Sunday, July 19, 2015

Insulin Resistance and Diet Myths and half Truths

As I read others blogs and published articles about Insulin resistance a small semantic matter keeps cropping up.  Lets be clear Insulin resistance is the same thing as "carbohydrate tolerance".
  Early warning signs of possible insulin resistance may include:  These are not necessarily specific ie there are other explanations:
  • increased  thirst
  • more frequent urination
  • excessive hunger
  • gaining a weight a few pounds here and there and having difficulty losing them
  • unexplained drowsiness or feeling tired most of the time, especially after eating
  • inability to concentrate
  • decreased endurance during physical exertion and exercise
  • inflammation with elevated CRP levels and or Sed Rate
  • chronic high blood pressure
  • low levels of  high-density lipoprotein (HDL, the “good” cholesterol)
  • high triglyceride levels
  • high fasting glucose levels 
  • rising hemaglobin A1c levels
  It is true that any carbohydrate gets turned into glucose in the digestive tract but when high levels of insulin are present in the blood stream (the insulin resistance syndrome) glucose is not absorbed or used by muscle cells.  It goes instead into fat storage.  Thus the saying "it is not just the fat you eat that makes you fat, it is the sugar you eat that makes you fat".  The reasons for why we become Insulin resistant are complex and involve several mechanisms. One is diet as discussed earlier but it is only one of several important factors. A diet that includes high fat intake AND high sugar intake will reliably induce insulin resistance.  ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4129661/) Eating a lot of refined or at least high glycemic index carbs will stimulate insulin production and a lifetime of bad eating habits will have consequences including insulin resistance, but that is not the only reason.   Another is genetics.  Since we can't change our parents or our DNA we are stuck with that one.
Another reason that is becoming clearer is stress.  That mechanism is  potentially something we can do something about.  The stress filled life keeps high levels of cortisol, a glucocorticoid, in the blood stream. Interestingly the pathway for making cortisol in the adrenal glands starts with cholesterol.  Cortisol is a control hormone that is responsible for selecting which type of nutrient is used for energy demands of the body. We all learned somewhere that cortisol and epinephrine together are part of the "fight or flight" mechanism.  Thus its production and use has survival value and is responsible for the heroic feats accomplished by people in desperate situations. The details are important.  When confronted with a threat to existence the hormonal cascade begins.  The adrenal glands secrete cortisol and epinephrine(adrenalin) .  Cortisol floods the blood stream with glucose to give muscles the energy for combat or running.  It also inhibits insulin production briefly to prevent glucose from going into fat storage, thus favoring its immediate use for energy.  Cortisol narrows arteries and epinephrine increases heart rate. IF the stress is resolved the hormonal cascade ends and the levels of cortisol and epinephrine return to normal. Cortisol is thus anti insulin in its hormonal effects. http://press.endocrine.org/doi/abs/10.1210/jcem-54-1-131   If stress is not relieved and cortisol levels remain high the adaptive mechanism is for more insulin to be produced to counter the anti-insulin effect. Thus the connection between chronic stress and chronically high insulin levels i.e.  insulin resistance.  That is simplified but generally true. So it seems one important factor in treating insulin resistance is to deal with stress.  Whither it is mental , physical or spiritual, stress reduction by meditation, yoga, exercise, music, hobbies, vacations, or whatever works for you can help to lower cortisol production and thus be helpful in treating insulin resistance.
Sleep deprivation may be another independent ? factor in developing insulin resistance. https://www.ncbi.nlm.nih.gov/pubmed/25248582
The other effects of cortisol on the immune system, the cardiovascular system, even on fertility and ED are discussed at length in the medical literature. The association with the immune system and the role chronic inflammation plays on cardiovascular risk is becoming clearer over time.  The beneficial effect of low dose aspirin on risk of heart attack probably is tied into its well know anti inflammatory properties and its ability to inhibit platelet aggregation around arterial plaques. Recently quantitative measures of C reactive protein (CRP) have been shown to be a fair measure of cardiac risk for MI.   
 One way to learn about your cortisol status is with the Adrenal Stress Index (ASI). The index test has been available since about 1989.   Results can be hard to interpret  but it is available as a home kit. (Available from Amazon for about $175.00)  It is based on saliva so no needles involved.  Usually several samples of saliva are collected at specific times and sent to a lab for analysis. If the test shows higher than generally accepted norms and if repeated studies confirm a concerted program at stress relief would seem to be in order.
Any discussion of the hormonal aspects of obesity, insulin resistance, metabolic syndrome, etc is incomplete with out discussing the effect of thyroid hormones and sex hormones.  but that is a topic for another time     

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