Chronic Inflammation Simply Explained

1. What It Is About

Chronic low-grade inflammation refers to when defence-system messenger substances remain slightly elevated over long periods without an acute illness being present. Such messenger substances include, for example, C-reactive protein, abbreviated CRP, interleukin-6 and TNF-alpha. They can be measured in the blood. In acute inflammation, for instance at a wound, they rise sharply for a short time. In silent inflammation they remain permanently a little higher than usual. The term Inflammaging has become established for this pattern: it refers to the observation that these values increase with age and occur more frequently in people with cardiovascular diseases, diabetes, dementia and frailty. Research focuses primarily on the measured values and on lifestyle habits such as diet, exercise, sleep and weight. One idea from the research is important: inflammation is a necessary bodily process. Therefore the aim is not to switch it off indiscriminately, but to understand how it is resolved in an orderly manner.

2. What Studies Show

The best-studied approaches are anti-inflammatory dietary patterns: plenty of vegetables, fruit, whole grains, fish, nuts and healthy oils, and few highly processed foods.

In ulcerative colitis, researchers followed 73 people with mild to moderate disease. One group received a faecal microbiota transplant — prepared stool from healthy donors transferred into the intestine — together with the anti-inflammatory diet over several weeks. The other group received improved standard care. After eight weeks more people in the first group responded to treatment, and inflammation resolved markedly more often. This advantage was still evident after 48 weeks. All participants knew which treatment they received, which can influence the result 1.

In a further study with 53 people with ulcerative colitis whose disease was in remission, the anti-inflammatory diet was compared with usual Canadian dietary recommendations over six months. In the first group the disease remained in remission in markedly more participants: 69 out of 100 versus 37 out of 100 3.

In rheumatoid arthritis, a chronic joint inflammation, a study with 50 participants tested an anti-inflammatory diet over ten weeks. The score used to measure disease activity improved, and participants had fewer tender and fewer swollen joints 2.

In multiple sclerosis a study with 100 participants examined an adapted anti-inflammatory diet over twelve weeks. Participants felt less fatigued and rated their quality of life higher 4.

In type 2 diabetes an overview summarised ten studies. Healthy dietary patterns such as the Mediterranean diet were associated with lower inflammatory markers in the blood 6.

In an observational study with 25 children with active Crohn’s disease, one group received three-quarters formula nutrition plus one meal from the anti-inflammatory diet. After six weeks the disease was in remission in most children in this group, at a similar rate to children who received only formula nutrition 5.

3. What Remains Unclear

Many studies measure only blood values. Whether this also changes the course of a disease has not yet been sufficiently investigated in humans. Inflammatory markers respond to many influences and are therefore weak evidence: a slightly lower value is first and foremost a laboratory result.

For the mild elevation in otherwise healthy people there is no recognised threshold at which action would be required.

Many studies were open-label, that is without blinding, had few participants or were short in duration. In multiple sclerosis, paraplegia and knee osteoarthritis, high-quality blinded studies with adequate participant numbers are still outstanding. Studies on individual food supplements are also still outstanding. Research into how the body resolves inflammation itself is at an early stage.

4. What This Means in Everyday Life

Readers of the reports can distinguish two things: the observation in humans and the measurement in the laboratory. For anti-inflammatory dietary patterns several controlled studies show positive results regarding symptoms and quality of life. For individual food supplements the situation is more open because human studies are still pending.

A single mildly elevated inflammatory marker says little by itself about how a person is doing. Therefore research places greater weight on courses and symptoms than on laboratory figures.

The next points to clarify are at what level a value means anything in otherwise healthy people, whether inflammation can be specifically resolved rather than merely dampened, and whether certain supplements together with an anti-inflammatory diet produce additional effects.

All details with study numbers and sources: detailed page on chronic inflammation. For children: Chronic inflammation for children.