How Intermittent Fasting Improves Gut Health

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You may have heard about fasting as a way to lose weight and improve your overall well-being, but did you know that it also has a remarkable impact on the complex ecosystem of our gut?

Recent scientific research has uncovered an extraordinary relationship between fasting and the trillions of microorganisms living in our digestive system. The discoveries have been truly astonishing, revealing a cascade of benefits that go far beyond just managing hunger.

In this blog post, we’re diving deep into the hidden wonders of this incredible connection between fasting and our gut microbes.

Fasting in animals

Recent research from the journal Cell Reports sheds light on the impact of fasting periods on gut microbes. In the study, two groups of mice were compared to examine the effects of feeding patterns.

The first group followed a “Time Restricted Feeding” (TRF) protocol, which meant they were only allowed to eat during their most active hours and refrained from eating during their sleep times. Since mice are nocturnal, these mice were exclusively fed at night.

The second group of mice had no restrictions on their eating habits and could eat at any time of the day or night.

The findings revealed that the mice with unrestricted eating schedules experienced a negative alteration in their gut microbiome. This change potentially contributed to worsened metabolic health and obesity, unlike the mice that were restricted to eating only at night.

Dynamic GI changes

But what caused this negative alteration in gut bacteria? Researchers attribute it to a decrease in the dynamic changes of the mice’s gastrointestinal system.

Let’s explore the concept of “dynamic changes in the gastrointestinal system.” When we eat throughout the day, our bodies adapt to our feeding rhythms. For instance, if we typically have three meals at 8 am, 12 noon, and 6 pm, our body prepares itself for food intake at those specific times. Our gut becomes active, producing stomach acid and digestive enzymes, and we might feel our stomach growling in anticipation of the meal.

When we finish eating, digesting, and head to bed, typically around midnight, our digestive system slows down and goes into a rest mode since it no longer needs to process food. This cycling of awakening and sleeping in our digestive system represents the dynamic changes in our gastrointestinal system.

However, when we develop a habit of eating at any time of the day or night, our digestive system is continuously active, with fewer periods of rest. This disrupts the dynamic changes in our gastrointestinal system.

In the study, the decrease in dynamic changes observed in the mice allowed for the proliferation of detrimental gut bacteria, which potentially promoted obesity and metabolic diseases.

Researchers believe that certain hormones and bile acids produced during eating can impact the types of gut bacteria that thrive in our bodies. Constant exposure to these digestive enzymes may have adverse effects on the gut microflora.

For the mice that could eat at any time, their digestive systems were constantly engaged, resulting in continuous exposure to digestive hormones and enzymes. Consequently, harmful gut bacteria flourished, potentially contributing to obesity, despite receiving the same food and quantity as the mice with restricted feeding.

Fasting in humans

This mechanism also applies to humans, as eating at any time of the day disrupts these dynamic changes in our gastrointestinal system.

Hence, consuming late-night meals might be detrimental to our health and increase the risk of obesity and metabolic diseases. Understanding the impact of intermittent fasting on gut health provides valuable insights into the importance of meal timing and its potential effects on our overall well-being.

Periods of fasting can positively impact gut microbes and provide various benefits for weight loss and metabolic health. By restricting your eating window, such as through intermittent fasting, you can increase the dynamic changes in your gastrointestinal system.

This approach allows your gut to “rest” by reducing constant exposure to digestive enzymes and hormones. This resting period is believed to support the growth of beneficial gut bacteria and enhance the diversity of the gut microflora.

It’s worth noting that the effects of intermittent fasting are independent of calorie intake. Even if the total amount of food consumed is the same, there can still be a difference in the gut microflora based on the timing of eating.

Eating late at night or allowing yourself to eat at any time throughout the day and night may have negative effects on your gut microbiome. This can increase the risk of metabolic diseases and obesity, even if you’re not consuming excessive amounts of food.

On the other hand, restricting your eating to specific times can be beneficial for your gut health and decrease the risk of obesity, even when the daily caloric intake remains constant.

Other benefits of fasting

So we know that fasting can help promote a healthy balance of gut microbiota. Fasting can also have several potential benefits for gut health in humans, particularly in those with IBS or other gut issues:

• Gut inflammation reduction: Fasting has been found to reduce inflammation in the gut. Inflammation in the gastrointestinal tract is linked to various digestive disorders, such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Fasting can help decrease the production of inflammatory markers and cytokines, thereby alleviating gut inflammation and improving gut health.
• Gut barrier function improvement: The gut lining acts as a barrier, preventing harmful substances from entering the bloodstream. Intestinal permeability, also known as “leaky gut,” refers to an impaired gut barrier function. Fasting can support the restoration of the gut barrier by promoting the regeneration of intestinal cells, tightening the junctions between them, and reducing the permeability. This can help prevent the passage of harmful bacteria and toxins from the gut into the bloodstream, thereby improving gut health.
• Gut motility regulation: Fasting can influence gut motility, which refers to the movement of food through the digestive tract. Controlled fasting periods can help regulate and optimize gut motility, promoting healthier digestion and preventing issues like constipation or diarrhea. By giving the gut a break from constant digestion, fasting allows it to rest and reset, improving overall gut function.
• Gut hormone regulation: Fasting can impact the production and regulation of various gut hormones, such as ghrelin, leptin, and insulin. These hormones play essential roles in hunger regulation, metabolism, and energy balance. Intermittent fasting, in particular, has been shown to improve insulin sensitivity and regulate appetite hormones, leading to better control over food intake and potential weight management. Maintaining a healthy weight is important for gut health as excess body fat can increase the risk of gastrointestinal conditions.

Gut microbes

The human gut is home to an astonishing number of bacteria, with estimates suggesting that there are approximately 100 trillion (10^14) microbial cells residing within our digestive system. This vast microbial community, collectively known as the gut microbiota or gut microbiome, comprises thousands of different species of bacteria, along with viruses, fungi, and other microorganisms.

These microbes play a crucial role in various aspects of human health, including digestion, immune function, metabolism, and even mental well-being and weight loss. The sheer abundance and diversity of bacteria in our guts highlight the intricate relationship we have with these microscopic inhabitants and their significant influence on our overall well-being.

Good

Several strains of bacteria are known to be beneficial for gut health. Here are a few notable ones:

• Bifidobacterium: This is a genus of bacteria that plays a vital role in maintaining a healthy gut. Bifidobacterium helps break down dietary fiber, produces essential vitamins, and supports a balanced immune response.
• Lactobacillus: Another important genus, Lactobacillus, promotes gut health by producing lactic acid, which helps create an environment unfavorable to harmful bacteria. It also aids in digestion and supports nutrient absorption.
• Faecalibacterium prausnitzii: This is a beneficial bacterium that produces butyrate, a short-chain fatty acid crucial for maintaining a healthy gut lining. It has anti-inflammatory properties and is associated with a balanced gut ecosystem.
• Akkermansia muciniphila: This bacteria species has gained attention for its potential benefits in gut health. It helps maintain the integrity of the gut barrier, promotes mucus production, and has anti-inflammatory effects.
• Streptococcus thermophilus: This strain of bacteria is commonly found in fermented dairy products like yogurt. It aids in the digestion of lactose and produces lactic acid, contributing to a healthy gut environment.
• Saccharomyces boulardii: While not a bacterial strain but a beneficial yeast, Saccharomyces boulardii has been extensively studied for its positive effects on gut health. It helps maintain a balanced gut flora, supports immune function, and can help alleviate diarrhea associated with various causes.
• Roseburia spp.: Roseburia species are butyrate-producing bacteria that contribute to a healthy gut. Butyrate is a short-chain fatty acid that nourishes the cells lining the colon and has anti-inflammatory properties.

Bad

While the gut microbiota consists of numerous beneficial bacteria, there are also certain strains or species that, when present in excessive amounts or under certain conditions, can have a negative impact on gut health. Here are a few examples:

• Clostridium difficile: Clostridium difficile is a bacterium that can cause infections, particularly in individuals who have taken antibiotics. It can lead to symptoms ranging from diarrhea to severe inflammation of the colon.
• Enterococcus faecalis: Enterococcus faecalis is a bacterium that can become problematic in certain circumstances, such as when it overgrows due to an imbalance in the gut microbiota. It has been associated with urinary tract infections, endocarditis, and other infections.
• Salmonella enterica: Salmonella enterica is a species of bacteria that can cause foodborne illness. It can lead to symptoms such as diarrhea, abdominal pain, fever, and can be particularly harmful to individuals with weakened immune systems.
• Escherichia coli (pathogenic strains): While most strains of Escherichia coli are harmless, certain pathogenic strains, such as E. coli O157:H7, can cause severe gastrointestinal illness. These strains are often associated with contaminated food or water.

It’s essential to remember that the presence of these bacteria alone doesn’t necessarily indicate a negative impact on gut health.

Should you fast?

So how can we leverage this knowledge to promote the growth of beneficial gut bacteria and improve weight loss and metabolic health?

One strategy is to give your gastrointestinal system a “rest” by limiting eating to daytime when you’re awake and active. Minimizing eating during sleep hours can be achieved by using distraction techniques like sipping water, chewing gum, or engaging in activities such as playing video games.

Creating obstacles for late-night snacking, such as brushing your teeth immediately after dinner or not keeping snacks at home, can also help. Another option is adjusting your sleep schedule and going to bed earlier.

It’s not necessary to follow this approach every single day. Research suggests that the benefits of restricted eating can still be present even if you have 1 or 2 cheat days a week. A study found that mice restricted to eating only five days a week, with unrestricted eating on weekends, still experienced positive effects.

Furthermore, fasting or intermittent fasting may offer additional benefits beyond calorie reduction. Therefore, if you’re practicing intermittent fasting and not seeing weight loss results, it may still be beneficial for your digestive system and the growth of metabolism-friendly bacteria.

Although studies haven’t directly compared different fasting durations and their impact on the microbiome, incorporating fasting or intermittent fasting into your routine periodically could be valuable. Even if weight loss is not your primary goal, fasting can provide your gut with resting periods.

Remember, when you eat can be just as crucial as what you eat. Therefore, consider implementing strategies to restrict eating to specific times and avoid late-night eating, as these factors can significantly influence your gut health.

Learn more about

• Intermittent Fasting for Weight Loss
• Fasting – A Quick How To

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