Robert Sorge, Ph.D. headed research at UAB to discover a link between diet and chronic pain. (Photo courtesy of Robert Sorge, Ph.D.)Tamara Imam - Copy Editorcopyed@insideuab.com
A research team at UAB headed by Robert Sorge, Ph.D. has shown that patients who suffer from chronic pain are more susceptible to certain health issues if they practice poor diet habits.
Pain research is of special relevance in the medical community because an increasing number of Americans are visiting a doctor complaining of pain.
“Pain is the number one reason that people see a doctor. Addiction and misuse of pain medication is also the number one controlled-substance problem in the US,” Sorge said. “Given these two findings, pain is of vital importance to medicine and learning how our lifestyle affects our pain and our recovery from injury (accidental or surgical) is equally as important.”
When coupled with obesity, chronic pain becomes more intense and prolonged. According to the Arthritis Foundation, obesity raises the risk of developing certain types of arthritis and increases chronic joint pain for those who already have arthritis.
Sorge and his team ultimately aimed to investigate the correlation between obesity and chronic pain, two ailments that are considered comorbid and are rising in prevalence in the United States. For instance, one in five Americans live with arthritis, but according to the Centers for Disease Control, that number rises to one in three for obese people, and two out of three Americans are overweight or obese.
The team focused particularly on the effects of the Total Western Diet on mice. TWD foods generally have fewer calories from protein and more calories from carbohydrates and fats.
According to Stacie Totsch, a graduate student in Sorge’s lab and the first author on the lab’s paper, the TWD is so named for its popularity in the western part of the world, particularly in the United States.
“We need to be concerned about the consequences our diet has on our bodies, and not just immediately with problems like weight gain, but also with long-term complications. That’s what we set out to investigate in this study,” Totsch said in an interview with UAB News.
The researchers fed the mice TWD foods for 13 weeks to investigate the physiological impacts of a nutritionally poor diet. At the end of the trial period, the TWD-fed mice showed an increase in fat mass and a decrease in lean mass.
The mice also showed an increase in systemic inflammatory responses and in the release of leptin, a hormone that regulates long-term appetite and energy expenditure.
Researchers then introduced the chronic pain aspect to the study, exposing the mice to heat and touch stimuli and measuring their response. In the nutritionally poor mice, hypersensitivity to these stimuli was more evident and sustained in length than in the control mice.
Sorge said that while clinical data showing that obese individuals take longer to recover from injury already exists, his lab is likely the first to suggest that poor diet is to blame. According to Sorge, a poor quality diet leads to chronic low-level inflammation that may “prime” one’s immune system to overreact, thus making obese individuals with chronic pain slower to recover.
“The clinical implications are that diet has a clear impact on your physiological state and may have a big impact on how well people recover from injury,” Sorge said. “We believe that diet has a major impact on many aspects of health and hope to translate our findings to clinical trials.”
Sorge and his team plan to build on their findings by teaming up with other researchers at UAB and through the Nutrition and Obesity Research Center to study how diet impacts other aspects of health.
“Our study is the first in a (hopefully) long line of diet studies that we are conducting here at UAB,” Sorge said. “We are interested in the impact of the diet on the immune system as well as whether healthy diets can reverse the negative effects of a poor quality diet.”
