A high-fat diet can induce pain sensitivity

A new study in mice conducted by researchers at the University of Texas at Dallas suggests that short-term exposure to a high-fat diet may be associated with pain sensations, even if there are no previous injuries or pre-existing conditions
such as obesity or diabetes.

The study compared the effects
of two groups of mice after eight weeks of different diets.
One group received a normal diet, while the other group went on a high-fat diet that did not accelerate the development of obesity or high blood sugar, both of which can lead to diabetic neuropathy and other types of pain
.

The researchers found that high-fat diets induced hyperactivation of pain sensation (a neurological change that represents the transition from acute to chronic pain) and ectopic pain (a type of pain caused by stimuli that don't normally cause pain).

"This study shows that you don't need to be obese to trigger pain; You don't need diabetes; You don't need pathology or injury at all," said
Michael Burton, Ph.
D.
, assistant professor of neuroscience in the School of Behavioral and Brain Sciences and corresponding author of the article.
"It's enough to eat a high-fat diet for a short period of time — a diet that's similar
to what all of us Americans have in some way.
"

The study also compared
obese, diabetic mice to mice that had just experienced dietary changes.

"It's amazing that things become clear that you don't need underlying pathology or obesity
.
You just need to go on a diet," Burton said
.
"This is the first study
to demonstrate the effect of short-term, high-fat diets on ectopic or chronic pain.
"

The Western diet is rich in fat, especially saturated fat, and it has been shown to be the culprit in the
epidemic of obesity, diabetes, and related diseases.
People who consume a lot of saturated fats, such as butter, cheese, and red meat, have high levels of free fatty acids circulating in their blood, which in turn triggers inflammation
throughout the body.

Recently, scientists have found that these high-fat diets also increase existing mechanical pain sensitivity in the absence of obesity, and they can exacerbate pre-existing conditions or hinder recovery
from injury.
Burton said, however, that no studies have clarified how high-fat diets themselves induce pain sensitization factors from non-painful stimuli, such as light skin touch
.

"We've seen in the past that in models of diabetes or obesity, only a small percentage of people or animals develop ectopic pain, and if they do, they also develop different symptoms, for reasons that are not clear
," Burton said.
"We assume there must be other predisposing factors
.
"

Burton and his team looked for saturated fatty acids
in the blood of mice fed a high-fat diet.
They found that a fatty acid called palmitic acid — the most common saturated fatty acid in animals — binds to a specific receptor on nerve cells, a process that causes inflammation and mimics neuronal damage
.

"Metabolites in the diet caused inflammation
before we saw the pathology develop," Burton said.
"Diet itself leads to markers
of neuronal damage.

"Now that we're seeing that sensory neurons are affected, how does it happen? We found that if you take away palmitic acid-bound receptors, you don't see sensitization effects
on those neurons.
This suggests that there is a way to block it
pharmacologically.
”

Burton says the next step will be to focus on the neurons themselves — how they are activated and how damage to them can be reversed
.
This is part of
a larger effort to better understand the transition from acute to chronic pain.

"The mechanisms behind this shift are important because the presence of chronic pain — regardless of its source — fuels the opioid epidemic
," he said.
"If we find a way to prevent this transition from acute to chronic, it could have a lot of benefits
.
"

Burton said he hopes his study will encourage health care professionals to consider the role of
diet in influencing pain.

"The biggest reason we do this kind of research is that we want to understand our physiology thoroughly
," he said.
"Now, when a patient goes to a clinician, they treat symptoms
based on the underlying disease or condition.
Perhaps we need to focus more on how the patient got there: whether the patient has inflammation caused by diabetes or obesity; Does a poor diet make them more sensitive to pain than they realize? This will be a paradigm shift
.
”