In my last two posts (here and here), I covered the basics of how the immune system works (if you’ve not read them yet, I suggest you do so now). In the next couple of posts, I want to look at what happens when the immune system does not work optimally. Chronic inflammation underlies so many conditions that understanding how this arises and what we can do about it, is really important.
Inflammation: useful when properly controlled
Inflammation is a key element of the immune response and is vital to successfully dealing with pathogens or tissue damage (tissue damage can be caused by injury, pathogen activity or the actions of the immune system itself). The purpose of inflammation is to cause a chain of reactions that send out calls for specialized immune cells to come to the area of infection or damage and increases the blood flow to the area in order to enable these reinforcements to arrive in large numbers. This increase in blood flow results in the redness, heat and swelling that is so typical of inflammation.
Once the immune system has dealt with the infection or damage, inflammation needs to resolve. If this does not happen properly, inflammation may become chronic.
Chronic inflammation is a factor in numerous conditions, including:
Obesity
Type 2 diabetes
High blood pressure
Cardiovascular disease
Irritable bowel syndrome (IBS) and inflammatory bowel diseases (IBD)
Arthritis
Multiple sclerosis
Asthma
Autoimmune diseases
Depression and mood disorders
Alzheimer’s disease
Some cancers.
Although chronic inflammation may not be the primary cause of these health conditions, it makes a major contribution. Thus, one of the first steps in helping the body to return to health is to address this inflammation.
Why does inflammation become chronic?
There are two main scenarios in which inflammation does not resolve:
1. The immune system fails to kill the pathogen or clear away tissue damage, and so continues to recruit more immune cells via the inflammatory process
2. The immune system successfully kills the pathogen (or clear tissue damage), but the resolution process is too weak to completely resolve inflammation.
It is really important to ensure that there is no continuing infection or cause of tissue damage that is driving the inflammation before you start encouraging the resolution process: suppressing the immune system with powerful medicines when an infection still exists will likely worsen the situation.
Persistent infection
It is possible, to have appeared to have recovered from an infection in terms of not having obvious symptoms, but the infecting organism has not completely been destroyed. Many pathogens have sophisticated ways of evading the immune system, for example they can form cysts or change their surface chemistry so that they do not trigger antibodies, they may be able to continue to live in places in our bodies that do not contain a large population of immune cells (e.g., joints, nerves). By these means, some organisms can to cause chronic inflammation but not enough to create obvious symptoms of infection. Pathogens well known for persisting long-term include the bacteria that cause typhoid, tuberculosis and syphilis, Helicobacter pylori (causes stomach ulcers), Escherichia coli (causes repeated urinary infections), herpes viruses, hepatitis B virus and HIV (human immunodeficiency virus).
Some organisms that are natural inhabitants of the body – and which do not normally cause disease – can cause chronic inflammation in certain circumstances. For example, Candida is normally kept under control by the immune system but can sometimes get the upper hand and grow enough to cause inflammation and perhaps even obvious symptoms (e.g., thrush).
Such persistent infections will be more likely if the person is not able to mount a totally effective immune response. This might be because of one or more of the following factors:
Sentinel cells fail to detect the presence of the pathogen
Insufficient immune cells to kill the pathogen, particularly neutrophils and macrophages
Failure of antigen-presenting cells to present antigen and so trigger antibody production and T-cell immune functions (see the adaptive immune system for explanations of these), perhaps due to poor flow of lymph or lack of enough antigen presenting cells
Pre-existing inflammation which can inhibit other aspects of the immune response
Stress and lack of sleep: acts to suppress the immune system
Lack of essential nutrients needed to fight infections, in particular selenium, zinc, vitamins C, E, D, B6, B12, and folate
Poor blood supply to the infected area preventing immune cells from reaching their targets.
Persistent inflammation without infection
The cause of chronic inflammation may not be due to failure to kill an infection but a failure of inflammation to be stopped once the immune system has successfully dealt with an infection or some kind of tissue damage. The process for controlling whether inflammation continues, or resolves, is highly complex relying on multiple mechanisms – so there is a fair scope for things to go wrong!
Some key players are macrophages and neutrophils which can either promote further inflammation or suppress it, by changing the kinds of cytokines they produce from pro-inflammatory to anti-inflammatory signals; essential “omega-3” fats which are needed to create proteins called resolvins which, as the name suggests, orchestrate resolution of inflammation; specialized regulator T cells; collagen and the building blocks to repair damaged tissue; and the process of programmed cell death (“apoptosis”) which safely removes tissue damage signals thereby preventing further inflammation.
Failure to resolve inflammation may occur for several reasons:
Persistence of some kind of trigger (perhaps unrelated to the original infection, such as food or airborne allergies, other microbes, presence of PAMPs and DAMPs from food/the environment/tissue damage)
Insufficient macrophages to phagocytose the short-lived neutrophils that specialize in killing pathogens (as explained in part 1, if neutrophils die before being eaten by macrophages, they spill their load of toxins, which is strongly inflammatory)
Apoptosis failing to work. A million cells die every second in our bodies and if this does not happen properly, they will stimulate inflammation. Toxins can interfere with apoptosis, so can high blood sugar levels as this pushes the body’s pathways into growth rather than controlled cell death (apoptosis is stimulated when we are not eating: intermittent fasting is a good way of encouraging healthy apoptosis)
Not enough omega-3 fats to make resolvins (oily fish are your friends).
What you can do to prevent chronic inflammation (and associated health problems)
Your first task is to ensure your immune system has all the building blocks for both a timely and effective response to infection and appropriate resolution.
Reduce stress
Sleep well
Keep blood sugar under control (avoid sugars, limit carbohydrates)
Eat 2 or 3 meals a day and avoid snacking
Eat a diet rich in vitamins and minerals (see advice on specific nutrients needed for good immune function here and here)
Ensure you are getting plenty of omega-3 fats, especially fish oil; avoid eating large amounts of omega-6 fats which oppose the effects of omega-3 fats and so may prevent resolution
Identify any possible triggers in terms of foods, toxins etc that you may be sensitive to.
If you already have problems with chronic inflammation, you will need to identify whether there is any ongoing infection that has not been picked up. This can take some detective work, and if you are working with me, we will spend some time looking for clues that there may be an infection. Once we know whether we need to address an infection or consider factors preventing resolution we will be able to make progress.
If you’d like to discuss how I can help you to find the cause of your inflammation, just contact me for a chat.