Vomiting is one of the most common reasons owners take their dog to the vet. Here at My Pet Nutritionist it is a common symptom too, but it is often misperceived for regurgitation.
There are a number of reasons for both, and they are very different mechanisms. So, let’s first establish the difference between vomiting and regurgitation, and focus specifically on reasons why your dog may be regurgitating.
Vomiting is an active process, where the dog is forcefully ejecting the contents of their stomach or intestines. It is often preceded by sound. Food is usually at least partially digested, or it may be bile that comes up.
In vomiting you will notice signs of nausea, like drooling or lip licking.
Regurgitation is more passive and usually happens while a dog is eating or shortly afterward. There is usually no sound beforehand. Regurgitation is often just water or undigested food.
Regurgitation can be common if a dog eats something that is too large – think large bones or chews. Some dogs will attempt to re-ingest it as soon as they’ve regurgitated it.
But there are also some other reasons for regurgitation.
Stress is a response in the body –and it is similar across humans and dogs. When exposed to a stressful trigger, the sympathetic nervous system fires up. During this process, resources are directed away from the digestive system and so digestive function is compromised. This can lead to the development of acid reflux which is one of the more common reasons for regurgitation.
Stress has also been seen to affect oesophageal sensitivity.
During stress, corticotropin releasing hormone plays a key role. This hormone is regularly implicated in hypersensitivity (which is why conditions like IBS are more common in those who are anxious or stressed). But what it means is that the oesophagus is more sensitive to mechanical distension, chemical stimuli and more, which may lead to regurgitation.
In the same strand, mucosal integrity also influences oesophageal hypersensitivity.
Just like we have a barrier in the skin and gut, we also have an oesophageal one. It too is made up of tight junctions and has its own plethora of defence mechanisms, including a mucosal barrier. But the presence of acid, in cases of acid reflux can injure the oesophageal epithelium and so, in turn, it damages the mucosal barrier, along with the tight junction formation.
During attempts to repair, the inflammatory response is called to action, and animal studies into oesophageal damage have suggested it is a double-edged sword. This inflammatory response has been seen to lower oesophageal pressure through its action on smooth muscle which, not only allows for further reflux of acid,but also then delays acid clearance.
The take home here is to restore mucosal integrity as soon as possible and modulate inflammation.
You may notice that your dog is more likely to regurgitate if they eat too soon after exercise. There is such a thing as good stress, but the response in the body will be the same.
When your dog is running, chasing and playing, they are asking their body to move away from homeostasis. Their body will need compounds at a higher rate than what they are needed at rest. It therefore places their body under stress and so, resources are redirected. Digestion is no longer a required function and energy conversion is more important.
The sympathetic nervous system is the functional stress response, the parasympathetic nervous system is the commande rthat walks into a room and states, “as you were!”
But this command can take time to be heard, and so, if your dog eats too soon after exercise, the entirety of the parasympathetic nervous system hasn’t yet got the message. Without a fully functioning digestive system,it propels the food back out again.
Always be mindful of when you choose to offer meals to your dog.
Regurgitation immediately after eating is in fact relatively common in dogs – but this doesn’t mean its normal. From experience, we often link it to the type of food being fed, as often in many cases, when the food is changed,the regurgitation stops.
This can be for a number of reasons,but in short, the body isn’t liking what is going in.
The enteric nervous system (ENS) is a subset of the autonomous nervous system and can function independently of the central nervous system. The enteric nervous system innervates the entirety of the digestive system and ENS neurons become hyperexcitable in the presence of toxins, bacteria, inflammatory and immune mediators.
Animal studies have demonstrated hyperexcitability of ENS neurons after sensitization withmilk ingestion, leading to mast cell degranulation and histamine release. What caused the sensitisation in this study isn’t relevant, the note to make is that hyperexcitability can occur after sensitization, leading to aberrant enteric function. And so, it pays to consider an inflammatory/immune component in cases of chronic regurgitation.
An elimination diet may be useful in this case. Check out our blog for more information.
Of interest here is the crosstalk between the microbiome and the enteric nervous system. ENS nerves are thought to detect microbial products because germ-free animals exhibit significantly altered enteric function. A healthy microbiome is therefore crucial for the correct digestive messages to get where they need to go. To support your dog’s microbiome, check out our blog:
There are cases where the structure of the oesophagus can result in frequent regurgitation. This can be a developmental abnormality or blockage. A thorough exam would be necessary to establish the severity of any structural issue.
In many acute cases of regurgitation, acid reflux often comes intoplay. If you would like to learn more then check out our blog:
It can often be linked to poor digestive function, so to fully understand the mechanisms, check out our blog:
It is essential to take a whole-body approach to fully understand whatis going on, so if you would like any support with your dog’s health, thenplease check out our services:
Thanks for reading,