Intermittent fasting (IF) and neurogensis

The population is aging Through the advent of technology, improved medicine, and zeal for better care facilities, humans are living longer. Even if people are living longer, a significant proportion of this increased life span can be spent in poor health. These conditions can limit patients’ physical and mental capabilities, thus restricting their daily activities. This not only affects the geriatric population but also places a burden on their relatives and the health care system in terms of the support they will require. Their are various molecular pathways linked to longevity, most notably autophagy and neurogenesis as a mechanisms, to promote health through the process of aging. It is to be noted that the process of autophagy and neurogenesis decreases with aging, but through implementation of caloric restriction, intermittent fasting, and nutraceuticals agents, has proven to be an efficacious means of stimulating ones lifespan and health span. 

Intermittent fasting (IF) has been gaining popularity in recent years as a way to improve overall health and potentially increase lifespan. This simple dietary intervention has been shown in a wide range of experimental animals to extend lifespan and decrease the incidence of several age‐related diseases.

But how does intermittent fasting affect the brain, and in particular, neurogenesis, the process of creating new neurons? 

But first, let's define intermittent fasting and how it works. Intermittent fasting is an eating pattern that involves cycling between periods of fasting and eating. There are several different types of intermittent fasting, including the 16/8 method, where you fast for 16 hours and eat during an 8-hour window. IF has been proven to be advantageous to various organ systems in the body and acts as a mild metabolic stressor. It has been postulated that IF is able to cause powerful changes in the metabolic pathways in the brain via an increase in stress resistance, and breakdown of ketogenic amino acids and fatty acids (Bruce‐Keller, Umberger, McFall, & Mattson, 1999; Kim et al., 2018). Experimental studies have also shown that IF is neuroprotective against acute brain injuries such as stroke, and neurodegenerative diseases (Arumugam et al., 2010; Halagappa et al., 2007; Manzanero et al., 2014). In addition, recent studies have also shown that IF can lead to an increase in neurogenesis levels in the hippocampus (Manzanero et al., 2014).

It turns out that intermittent fasting may have a positive effect on neurogenesis, at least in animal studies.

One study conducted on mice found that intermittent fasting increased the proliferation of neural stem cells, which are responsible for generating new neurons. It also increased the production of brain-derived neurotrophic factor (BDNF), a protein that plays a crucial role in the survival, differentiation, and growth of neurons. Another study found that intermittent fasting increased the number of new neurons in the hippocampus, a region of the brain important for learning and memory. These findings suggest that intermittent fasting may have the potential to improve brain function and protect against age-related cognitive decline.

In addition to its potential effects on neurogenesis, intermittent fasting has also been linked to a variety of other health benefits. These include weight loss, improved insulin sensitivity, reduced inflammation, and protection against chronic diseases such as cardiovascular disease and cancer.

As stated above autophagy is reduced with aging. The National Institutes of Health, the definition of autophagy is a process by which a cell breaks down and destroys old, damaged, or abnormal proteins and other substances in its cytoplasm. The breakdown products are then recycled for important cell functions, especially during periods of stress or starvation. Reduced autophagy appears to have a negative effect on the vascular system. Reduction in calorie intake is one way, in which autophagy can be induced in organisms (and humans). Caloric restriction is defined as a 30%-50% reduction in the calories an organism would require daily, without causing malnutrition.

So, what does all of this mean for longevity? 

We know that the world’s population is currently living longer. This is especially problematic, given the increase in the prevalence of chronic conditions resulting from an increased aging population, thus negatively affecting the healthspan and quality of life of the affected individuals. Although autophagy is downregulated as people age, stimulation of this pathway through caloric restriction, intermittent fasting, and supplementation of agents can reinstate autophagy in older individuals. Induced autophagy promotes the longevity of cardiovascular health, thereby instigating the role of autophagy in the prevention of chronic conditions such as cardiovascular ailments. 

Resveratrol and nicotinamide mononucleotide supplementation induce autophagy in humans through activation of the sirtuin-1 pathway as discussed.

It's important to note that intermittent fasting is not for everyone and may not be suitable for certain individuals, such as pregnant women, children, and people with certain medical conditions. It is always a good idea to speak with a healthcare professional before starting any new diet or exercise program.

To summarize, intermittent fasting may have the potential to improve neurogenesis and overall health, potentially leading to increased lifespan and health span. While more research is needed to confirm these effects, intermittent fasting may be worth considering as a way to improve your overall health