Findings from this study reinforce the well-established connection between body weight and chronic pain.
There is the suggestion here that dietary intake could well be a significant behaviour in managing long-term pain in overweight individuals.
Specifically, painful inflammation could be managed by certain foods that are abundant in certain diets. The Mediterranean diet for example is rich in anti-inflammatory foods such as green leafy vegetables, seeds and fish.
"Obesity and pain are significant public health problems. This was an attempt to take a very detailed snapshot of how they might be related," said lead researcher Charles Emery, a professor of psychology at Ohio State University.
"We were interested in the possibility of an inflammatory mechanism explaining the connection because we know there's a high degree of inflammation associated with obesity and with pain."
Dr Emery’s team pinpointed the component most likely to be driving the mediation effect was the high content of anti-inflammatory omega-3 fatty acids in seafood.
The diet also included plant proteins such as nuts, seeds and soy products, which have also demonstrated anti-inflammatory effects.
98 healthy adults (60% women with an age range of 20-78 years) participated in a home-based study that looked at their environment, food-related behaviours, health and weight.
Three measures of body fat were collected, including height and weight for calculation of body mass index (BMI).
Subjects also completed a 24-hour food recall interview and self-reported measures of bodily pain and psychological state.
A model was then used to determine to what extent aspects of an anti-inflammatory diet (high in fruits and vegetables, whole grains and healthy fats) would play in the chances a person's weight contributed to their pain.
The model took body mass index, waist circumference and body fat percentage into account. In all three cases, proof existed that anti-inflammatory proteins may explain the link between increased weight and pain.
“The documented mediation model indicates that poorer food choices among individuals with higher body fat may contribute to symptoms of pain,” the study observed.
“We were interested in the possibility of an inflammatory mechanism explaining the connection because we know there's a high degree of inflammation associated with obesity and with pain," added Dr Emery.
Powers of pain
As well as the consumption of seafood and plant protein, the team delved further into possible mechanisms that release inflammatory cytokines in the body that contribute to pain levels.
“Dietary intake of anti-inflammatory foods may be associated with lower levels of inflammatory markers such as C-reactive protein,4 interleukin-6, and tumour necrosis factor–alpha," the study mentioned.
Biomechanical factors have also been put forward as a possible mechanism in the past, with obesity leading to postural changes that affect loading on joints as well as joint structure changes.
“With rates of obesity increasing worldwide, the consequences for health status are likely to be profound,” the study warned.
“In particular, obesity may be linked to increased prevalence of pain symptoms and greater demand for pain management strategies.“
The study was not without its limitations as Dr Emery lamented over the lack of blood samples that allowed the team to inspect the inflammatory markers and the scale of the pain measurement.
The pain evaluation provided an indicator of pain experienced during the previous month, but did not account for chronic pain of a longer duration.
Published online ahead of print: doi: 10.1097/j.pain.0000000000000754
“Dietary intake mediates the relationship of body fat to pain.”
Authors: Emery, Charles F; Olson, KayLoni L; Bodine, Andrew; Lee, Victoria; Habash, Diane L.