What is Inflammation?
Inflammation is a complex biological process that the body activates in order to heal itself when injured, damaged by toxic chemicals or invaded by harmful micro-organisms.
Various cells, enzymes and hormonal-like substances are involved in the process. When triggered or ‘activated’, inflammation rapidly escalates into a cascade of consecutive biological events, a process that is largely controlled by small protein-based molecules called cytokines. After activation, inflammation has an immediate and local effect. Over time, this effect usually branches out and spreads to other parts of the body. Ideally, once inflammation has achieved its purpose of healing, it should automatically switch itself off. This is where things can potentially go wrong, since unregulated inflammation often becomes chronic and, instead of protecting the body, it starts damaging it.
What are the symptoms of inflammation?
When inflammation involves the skin, symptoms can be interpreted visually. With dermatitis or eczema, a rash appears. Early signs include redness, scaling, swelling or crusting. If allowed to progress, blistering, cracking and oozing may result. The body also perceives the presence of inflammation through the experience of pain.
A large number of inflammatory processes that take place within the body, however, do not present with any obvious symptoms. Although they remain active, they often go undetected until disease strikes its first blow. An example of this so-called “silent inflammation” is the process that takes place inside blood vessels such as arteries, veins and capillaries. Over time, this process damages the lining of blood vessels and leads to many life threatening cardio-vascular complications such as heart attacks, stoke and gangrene.
Of renewed medical interest is the inflammation that takes place within body fat. Whilst largely unrecognised in the past, the inflammatory consequences and detrimental biochemical agents that are produced by fat cells contained within fatty tissue are now directly associated with the development of insulin resistance and various other life threatening medical conditions associated with Metabolic Syndrome (MetS).
“Inflammatory soup” – the ultimate biological brew
In response to injury or infection, a variety of chemicals are released by tissue cells, nerve fibres and immune cells at the site of the problem. These include various enzymes and pro-inflammatory messenger molecules called ‘cytokines’. Soon, additional cells and chemical substances produced in other parts of the body arrive at the scene of the action, summoned by the cytokines and shipped to the region via the bloodstream. A consequence of this brew of biological and cellular activity is inflammation and the milieu that it occurs within is commonly referred to as “inflammatory soup”.
Collateral damage – the consequence of chronic inflammation
When an injury occurs or the body is overrun by infection, blood vessels in the immediate region dilate to encourage the increase of blood flow to the problem region. This allows white blood cells to migrate towards the battlefield in large numbers. Arriving at the front-line, these immediately go to war. Of their most effective weapons are powerful inflammatory enzymes that, almost like pool acid, have the ability to dissolve protein.
When these enzymes dissolve enemy microbes and injured bodily tissue, it’s obviously beneficial. However, healthy tissue such as organs, blood vessels, nerve tissue and joints are also made out of protein and can therefore also be partially dissolved through the same process. The reality is that the effects of these enzymes cannot selectively be focussed, but more like carpet bombing, involve the entire region. In this case, inflammation causes cellular and structural damage to healthy tissue for no good reason.
Normally, once injured or affected tissue has been healed, the body shuts the process down by decreasing the production of its sabre-rattling warmongers, the ‘pro-inflammatory cytokines’ and increasing the production of its diplomatic peace-makers, the ‘anti-inflammatory cytokines’. The inflammatory process consequently burns out and the system returns to a non-inflamed state.
With chronic inflammation, however, the body for various biochemical reasons continues to produce pro-inflammatory cytokines. Like mercenaries without a war, these tend to get up to mischief, not only at the site of injury or infection, but by drifting off to other regions as well, thereby spreading inflammation and the consequences thereof throughout the body. Since this process has no benefit to the body, it is considered a pathological disease state.
Who is at risk of developing chronic inflammation?
A multitude of factors contribute to the development of chronic inflammation. These include environmental factors, diet, genetic make-up and stress levels. Excess body fat, especially when occurring in the abdominal area, is also linked to chronic inflammation. High-fat diets, low levels of physical activity and stress also play a role in increasing an individual’s risk of inflammation.
What is the link between inflammation and the metabolic syndrome?
Chronic low-grade inflammation is found in the majority of patients with the metabolic syndrome. It is also now known to play a dominant role in the development of the individual components of MetS, such as high blood pressure, abnormal cholesterol, glucose intolerance and obesity.
What is the link between inflammation and cancer?
Systemic inflammation and its biochemical impact play a pivotal role in the development of cancer. Once activated, chronic inflammation becomes a major breeding ground for cancerous mutations. Insulin resistance, especially in the presence of obesity, and its many interconnections with inflammation have directly been linked to a substantial increase in the incidence of cancer. In a recent study involving more than five million people, researchers investigated the effects of excess body fat on 22 different forms of cancer that represent 90% of all cancer cases diagnosed in the United Kingdom. It was found that Body Mass Index (BMI) was directly associated with 17 of the 22 cancers, especially cancers of the uterus, gallbladder, kidney and liver.
However, systemic inflammation is not exclusively linked to obesity and people of normal weight may also experience chronic inflammation as a result of other factors, including diet and physical inactivity. These individuals are therefore also at a higher risk of developing cancer.
What is the link between inflammation and pain?
A routine consequence of inflammation is the release of various biochemical substances that trigger the sensation of pain. Just as light reaching the receptors of the eyes sets off a biochemical reaction that result in sight, certain biochemical agents that are released during the process of inflammation activate pain receptors in the body. Once switched on, these pass pain messages via the nervous system to the brain. Chronic inflammation, therefore, plays a dominant role in a number of chronic pain syndromes, including joint and muscle pain, headaches and gastrointestinal pain.
What is the link between inflammation and stress?
Studies have shown that psychological contributors to systemic inflammation include stress, anxiety disorders and depression. Sleep disorders, including inadequate, interrupted or poor quality sleep, also contribute to increasing levels of chronic inflammation.
Chronic inflammation also causes an increase in the stress hormone cortisol which has the potential to disrupt the body’s immune system. This may result in an increased susceptibility to colds and other infections, as well as an increased risk of cancer.
How can lifestyle changes improve or manage chronic inflammation?
Medical science has increasingly been demonstrating that we are able to intervene in the process of chronic inflammation by making certain changes to our lifestyles. This helps to balance the body’s natural immune response and allows inflammation to achieve a more beneficial outcome instead of spiralling out of control and causing damage.
These lifestyle changes should address the environmental factors that contribute to chronic inflammation such as eating habits, physical activity, stress and excess body fat. A diet rich in whole foods with fibre and monounsaturated fats is inherently anti-inflammatory in biochemical terms. It will also contribute to weight loss when combined with restricted calories and exercise.
Mounting evidence also shows that regular exercise reduces inflammation, improves immune function, strengthens the cardiovascular system and corrects as well as prevents insulin resistance. Exercise also helps to reduce the negative consequences of stress on the system.
- Faloia Emanuela et al. Inflammation as a Link between Obesity and Metabolic Syndrome. Journal of Nutrition and Metabolism Vol 2012.
- Rosario Monteiro and Isabel Azevedo. Chronic Inflammation in Obesity and the Metabolic Syndrome. Mediators of Inflammation, Vol 2010.
- K Bhaskaran – Body-mass index and risk of 22 specific cancers: a population-based cohort study of 5·24 million UK adults The Lancet, 14 August 2014.