This is Part 4 of our series on the fight-or-flight response, and we’re here to continue with an in-depth look at the way chronic pain is connected to an overactive stress response. 

As we discussed previously in the “fight-or-flight” series, chronic or ongoing stress response is directly connected to chronic inflammation and pain. When stress continues beyond the acute response, the adrenal glands release a hormone called cortisol. Cortisol causes glucose to be released into the bloodstream so that the brain can use glucose for additional energy. 

Cortisol also turns off certain systems in the body to allow it to focus on the stress response. Cortisol levels do not return to normal until the stress goes away; and if the stress does not go away, the body’s stress response continues and can lead to cell damage and inflammation. 

As we discussed in Part 3, chronic pain is often linked to chronic inflammation, and its effects on our daily habits and overall health status can be profound. 

How does chronic pain affect our body’s nutrition and our eating patterns? 

• Weight gain or loss: Everyone has different responses to stress. Although the body's metabolism is typically elevated with chronic stress, some individuals with chronic pain don’t feel like eating because of their pain, while others eat more. With elevated cortisol levels, the body more quickly stores excess calories as fat in an attempt to prepare for the next high stress situation. Elevated cortisol levels also result in lowering levels of leptin (responsible for the full feeling after a meal) and increases levels of ghrelin (that makes you feel hungry).   
• Eating more refined sugars, carbohydrates, comfort foods: This can be related to both the emotional stress of being in pain and also elevated cortisol levels. Note: people taking opioids for pain management commonly prefer sweet foods, which may contribute to weight gain.  
• Eating less protein: When there are cravings for carbohydrates and comfort foods, these food choices may replace other nutrient-dense foods including protein foods. 
• Vitamin and mineral deficiencies: A decreased intake of nutrient-dense food, a loss of appetite, or a craving for only certain foods can result in vitamin and mineral deficiencies.
• Digestive issues: Not only are poor food choices and changes in appetite common due to chronic inflammation and pain, but so are symptoms such as heartburn, flatulence, diarrhea, and constipation, which only serve to make matters worse. 
• Poor sleep and eating: Chronic pain can result in disrupted sleeping patterns, which can cause ongoing fatigue throughout the day. Many people cope with this fatigue by eating high-calorie snacks and foods or drinking more beverages with caffeine and added sugars. 
• Obesity and chronic pain: There is a direct correlation between obesity and experiencing chronic pain. Obesity (BMI >30) is considered an independent predictor of pain relating to increased strain on weight bearing joints, decreased physical activity, and overall deconditioning. 

It is also important to note that the use of pain-relieving medications, such as NSAIDS (e.g. ibuprofen, aspirin, advil) and opioids (morphine) can contribute to some of these symptoms. We will touch on these briefly, but if you are taking some of these medications, it is important to consult with your doctor and seek further medical advice if you have questions.

What should you be eating if you experience chronic inflammation and pain?
Although there is no official “pain diet” recommendation, the general consensus is that adherence to an anti-inflammatory diet does indeed aid in reducing chronic pain. Eating foods and nutrients that improve the inflammatory state and decrease oxidative stress can contribute to pain management and a reduction of cardiovascular risk factors related to pain. So, what types of foods can help?

Fruits and vegetables: Fruits and vegetables are not only full of vitamins and other phytochemicals, but also have significant antiinflammatory effects from a substance called butyrate, which is a byproduct of bacterial fermentation of the fiber from fruits and vegetables. Further, fruits and vegetables have been found to decrease the oxidative effect in both adults and adolescents. In addition, flavonoids found in berries, citrus, apples, cauliflower, and tomatoes can benefit the health of the intestinal barrier function (that can become inflamed during chronic stress), which provides proper separation between the body and the gut. 

Fish and lean white meat; little to no red meat: The importance of lean protein is significant when talking about pain. First, chronic pain is commonly accompanied by a decrease in physical activity and, in turn, a loss of muscle mass. Maintaining adequate protein in the diet is really important for the maintenance of muscle tissue and joint tissue, including cartilage and intervertebral discs. Second, essential amino acids from proteins are vital building blocks for the production and maintenance of not only muscle tissue, but also compounds that are important to the body's natural pain management system. Examples of these compounds are endorphins, dopamine, serotonin, and γ-aminobutyric acid (GABA).  

Omega-3 and -6: These essential fatty acids have been found to aid in our body’s pain management response and have anti-inflammatory properties. Therefore, eating adequate amounts of each is essential. Omega-3 fatty acids can be found in fish such as bluefish, mackerel, anchovies, sardines, and tuna; sources of omega-6 fatty acids include soybeans, nuts and seeds, corn, and safflower and sunflower oils.

Olive oil: Olives and olive oil are great sources of monounsaturated fatty acids (MUFA). For decades, olive oil has been an important component of Mediterranean diets and has been linked to both antioxidant and antimicrobial properties. Other seed oils do not seem to have the same health benefits as olive oil when it comes to chronic pain, so daily raw extra virgin olive oil consumption and a weekly consumption of olives may be wise.

Yogurt/probiotics:  Probiotics are very important tools to combat chronic pain because of the risk for digestive stress and changes in the microbiome of the gut. Some research points to gut microbiota as regulators of pain in the peripheral and central nervous system. Related: Fight-or-Flight Series (Part 5): Nutrition and Gut Health as Related to Chronic Inflammation.

Fiber, low glycemic grains, and starches: As stated above, in chronic inflammation situations, cortisol is typically elevated, which can affect our body’s insulin use. Ongoing opioid (morphine) use for pain management can also cause unstable blood sugar levels along with increased sugar cravings, and glycaemic spikes are actually known to cause inflammation. Increased sugar intake, followed by spikes of sugar in the blood, can cause a vicious cycle resulting in weight gain, increased inflammation, and insulin resistance. To combat this, diets should include daily amounts of whole grains (whole rice, Basmati rice, barley, quinoa, rolled oats, etc.), since high fiber and protein content release glucose into the blood much more slowly than processed sugars and white flours (called “low glycemic index”). This has been shown to help inflammation, aid blood glucose management/insulin resistance, and help with keeping bowel movement regular. 

Vitamin D: There has been some research related to the idea that vitamin D deficiency may cause changes to the endocrine system, the neurological system, and the immune system, which may increase the risk for chronic pain. If you have vitamin D deficiency and are unable to increase your exposure to sunshine each week, one option would be vitamin D supplementation, but there are other ways to increase your vitamin D intake with whole foods, such as certain fish, wild mushrooms, and some fortified foods.

Hydration, dehydration, and pain: Dehydration has actually been linked to greater pain. Although the mechanism behind this is unclear, it may have to do with cortisol regulation. Adequate hydration is also vital to avoiding constipation. If constipation is an issue with the use of pain medications, it is even more important to be getting enough water every day.

Alcohol and caffeine: Limiting caffeine and alcohol consumption can be helpful in decreasing inflammation in the body. However, moderate amounts of red wine have antioxidant properties related to a compound from red grapes called Resveratrol, which plays a role in neurological sensitivity. In addition, flavonoids in red wine have a significant positive effect on immune system functions and on inflammatory cells. Note: please consult with your doctor if you are on any medications as there can be drug interactions with alcohol.

Intentional changes in diet and lifestyle can be incredibly powerful ways to reduce inflammation, chronic pain, and stress in the body.  As always, we suggest thinking about pain and inflammation management in a holistic way—in a way that can become sustainable lifestyle practices. 

Up next is the final part of our fight-or-flight series, which will explore nutrition and gut health as related to chronic inflammation. We will discuss the gut’s response to an ongoing fight-or-flight response and ways to start the healing process for a stressed gastrointestinal system. 

Share your experience with us by leaving a comment below. Have questions or want to learn more? Just ask—we're always listening! 

Read the whole series: 

• Part 1: What is the Fight-or-Flight Response? 
• Part 2: What Happens During Fight or Flight and 4 Ways to Prevent It
• Part 3: Understanding Chronic Pain
• Part 4: Anti-Inflammatory Diet to Decrease Chronic Pain (You are here!)
• Part 5: Nutrition, Gut Health, and Ways to Tackle Chronic Inflammation

Written for Fitness Blender by Natalia Holguin, RDN LDN CPT 
Certified Nutrition Coach

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Mills, Sarah E. E., et al. “Chronic Pain: A Review of Its Epidemiology and Associated Factors in Population-Based Studies.” British Journal of Anaesthesia, vol. 123, no. 2, 2019, pp. e273–83. Crossref, doi:10.1016/j.bja.2019.03.023.

Team, Chronic Conditions. “How an Anti-Inflammatory Diet Can Relieve Pain as You Age.” Health Essentials from Cleveland Clinic, 2 Oct. 2020, health.clevelandclinic.org/anti-inflammatory-diet-can-relieve-pain-age.

Harvard Health Publishing. “Can Diet Heal Chronic Pain?” Harvard Health, 15 Feb. 2021.

Wright, KC. “Pain — The Role of Nutrition.” Today’s Dietitian, Today’s Dietitian, Oct. 2019.

Rondanelli, Mariangela, et al. “Food Pyramid for Subjects with Chronic Pain: Foods and Dietary Constituents as Anti-Inflammatory and Antioxidant Agents.” Nutrition Research Reviews, vol. 31, no. 1, 2018, pp. 131–51. Crossref, doi:10.1017/s0954422417000270.

Lalchhuanawma, Andrew, and Divya Sanghi. “The Link Between Emotional and Psychological Distress with Myofascial Pain Syndrome.” American Journal of Sports Science, vol. 7, no. 4, 2019, p. 177. Crossref, doi:10.11648/j.ajss.20190704.18