BLOOD SUGAR: THE PANCREAS, GLUCAGON AND INSULIN, AND HOW THEY INTERACT WITH THE ADRENAL GLANDS
DON’T STRESS, I’M BACK!
Last week we talked about our adrenals, what it means and looks like when they’re “insufficient”, and some of the ill-effects that chronic sympathetic activation can have on long-term health. This week, in part 2, we’ll be examining the interrelationship between irregular blood sugar, the stress response, cortisol, and the adrenals.
BUT FIRST… ANATOMY!
Have you heard of the small-but-mighty organ known as the pancreas? This organ is actually also a gland! Our pancreas is located on the left side of our abdomen posterior to the stomach and sits right around the junction of the stomach and small intestine (7). It is here that it serves its first purpose of producing digestive enzymes as we discussed in blog post 1. These digestive enzymes help to break down carbs, proteins, and fats. This accounts for ~95% of its function (2).
The pancreas has another function: the production of hormones glucagon and insulin (7). This will go along more with our topic today. These hormones work synergistically to balance your blood glucose from becoming too dangerously high or too low which can have detrimental effects on other organ systems.
When blood sugar is too high, beta cells of the pancreas release the hormone insulin (2). High blood sugar is commonly referred to as hyperglycemia. When we’re chronically showing symptoms of hyperglycemia—like high blood glucose readings, sleepiness and tiredness after meals, frequent thirst, headaches, a hard time concentrating, frequent urination, weight changes, lethargy, and fatigue—insulin might not be showing up to do its job as insulin signals for cells to “knock knock, open up!” and let glucose into the cell. Blood glucose rises after eating (specifically high carbohydrate meals!) as nutrients are digested and absorbed into the bloodstream. We need insulin to signal to cells to regulate transport inside to begin its utilization into energy and to be stored as glycogen for later use. It’s important to note that there are always levels of insulin within the blood. However, more is produced when food is consumed to account for the influx of higher blood glucose.
Hyperglycemia is most commonly associated with diabetes mellitus, and over time one may resort to exogenous insulin or drugs like metformin to mediate its symptoms. What’s the big deal about high blood sugar? Well, too much blood glucose floating around in the bloodstream can contribute to oxidative damage, as extracellular glucose molecules function as free radicals (8). Over time, we may start to see vascular damage resulting in sclerotic plaques, inflammation, and nerve damage as coverings of neurons (myelin) are affected (8). In this sense, high blood sugar can contribute to neuralgia, neurodegenerative disease, and cardiovascular disease (8). Inflammation and degeneration of the body can contribute to a heightened stress response, which influences the release of cortisol from adrenal glands.
ON THE FLIP SIDE…
…when blood sugar falls too low, the pancreas releases glucagon from its alpha cells (2). Low blood sugar—otherwise known as hypoglycemia—can result from the absence of glucose within the bloodstream, from blood-sugar-lowering medications (like exogenous insulin), or when high amounts of insulin are released from the pancreas to lower blood glucose and remain in the bloodstream for too long. The last-mentioned possibility is referred to as reactive hypoglycemia (remember this for later). Remember how insulin shuttles glucose into the cell to be stored as glycogen? Glucagon is the hormone that signals to the liver to access muscle and liver glycogen to synthesize glucose (3). When we have low blood sugar, glucagon becomes the active hormone between meals, when fasting, during stress, and during exercise to trigger the release of stored glucose (as glycogen) to be used as energy.
Source 9: Dr. Lam Coaching,
NOW, INTO THE GOOD STUFF…
Remember how we talked about cortisol in the previous post? Well, low blood sugar is a stressor upon the body. Symptoms of low blood sugar can include: waking in the middle of the night, “hangriness”, dizziness, trembling, sweating, hunger, nervousness, and heart palpitations (6). In severe cases, we can see seizures and loss of consciousness—although this is typically a result of the inability to properly produce a glucagon response (like in type 1 diabetes). When we experience low blood sugar, our bodies release epinephrine and cortisol. The release of these stress hormones contributes to some of the “nervous-like” hypoglycemic symptoms. These stress hormones prompt a blood sugar response by triggering the release of glucagon. Glucagon signals to the liver to commence glycogenolysis where glycogen stores are broken into glucose, raising blood sugar. What does this mean? When epinephrine, adrenaline, and cortisol are released, we trigger the release of glucagon and inherently a hyperglycemic flux.
This mechanism was hypothesized to have developed to help an individual in the fight-or-flight response to get a rush of energy to escape acute danger. If you can recall, cortisol’s main job—okay, its main job is heart rate and blood pressure, but other than that—is to have the body ready for a stress response. By triggering glycogen stores to be released, it can generate energy to power muscles and the brain. In a stressed-out state, it will also keep insulin from being produced to block glucose from being stored as glycogen. This is to support immediate use (5). When we are chronically stuck in fight-or-flight, this is how our insulin response can become degraded over time.
ARE YOU A STRESS EATER?
Have you found yourself in chronic stress that is always plagued with eating? Would it be surprising that they’re interrelated? We’re in our heads about the three exams we have tomorrow or the two bids coming up next week. Stress, stress, stress. We’re on the mend and looking for a nice dopamine and serotonin hit! We reach for a sugary donut, which gives us what we’re looking for. This sugar-laden treat might be fine for a one-and-done, but oftentimes it spikes our blood glucose… only to plummet it a few hours later. We then display hypoglycemia symptoms once more and may go back to feelings of low emotion and energy. What do we look for again? Another hit of happiness—only in the form of a cupcake this time around! When we chronically give into our glucose-fluctuating cravings with sweet treats, we can contribute to the vicious cycle of poor insulin sensitivity.
As our inner emotions scream “STRESS!”, our body can decide to trigger the release of cortisol and other stress hormones. As we discussed earlier, this triggers the release of glucagon, increases our body’s demand for food, and can inherently contribute to those constant walks to the fridge. Instead of “HUNGRY…. GRAB A SNICKERS”, we can maybe look to do some deep breathing and grab a high-fat, high-protein snack to keep our blood sugar stable. It might not be as much fun, but it’s a little bit friendlier to your well-being.
CHRONIC STRESS AND WEIGHT GAIN
Keep in mind, cortisol blocks the release of insulin to let glucose into the cell (5). When we’re eating and not producing insulin to shuttle this glucose into a cell, our bodies are essentially “starving” despite the extracellular energy buffet. Your cells are CRYING for energy, but no one is there to unlock the insulin door! This is when we can see endless eating despite overeating, and inherent weight gain when this glucose goes unused. When our diets are mostly carb-based, this stress compiles or goes unresolved (or we begin to stress out about all of the weight we’ve gained…) the problem continues to compound, and it becomes harder and harder to regulate our insulin response. Personally, I’ve begun seeing this within my practice with high-intensity endurance athletes. Given their high-stress training regimens and high-carb diets, we can see inherent and confusing weight gain.
Remember last week how we discussed the hypothalamus-pituitary-adrenal axis, otherwise known as the HPA axis? It’s interesting to note that cortisol has been shown to potentially have the ability to bind to hypothalamus receptors. What does this mean? As the hypothalamus regulates hunger, it can block signals that we’re full. This can further contribute to overeating or under-eating in some.
CHRONIC STRESS AND WEIGHT LOSS
When we’re in a fasted state from being in between meals, exercising, or sleeping or when we’re embarking on a purposeful fast, we’re engaging glucagon. Glucagon is allowing us to access our stored glycogen in the liver and within our muscle cells. We are eating at nutritional stores our body has saved up. This means weight loss! When we’re looking to do this in balance with triggering insulin to take glucose in, this isn’t a problem. It also can be beneficial when we have (some) fat stores to lose. However, when we’re chronically hypoglycemic we’re constantly dipping into our glycogen reserves. Over time, these become depleted. We start to dip into our fat tissue, and then into our muscles (these are our “running in E” reserves). In time, we begin to lose excess muscle mass and can see weight loss, decreased lean muscle mass, and fat gain where muscle used to be. Ever heard of the term “skinny fat”?
Chronic stress can contribute to hypoglycemia-induced weight loss. Similarly, when we’re not eating enough calorically or we’re not absorbing our foods properly, we’re not getting enough glucose to be used for energy. This causes our bodies to go for energy where we have it—in our fat and muscle stores.
THE TIE-IN OF ADRENAL-BLOOD SUGAR BALANCE
I know I’m beating some of these points over the head, and it may be annoying to some. That’s okay—I now appreciate the teachers that did the same for me to make their points known. It’s the only way I could remember anything from physics… (joke).
Our adrenal glands produce cortisol, epinephrine, and adrenaline—and in heightened amounts when we’re stressed.
Cortisol blocks the release of insulin, which can leave us in a catabolic-like state for too long (5). This can contribute to ravenous hunger—our bodies are physically eating, but chemically there is no glucose getting into the cell. When we’re in this state, we’re eating endlessly and we run the risk of storing this food as fat (as insulin isn’t around to let glucose into the cell).
When our insulin sensitivity is impaired—from stress, from poor diet, or from other environmental issues—we run the risk of being hyper-glycemic. This can contribute to vascular inflammation, cardiovascular disease (in time), nerve damage, and epithelial damage.
It may sound paradoxical, but hyperglycemia can contribute to hypoglycemia. Huh!? As mentioned earlier, reactive hypoglycemia results after too much insulin are released to correct blood sugar (like after a high-carb meal) and plummet blood glucose. This triggers hypoglycemia, which releases stress hormones and glucagon and engages a stress response (1, 4).
Cortisol, epinephrine, and adrenaline all can contribute to the release of glucagon which can raise blood sugar to access stored glycogen for a “fight or flight” response (4, 5). In acute situations, it’s safe. Chronically, it can lead to catabolism of muscle tissue, muscle wasting, and weight loss.
When stress hormones trigger glucagon to raise blood sugar, it often falls after the initial threat (think of that initial scare when you find out you have a term paper due, a bid due, or the initial shock of some drama with a friend, parent, or partner). This can lead to a flux in blood glucose without even eating that only further stresses the adrenal glands!
IN CONCLUSION…
Stressors upon the body can contribute to insufficient adrenal function. Insufficient or malfunctioned adrenal function can have a negative impact on blood glucose. And… conversely… erratic blood glucose can have a negative effect on cortisol and adrenal health. We may think of each imbalance as independent of one another, but these two work together in a very complementary fashion. In short: if you’re dealing with blood sugar imbalance, it’s recommended to consume lower glycemic foods to avoid erratic fluctuations. It’s also equally important to control your stress levels!
Stay tuned next week for an interesting discussion on plant-based diets…
Sources:
1. https://www.livestrong.com/article/464195-hypoglycemia-weight-gain-or-loss/
2. https://www.google.com/amp/s/www.endocrineweb.com/amp/26
3. https://www.diabetesatschool.ca/schools/glucagon
4. https://dtc.ucsf.edu/types-of-diabetes/type2/understanding-type-2-diabetes/how-the-body-processes-sugar/blood-sugar-stress/
5. https://www.todaysdietitian.com/newarchives/111609p38.shtml
6. https://www.medicinenet.com/hypoglycemia/article.htm
7. https://columbiasurgery.org/pancreas/pancreas-and-its-functions
8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603044/
