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Insulin Resistance, Hypoglycemia, & Thyroid Health – Part 1

Many people with thyroid and autoimmune thyroid conditions have blood sugar imbalances.  However, there are different types of these imbalances.  Two of the most common health issues involving blood sugar imbalances are hypoglycemia and insulin resistance.  In the past I’ve spoken about these in separate articles, but since so many people suffer from blood sugar problems I figured it would be a good idea to talk about the similarities and differences between these two conditions.  In this post I will focus on insulin resistance, and then in the next post I will talk about hypoglycemia, and I will also discuss what you can do to correct blood sugar imbalances.

Glycemia refers to the presence of glucose in the blood.  As the name implies, hypoglycemia is a condition characterized by low blood sugar levels, whereas insulin resistance is more characteristic of hyperglycemia, which of course involves high blood sugar levels.  And the solution might seem simple, as if someone has high blood sugar levels  then they obviously want to reduce their sugar intake, and if someone has low blood sugar levels they will want to eat more regularly, right?  For the most part this is true, but while dietary factors are obviously important with both hypoglycemia and insulin resistance, these conditions are frequently complex and require more than simple dietary changes.

Before talking about insulin resistance I’d like to briefly talk about insulin.  Insulin is a hormone that is produced by the beta cells of the pancreas.  Insulin has numerous roles, but one of the primary roles is the regulation of blood glucose levels.  So when someone eats a meal, this will cause their blood sugar levels to rise, and the beta cells will secrete insulin to help the body utilize or store the glucose.

As for how insulin reduces blood glucose, it does so by inducing glucose uptake into insulin-sensitive tissues such as skeletal muscle, fat, and heart (1) [1].  Insulin also inhibits glucose production in the liver, kidney, and small intestine in the control of blood glucose (1) [1].  Insulin has other functions, as it stimulates the synthesis of fatty acids and glycogen (2) [2], and it also plays a role in mitochondrial function.  What happens with insulin resistance is that the body is no longer responsive to the effects of insulin.  This in turn can lead to other conditions such as type 2 diabetes, accelerated atherosclerosis, hypertension or polycystic ovarian syndrome (3) [3].

What Causes Insulin Resistance?                                                    

But in order to understand how to correct insulin resistance, it’s important to understand how insulin resistance develops.  Although eating a poor diet and a lack of exercise are definitely factors in many people, the development of insulin resistance is usually more complex.  Here are some of the factors which are thought to cause or contribute to insulin resistance:

1) Inflammation.  Inflammation is one of the biggest factors associated with insulin resistance, and this is one of the primary reasons why weight loss is so challenging in those with autoimmune thyroid conditions.  The following information is going to be somewhat advanced, but then I’m going to do my best to clarify it so that you better understand it.  Activation of immune cells is closely associated with insulin sensitivity, and research shows that classically activated (M1) macrophages sustain insulin sensitivity, whereas alternatively activated (M2) macrophages induce insulin resistance through the secretion of proinflammatory cytokines (4) [4].  Apparently in a lean state Th2 cells, regulatory T cells, natural killer cells, or eosinophils contribute to the M2 activation of macrophages, whereas obesity causes alteration of the constituent immune cells, in which Th1 cells, B cells, neutrophils, or mast cells induce M1 activation of macrophages (4) [4].

So what exactly does this mean?  Essentially the activation of certain immune system cells will cause insulin resistance, while the activation of others will decrease insulin resistance.  One of the main takeaways is that Th1 dominant conditions are more commonly associated with insulin resistance, whereas Th2 dominant conditions involve an increase in insulin sensitivity.  Since most people with Hashimoto’s Thyroiditis are Th1 dominant, this can be another mechanism which makes it difficult for people with this condition to lose weight.  If this is the case, the main factor which will help with losing weight is to suppress the autoimmune component and decrease the inflammation, which can be very challenging, and has been discussed in other blog posts and articles.  Graves’ Disease is in most cases a Th2 dominant condition, although this doesn’t mean that people with this condition can’t develop insulin resistance.

2) Mitochondrial dysfunction.  Mitochondria are located in the cytoplasm of our cells, and they are where cellular respiration occurs.  I’ve written a separate article on Mitochondria entitled “The Relationship Between Mitochondria and Thyroid Health [5]“, and so if you’re not familiar with mitochondria I would read this article when you get the chance.  There is evidence that dysfunction of the mitochondria can play a role in insulin resistance (5) [6] (6) [7] (7) [8].  But how can damage to the mitochondria cause insulin resistance?  Well, adipocytes (fat cells) play an important role in regulating energy metabolism and glucose homeostasis, and it appears that free radicals which are caused by mitochondrial dysfunction causes impairment of the function of adipocytes in maintaining glucose homeostasis (7) [8].  So what this is essentially saying is that the mitochondria helps to regulate glucose homeostasis in fat cells, but when there is mitochondrial dysfunction, this causes free radicals, which in turn impairs the fat cells.

As a result, if someone has insulin resistance then it probably would be a good idea to do some things to help improve the health of the mitochondria.  But how can one tell if they have mitochondrial dysfunction?  Well, this can be challenging, and one of the methods of determining problems with the mitochondria is through an organic acids test, although other testing methods which can be useful include an amino acid analysis and a carnitine analysis (8) [9].

3) Lipotoxicity.  Lipotoxicity refers to an excess of free fatty acids in certain tissues, which can include skeletal and cardiac muscle cells, hepatocytes (liver cells), and pancreatic beta cells (9) [10] (10) [11].  This can be a factor in insulin resistance and metabolic syndrome, and it will typically show up as elevated triglycerides on a lipid panel.  A good example of a condition associated with lipotoxicity is nonalcoholic fatty liver disease (NAFLD), which not surprisingly is usually associated with insulin resistance.  I’ve written a separate article on NAFLD entitled “Nonalcoholic Fatty Liver Disease and Thyroid Health [12]“.  But just as a reminder, these fatty acids can accumulate in other cells as well, and not just the liver cells.

4) Gut dysbiosis.  Accumulating evidence indicates that the gut microbiota play a significant role in the development of obesity, obesity-associated inflammation, and insulin resistance (11) [13].  Many people with thyroid and autoimmune thyroid conditions have gut dysbiosis, which I discussed in an article I wrote entitled “Intestinal Dysbiosis and Thyroid Health [14]“.  I’ve also spoken about PCOS in the past, which is characterized by insulin resistance.  And there is evidence that gut dysbiosis can cause activation of the immune system, thus interfering with insulin receptor function, driving up serum insulin levels (12) [15].

5) Circadian disruption.  I’ve spoken about the circadian rhythm in the past when discussing the adrenals and cortisol.  Circadian rhythms follow a 24-hour cycle.  So for example, cortisol is normally at the highest levels when a person first wakes up, and should be at the lowest levels right before going to bed.  The opposite is true with melatonin, as this hormone should be at the lowest levels upon waking up, and at the highest levels upon going to bed.  Many hormones that modulate insulin secretion and glucose homeostasis are regulated by the circadian system, and in addition to cortisol and melatonin, this includes hormones such as leptin, glucagon, growth hormone, and the catecholamines (13) [16].  Disruptions in the circadian rhythm can lead to an increase in body weight, elevated leptin levels, and increased insulin secretion (14) [17] (15) [18].  As a result, if you are having problems with sleep, you most likely have problems with the circadian rhythm, which can be a cause of insulin resistance.

6) Genetics.  Yes, genetics is also a factor in insulin resistance.  However, just as is the case with most other chronic health conditions, lifestyle and environmental factors usually trigger the genetics.  Although some people are more susceptible to developing insulin resistance due to genetic factors, the good news is that it is possible to change the expression of our genes by modifying our lifestyle and environment.

So hopefully you have a better understanding with regards to the different factors that can cause insulin resistance.  In the next post I’m going to talk about hypoglycemia.  And then at the end of the post I will discuss seven factors which can help to balance the blood sugar levels.