THE WASHINGTON POST – We all had early experiences with inflammation: a splinter that turned the skin around it red, a sprained ankle that swelled and displayed disturbing bluish-black hues. We came to understand that these reactions, termed acute inflammation, are the body’s way of protecting us, by sending white blood cells to the site of an injury to ward off further damage, promote healing and fight infection. The five signs of acute inflammation – redness, heat, swelling, pain and loss of function – usually fade as the wound heals.
But there’s another type of inflammation that you may not have heard much about: chronic inflammation. Unlike acute inflammation, chronic inflammation is not a healing process, but a destructive one – an unhealthy state of constant alarm that can affect both physical and mental health. There has been a recent clamour about it, including a profusion of research studies, because medical professionals are recognising its serious consequences and the need to treat and prevent it.
According to an article published recently in Nature Medicine, diseases linked to chronic inflammation are “the most significant cause of death in the world today”, accounting for more than 50 per cent of global deaths. These include heart disease, diabetes, high blood pressure, cancer and dementia, among others.
But research also has shown that steps can be taken to prevent or reduce chronic inflammation. Although scientific exploration remains in the early stages, “we shouldn’t wait 20 years to take action”, Mayo Clinic cardiologist Veronique Roger said. “For the public health, we need to convince more people to make behavioural, lifestyle changes now.”
One key change is to increase physical activity. A recent exercise-and-chronic-inflammation paper in the Journal of Applied Physiology reached a striking conclusion: A group of 75-year-old men who were lifelong aerobic exercisers had inflammation profiles much closer to those of 25-year-old exercisers than to their healthy 75-year-old peers who did not exercise.
The study authors from Ball State University measured levels of blood and muscle inflammation in their three subject groups at rest and after a strenuous strength-training workout. Their conclusion? “This study supports the recent evidence that exercise-training is anti-inflammatory,” the researchers reported. “Lifelong aerobic exercise promotes an overall anti-inflammatory profile.”
In addition, the lifelong exercisers produced far fewer inflammatory “distress signals” after the strength workout than their inactive peers. When stress reared its head, they coped better.
In an email, senior author Todd Trappe noted that exercisers have greater and more functional muscle strength. “We see chronic inflammation through the lens of muscle mass and muscle adaptability,” he added. “This is a real ‘bread and butter’ issue related to greater quality of life and physiologic reserve above the frailty threshold.”
Roger put it very simply: “An increase in physical activity is the single best thing most people can do to lower their inflammation.”
Diet plays an important role in chronic inflammation. The Nature Medicine paper gathers anti-inflammatory and pro-inflammatory food in two separate lists. The beneficial food include: fruit and vegetables (both high in inflammation-fighting polyphenols); omega-3 fatty acids; high-fiber food; and food high in zinc and magnesium. Harmful food include: processed food, especially those with emulsifiers; fried food; salt; sugar; and alcohol.
In 2018, a team of diet and ageing experts from across the United States (US) conducted a systematic review and meta-analysis of drug and nutritional approaches to reduce chronic inflammation. Their paper, published in Ageing Research Reviews, focussed on measures that were safe, affordable and studied in randomised controlled trials. They found good evidence to back two prescription medications, metformin and angiotensin II receptor blockers (used to treat high blood pressure); and also probiotics and omega-3 fatty acids. They found no support for vitamin D and resveratrol.
“Based on our review, probiotics seem to have the most supporting evidence,” said senior author Stephen Anton, a clinical psychologist who works in the University of Florida’s ageing and geriatric research department.
“This was initially a surprise, but more and more research is showing a link between gut health and the health of every cell in the body,” Anton said in an email. “I also think intermittent fasting can be a great approach.”
This last position was reflected in a December article in the New England Journal of Medicine. There, the authors wrote: “Intermittent fasting elicits evolutionarily-conserved, adaptive cellular responses that . . . suppress inflammation.”
Obesity is clearly associated with chronic inflammation, and inflammation experts are particularly concerned about the rapid increase in child and adolescent weight problems. What starts at a young age often extends through life. “The childhood obesity epidemic might thus be playing a key role in promoting inflammation,” reported the Nature Medicine paper.
Reversing the tide of childhood obesity has not proven easy, but a few simple steps could help. Children need even more exercise than adults – 60 minutes a day, according to federal guidelines. Family walks and hikes are a great idea, along with modest caps on screen time that steals from other activities. Don’t attempt draconian diet measures, but consider limits on a few food – sugary drinks, pizza and french fries, for example.
Consider your environment. Cigarette smoking is a known cause of chronic inflammation, and vaping probably is, according to increasing reports. Try to avoid heavily trafficked streets during high-air-pollution rush hours, and likewise use as few household cleaners as possible, because some release irritating chemicals. Indeed, a few experts have advanced an “old friends” hypothesis, which proposes that we are too hygienic. They believe that previous generations had lower inflammation in part because they had more exposure to healthful microbes from dirt and animals.
These are changes experts recommend both to stave off and address existing chronic inflammation. But how do you know if you have it? Chronic inflammation doesn’t lend itself to simple measures such as the bathroom scale and blood-pressure arm cuffs. The most common blood test is the one for C-reactive protein, or CRP. “CRP is a robust measure of inflammation, and high levels generally indicate elevated risk of inflammation-related health problems,” said George M Slavich, director of UCLA’s laboratory for stress assessment and research and co-author of the paper in Nature Medicine.
A 2015 paper in PLOS One looked at CRP levels and mortality rates of 160,000 Scottish citizens, almost two-thirds under age 65. It concluded that individuals with high CRP were two to seven times more likely to die during an eight-year period. (A normal reading is under three milligrammes per litre.)
If you are curious or concerned about your level of chronic inflammation, discuss it with your doctor. A CRP blood test can be performed for about USD50, and it’s generally free with a doctor’s prescription. “In some cases, I find the CRP test is definitely worth it,” Roger said. “It can help me and the patient personalise a behavioural lifestyle approach.”
Although the recent research highlighting chronic inflammation as widely spread, underdiagnosed and life-threatening is alarming, keep in mind that the condition is highly modifiable. A 2015 analysis of 210 twins in good health, published in the journal Cell, found that 77 per cent of the variation in chronic inflammation resulted from “non-heritable influences”.
This is a point that Slavich, who worries that chronic inflammation might appear so overwhelming that people won’t take responsibility and action, often emphasises. “It’s true that inflammation is influenced by many factors,” he said. “But when you look at that another way, it means there are many strategies for reducing it, including changes in exercise, diet, sleep and stress.”