Chronic Inflammation and Circadian Rhythm
Written by: Kevin Cann
In my last article I explained the suprachiasmatic nucleus’ (SCN) role in maintaining our circadian rhythm. If you have not read that yet you can do so here, http://robbwolf.com/2013/08/15/maintaining-natural-balance/. Due to the SCN’s role in maintaining the natural states of hormones we must ensure our lifestyles follow a path for this piece of the hypothalamus to function properly. In this article I am going to discuss the role inflammation plays on the SCN.
Studies have shown that the SCN is affected by chronic inflammation. The good thing though is that any damage done may be reversible (http://www.ncbi.nlm.nih.gov/pubmed/17936367). We are all under chronic stress whether we admit it or not. Money problems, family issues, sitting in traffic, decreased sleep window, the foods we choose to eat, etc. all play a part in our overall health. One way they affect our health is the dysfunction that they may cause in our SCN.
In addition to the cells of the SCN being altered by inflammation, they are also targeted during the aging process (http://www.ncbi.nlm.nih.gov/pubmed/16687317). Perhaps this is why some people who make poor lifestyle choices age more quickly than those living a healthier lifestyle. For example, we all know that smoking tends to age people more quickly. Smoking affects the cells of the SCN (http://www.sciencedirect.com/science/article/pii/S0169328X99000042).
Most studies on the SCN focus on subjects that are subjected to shift work. This is due to the unnatural 24 hour sleep-wake cycle that they are accustomed to. Basically, not getting enough sleep induces a release of pro-inflammatory cytokines. This alters our immune response as well as most of our physiological processes (http://www.jimmunol.org/content/185/10/5796.short). This may be a mechanism behind why we tend to get sick more easily under high stress conditions or limited sleep.
New evidence is suggesting that there may be bidirectional communication between the immune system and our SCN (http://www.sciencedirect.com/science/article/pii/S0006899308018131). This is important to understand because anything that we do to elicit an immune response is going to affect our circadian rhythm. This includes the foods that we eat.
This bidirectional communication may be important to understand to help control food intake. Our SCN plays a role in the regulation of our energy homeostasis hormones as I explained in my previous article. The SCN may also play a role in the timing of food intake as well as metabolic state (http://onlinelibrary.wiley.com/doi/10.1002/1096-9861(20010319)431:4%3C405::AID-CNE1079%3E3.0.CO;2-D/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false). Therefore, if we are consuming foods that elicit an immune response it will affect the SCN. This in turn may lead to a cycle of dysfunctional eating and all the hormones associated with energy homeostasis.
Insulin secretion effects the SCN as well. Earlier in the article I mentioned how stress affects the SCN. This is due to an inverse relationship between the sympathetic nervous system and the SCN. Insulin secreted into the SCN causes a decrease in sympathetic activity (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC303506/). Circadian dysfunction may then play a role in stress eating. Which in turn causes more issues in the SCN and the cycle continues and health continues to spiral downward.
What all this is teaching me is that there is never going to be one simple solution to cure disease or obesity. Western science is too entrenched in one disease, one cure. Most diseases share multiple facets in their pathophysiology and one of them is inflammation. It is important to understand that health is a spectrum. The more we can do to encourage positive gene expression the healthier and longer we will live.