that simple dietary interventions hold significant promise for supporting cognitive function. If we continue to leverage the gut-brain axis and induce beneficial metabolic changes, we can theoretically reduce oxidative stress, inflammation, and improve mitochondrial function, ultimately supporting brain health.  Additionally, focusing on the quality of our diet during our eating window, can surely only augment these benefits.

 

 

 

 

 

 

 

Reference List

1. Teker, H.T.; Ceylani, T. “Intermittent fasting supports the balance of the gut microbiota composition.” Int. Microbiol. 2023, 26, 51–57.
2. Ooi, T.C., et al. “Intermittent fasting enhanced the cognitive function in older adults with mild cognitive impairment by inducing biochemical and metabolic changes: a 3-year progressive study.” Nutrients. 2020, 12(9), 2644.
3. Rajeev, V., et al. “Intermittent fasting and vascular cognitive impairment.” J Obes Metab Syndr 2024;33:92-107.
4. Mattson, M.P., Arumugam, T.V. “Hallmarks of brain aging: adaptive and pathological modification by metabolic states.” Cell Metab 2018;27:1176-99.