There are some well-known factors that cause chronic inflammation, and thus predispose to disease; and some not so well known ones. Let’s start with the familiar, and gradually merge into the strange….
Numero uno, tobacco. Smoking kills, according to the cigarette packs, and one of the ways in which it does is via chronic inflammation. Inhaling almost any kind of smoke does the same, as does typical urban air loaded with diesel particulates.
Nummer zwei, a diet full of pro-inflammatory compounds such as Advanced Glycation End Products (AGE’s) and Advanced Lipoxidation End Products (ALE’s). You will find these in food cooked at high temperatures, which include barbecued, roast and deep fried foods; and in many processed foods, which often involve high temperature mass production processes such as spray drying.
Numero trois, a diet depleted in anti-inflammatory factor such as the top table trio (omega 3 fatty acids from seafoods, polyphenols and 1-3, 1-6 beta glucans) and other more esoteric compounds such as palmitoyl ethanolamide and glycosyl ceramide. These last two compounds are fascinating if slightly obscure molecules, and will find multiple uses in future foods and supplements.
Nummer fyra, a diet with an excessive omega 6:omega 3 ratio. This tips the balance towards pro-inflammatory chemistry in the body, which makes everything worse. Unfortunately, an excessive 6:3 ratio is typical in the modern diet, which is why most people’s 6:3 ratios are pro-inflammatory, and why degenerative disease is so popular today.
Numero cinco, insufficient or excessive exercise. Moderation may be an unfashionable virtue, but it is a valuable one.
Nomer shect, obesity. Excessive adipose tissue is definitely pro-inflammatory, which explains why being overweight increases the risk of many forms of disease.
Numero sete – bad relationships. Just when you thought you were doing everything right…
In couples, arguments, fights and poor sleep patterns lead to higher levels of important pro-inflammatory compounds in the blood; specifically, stimulated Interleukin 6 (IL6) and Tumour Necrosis Facor alpha (TNF-alpha). Unless those couples used emotional regulation strategies such as emotion expression or cognitive reappraisal (and probably make-up sex), in which case they were protected (1). Interesting, no?
It seems that going to bed still conflicted, with your bad feelings bottled up and unexpressed, leads to bad sleep, inflammation, and eventually to disease.
Another way of looking at this is to measure heart rate variability (HRV). High heart rate variability is a good thing, as it indicates that you can change your heart beat quickly and easily when the situation demands it. This denotes flexibility and adaptability; conversely, a low HRV is linked to an increased risk of heart attack, stroke and diabetes.
HRV tends to increase when you are undergoing a stressful experience, and this can be used to measure both stress, and how well you respond to it. Back to the warring couples …
In arguing couples, if their hearts beat together this is NOT a good thing. If their HRV’s track together, this indicates that they are getting stressed together (as opposed to finding agreement and reconciliation), and the more their HVR’s track together, the higher their blood levels of pro-inflammatory messengers IL6, stimulated TNF-alpha and another compound S-VCAM1 (2). This is not healthy at all, because these compounds create inflammatory changes in the linings of arteries that lead fairly directly to hypertension and coronary heart disease.
To make matters worse (or at least more complicated), the stressed couples showed signs of changes to the microbiome, probably caused by changed intestinal secretions, which in turn lead to increased inflammation in the gut, and increased ‘leakiness’ (3). This lead to various bacterial toxins getting into the bloodstream, a process known to trigger further inflammation; and was sufficiently powerful to over-ride the otherwise protective (anti-inflammatory) effects of healthy food choices (4).
Everything is worse when children are involved. In humans who have been exposed to 6 or more traumatic events in their childhood – and survived them – stress responses seem to be set permanently on high. They tend to smoke more, they are more prone to substance abuse, to be overweight or physically inactive – and, with a life expectancy shortened by around 20 years, are twice as likely to die by 65 years than people who had none of those adverse childhood experiences (5). A physiology on permanent high alert sets the stage for chronic inflammation, which harms the individual. It also increases the need for self-medication and the likelihood of dangerous, anti-social and criminal behavior, which harms all of us. The recent mass illegal migrations into Europe have already come with a terrible cost. There will be more.
This is tied in somehow with depression. Not all depressed patients have chronic inflammation, although levels of inflammatory markers such as CRP correlate rather well with the severity of depression (6). And not everyone with inflammatory stress has depression; the US average 6:3 ratio is about 25, which indicates that most Americans have chronic inflammation, yet the incidence of depressive illness – while it has increased dramatically – is still only 10-14%.
Stepping back from the details, it looks as if there are various ways of slipping into depression, and one of these is probably inflammatory stress, but it is clearly not the only one and it may not be sufficient on its own. On the other hand – and there is always another hand – I have found a combination of the anti-inflammatory omega 3’s and polyphenols to be very helpful in many cases of depressive illness.
I can’t conclude this mini-essay without citing Janice Kiecolt-Glaser, a visionary academic and professor at Ohio State University. I don’t fully agree with her definition of what constitutes healthy food (4), but her work on the interactions between stress, physiology and psychiatry is instructive and beautiful.
- Wilson SJ, Jaremka LM, Fagundes CP, Andridge R, Peng J, Malarkey WB, Habash D, Belury MA, Kiecolt-Glaser JK. Shortened sleep fuels inflammatory responses to marital conflict: Emotion regulation matters. Psychoneuroendocrinology. 2017 May;79:74-83.
- Wilson SJ, Bailey BE, Jaremka LM, Fagundes CP, Andridge R, Malarkey WB, Gates KM, Kiecolt-Glaser JK. When couples’ hearts beat together: Synchrony in heart rate variability during conflict predicts heightened inflammation throughout the day. Psychoneuroendocrinology. 2018 Jul;93:107-116.
- Kiecolt-Glaser JK, Wilson SJ, Bailey ML, Andridge R, Peng J, Jaremka LM, Fagundes CP, Malarkey WB, Laskowski B, Belury MA. Marital distress, depression, and a leaky gut: Translocation of bacterial endotoxin as a pathway to inflammation. Psychoneuroendocrinology. 2018 Aug 4;98:52-60.
- Kiecolt-Glaser JK, Fagundes CP, Andridge R, Peng J, Malarkey WB, Habash D, Belury MA. Depression, daily stressors and inflammatory responses to high-fat meals: when stress overrides healthier food choices. Mol Psychiatry. 2017 Mar;22(3):476-482.
- Brown DW, Anda RF, Tiemeier H, Felitti VJ, Edwards VJ, Croft JB, Giles WH. Adverse Childhood Experiences and the Risk of Premature Mortality American Journal of Preventive Medicine, Vol. 37, Issue 5, p389–396
- Hernandez NV, Ramirez JL, Khetani SA, Spaulding KA, Gasper WJ, Hiramoto J, Lindqvist D, Wolkowitz OM, Hills NK, Grenon SM, Zahner GJ. Depression severity is associated with increased inflammation in veterans with peripheral artery disease. Vasc Med. 2018 Jul 1:1358863X18787640.