Why Is Glucose Important? - Dr. Michael Ruscio, DC

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Why Is Glucose Important?

Glucose isn’t something to fear, but we should be mindful of blood sugar regulation.

Key Takeaways:

  • Glucose is the body’s preferred energy source, fueling all cells, tissues, and organs.
  • The brain alone accounts for 20% of the body’s glucose needs. 
  • Glucose and blood sugar itself are not bad or evil, but imbalanced regulation of blood sugar can cause health issues like diabetes, heart disease, and hormone imbalances.
  • Large blood sugar fluctuations can also cause more immediate symptoms like fatigue, anxiety, and brain fog. 
  • Men and women may respond differently to glucose and have different blood sugar responses based on hormones and other factors. 
  • There are some individuals who do better with more glucose in their diets, as healthy complex carbs (and some with less).
  • While they’re not accessible to everyone (yet!), a continuous glucose monitor can give you insights into how you respond to glucose and help you personalize your healthiest diet. 
  • An easy hack for blood sugar balance: eating vegetables first, followed by protein and fat, and then eating carbs last has the biggest effect on stabilizing blood sugar post-meal.

What do you think of when you hear the word “glucose?” Do you cringe and want to push it away? Do you think it’s something that only diabetics should be concerned about? Does it trigger an association in your brain that glucose = bad? Why is glucose important?

If you have any of the above reactions, you’re not alone. But the truth about glucose and its role in your body isn’t that black and white. While the narrative around glucose (aka, sugar that our body turns into energy) often makes it the bad guy in everyone’s diet, the truth is that we need glucose to survive. We even need it to thrive optimally. 

In this article, we’ll discuss why glucose is important, the role of glucose and blood sugar levels, reasons you might need more glucose (aka carbs) in your diet, and how to test your blood glucose levels. This is (pretty much) everything you need to know about glucose and its role in the human body.

What is Glucose and What Does it Do in the Body?

Here’s the bottom line: glucose is the primary (and preferred) energy source for your brain and body. Complex chemical reactions performed by your mitochondria turn glucose into ATP, the molecule which fuels all of the body’s cells. Every last one. That makes glucose pretty important for our survival. 

Glucose is also the only fuel for a developing fetus, making it especially important for pregnant women to meet both their own and their baby’s glucose needs [1]. 

Glucose is such an important fuel source that the body has several different ways to make it [2]. The body can make glucose by breaking down sugars we eat, such as galactose (in milk and complex carbs), fructose (from foods like fruit), lactose (from dairy), sucrose (table sugar), and starch (from foods like tubers and rice). We can also get glucose from the process of breaking down fat and protein.

Our bodies (especially the liver and muscle tissue) can also store excess glucose as glycogen and can turn glycogen back into glucose when we need energy during a fast. 

Finally, glucose is the main energy source for the brain, and the brain accounts for about 20% of the entire body’s glucose use [3]. 

Glucose and Blood Sugar

When your tissues need energy, the blood carries glucose to them. This is where we get the phrase “blood sugar” from. Your pancreas secretes a hormone called insulin to lower blood sugar levels in response to the food you eat. Diabetics (both type 1 diabetes and type 2 diabetes), don’t make enough insulin to support healthy blood sugar levels and need to take insulin to make sure their blood sugar stays in an optimal range.

Most people only hear about blood sugar in relation to having too high blood sugar, which can contribute to metabolic syndrome and increase your risk of heart disease, kidney disease, insulin resistance, and type 2 diabetes, resulting in downstream complications, one of the biggest being loss of blood flow to the brain [4]. 

This is an important discussion to have, and we should be concerned with keeping our blood sugar levels balanced. But I want to stress that glucose or blood sugar itself is not bad or evil. Your cells, organs, tissues — all of your systems need glucose to function. Your brain alone spends glucose in massive quantities. Glucose metabolism is a requirement for human survival and optimal body function. 

That said, our goal with glucose in the body is to keep our blood sugar stable as opposed to high peaks and low valleys, which can cause a big swing in energy followed by a crash. When you have stable blood sugar levels, you’ll have [2, 5, 6, 7, 8]:

  • Stable energy
  • A more efficient metabolism
  • Lower stress
  • Balanced mood
  • Healthy hormone production
  • Better sleep

The symptoms of high and low blood sugar can be scary and make you feel anxious, and both high and low blood sugar cause stress to the body [2, 7]. Many hormones — including insulin, cortisol, epinephrine, thyroxine, growth hormone, and ACTH — are involved in maintaining the blood sugar levels your body needs to function well [2]. Similarly, one of the important functions of ATP that comes from glucose is to make hormones [1]. So blood sugar that is too high or too low can cause imbalances in hormone function and production [1, 2].

One study showed that high glucose levels are associated with insufficient breathing and low oxygen levels during sleep, as well as fragmented sleep [9]. Another study showed a clear association between eating more added sugar and worse sleep quality [8]. So if our goal is better sleep, blood sugar balance is important as well.

Low Blood Sugar

What does it look like when you have low blood sugar (hypoglycemia)? Relatively speaking, low blood sugar is not as common as high blood sugar in people without diabetes, but it can happen in those who are chronically undereating, taking certain medications, have certain hormonal imbalances, or are under high stress (therefore burning a lot of glucose to manage that stress). 

Most commonly, we notice the symptoms of low blood sugar after we’ve eaten a meal high in glucose (carbohydrates) with not enough protein and fat, causing a high blood sugar spike and then a steep drop, before blood sugar stabilizes again. 

Hypoglycemia can cause [7]: 

  • Pale skin
  • Fatigue
  • Anxiety or irritability
  • Mood swings
  • Feeling shaky
  • Headache
  • Muscle weakness, numbness, or pain in the hands and feet
  • Sweating
  • Hunger
  • Nausea
  • Irregular or fast heartbeat
  • Loss of focus
  • Dizziness or lightheadedness

High Blood Sugar

High blood sugar, or hyperglycemia, is the more common blood sugar imbalance and can eventually lead to metabolic syndrome, type 2 diabetes, and other health complications. Recent research shows that patients with high blood sugar, even without type 2 diabetes, are more likely to develop dementia. High blood sugar also likely worsens dementia-related symptoms and outcomes [10, 11, 12]. 

Many people, despite not having consistently high blood sugar, are more susceptible to glucose spikes or the glucose rollercoaster of highs and lows. This isn’t good either, and similar negative health effects can result from riding the glucose rollercoaster long term as having consistently high blood sugar. You may also respond differently to glucose based on age, sex, health status, and your microbiome, among other factors.

Current research shows that women tend to have lower fasting glucose and higher 2-hour glucose (after eating) than men, meaning that women may be more prone to glucose spikes than men. Men are more likely to have impaired fasting glucose than women, while women are more likely to have impaired glucose tolerance [13]. Still, more research needs to be done to solidify the differences in glucose response between men and women.

We don’t have a lot of current data on how glucose spikes affect men vs. women differently, but one clinical study compared men’s vs. women’s data from continuous glucose monitors and fatigue ratings for 5 days. Compared to men, women had more fatigue related to glucose excursions (spikes) [14]. This data doesn’t provide conclusive evidence on how men and women react to glucose differently, but it’s worth noting when you’re examining your own glucose tolerance. 

The easiest way to prevent big glucose spikes is to make sure you’re eating balanced meals with protein, fat, and carbs. 

The order in which you eat those food groups can also make a big difference in the glucose response. Eating vegetables first, followed by protein and fat, and then eating carbs last has the biggest effect on stabilizing blood sugar post-meal. 

You might not choose to eat every meal this way, but it’s helpful to know when you have the option to do so. Drinking a tablespoon of apple cider vinegar or plain white vinegar mixed with a few ounces of water before meals can also help even out the glucose response. 

Reasons You Might Need More Glucose (aka Carbs)

As I said before, it’s important to be aware of your blood sugar balance and how you personally react when you consume glucose. That being said, glucose is not the enemy it’s been made out to be in some corners of the health space and the media. In fact, there are some cases where more dietary glucose, aka complex carbs (from healthy sources), is totally necessary and optimal for certain individuals. 

  • For pregnant women: Glucose demands are much higher than usual during pregnancy to sustain a growing fetus. Pregnant women should not restrict their carb intake for this reason.
  • Before exercise: Some people, particularly women, find that they perform better and feel better when they eat a small amount of carbs before physical activity. When you eat carbs pre-workout, that energy is going to be pretty quickly used to help you exercise as opposed to being stored for later use.
  • Those under high stress: If you’re stressed out, your body is using extra glucose to buffer that stress. You may find that increasing your carbs helps you better manage stress on a daily basis. 
  • Those with high cognitive demands: Remember, your brain uses 20% of the body’s glucose demands just to function. If you’re someone who uses a lot of mental energy every day, you might find that you have a higher need for healthy carbs. 

The point here is that carbs are not automatically bad for you, and some people need more than others to feel their best. I’ve found in my clinical practice that this can be especially true for some women who are eating very low-carb diets (generally because they’ve been told that’s the healthiest option). When they increase their carb intake a bit, not overdoing it but adding in things like whole fruit and potatoes, they often feel a lot better. 

Blood Sugar Balance and Mental Health

I want to briefly touch on the connection between blood sugar and mental health. While poor mental health is a complex topic with many potential root causes, I think poor blood sugar regulation is one root cause that isn’t talked about enough. The blood sugar rollercoaster can cause anxiety, mood swings, depression, and even cause you to be more critical of yourself and others. 

For example, one study looked at the effect of glucose spikes on social decision-making. Participants ate a breakfast that caused a big spike in glucose or one that caused a lower spike. Then they were asked to participate in a scenario where they could punish somebody who had done something wrong. Those who had the big glucose spike punished more people than those who had a smaller spike after breakfast. The thought behind this is that the big spike led to lower tyrosine levels (a neurotransmitter) in the brain, changing the participants’ mood more dramatically [15]. 

If you struggle with mental health issues, looking into your glucose spikes and blood sugar balance and tracking your symptoms could provide helpful insight into these issues. 

How to Test Your Glucose Levels

Diabetics must test their blood sugar regularly to make sure they have enough insulin to manage their blood sugar levels, but continuous glucose monitoring (CGM) devices are now being used and recommended for those who want to track their blood sugar for general health and wellbeing. 

With a device like this, you can get real-time feedback from your body on what causes you to experience blood sugar spikes. This can be an excellent tool for those who are extra glucose-sensitive to learn what foods and other factors trigger high glucose spikes for them and how to prevent big spikes from occurring. While these devices aren’t often covered by insurance for non-diabetics, they are becoming more popular as a health optimization tool, so we may see them become affordable sooner rather than later. 

I’ve been fortunate to have the opportunity to experiment with one of these devices and learned a few things about how different factors like exercising, drinking alcohol, and drinking juice on an empty stomach affected my own blood sugar regulation. 

If you do try a device like this, remember not to let it stress you out too much. Seeing a blood sugar spike doesn’t need to be a cause for alarm — it’s just another data point for you to use in your future decision-making. And keep in mind that it’s normal for blood sugar levels to fluctuate to some extent, what we want is to keep huge spikes and drops from happening most of the time. Try to focus on the big picture and overall patterns.

Glucose is Not Your Enemy

Ultimately, glucose is necessary for human survival, but some people are more sensitive to it than others. If you suspect you are more glucose sensitive, try implementing easy glucose hacks like drinking a tablespoon of apple cider vinegar diluted in water before meals, or eating your vegetables first, protein and fat second, and carbs last when you eat a meal. These are simple changes that can make a big difference in your daily energy levels, mood, and cognition.

There are also some individuals who find they may need more healthy carbs to keep their energy levels up, hormones balanced, and mood stable. If you are eating low-carb and not feeling your best, see if adding a small amount of complex carbs to your diet improves your energy.

For more personalized advice on your diet and managing glucose levels, speak with one of our health coaches at Ruscio Institute for Functional Health

The Ruscio Institute has developed a range of high-quality formulations to help our patients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you.

➕ References
  1. Nakrani MN, Wineland RH, Anjum F. Physiology, Glucose Metabolism. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022. PMID: 32809434.
  2. Hantzidiamantis PJ, Lappin SL. Physiology, Glucose. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022. PMID: 31424785.
  3. Kleinridders A, Ferris HA, Reyzer ML, Rath M, Soto M, Manier ML, et al. Regional differences in brain glucose metabolism determined by imaging mass spectrometry. Mol Metab. 2018 Jun;12:113–21. DOI: 10.1016/j.molmet.2018.03.013. PMID: 29681509. PMCID: PMC6001904.
  4. Swarup S, Goyal A, Grigorova Y, Zeltser R. Metabolic Syndrome – 2021 REVIEW – CME – PUBMED -. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2021. PMID: 29083742.
  5. Mouri Mi, Badireddy M. Hyperglycemia. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022. PMID: 28613650.
  6. High blood sugar – self-care: MedlinePlus Medical Encyclopedia [Internet]. [cited 2022 Apr 26]. Available from: https://medlineplus.gov/ency/patientinstructions/000332.htm
  7. Hypoglycemia – Symptoms and causes – Mayo Clinic [Internet]. [cited 2023 Mar 13]. Available from: https://www.mayoclinic.org/diseases-conditions/hypoglycemia/symptoms-causes/syc-20373685
  8. Alahmary SA, Alduhaylib SA, Alkawii HA, Olwani MM, Shablan RA, Ayoub HM, et al. Relationship Between Added Sugar Intake and Sleep Quality Among University Students: A Cross-sectional Study. Am J Lifestyle Med. 2022;16(1):122–9. DOI: 10.1177/1559827619870476. PMID: 35185434. PMCID: PMC8848117.
  9. Yano Y, Gao Y, Johnson DA, Carnethon M, Correa A, Mittleman MA, et al. Sleep characteristics and measures of glucose metabolism in blacks: the jackson heart study. J Am Heart Assoc. 2020 May 5;9(9):e013209. DOI: 10.1161/JAHA.119.013209. PMID: 32342760. PMCID: PMC7428566.
  10. Crane PK, Walker R, Hubbard RA, Li G, Nathan DM, Zheng H, et al. Glucose levels and risk of dementia. N Engl J Med. 2013 Aug 8;369(6):540–8. DOI: 10.1056/NEJMoa1215740. PMID: 23924004. PMCID: PMC3955123.
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  12. Kirvalidze M, Hodkinson A, Storman D, Fairchild TJ, Bała MM, Beridze G, et al. The role of glucose in cognition, risk of dementia, and related biomarkers in individuals without type 2 diabetes mellitus or the metabolic syndrome: A systematic review of observational studies. Neurosci Biobehav Rev. 2022 Apr;135:104551. DOI: 10.1016/j.neubiorev.2022.104551. PMID: 35104494.
  13. Mauvais-Jarvis F. Gender differences in glucose homeostasis and diabetes. Physiol Behav. 2018 Apr 1;187:20–3. DOI: 10.1016/j.physbeh.2017.08.016. PMID: 28843891. PMCID: PMC5826763.
  14. Fritschi C, Park C, Quinn L, Collins EG. Real-Time Associations Between Glucose Levels and Fatigue in Type 2 Diabetes: Sex and Time Effects. Biol Res Nurs. 2020 Apr;22(2):197–204. DOI: 10.1177/1099800419898002. PMID: 32008368. PMCID: PMC7273801.
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