The weather is hot and humid, don't let the intestinal flora get suffocated

Do you always feel that your stomach becomes more sensitive during summer or when traveling in tropical areas, or even have diarrhea or loss of appetite? This may not only be due to dietary changes, but also may be related to the "intestinal flora" in your body!

The intestine is not just a digestive tract, it is actually a micro-ecosystem, inhabited by trillions of good and bad bacteria, which are the so-calledIntestinal floraThese flora not only help us digest, but also regulate immunity, metabolism, and emotions... They can be said to be the invisible health command center of the human body. Recent studies have found that hot weather and high humidity can quietly change the composition and function of these flora, and even affect emotions and metabolism.

How does a hot and humid environment affect intestinal bacteria?

In high temperature and high humidity environment (Like Taipei's summer), the human body will face a series of environmental pressures, which will indirectly or directly change the ecological balance of intestinal bacteria:

1. Heat stress and dehydration: In order to dissipate heat, the body pulls blood from the intestines to the surface of the skin, which weakens the digestive function. At the same time, if the water intake is insufficient, the intestinal peristalsis will slow down and the flora environment will become unstable.
2. Loss of appetite and changes in diet: When the weather is hot, we usually have a decreased appetite and consume less vegetables and fiber. This will reduce the number of beneficial bacteria (such as lactic acid bacteria) that rely on dietary fiber, resulting in a lack of good bacteria and the growth of bad bacteria.
3. More opportunities for contact with external bacteria: In a humid environment, food and water are more likely to breed bacteria. If you do not pay attention to food hygiene, you may ingest pathogenic bacteria, further disrupting the balance of intestinal flora.
4. Impaired intestinal barrier function: The hot and humid environment causes the intestinal mucosa to become thinner and the villi structure to be damaged, resulting in increased intestinal permeability, making it easier for toxins to enter the body (commonly known as leaky gut) and even causing inflammation.
5. Changes in intestinal flora function (metabolites):
   • The reduction in bacteria that can produce SCFAs (short-chain fatty acids that can regulate immune function, affect metabolism and overall health) has led to a significant decrease in SCFA production, which may further weaken the intestine's ability to fight inflammation.
   • High temperature and humidity environment leads to a decrease in the metabolism-related incretin GLP-1, affecting blood sugar stability and appetite control.
     

How to protect intestinal bacteria in a hot and humid environment?

1. Sufficient water intake: Lack of water will give bad bacteria an opportunity to take advantage and intestinal motility will slow down, so replenishing water is the most important thing, and electrolytes should also be replenished when necessary (after sweating a lot).
2. Eat enough fiber: Green vegetables, fruits, whole grains, and beans are all prebiotics that feed good bacteria and maintain intestinal diversity.
3. Supplement probiotics: Fermented foods such as yogurt, kimchi, and kombucha are refreshing and fungal choices on hot days.
4. Pay attention to food hygiene: High temperatures can easily cause food to spoil, so avoid eating food that has been left at room temperature for too long, and keep the refrigerator and drinking water clean.
5. Slow down your pace of life: High temperature itself is a kind of stress. Proper rest and stress reduction can also help maintain the stability of intestinal flora and avoid stress from exacerbating the imbalance of intestinal flora.

summary

Hot and humid weather not only affects your mood and physical sensation, but it can also "stifle" your intestinal flora! The decrease in good bacteria and the increase in bad bacteria, coupled with inflammation and decreased digestive function, not only causes gastrointestinal discomfort, but can also affect blood sugar, metabolism and even mood. (Next time someone tells you you have a bad temper, blame it on your unbalanced gut bacteria.）

In addition to bringing a small electric fan and a parasol when going out, paying attention to your daily diet, hydration and pace of life, and properly supplementing with probiotics can also help you avoid the uncomfortable feeling of dampness and heat!

References

• Chen, S., Hu, Z., Tang, J. et al. High temperature and humidity in the environment disrupt bile acid metabolism, the gut microbiome, and GLP-1 secretion in mice. Commun Biol 7, 465 (2024). https://doi.org/10.1038/s42003-024-06158-w
• Wu Y, Feng X, Li M, et al. Gut microbiota associated with appetite suppression in high-temperature and high-humidity environments. EBioMedicine. 2024;99:104918. doi:10.1016/j.ebiom.2023.104918
• Weng H, Deng L, Wang T, et al. Humid heat environment causes anxiety-like disorder via impairing gut microbiota and bile acid metabolism in mice. Nat Commun. 2024;15(1):5697. Published 2024 Jul 7. doi:10.1038/s41467-024-49972-w
• Sato K, Hara-Chikuma M, Yasui M, Inoue J, Kim YG. Sufficient water intake maintains the gut microbiota and immune homeostasis and promotes pathogen elimination. iScience. 2024;27(6):109903. Published 2024 May 3. doi:10.1016/j.isci.2024.109903