Can you find pain relief in the kitchen? Jim Mora spoke with Rowena Field from the Pain Management Research Institute at Sydney University, who has been writing about their research into how patients at her clinic and in overseas studies respond to dietary changes.  

Field is a physiotherapist with more than 25 years experience, and this research is part of her PhD studies at the Faculty of Health and Medicine at the University of Sydney.

"It's very much looking at pain as a protective device that our bodies have - and in some people that tends to go a little bit wrong over time, it becomes a mal-adaptive response.

"So part of what we do is educate people about what sort of things are driving that threat response and that protection response in the body."

Inflammation is part of many different diseases and causes pain. For some of these diseases, like rheumatoid arthritis, the inflammation is considerable, but for many others blood testing shows only a low level of inflammation, Field says.  

"What we eat will affect that inflammatory loading that we have in the body. We know that if we put somebody on a diet, that they will get some sort of improvement in their pain outcome."

She carried out a meta-analysis of research previously published where specific diets were tested to see if they improved pain outcomes.

They looked at more than 40 studies, and from them found there was evidence for a "clinically relevant reduction in pain levels" from a whole food diet, and a greater pain reduction than for participants in control groups who didn't change their diet at all.

"There was all sorts of different diets in there - vegetarians, vegans and Mediterraneans, and diets that remove gluten, and all those sorts of things.  And if you have a look at them - if we put someone on a whole food diet, then their pain improves a little bit."

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She says the evidence has been clear for some time that processed foods cause an inflammatory response.

"We're looking at inflammation being one of those things that's potentially being helped."  

Field's team then took a closer look into whether a low carbohydrate diet can affect pain outcomes, and found good data to support this.  

Their research pointed to a ketogenic diet being particularly of interest. Often known as keto, this is a diet with very low carbohydrate levels, high fats and moderate proteins.  Those who maintain a low enough carbohydrate level consistently go into a phase called 'nutritional ketosis', where their body changes the way it burns energy.

"We ran a clinical pilot trial to look at this, we wanted to see 'can we actually look at a specific type of diet that's going to be even better?' "

They tested both a group of participants who changed to a whole food diet (no processed food), and a group who changed to a ketogenic diet, and found both groups showed a significant reduction in pain outcomes. But those on the keto diet showed added improvements not seen on the others.

"Their inflammatory markers went down - the first group didn't get any improvements in their inflammatory markers, but the ketogenic group did.  [They] lost a significant amount of weight, whereas the other group didn't, and we also got better improvements on some of the psychological scores that we did - measures of anxiety and depression.

"So taking that a step further and using a ketogenic diet as a treatment intervention for a time definitely can get you that bit further from a pain management perspective."

The trial included a broad range of people suffering a wide range of problems, including rheumatoid arthritis, back pain, neck pain, plantar fasciitis, fibromyalgia, from a range of ages.  Field says future studies could help by narrowing the test groups to test diets' impact on pain for just one disease at a time.  

Her team's research also included surveying what chronic pain patients think about their diet. She found they commonly over-estimated how healthy their diet is, and few considered their diet when thinking about pain management strategies.

But Field says those with chronic pain should particularly consider losing weight. Having less mechanical loading on the body is one factor, but she there's strong evidence this isn't the only factor.

"Adipose tissue or fat, particularly the fat around our belly - what those fat cells do is part of their protective response is producing inflammatory cytokines (or inflammatory chemicals) and that adds to this inflammatory problem that's causing pain.

"So losing weight will also improve pain outcomes for both of those reasons - the inflammatory loading and potentially some of the bio-mechanical side of it as well."

Eating high antioxidant foods can also help mop up some oxidative stress in the body, which is a factor in inflammation. However Field says it's not a case of counting on these good antioxidant foods negating the negative effect of processed foods - you still have to take out the processed foods no matter how many good antioxidants you eat.

"If you get enough [antioxidants] in that helps to address the imbalance. But often we find that our body is so poor that we can't really actually take in enough antioxidants to meet that demand [for anti-oxidants] - so removing [processed foods] from the diet is the easiest way to manage that problem."