The causes (and dangers) of chronic inflammation

• Inflammation is the body’s response to infection or injury, but can also develop as a result of diet or lifestyle choices. When inflammation becomes chronic, it can start harming the body rather than healing it.
• Chronic inflammation can cause several serious health issues via ongoing damage to the body’s tissues and organs. It can also lead to changes in cellular DNA that cause cancer. 
• Chronic inflammation has a variety of sources, many of them–including diet, sleep, and lifestyle choices–controllable.

What is chronic inflammation (and what does it do in your body)? 

Inflammation is a normal response to infection or injury in the body, and is in fact a sign of the body working hard to heal itself. Swelling, heat at an injury site, or fever are all forms of acute inflammation, which usually clears within a matter of days or weeks, and is unlikely to have any long-term negative impacts on your health. 

When acute inflammation lingers, however, it can transform into chronic inflammation. Chronic inflammation can also develop based on lifestyle choices or longer-term health conditions. Occasionally, this inflammation can be systemic,^[1] meaning across the whole body. Signs that might indicate chronic inflammation include: 

• Joint pain or stiffness
• Chest pain
• Fatigue/insomnia
• Abdominal pain
• Unexplained or long term fever
• Skin rash
• Mouth sores
• GI issues (including diarrhea, reflux, and constipation) 
• Unexplained weight gain/loss
• Frequent infection

Instead of healing the body, chronic inflammatory responses actually damage various tissues and organs. In addition to the unpleasant symptoms that indicate this misdirected inflammatory response is occurring, chronic inflammation can cause or exacerbate several serious health issues. 

Causes of chronic inflammation
Chronic inflammation can be triggered in multiple ways. Some of the best understood include: 

• Infection: Clearing infection effectively is one of the primary purposes of the acute inflammatory response, but for some illnesses, the body is not able to clear the underlying source of infection, causing a continuous inflammatory response. Infections of this type include H. pylori^[2] (known to cause the majority of stomach ulcers), chronic hepatitis B^[3] and C,^[4] mycoplasma infections, HIV,^[2] and the bacteria responsible for tuberculosis^[5] and certain forms of pneumonia.^[2] Fungal or parasitic infections may also lead to chronic inflammation if the body is unable to clear them.^[5]

• Diet: Certain foods^[6] can directly cause inflammatory responses, or create conditions in the body that heighten inflammation. Some of the worst offenders include:
  
  • Red and processed meats - High levels of saturated fats and salt can trigger inflammatory responses throughout the body. Additionally, heme iron and the nitrates and nitrites used to preserve processed meat may create a pro-oxidative environment in the body.
  • Added sugars - These rapidly spike blood sugar levels, creating a proinflammatory environment in the body.
  • Refined carbohydrates - Though they’re not precisely the same as sugars, highly processed breads, pastas, crackers, sugary cereals, and white rice all lack the fiber or protein content that would slow the digestion process. Without this vital nutritive element, these foods cause blood sugar spikes similar to those seen with added sugars, with a similar proinflammatory result. 
  • Trans fats - Created by food manufacturers via the hydrogenation of naturally occurring fats, trans fats help with shelf life, texture, and flavor, and are often present (albeit in small amounts) even in foods labeled “trans-fat free.” Microwave popcorn, margarine, packaged baked goods, and nondairy creamers are all likely to contain this inflammation-causing ingredient. 
  • Fried foods - Omega-6 fatty acids are essential, and can’t be produced in the body. When the balance between these fats and healthier omega-3s tilts too far towards omega-6s, however, it can lead to inflammation in the body. Oils typically used in frying–such as canola oil, peanut oil, and corn oil–contain large amounts of omega-6 fats, and should be used in moderation (essentially an impossibility if you consume excessive amounts of fried foods).  

• Stress: Stress, regardless of the cause, triggers familiar pathways in the body, including the sympathetic nervous system (SNS), responsible for the “fight or flight” response in the body, and the hypothalamic-pituitary-adrenal (HPA) axis, which releases cortisol in response to stress (a hormone that can help sustain energy during periods of stress).^[7] The flood of hormones from these endocrine responses can lead to the creation of proinflammatory cytokines and systemic inflammation.^[8] 
• Sleep: A lack of sleep, or poor sleep, has consistently been shown to correlate with systemic inflammation. Some theories to explain this connection are that without adequate sleep, blood pressure remains elevated, preventing essential relaxation of the vascular system. This may trigger an inflammatory response in cells in the lining of the vessels. Another theory is based around how the central nervous system functions during deep sleep. Typically, this phase engenders a flood of cerebrospinal fluid through the brain, which removes the beta-amyloid proteins associated with degenerative brain conditions such as Alzheimer’s. If this protein is instead allowed to remain and accumulate, inflammation sets in, which in turn makes it difficult for the brain to enter deep sleep in the future, creating a potentially dangerous cycle.^[9] 
• Autoimmune conditions: Autoimmune conditions–such as lupus, psoriasis, IBD, Crohn’s disease, and rheumatoid arthritis–are characterized by long-term and widespread inflammation in the body. Working with your medical provider to control these conditions can reduce the impact of that inflammation.^[10]
• Obesity: Obesity is known to cause widespread subacute inflammation. The excess of macronutrients in adipose (AKA fat) tissue stimulates the release of inflammatory substances and reduces the production of hormones that aid in blood-sugar regulation, leading to widespread low-level inflammation.^[11]
• Smoking: The chemicals in cigarette smoke cause a cascade of reactions in the body, including reduced immunity and the triggering of several inflammatory pathways. These pathways lead to widespread inflammation^[12] in addition to inflammation at the smoking “source” (i.e., direct inflammation in the mucus membranes of the mouth, nose, and throat caused by contact with the chemicals present in cigarette smoke). The good news: studies have shown that several inflammatory markers decline rapidly within just the first few weeks of quitting smoking.^[13]
• Alcohol: Heavy drinking appears to disrupt the body’s immune responses and contribute to a proinflammatory environment.^[14]
• Environmental exposures/toxins: Exposure to air pollution, industrial chemicals, and hazardous waste have all been shown to cause systemic inflammation.^[10] While more research is needed, common endocrine disruptors, microplastics, and “forever chemicals” may all cause chronic inflammation as well.
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Health risks linked to chronic inflammation

While certain health conditions are known to cause chronic inflammation, inflammation in the body has also been shown to contribute to a wide variety of health conditions, some of which lead to further inflammation, creating a dangerous feedback loop:  

• Metabolic syndrome / type 2 diabetes: Multiple studies have linked chronic inflammation to the development of metabolic syndromes, such as type 2 diabetes. Inflammation appears to lead to insulin resistance, a known precursor to these disorders.^[15]
• Obesity: The insulin resistance that results from chronic inflammation can both stem from and cause obesity. Glucose is a main source of energy for the body, but insulin resistance makes it difficult for the body to process glucose. The body then sends hunger signals in an attempt to get the energy it’s lacking. This can create a vicious cycle of inflammation and obesity feeding into one another.^[16]
• Depression, anxiety, and other mood disorders: Multiple studies have tied higher levels of inflammatory markers to a host of mood disorders,^[17] including depression, anxiety, and even schizophrenia.^[18] One theory behind this connection is that chronic inflammation can disrupt neurotransmission pathways for hormones such as serotonin and dopamine. 
• Cardiovascular disease (CVD): Several studies have observed a strong link between chronic inflammation and cardiovascular diseases, such as heart attacks and strokes.^[15] The exact mechanisms by which inflammation influences the progression of heart disease are still being uncovered, but it appears that, as with obesity, CVD and inflammation may create a “feedback loop,” where each can lead to the other.^[19]
• Cancer: Over time, chronic inflammation can lead to the DNA changes in cells that eventually become cancer. This link holds for multiple forms of cancer, including colorectal, esophageal, head and neck, and gastric cancers, among others. Additionally, several other health problems caused by inflammation are considered independent risk factors for various cancers.^[20] 

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Steps you can take to reduce inflammation

While there are many causes of inflammation that are outside of an individual’s control, such as genetic diseases, there are several ways to proactively reduce inflammation in your body: 

• Anti-inflammatory diet: Many foods create proinflammatory conditions in the body, but there are just as many choices available that work to reduce inflammation. Foods high in Omega-3 fatty acids (such as oily fish, nuts and seeds, and avocados), fruits and vegetables (which contain a wide variety of antioxidants), and foods rich in polyphenols (including whole grains, olive oil, coffee, tea, and dark chocolate) will all work to counteract inflammation in the body.^[21]
• Lifestyle changes: Alcohol consumption and smoking are strongly tied to increased inflammation; reducing or ceasing these behaviors has an almost immediate impact on inflammatory markers in the body.^[13] Drinking less is also associated with better sleep, which is separately tied to inflammation reduction. 
• Exercise: Exercise, particularly aerobic exercise, can significantly reduce inflammation in the body. It can also help with sleep, another important factor in chronic inflammation.^[22]
• Brush your teeth: Inadequate oral care is tied to a surprising array of health conditions, including multiple forms of cancer, in part via inflammation pathways. Proper dental hygiene can not only improve site-specific inflammation of the gums and oral cavity, it can prevent oral bacteria from traveling to other parts of the body–such as the heart–and spreading that inflammation.^[22]‍
• Create a sleep routine: It’s impossible to maintain perfect sleep conditions at all times, but in addition to common advice for how to get better sleep–including limiting caffeine and alcohol, particularly later in the day, and avoiding blue light sources before bed–creating a sleep routine might have significant health impacts. A recent cohort study found that individuals with the highest sleep regularity–i.e., the most consistent timing of sleeping and waking–saw the greatest overall health benefits, even when the duration of their sleep was lower.^[23] While targeting 7-9 hours is generally a good idea, it may be even more important–and more achievable–to focus on sticking to a consistent sleep schedule. ‍
• Reduce stress (quickly, and anywhere): Stress reduction is an elusive goal; for many people, finding time to include activities such as meditation, time outdoors, or restful leisure activities can feel like an added source of stress. However, even just a few minutes of deep breathing or quiet meditation can reduce blood pressure and cortisol levels, and improve self-reported stress measures.^[24] One simple technique that can be performed almost anywhere is called “box breathing.” It involves visualizing a square, and breathing “along” its sides. While inhaling for 3-4 beats, you imagine traveling up one side of the square, hold the breath for 3-4 beats as you travel along the top, exhale for 3-4 beats as you travel down the opposite side, and hold the breath for another 3-4 beats as you travel along the bottom. Repeating this pattern for just a few minutes each day can be a very effective and accessible technique for almost anyone. 

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Chronic inflammation has been shown to lead to a variety of health conditions, including several which can themselves worsen inflammation, creating a dangerous cycle. Taking steps to reduce sources of inflammation, as well as to fight existing inflammation in the body, can yield significant and rapid health improvements. Diet, exercise, and lifestyle choices are all simple but effective ways to improve the inflammatory environment in the body. 

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