Skip Breakfast, Pass on Lunch, Lose our Cookies
Updated: Aug 9, 2021
My grandma. She came to the United States when she was 5 years old. Over the following ninety some odd years, she made a life for herself in a new country. As a child, she made the long journey by boat to the U.S. As a young adult, she survived The Great Depression. Later on in life, she worked hard every day to put seven children through college. It wasn’t an easy life.
She was a remarkable lady. I credit a lot of my own drive and determination to her influence. In addition, there was one extra-special gift she bestowed upon me. This was her habit of making me eat huge bowls of food every time I would go to visit.
Of course, it was out of love. But as a kid, I remember having to psych myself up as we turned the corner onto her street. As soon as I walked through her door, she’d sing, clap her hands, snap her fingers, and finish up by squeezing my cheeks. Then she’d usher me over to her kitchen table and serve me up big bowls of her homemade Mediterranean food.
There must have been something about the fear of starvation that motivated her. Uncertainty about the next meal was definitely a part of her youth. Yet, this fear of going hungry was completely absent in mine.
My grandma was fond of saying, “your health is your wealth!” To her, food was medicine. Being well-fed was a big part of being healthy and making it in life. Lucky for me, she literally jammed that lesson down my throat. Thanks grandma!
Perhaps, in her mind, if I was curled up on her couch, clutching my stomach an hour after I got to her house, she was doing right by me. All that good food she stuffed me with would eventually find a way to be absorbed, and I’d be better for it. Maybe she felt that by filling me up with good food would prepare me for life. Somehow, it would keep me safe.
This whole routine was not good for my waistline. Then again, it taught me something important about food, family, and health: Everything will be okay as long as everyone’s well-fed.
Here we are, many years later, in a world where food is fast, cheap, disposable, and way less cherished. It’s human nature to take things for granted. When things are less valued, they become less of a priority. That’s when these things tend to disappear from our daily lives. This is how breakfast became optional.
Song credit: John Doney - Granite Heights
One More Cup of Coffee Then I’ll Go
When life gets busy, it does seem more efficient to simply get up and go in the morning, doesn’t it? Nowadays, many of us either forgo breakfast altogether, or just eat a coffee for breakfast. Many of us wake-up feeling too tired to cook. At the same time, we often feel an urgent need to get out the door as quickly as possible. Am I right?
But how is it that we can keep going all day long when our tank is on empty? Anytime we go long periods without eating, our blood glucose (AKA blood sugar) levels will naturally decrease.
A significant-enough drop in blood glucose levels will trigger the release of stress hormones like epinephrine (also known as adrenaline) and cortisol (Tesfaye 2010). In a way, epinephrine and cortisol are our saviors.
Friends in Low Places
These stress hormones protect us from the immediate harms of low blood glucose episodes. But, how exactly does it feel to be low on blood glucose?
The body’s response could include shakiness, anxiety, tension, palpitations (sensation of heart pounding against the chest wall), weakness, confusion, fatigue, visual changes, sweating, altered mood, and of course awakening in the night (Tesfaye 2010).
In addition, low blood glucose levels can trigger mental and emotional symptoms. Low blood glucose feels like a low hum of excessive worry, inner tension, dark moods, and scattered thoughts (Salzer 1966). Without an adequate supply of energy in the brain, we experience fatigue, excessive worry, somber moods as our emotions go unmuted (Gold 1995).
In addition, inadequate blood glucose in the bloodstream can lead to scattered thinking and poor concentration (Graveling 2013). When the brain is thinking, it’s using up a lot of glucose (Scholey 2001). And, that glucose is delivered to the brain through our bloodstream. So when we are using our brains, we absolutely need that supply to be there.
With a low blood glucose level, there are the physical signs and there are mental and emotional symptoms. It’s not a good situation to be in.
How low is too low? Blood glucose measurements are often captured in the morning, after an 8+ hour overnight fast. For that morning reading, an optimal fasting blood glucose is between 85-100 mg/dL.
At any point in the day, symptoms of hypoglycemia can present when your blood glucose level dips below 70mg/dL. Stress hormone release is typically triggered once the blood glucose level falls below 55mg/dL (Jauch-Chara 2007).
What I Got
When the level of glucose in the bloodstream drops below a certain threshold, these stress hormones are called in to do a specific job. They are released from the adrenal glands and head to the liver and the muscles. Once they reach the liver and muscle tissues, they stimulate the breakdown of glycogen.
Glycogen is the boxed-up, storage form of glucose. It’s a small energy savings account that resides primarily in the liver and muscles, as well as other tissues in the body. Once glycogen is broken down, it turns into glucose. Glucose is then free to enter the bloodstream, which raises blood glucose levels back up (Tesfaye 2010). Problem solved.
This compensatory reaction is vital. In the body and brain, glucose combines with oxygen to produce energy in the body and brain. With adequate energy supply in the brain, we can think clearly and feel well.
When a Hero Comes Along
Clearly running on an empty tank is a poor choice. But, if we find ourselves in a low blood glucose situation, we can temporarily rely on epinephrine and cortisol. The release of these heroic stress hormones is how we can keep going all day, even on an empty tank. Let’s take a closer look at each.
When needed, epinephrine helps us respond in an emergency. It’s the fight or flight hormone. Epinephrine is what gives us a lump in our throat, butterflies in our stomach, and the flutter in our heart. On the positive side, epinephrine comes in handy if we have to deliver a presentation in front of a large group, or perhaps need to engage in hand-to-hand combat for whatever reason.
Cortisol also helps us respond to stress, just in a different way. Compared to epinephrine, cortisol provides a more subtle, longer-lasting effect. Cortisol sustains our energy, limits our immune responses, keeps electrolytes in balance, and helps us form memories (Hall 2016). These would be some of the benefits of cortisol - adequate, normal levels of cortisol. It’s actually a great system. It’s there to back us up when we need it.
Epinephrine and cortisol, are the keys that unlock our stored-up glucose savings account that resides in our liver, muscles, and other bodily tissues.
Skip breakfast? Cortisol has got your back. Procrastinated on your work? Cortisol is there to kick your brain into gear at the 11th hour. Overwhelmed with emotional hurts? Cortisol can help you clean your house like a mad man/woman so you don’t have to think about it too much.
Paradise By the Dashboard Light
In the moment, cortisol rescues us from bad situations. Cortisol is a salve. It protects us from the harsh winds of life. It desensitizes us to pain and fear, so that we can fight on for just a little while longer.
Cortisol mobilizes internal energy reserves in the body, which helps us respond to the stress and demands in our environment. In addition to the increased access to energy, cortisol increases blood flow to the brain (Sapolsky 2000). Further, as cortisol washes over our brains, it increases our ability to focus and remember what just happened. Unless that thing that just happened is highly emotionally charged. Then cortisol actually impairs memory of what just happened (Rimmele 2003).
Something stressful happens. We immediately begin to feel it. In that immediate term, we have a split second choice. We can go with the emotions welling up from within. Or, we can pause and try to think it through. In that immediate term, cortisol turns up activity in the thinking center of our brain. Increased activity here helps us think through our problems.
At the same time, cortisol turns down negative emotions percolating in the center of the brain, which allows our brains to engage in cognitive reappraisal (Jentsch 2019). Cognitive reappraisal is basically the process of putting your overly negative thoughts and emotional reactions in check. We changed our minds. Cortisol helped us get there.
Once those strong negative emotions ping you, cognitive reappraisal puts an end to the violent uprising. Cognitive reappraisal creates a different, more fair and neutral story of the situation. Cognitive reappraisal, as a coping technique, reduces activity of the amygdala (Buhle 2014).
To review, when a difficult situation strikes, cortisol kicks in to help us cope. At first, we are lit up with emotions. In a few moments, the release of cortisol reaches our brain and helps us come to our senses. In sum, cortisol engages our thinking brain and at the same time, quiets our emotional brain.
Rock You Like a Hurricane
Clearly, my grandma would not approve of skipping breakfast. But, is there any research to support the idea that we have to be well-fed, in order to thrive and feel well? Common sense says that force-feeding children is not recommended. But, is there any scientific evidence to support the practice of being well-fed throughout the day?
In fact, yes! To start, the “skipping breakfast” research (it’s really a topic that’s been studied) points to increased rates of depression in subjects who routinely pass on breakfast (Yoshikawa 2019). In adolescent subjects specifically, higher rates of anxiety (Zahedi 2020) and impaired concentration (Boschloo 2012) have been observed in breakfast skippers.
When we begin to run low, epinephrine is the first on the scene (Jauch-Chara 2007). It acts quickly to trigger the release of stored glucose. This obviously raises the amount of blood glucose in the bloodstream quickly.
Again, we pay a price for excess epinephrine, especially if the situation doesn’t call for this kind of response. Epinephrine is increased during anxiety. Epinephrine, along with norepinephrine, surges during episodes of anger (Wenger 1960). With modern life being so stressful, epinephrine activity can be all too frequently triggered, helping us to feel constantly tense and always right at the edge of full-blown anxiety. It may also be the reason why the rate of Diabetes (disorder of elevated blood glucose) has steadily climbed over the past 20 years (CDC 2018).
Cortisol helps us dig deep. It temporarily turns off our emotional brain, turns up our thinking brain, switches on our safety radar, and helps us to act. Unfortunately, there’s a price to be paid for the short-term benefits of cortisol. Over time, if we excessively access the cortisol “get out of jail free card” we will experience the opposite effect. After months and years of repeatedly dipping into the well of cortisol, our brain function and mental wellness will suffer. Excessive cortisol secretion over time will impair our ability to think, to remember, to feel well, and to function overall (Huang 2009, Hansen 2010, Dienes 2013).
Reliance on cortisol for temporary fixes to our problems results in short-term gains, but long-term harm. Specific areas of the brain that cortisol alters include the hippocampus, the amygdala, and the prefrontal cortex (Vyas 2002). Excess stress hormones can rewire our brains, for the worse (Huang 2009).
Here’s a run down of the key areas of the brain that are negatively impacted by inadequate blood glucose levels and over-reliance on stress hormones.
The hippocampus is the relay station for memory formation in the brain. Our hippocampus is responsible for converting that short-term memory into long-term memory (Kryukov 2008). Over time, however, higher than normal (or more than is truly necessary) secretions of cortisol interrupt important connections from the hippocampus to other parts of the brain (Vyas 2002).
A lifetime of chronic stress and excessive cortisol secretion can actually lead to shrinkage of the hippocampus (Gianaros 2007, Kim 2105). In repeated studies, higher levels of cortisol secretion were associated with a total decrease in size of the hippocampus (Starkman 1999, Huang 2009, McEwen 2016). Smaller hippocampus size is commonly found in older adults with Depression (Videbeck 2015) and Alzheimer’s Disease (Jack 2005).
Even before the shrinkage occurs, excess cortisol secretion impairs our memory and contributes to increased anxiety and unstable mood. (Cha 2016).
The amygdala is the brain’s fear center. The amygdala is very sensitive to signals that there is potential danger in the environment. In a way, fear keeps us safe. Without a functioning amygdala, we might be willing to do crazy things like jump out of an airplane without a parachute.
But, fear can also be problematic. Fears that have a limited basis in reality can immobilize us. Fear can prevent us from living a fulfilling life. In the immediate-term, cortisol increases the activity of the amygdala. With repeated stress, it decreases it’s activation (Vaisvaser 2013).
But by that time, it’s too late. That increased activity increases the connections between the amygdala and other important parts of the brain. Over time, with repeated activation of the amygdala, our brain makes more and more associations between various things in the environment and the perception of danger. This is how we learn fear (McEwen 2016).
Thankfully, we have the prefrontal cortex to fact check our fears. Jump out of the plane without a parachute? Not smart. Take a deep breath and try to center yourself as you begin to give that big presentation at work despite feeling like you want to run in the other direction? Smart. The prefrontal cortex knows how to navigate life’s tough decision points.
The prefrontal cortex is the adult part of the brain. It helps us pick a goal and move thoughtfully in that direction. It also mutes intense emotions (Sotres-Bayon 2010). The prefrontal cortex can reach back into the brain and shush the excessive fear bubbling up from the amygdala (McEwen 2016). Unfortunately, a long-standing pattern of excessive cortisol secretion will impair prefrontal cortex function (Arnsten 2015).
Again, excessive cortisol secretion results from chronic life stress. And, it can also be a consequence of unnecessary dependence on cortisol to correct dips in blood glucose (which may be happening if you forget to eat breakfast).
With or Without You
Low blood glucose levels equals a mind lost to emotions, distractions, and fatigue. Obviously, that’s not ideal. If our supply of glucose in the bloodstream runs low, we can access a short-term supply of energy reserves with the help of stress hormones (Sapolsky 2000). These stress hormones help fill in the gaps, so we can keep going.
In a way, those stress hormones surge in an effort to bring the blood glucose levels back up and prevent us from losing our minds. For the brain to function optimally, glucose has to be there, in an adequate supply (Graveling 2013, Scholey 2001). Cortisol (and epinephrine) help with that.
In creating an energy/glucose deficit by skipping breakfast, we then force ourselves to rely on our stress hormones. In the long run, skipping breakfast - and by extension relying on stress hormones for energy mobilization - can push us toward experiencing anxiety, anger, agitation, and disturbed sleep (Ehlert 2001).
In summary, stress hormones are the key that unlocks the stored up glucose (in the form of glycogen in the liver and muscles) when we need it. It’s a great system. But, there’s a problem. The problem is that we tend to pay a price for the unnecessary & excessive release of stress hormones - cortisol and epinephrine rewiring our brain for the worse. These stress hormones save us in the moment, but harm our brains in the long run. Perhaps my grandma was right.
One Step Closer
Going back to our original game plan - coffee for breakfast, vending-machine snack lunch, and a sensible dinner - we can see how this leads to dips in blood glucose levels and excessive reliance on stress hormones. With plenty of stress hormones circulating in the body and brain (to compensate for a depleted blood glucose level), we feel okay for the first few hours of the day. It’s all good, until sometime in the early afternoon. That’s when the crash hits. What initially felt like a great idea begins to backfire. Energy tanks. Mood shifts. Confidence wanes. The fog settles in.
Let’s talk about you? Ever had a day when you skipped breakfast, but somehow still had enough energy to persist throughout the work day? For a while, it feels kinda good. Just getting up and going can help us feel extra productive. As a side benefit, skipping breakfast saves time and avoids the hassle of having to put time and energy into making food.
But what about the mid-to-late afternoon crash? What about the middle-of-the-night awakenings? What about the personality change? How about that uber-pleasant combo of an extra-sharp and irritable tone with an exceptionally dull and non-existent memory?
Let’s dig a little deeper into what can happen for us mentally and emotionally when we skip breakfast.
If skipping meals for the first half of the day is your daily routine, the consequence may be a brain that’s wired to focus on the negative. With a dip in blood glucose levels, your amygdala will initially become overactive. But as hypoglycemia continues over time, the amygdala will become desensitized. Future blood glucose dips and stress hormone surges won’t wake up your amygdala in the same way. After a time, the amygdala will become under-responsive (Dunn 2007).
Similarly, low blood glucose levels disable the prefrontal cortex, which shushes the amygdala (Graveling 2013). That double negative doesn’t exactly cancel itself out. Both the amygdala and prefrontal cortex going off-line is not good for our mental wellness. Deactivation of the amygdala and prefrontal cortex means that two important parts of the brain, both designed to protect us, are no longer able to keep us safe… and sane.
Instead, our brain will be stuck on auto-pilot. It will be fine tuned to zero in on negative events and situations. Negativity will reign over all else. Once the amygdala gets going, even the thoughts about the possibility of negative things happening will become sticky (Admon 2018). Excess cortisol will condition us to be more sensitive to pain, but less able to learn how to avoid pain (Benson 2019). This turns us into sitting ducks.
Perpetually fearing the negative outcomes is a hard road to travel. This is how chronic blood glucose dips and surges of cortisol set us up for depression, anxiety, and cognitive impairment (foggy brain) in the long run.
With a boost from cortisol, and maybe epinephrine here and there, we made it through another tough day. Then night falls. Bedtime approaches and it’s insane how we are simultaneously so physically exhausted in our bodies, but firing on all cylinders in our minds. It’s the middle of the night, and we can’t sleep. We’re laying there, staring at the ceiling, frustrated and confused.
Alternatively, maybe exhaustion strikes and it’s both physical and mental. In this case, we basically fall asleep mid-air as we floop onto our bed, then suddenly awake in the middle of the night, hot, sweaty, with a racing mind.
Dips in blood glucose levels can lead to sleep disruption (Jauch-Chara 2007). Most often, this is that scenario where we fall asleep just fine, but a couple hours later find ourselves, without any clear reason, wide awake. It’s confusing why we are wide-awake. We know we are a little grumpy. We’re also anxious for some unknown reason. And, it’s not morning time yet. It’s midnight. It’s 2am. It’s 3:30am. It’s awful.
Physiologically, it makes perfect sense. During the night, as we are asleep, our blood glucose levels drop. Obviously, we are not eating while we are sleeping. Glucose in the bloodstream drains, as the body is still humming along. Even though we are asleep, our body and brain still require an energy source to keep everything functioning.
Our brain can sense when blood glucose levels fall below critical levels (Verberne 2014). There’s only two ways to increase blood glucose levels back up - eating food or triggering the release of these stress hormones. Again, if we’re asleep, we aren’t going to be eating. So, the body handles this problem with little squirts of cortisol and epinephrine (Tesfaye 2010).
If the body relies on this mechanism too much, then at a certain point, too much of these stress hormones have been released for us to remain soundly asleep (Jauch-Chara 2007). Instead, we wake up - sometimes hot and sweaty, sometimes with a surge of energy, always frustrated that we are awake. So, grandma was right.
To be well, we gotta eat. When it comes to sleep, we have to have an adequate energy supply to keep our body functioning while we get our sleep. This energy is delivered in the form of glucose readily available in the bloodstream. Glucose in the bloodstream can directly come from eating glucose (sugar) or carbohydrates in general. Yet, even consuming protein and fat will help. These dietary macromolecules can easily be converted into glucose and delivered into the bloodstream for use.
Stuck in the Middle With You
If you identify with any of the above, below are some simple steps that can be taken to avoid the blood glucose dips, and subsequent release of excess stress hormones.
These interventions are geared towards keeping the glucose levels stable. Blood glucose levels are best kept in a medium range, not too high, not too low. We’ve covered how too low is bad. But too high is also problematic. Chronic elevation of blood glucose levels is also associated with depression (Lustman 2000) and anxiety disorders (Li 2008).
In our busy modern lives, we are all invited to neglect breakfast (and other meals) in order to get more done. That’s not helpful. On the other hand, my grandma overshot it. As a result, I suffered a fair amount of indigestion. That wasn’t ideal either.
Like most things in life, we should think about balance. Aiming to keep blood glucose levels in the middle is the best way to go.
Don’t Stop Me Now
Remember, everything will be okay when everyone’s well-fed. Here’s some simple tips to begin with.
Try to take in at least a few hundred calories for breakfast (the time of the day when you are supposed to ‘break the fast’)
Regular cardio and strength training improves our overall metabolic health and building muscle offers us an additional metabolic reserve that we can tap into when low on glucose in the bloodstream (Cohen 1995).
3) Protein, Fat, & Fiber:
Focus on protein, fat, and fiber. These foods provide energy in a delayed-release manner. They help sustain the energy release over the few hours after we have eaten. Protein, fat, and fiber avoid the sharp rising and falling of our blood glucose level (Bell 2015). If you have a poor appetite in the morning, you can eat eggs, animal meat, smoothies with protein powder, or nuts if you have to.
4) Avoid Sugar:
Sugar and other quick-releasing carbohydrate foods initially produce a big spike in blood glucose. If the massive amount of blood glucose absorbed slowly from that point on, everything would be fine. But, soon after noticing the dramatic rise in blood glucose, insulin spikes. This spike in insulin is the body’s way of compensating for the rise in blood glucose. Insulin corrects this imbalance by rapidly driving down the level of glucose in the blood. What can unfortunately happen next is that insulin drives our blood glucose levels too low. This is called reactive hypoglycemia (Hofeldt 1989).
That’s a blood glucose rollercoaster, which can, in the end, dump you into a low blood glucose state, and thus trigger unnecessary stress hormone response and subsequent mood changes (Salzer 1966).
5) Reduce Stress:
Stress will increase blood glucose (Marik 2013). Stress also increased pro-inflammatory messengers. In light of evolution, this response is protective. With more available glucose in our bloodstream we’re able to run from those tigers. With an increased amount of inflammatory messengers, we are able to heal from the deep scratches the tiger left in our backs as we narrowly escaped. In modern times, we only see tigers on Netflix documentaries. So this evolutionary response (surge in blood glucose and inflammation) is no longer as useful. Today, we just experienced the harms of chronic, and sometimes acute, stress. This is why we need to do all we can to try and reduce our stress, so as to avoid the highs and lows of the blood glucose rollercoaster. Meditation is popular, but often challenging. Tennis is fun. Reading works. Long walks will do it. Whatever you like, you’ll probably be able to stick with. Just try to notice the tension in your body and then take a moment to bring it down as best you can, as often as you can.
6) Limit Inflammation:
Inflammation can trigger a hormone called GLP-1 (Kahles 2014). This hormone is also released in response to the body sensing food intake. GLP-1, in turn, increases insulin secretion (Kjems 2003). Insulin drives glucose out of the bloodstream and into body cells and tissues. So more inflammation equals greater insulin response equals lowered levels of blood glucose. The best way to limit this effect of inflammation would be a solid health regimen based on good sleep, balanced diet, regular exercise, and some form of stress management.
#thementalwellnessdiet #functionalmedicine #bloodglucose #inflammation #mentalhealth #brainhealth #depression #anxiety #insomnia #sleep #1000waystowell
Admon, R., Vaisvaser, S., Erlich, N., Lin, T., Shapira-Lichter, I., Fruchter, E., … Hendler, T. (2018). The role of the amygdala in enhanced remembrance of negative episodes and acquired negativity of related neutral cues. Biological Psychology, 139, 17–24. doi: 10.1016/j.biopsycho.2018.09.014
Bell, K. J., Smart, C. E., Steil, G. M., Brand-Miller, J. C., King, B., & Wolpert, H. A. (2015). Impact of Fat, Protein, and Glycemic Index on Postprandial Glucose Control in Type 1 Diabetes: Implications for Intensive Diabetes Management in the Continuous Glucose Monitoring Era. Diabetes Care, 38(6), 1008–1015. doi: 10.2337/dc15-0100
Benson, S., Siebert, C., Koenen, L. R., Engler, H., Kleine-Borgmann, J., Bingel, U., … Elsenbruch, S. (2019). Cortisol affects pain sensitivity and pain-related emotional learning in experimental visceral but not somatic pain: a randomized controlled study in healthy men and women. Pain, 160(8), 1719–1728. doi: 10.1097/j.pain.0000000000001579
Boschloo, A., Ouwehand, C., Dekker, S., Lee, N., Groot, R. de, Krabbendam, L., & Jolles, J. (2012). The Relation Between Breakfast Skipping and School Performance in Adolescents. Mind, Brain, and Education, 6(2), 81–88. doi: 10.1111/j.1751-228x.2012.01138.x
Buhle, J. T., Silvers, J. A., Wager, T. D., Lopez, R., Onyemekwu, C., Kober, H., ... & Ochsner, K. N. (2014). Cognitive reappraisal of emotion: a meta-analysis of human neuroimaging studies. Cerebral cortex, 24(11), 2981-2990. https://doi.org/10.1093/cercor/bht154
Cha, J., Greenberg, T., Song, I., Simpson, H. B., Posner, J., & Mujica‐Parodi, L. R. (2016). Abnormal hippocampal structure and function in clinical anxiety and comorbid depression. Hippocampus, 26(5), 545–553. doi: 10.1002/hipo.22566
Cohen, N., Rossetti, L., Shlimovich, P., Halberstam, M., Hu, M., and Shamoon, H. (1995). Counterregulation of Hypoglycemia: Skeletal Muscle Glycogen Metabolism During Three Hours of Physiological Hyperinsulinemia in Humans. Diabetes, 44(4), 423–430. https://doi.org/10.2337/diab.44.4.423
Dienes, K. A., Hazel, N. A., & Hammen, C. L. (2013). Cortisol secretion in depressed, and at-risk adults. Psychoneuroendocrinology, 38(6), 927–940. doi: 10.1016/j.psyneuen.2012.09.019
Dunn, J. T., Cranston, I., Marsden, P. K., Amiel, S. A., & Reed, L. J. (2007). Attenuation of amydgala and frontal cortical responses to low blood glucose concentration in asymptomatic hypoglycemia in type 1 diabetes: a new player in hypoglycemia unawareness?. Diabetes, 56(11), 2766-2773 https://diabetes.diabetesjournals.org/content/56/11/2766.short
Ehlert, U., Gaab, J., and Heinrichs, M. (2001). Psychoneuroendocrinological contributions to the etiology of depression, posttraumatic stress disorder, and stress-related bodily disorders: the role of the hypothalamus–pituitary–adrenal axis. Biological Psychology, 57(1–3), 141–152. https://doi.org/10.1016/s0301-0511(01)00092-8
Gianaros, P. J., Jennings, J. R., Sheu, L. K., Greer, P. J., Kuller, L. H., & Matthews, K. A. (2007). Prospective reports of chronic life stress predict decreased grey matter volume in the hippocampus. NeuroImage, 35(2), 795–803. doi: 10.1016/j.neuroimage.2006.10.045
Gold, A. E., MacLeod, K. M., Frier, B. M., & Deary, I. J. (1995). Changes in Mood During Acute Hypoglycemia in Healthy Participants. Journal of Personality and Social Psychology, 68(3), 498–504. doi: 10.1037/0022-3522.214.171.1248
Graveling, A. J., Deary, I. J., & Frier, B. M. (2013). Acute Hypoglycemia Impairs Executive Cognitive Function in Adults With and Without Type 1 Diabetes. Diabetes Care, 36(10), 3240–3246. doi: 10.2337/dc13-0194
Hall, J. E. (2015). Guyton and hall textbook of medical physiology (13th ed.). W B Saunders.
Hansen, Å. M., Blangsted, A. K., Hansen, E. A., Søgaard, K., & Sjøgaard, G. (2010). Physical activity, job demand–control, perceived stress–energy, and salivary cortisol in white-collar workers. International Archives of Occupational and Environmental Health, 83(2), 143–153. doi: 10.1007/s00420-009-0440-7
Hofeldt, F. D. (1989). Reactive hypoglycemia. Endocrinology and Metabolism Clinics of North America, 18(1), 185–201.
Huang, C.-W., Lui, C.-C., Chang, W.-N., Lu, C.-H., Wang, Y.-L., & Chang, C.-C. (2009). Elevated basal cortisol level predicts lower hippocampal volume and cognitive decline in Alzheimer’s disease. Journal of Clinical Neuroscience, 16(10), 1283–1286. doi: 10.1016/j.jocn.2008.12.026
Jack, C. R., Shiung, M. M., Weigand, S. D., O’Brien, P. C., Gunter, J. L., Boeve, B. F., … Petersen, R. C. (2005). Brain atrophy rates predict subsequent clinical conversion in normal elderly and amnestic MCI. Neurology, 65(8), 1227–1231. https://doi.org/10.1212/01.wnl.0000180958.22678.91
Jauch-Chara, K., Hallschmid, M., Gais, S., Oltmanns, K. M., Peters, A., Born, J., and Schultes, B. (2007). Awakening and Counterregulatory Response to Hypoglycemia During Early and Late Sleep. Diabetes, 56(7), 1938–1942. https://doi.org/10.2337/db07-0044
Jentsch, V. L., Merz, C. J., & Wolf, O. T. (2019). Restoring emotional stability: Cortisol effects on the neural network of cognitive emotion regulation. Behavioural Brain Research, 374, 111880. doi: 10.1016/j.bbr.2019.03.049
Kahles, F., Meyer, C., Mollmann, J., Diebold, S., Findeisen, H. M., Lebherz, C., … Lehrke, M. (2014). GLP-1 Secretion Is Increased by Inflammatory Stimuli in an IL-6-Dependent Manner, Leading to Hyperinsulinemia and Blood Glucose Lowering. Diabetes, 63(10), 3221–3229. https://doi.org/10.2337/db14-0100
Kim, E. J., Pellman, B., & Kim, J. J. (2015). Stress effects on the hippocampus: a critical review. Learning & Memory, 22(9), 411–416. doi: 10.1101/lm.037291.114
Kjems, L. L., Holst, J. J., Volund, A., & Madsbad, S. (2003). The Influence of GLP-1 on Glucose-Stimulated Insulin Secretion: Effects on -Cell Sensitivity in Type 2 and Nondiabetic Subjects. Diabetes, 52(2), 380–386. doi: 10.2337/diabetes.52.2.380
KRYUKOV, V. I. (2008). THE ROLE OF THE HIPPOCAMPUS IN LONG-TERM MEMORY: IS IT MEMORY STORE OR COMPARATOR? Journal of Integrative Neuroscience, 07(01), 117–184. doi: 10.1142/s021963520800171x
Li, C., Barker, L., Ford, E. S., Zhang, X., Strine, T. W., & Mokdad, A. H. (2008). Diabetes and anxiety in US adults: findings from the 2006 Behavioral Risk Factor Surveillance System. Diabetic Medicine, 25(7), 878–881. doi: 10.1111/j.1464-5491.2008.02477.x
Lustman, P. J., Anderson, R. J., Freedland, K. E., Groot, M. de, Carney, R. M., and Clouse, R. E. (2000). Depression and poor glycemic control: a meta-analytic review of the literature. Diabetes Care, 23(7), 934–942. https://doi.org/10.2337/diacare.23.7.934
Marik, P. E., and Bellomo, R. (2013). Stress hyperglycemia: an essential survival response! Critical Care, 17(2), 305. https://doi.org/10.1186/cc12514
McEwen, B. S., Nasca, C., and Gray, J. D. (2016). Stress Effects on Neuronal Structure: Hippocampus, Amygdala, and Prefrontal Cortex. Neuropsychopharmacology, 41(1), 3–23. https://doi.org/10.1038/npp.2015.171
Rimmele, U., Domes, G., Mathiak, K., & Hautzinger, M. (2003). Cortisol has different effects on human memory for emotional and neutral stimuli. NeuroReport, 14(18), 2485–2488. doi: 10.1097/00001756-200312190-00038
Salzer, H. M. (1966). Relative Hypoglycemia as a Cause of Neuropsychiatric Illness. Journal of the National Medical Association, 58(1), 12.
Sapolsky, R. M., Romero, L. M., & Munck, A. U. (2000). How Do Glucocorticoids Influence Stress Responses? Integrating Permissive, Suppressive, Stimulatory, and Preparative Actions. Endocrine Reviews, 21(1), 55–89. doi: 10.1210/edrv.21.1.0389
Scholey, A. B., Harper, S., & Kennedy, D. O. (2001). Cognitive demand and blood glucose. Physiology & Behavior, 73(4), 585–592. doi: 10.1016/s0031-9384(01)00476-0
Sotres-Bayon, F., and Quirk, G. J. (2010). Prefrontal control of fear: more than just extinction. Current Opinion in Neurobiology, 20(2), 231–235. https://doi.org/10.1016/j.conb.2010.02.005
Starkman, M. N., Giordani, B., Gebarski, S. S., Berent, S., Schork, M. A., & Schteingart, D. E. (1999). Decrease in cortisol reverses human hippocampal atrophy following treatment of Cushing’s disease. Biological Psychiatry, 46(12), 1595–1602. doi: 10.1016/s0006-3223(99)00203-6
Tesfaye, N., of, E. S. A. of the N. Y. A., and 2010. (n.d.). Neuroendocrine responses to hypoglycemia. Wiley Online Library.
Vaisvaser, S., Lin, T., Admon, R., Podlipsky, I., Greenman, Y., Stern, N., … Hendler, T. (2013). Neural traces of stress: cortisol related sustained enhancement of amygdala-hippocampal functional connectivity. Frontiers in Human Neuroscience, 7, 313. doi: 10.3389/fnhum.2013.00313
Verberne, T., Sabetghadam, A., & Korim, W. (2014). Neural pathways that control the glucose counterregulatory response. Frontiers in Neuroscience, 8. doi: 10.3389/fnins.2014.00038
Videbech, P., and Ravnkilde, B. (2004). Hippocampal Volume and Depression: A Meta-Analysis of MRI Studies. American Journal of Psychiatry, 161(11), 1957–1966. https://doi.org/10.1176/appi.ajp.161.11.1957
Vyas, A., Mitra, R., Rao, B. S. S., and Chattarji, S. (2002). Chronic Stress Induces Contrasting Patterns of Dendritic Remodeling in Hippocampal and Amygdaloid Neurons. Journal of Neuroscience, 22(15), 6810–6818. https://doi.org/10.1523/jneurosci.22-15-06810.2002
WENGER, M. A., CLEMENS, T. L., DARSIE, M. L., ENGEL, B. T., ESTESS, F. M., & SONNENSCHEIN, R. R. (1960). Autonomic Response Patterns During Intravenous Infusion of Epinephrine and Nor-epinephrine. Psychosomatic Medicine, 22(4), 294–307. doi: 10.1097/00006842-196007000-00009
Yoshikawa, E., Nishi, D., & Matsuoka, Y. J. (2019). The relationship between skipping breakfast and depression among workers with a focus on psychosocial factors. doi: 10.21203/rs.2.11219/v1
Zahedi, H., Djalalinia, S., Sadeghi, O., Garizi, F. Z., Asayesh, H., Payab, M., … Qorbani, M. (2020). Breakfast consumption and mental health: a systematic review and meta-analysis of observational studies. Nutritional Neuroscience, 1–15. doi: 10.1080/1028415x.2020.1853411