Explainer | What is inflammation? Causes, types, symptoms, treatment for chronic cases, and its link to cancer and autoimmune diseases
- Inflammation is a process that helps the body fight infection and injury, but unchecked, it may trigger autoimmune diseases and other serious illness
- Experts’ advice on dialling it down includes replacing processed foods with immunity-strengthening whole foods, managing stress, and getting exercise and sleep
Heart disease, type 2 diabetes, Alzheimer’s disease and cancer are all serious conditions that share a link with chronic inflammation.
Inflammation isn’t actually a bad thing – it’s when acute inflammation doesn’t resolve and becomes chronic that it starts to have a negative impact on our health.
“We need inflammation to fight infections and injuries,” says Maxi Schoenteich, an osteopath and functional medicine practitioner at Integrated Medicine Institute in Hong Kong. “However, when inflammation does not stop and persists beyond the initial infection or injury, we run into problems.”
Some of these molecules travel through our body to our brain to trigger an increase in body temperature – this explains why we get a fever when we have a cold or flu.
A higher body temperature makes it more difficult for viruses and bacteria to survive; the fever, aches, pain and brain “fog” that you experience during a cold or flu aren’t actually caused by the virus, but by your immune system, to fight the infection and force you to stay in bed and rest.
Once the infection has been successfully fought, our body sends out what’s called “pro-resolution” molecules that communicate with our immune system to stop the acute inflammatory response and return to baseline.
“Our immune system is actively down-regulated,” Schoenteich adds. “In some people, this doesn’t happen successfully and their immune system keeps fighting despite no infectious agent being present. If the inflammatory response doesn’t subside afterwards and instead continues, we start to experience chronic inflammation.”
Typical symptoms of acute inflammation include redness, pain, heat, swelling and loss of function. Chronic inflammation is harder to identify as its symptoms are multifactorial and non-specific. These include brain “fog”, forgetfulness, chronic fatigue, widespread aches and pains, frequent infections, insulin resistance, blood clotting and hardening of the arteries (atherosclerosis), and digestive issues.
Schoenteich explains that inflammation is highly taxing on the body; to keep the process going, the body requires a lot of energy and resources. Inflammatory molecules are also damaging to our tissues.
“Thus, with ongoing inflammation we start to see issues like insulin resistance, hardening of the arteries and joint pain. Inflammatory molecules can also damage our blood-brain barrier – a tight barrier that protects our brain – and lead to inflammation in the brain,” she says.
Recently, scientists found strong evidence that C-reactive protein (CRP), a biomarker of chronic inflammation, may be linked to an increased risk for major depressive disorder. These findings were shared this April in the journal Neuroscience.
Chronic inflammation has a lot to do with lifestyle factors, which is why health experts use the term “lifestyle diseases” to describe conditions like heart disease and cancer.
Being overweight or obese, for instance, is a potential cause of chronic inflammation because body fat stores pro-inflammatory molecules, says Naras Lapsys, a consultant dietitian and longevity medicine practitioner at The Integrative Medical Centre in Singapore.
Other big contributors to chronic inflammation include smoking, an excess consumption of alcohol, not exercising enough or at all, poor-quality or insufficient sleep, loneliness and isolation, and chronic stress.
A diet high in unhealthy and processed foods is another huge contributor – think biscuits, pizza, crisps, deli meats, fried foods, sugar-laden snacks and foods containing trans fats. In some people, eating gluten and grains can cause inflammation, too.
“Our gut houses 80 per cent of our immune system,” Schoenteich says. “Whatever enters your mouth has the potential to calm or trigger your immune system, and processed foods are pro-inflammatory.”
“Bacteria found in the oral cavity have been found in the plaques of heart attack patients. This is how far these bacteria can travel, and if not kept in check, they can cause a lot of damage,” Schoenteich points out.
New research, published in April in the journal Cell, found that one inflammatory disease may increase our risk of having another. Using mice, the scientists found that an inflammatory disorder like gum disease led to changes occurring in cells in the bone marrow that increased the animals’ risk of developing arthritis, another chronic inflammatory disorder.
According to the researchers, these cell alterations are “a central mechanism, a unifying principle underlying the association between a variety of comorbidities”.
Supplements, like curcumin, fish oil and vitamin D, may also help.