Opioids and the Gut-Brain Axis

Unfortunately, there is not currently a lot of research in this area.

However, there is some research that investigates the effects of morphine in mice. It is likely that this information can be applied to other substances that are related to morphine such as heroin and opioids. These studies offer clues on how opioids have an impact on the gut-brain axis in humans.

Here are some of the ways that morphine creates change in the gut:

1) Changes in transit time

A side-effect of morphine/opiates/opioid use is constipation due to slowed gut transit time. This is the amount of time it takes for food to move through the digestive tract. Increased gut transit time (diarrhea) can occur during periods of withdrawal. Both of these conditions are factors that affect the makeup of the gut’s bacterial residents.

2) Altered bile composition

Another change that happens in the gut from morphine is an alteration in the composition of bile. This is another mechanism in the alteration of gut bacteria.

3) A pro-inflammatory bacterial landscape

Research has shown that morphine can cause unique changes in the types of bacteria that are present in the gut. This is sometimes termed the microbiota’s fingerprint. Alcohol use, depression, and other conditions have been shown to have unique microbiota fingerprints. In this case, morphine use can create a unique pattern of gut bacteria and this pattern is one that is considered to be of a pro-inflammatory combination. Beneficial bacteria are reduced, and bacteria that contribute to inflammation are increased.

4) Leaky gut

Morphine is also shown to disrupt the barrier in the gut’s wall leading to increased gut permeability, frequently termed “leaky gut”. This is a source of neuroinflammation, which is the activation of immune components in the brain and spinal cord. It has been established that opioids cause neuroinflammation and it is thought that this one of the mechanisms by which this occurs.

Neuroinflammation can make one more sensitive to pain and increases the level of anhedonia, the inability to feel pleasure.

A common experience for those that have been dependent on opioids.

Feeling lousy certainly increases the risk for relapse.

It’s not uncommon for people to report that this is prolonged, often occurring for many months. For some, even longer.

Hopefully supporting the body’s return to a balanced state can help to reduce the risk for relapse and enable a strong foundation for recovery.

Therefore, it makes sense to target gut health as another way to support healing in those that are recovering from opioid use disorder.

References:

Lee K, Vuong HE, Nusbaum DJ, Hsiao EY, Evans CJ, Taylor AMW. The gut microbiota mediates reward and sensory responses associated with regimen-selective morphine dependence. Neuropsychopharmacology. 2018;43(13):2606-2614. doi:10.1038/s41386-018-0211-9

Wang F, Meng J, Zhang L, Johnson T, Chen C, Roy S. Morphine induces changes in the gut microbiome and metabolome in a morphine dependence model. Sci Rep. 2018;8 doi:10.1038/s41598-018-21915-8