Many of the chemicals on that list are neurotransmitters that are not at all surprising. There is currently plenty of exciting research going on trying to link the brain and gut together. This blog article will focus on melatonin and how it relates to our digestion.

What is Melatonin?

Melatonin is a neurotransmitter that was originally believed only to be produced by our pineal gland within the brain.1 It is very important to the overall function of the human body acting as antioxidant, regulating circadian rhythm (our internal clock) to help us sleep, reduces blood pressure, and leptin levels (the hormone that inhibits hunger) during sleep.2 3 4 Melatonin has also recently been discovered in large quantities in other organs as well.

Recent studies have shown that melatonin is also synthesized by our gut flora and rates at least 400 times greater than our pineal gland.5 Large quantities of melatonin have been located in the vermiform appendix, which appears to be a safe house for probiotic flora during gastrointestinal infection.6 Bacteria, like other lifeforms on Earth, have a circadian rhythm, so they also produce melatonin in the dark and possibly as a signaling hormone.7

Melatonin and the Gut

There currently is not a lot of information about melatonin and its relation to the gut, because it is a recent discovery. Nevertheless, the information that we have from studies and from proposed theories about a neurotransmitter that we believed was only important for healthy sleep is jaw dropping.

Here are some theories on the importance of melatonin and our gastrointestinal health:

  • Melatonin protects the gastric mucosa from free radicals, medications (NSAIDS), and gastrotoxic agents.8
  • Reduces production of HCL and pepsin production when sleeping. Reduces the chance of esophageal, peptic, and duodenal ulcers.9
  • Reduction of reflux while sleeping and surprisingly also when awake.10
  • Improves LES (lower esophageal sphincter) and UES (upper esophageal sphincter) pressure regulation.11
  • Reduces the risk of developing Barrett’s esophagus by increasing blood flow to the esophagus and reducing inflammation.12
  • Reduction of bowel spasms and improving MMC function in people with SIBO-D.13
  • Reinforces proper MMC function during sleep by regulating the interstitial cells of Cajal. A majority of MMC function occurs while we sleep, it is the longest period of fasting for our body.14 15

Sleep Hygiene and Melatonin

We are supersaturated with blue light during the night. Blue light (part of the light spectrum or the color spectrum) reduces melatonin production and increases serotonin that helps us to be awake.16 The light from our cell phone screens and LED monitors. Even the light pollution that creeps in through our blinds at night is interfering with our sleep.

So what do we do to ensure that we have proper melatonin production?

First, before we even discuss reducing blue light to increase melatonin production, we have to make sure our gut flora is happy and well fed and remember, diversity is key! We should avoid sugar and polyols as much as possible and focus on a diverse seasonal diet. We should eat prebiotic fiber (limit supplemental prebiotics, except for GOS occasionally) from time to time and fermented foods including organic grass fed sour cream, kimchi, fermented cabbage, and fermented pickles. Remember, the flora in our gut produce a lot of melatonin, so we have to make sure that it is happy to assist us with proper digestion.

Second, this is what everyone writes about; we need to limit blue light at night. Here are some tips:

  • Wearing blue light blocking glasses at night to increase melatonin. I do not recommend doing this if you are driving however, since you need to be awake while you drive, and some people like Dr. Kruse believe that blue light hitting the retina is important for global positioning (this does weirdly make sense, I felt weird while going to the store a few times wearing the glasses.)17
  • Install programs like F.lux on your PC or Mac to reduce blue light or Twilight on your Android phone.
  • Do not fall asleep with the television or any electronic device on if possible that emits blue light. If you have any emitting LED light in your room, try to block it or cover it with electrical tape.
  • If your child requires a night light while they sleep, get one that emits low levels of blue light.
  • If you cannot limit blue light while you sleep, try to wear an eye mask if possible.
  • If you live in an area with heavy light pollution, you might need to put up blackout curtains (caution, it is talked about in the health blogosphere that most are heavily treated and contain VOC’s so you want them to out gas awhile before hanging) and try to make your room as dark as possible. If you live out in the country, it might be best to make your room as dark as possible since the proper reflection of moonlight when the moon is fuller might tie into a proper circadian rhythm. Even though the light reflected from the moon is of course sunlight that has plenty of blue light, the light is not bright enough to reduce melatonin production.18

Finally, here are some tips to improve your sleep hygiene:

  • Do not sleep in a frigid or sweltering bedroom. It is optimal for you to keep the room temperature between 60 – 70 degrees at night.19
  • Do not go to sleep on a full stomach. Melatonin production at night hinders the stomach’s capacity to digest food. It tightens the sphincters and reduces HCL and pepsin production.
  • Sleep on your left side or back with only one pillow for greatest oxygen saturation during sleep. Sleeping on your left side puts more pressure on the LES keeping it closed and prevents reflux.20
  • Do however take in a small amount of carbohydrates before bed. One to two teaspoons of raw honey or twenty grams of trehalose before bed mixed with spring water can help improve sleep by stabilizing your blood glucose during the night.21
  • Turning off non-native EMF (while experimental) may help improve sleep quality. I turn off my Wi-Fi at night and place my phone as far away from the bed as possible.22

There are several endogenous chemicals affect digestion including: