Insulin. We have heard this word discussed throughout the program as an important part of The Livy Method process. We are encouraged to eat high quality foods, support our bodies with supplements if we can, approach eating to the point where we feel satisfied, incorporate some exercise or activity to move our bodies, manage our stress levels, and prioritize having good, restful sleep. All of these things will help not only improve our health, wellness, and promote weight loss, but will also help to naturally lower our insulin levels.
In this science post we will be taking a deeper dive in the exploration of this highly discussed hormone. So, what exactly is insulin, and what exactly is its role in the body?
Insulin
Insulin is a very important hormone in digestion, and has a huge role in helping to process and store the energy provided from the food that we eat! It is composed of 51 amino acids and for this reason is called a peptide hormone (hormones that are composed of small chains of amino acids). It plays an important part in glucose regulation, cell growth, and metabolism.
Insulin was previously believed to be solely produced by special cells in the pancreas called beta cells; however, recent evidence has shown that low concentrations are also found in certain neurons of the central nervous system!
As we have discussed in previous articles, the pancreas plays a principal part in digestion by producing hormones and enzymes that are crucial to the digestive process. However, this amazing organ also has a critical role in using and storing the energy (in the form of glucose) that it had just helped to break down and process, from the foods that we just ate!
So, let’s back up this conversation a bit further. Let’s recap the basics of digestion and then discuss how the foods we eat are processed for their energy.
Short recap on digestion
All parts of our body need energy to work, and this energy comes from the food we eat. As discussed, our bodies begin the digestive process when we think about and use our senses when preparing our food. When we ingest it, it begins mixing in with the saliva and enzymes in our mouths through the process of chewing. Then, the food bolus enters the stomach by way of the esophagus, and begins mixing with fluids (containing acids and enzymes) in the stomach. As the stomach churns and mixes, the food is processed and broken down further, resulting in reducing the carbohydrates we eat (sugars and starches) to their simplest form, a sugar called glucose. Proteins are broken down into amino acids and fat is broken down into fatty acids to be used by the body.
Glucose is the main energy source for our body’s cells, and what keeps us functioning at all times whether it is when we are active and moving, resting and sleeping, it keeps our heart beating and lungs breathing. It is what allows all the organs and cells in our bodies to do what they need to do to keep us alive!
So, let’s break it down even further, let’s take a deeper look at what glucose actually is.
What is glucose?
Glucose is the simplest form of carbohydrates and only has one sugar molecule, which is called a monosaccharide. Other monosaccharides that may sound familiar include fructose, galactose, and ribose, which the body also processes or may produce for energy. To understand the differences, let’s look at all these in more detail!
Glucose
Glucose comes from the Greek word for "sweet" (Watson, S., & DerSarkissian, C. 2020, June). As discussed, glucose is a type of sugar you get from the foods you eat, and is what your body uses for energy. You may have heard the terms blood glucose or blood sugar, which are often used to describe the amount of glucose measured in your blood as it travels through your bloodstream to your cells. This can be quantified in a lab blood test, and results can be measured in that moment in time as a blood sugar, as a “fasted” blood sugar (taking your blood sugar after not eating or drinking for 8-12 hours), and as an A1C [which measures the percentage of hemoglobin (a protein in your red blood cells) that are coated in sugar, and can analyze your average blood sugar for the last 3 months].
Glucose is the most common monosaccharide found in nature. Some plants store glucose in linked chains. These chains are called starch. Common starch-containing foods include corn, potatoes, rice, and wheat. Glucose monosaccharides are also found naturally in some foods. The most concentrated whole food source of glucose monosaccharides are honey, followed by dried fruits such as dates, apricots, raisins, currants, cranberries, prunes and figs.
Most of the cells in your body use glucose along with amino acids (the building blocks of protein) and fats for energy. However, glucose is the main source of fuel for your brain. Nerve cells and chemical messengers located there need it to help them process information, and having access to glucose is very important for overall brain function. Your brain uses about 60% of the glucose that our bodies use. However, glucose does not always have to come immediately from foods and beverages. Glucose is also generated by the body to ensure that we always have the amount that is needed. One way that this is achieved is by breaking down something called glycogen, in order to free up the glucose it contains.
Glycogen is released by an important hormone called glucagon. When the body does not need to use glucose for energy, it is stored in the liver and muscles by insulin. This stored form of glucose is made up of many connected glucose molecules and is the glycogen. When the body needs a quick boost of energy or is not getting glucose from food, glycogen is broken down to release glucose into the bloodstream to be used as fuel for the cells. Your body can store enough glycogen in order to keep you fueled for about a day.
The body can also produce glucose through a process called gluconeogenesis. This process occurs when the body (mainly the liver, followed by the kidneys, and to a lesser extent the small intestine) makes glucose from non-carbohydrate sources which include lactate (what our bodies produce during exercise), glycerol (is produced when fats are digested, can be used for energy or stored in adipose tissue) and amino acids. Gluconeogenesis occurs when glycogen stores become low and glucose consumption is too low or nonexistent, such as during periods of starvation or prolonged fasting. Although the body has enough glycogen stored in the muscles and liver to last about a day, after about 14 hours in a fasted state it will begin to increase its percentage of gluconeogenesis, generating energy in increased ratios as time goes on (Chourpiliadis, C., & Mohiuddin, 2021).
One very important consideration is that skeletal muscle (composed of amino acids) can be used as a source when generating glucose through this pathway. This can lead to muscle wasting and loss over time, which can have a major impact on the body!
An additional alternative form of energy that can be generated if needed, is the formation of ketone bodies from our fat reserves. Ketone bodies can serve as a fuel source if glucose levels are too low in the body. Ketones serve as fuel in times of prolonged starvation, carbohydrate deprivation, or when patients suffer from uncontrolled diabetes and cannot appropriately utilize the circulating glucose. In these scenarios, fat stores are liberated, generating ketone bodies that are sent to the body and brain for energy.
This brings us to the conversation about the famous Keto diet that has been popularized in recent years. There seems to be a lot of compelling research arguing the benefits of using Keto as a means for weight loss. However, a recent study out of George Washington University School of Medicine examined available literature looking at the Keto diet (Crosby, L., Davis, B., Joshi, S., Jardine, M., Paul, J., Neola, M., & Barnard, N.D., 2021). They found that the diet was especially unsafe for pregnant women, women who may become pregnant, and those with kidney disease. They concluded that keto could also lead to long-term health complications, such as cancer, heart disease, and Alzheimer’s Disease for most people. The rationale behind this was that this diet includes foods like meats, fish, nuts, and fibrous vegetables while eliminating most fruits, grains, beans, and starchy vegetables resulting in low vitamins, minerals, micronutrients and fiber intake. As we know from our last few science posts, these are all very important components of improving our overall digestion, microbiome and health! This study further corroborates the evidence that the Livy Method, which includes the food listed above, while minimizing added sugar, sets up our bodies for the best success!
If you want to go even further down the rabbit hole of understanding glucose at the chemical level, check out this video that discusses the structure of glucose in a more simplified way!
Galactose
The main dietary source of galactose comes in the form of lactose. Lactose is derived from milk and yogurt, and then digested and processed by the body, and broken down into the simpler forms of galactose and glucose. Interestingly, foods containing small amounts of free galactose include low-lactose or lactose-free milk, certain yogurts, cheeses, creams, ice cream, and other foods artificially sweetened with galactose. Plain natural foods like fruits, vegetables, nuts, grains, fresh meats, eggs, and milk, usually contain less than 0.3 g galactose per serving.
Galactose is not an essential nutrient! This means that you do not need to get it from food to be healthy, as galactose can be synthesized from glucose in our bodies if we need it. This is why we are able function just fine if we need to limit dairy, such as with those that live a vegan lifestyle, those with lactose intolerance or issues processing galactose like the genetic issue galactosemia.
Galactose, like glucose, is absorbed in the small intestine and carried by special proteins called “transport proteins” in the lining of the small intestine. From here, most of the absorbed galactose enters the liver where it is mainly converted to glucose, which is then either incorporated into glycogen or used for energy. Interestingly galactose ingestion, like fructose ingestion (as you will see below), results in lower blood glucose and insulin levels than glucose ingestion.
A common question that many members have when learning about the food plan, is how come they can have something like milk as part of their fluid intake? The thought being, will it increase our blood sugars like juice? It is a liquid, do our bodies not have to work as hard to break it down like food? This is a great question, and one that can be answered in 2 ways!
Milk, although easier to digest, does not raise our insulin levels the way a sugary drink would because of its absorption pathway in the liver (as it contains lactose which is broken down into galactose and glucose). Glucose (which is found in that sugary drink) would more likely be transported directly from the small intestine to the bloodstream increasing blood sugar. Insulin would be released in order to process and store that sugar (do not worry, we are getting to the discussion of insulin in due time, but all this is vital to understanding the role of insulin)! Interestingly, glucose can be absorbed at the wall of the small intestine as well as the liver. The second reason that drinking milk may not increase blood sugar levels, is that it contains protein and fat, that helps slow down our gastric emptying time, which also slows the processing of the blood sugar by the body. However, all this being said, it is still important to remember that most of our fluid intake should still come in the form of water!!
Ribose
Ribose is a type of monosaccharide that is made by our bodies from glucose. It is an essential component of adenosine triphosphate (ATP) which supplies energy to our cells, (RNA) ribose nucleic acids and (DNA) deoxyribose nucleic acids. DNA is known as the information molecule and stores all the genetic material of a cell. It also contains instructions for the synthesis of other molecules, like proteins. While RNA’s function is to carry out the instructions that are encoded in DNA.
Ribose can be found in both plants and animals, including: mushrooms, beef and poultry, cheddar cheese and cream cheese, milk, eggs, caviar, anchovies, herring, sardines, and yogurt. However, it is found in these foods in very small quantities.
Fructose
Fructose is a fairly sweet, naturally occurring sugar. It comes from most fruits, and even some vegetables.
Pure fructose is also much sweeter than other types of sugar. As a result, people can use less fructose than other sugars in cooking to achieve the same sweetness. The most significant sources of fructose in today’s diet include: table sugar (which is called sucrose, made from sugar cane or beets, is composed of 50% glucose and 50% fructose), honey, agave nectar, fruit juices, palm sugar and (HFCS) high fructose corn syrup (HFCS is a highly processed, inexpensive substitute for cane sugar that was introduced in the 1970s, and is made from corn. It is used to sweeten a variety of processed foods, including soda, candy, baked goods, and cereals).
After we ingest food, the stomach and small intestine go right to work in breaking the food down into its simplest form of glucose, which is absorbed and then released into the bloodstream. Once in the bloodstream, glucose can be used immediately by the cells for energy, or stored in our bodies to be used later. However, glucose and fructose are metabolized very differently by the body. Before it can be used by the body, fructose needs to be converted into glucose, which is conducted by the liver. While every cell in the body can use glucose, the liver is the only organ that can metabolize fructose when ingested in significant amounts!
How has fructose changed?
Before the mass production of refined sugar, humans rarely consumed fructose in high amounts. But as food science has developed over the years, our food has greatly changed from its very simple former self (that is a whole other science article!!!)
While most whole fruits and some vegetables contain fructose, they provide relatively low amounts. Some examples of vegetables that include fructose are artichokes, asparagus, broccoli, leeks, mushrooms, okra, onions, peas, red peppers, shallots and tomatoes.
Unlike glucose, fructose causes a low rise in blood sugar levels. Therefore, some health professionals recommend fructose as a “safe” sweetener for people with type 2 diabetes.
However, here is the crux. Many others are worried that excessive fructose intake may in fact contribute to several metabolic disorders. There is quite the debate in the scientific community around this!
When people eat a diet that is high in calories and high in fructose, the liver is thought to become overloaded and starts turning the fructose into fat. Many scientists believe that excess fructose consumption may be a key driver in many of the most serious diseases today (Gunnnars, K., 2018, April). These include obesity, type 2 diabetes, insulin resistance, heart disease, and even cancer. However, more human evidence is needed. Although, researchers debate the extent to which fructose contributes to these disorders, there is a considerable mounting body of evidence justifying the concerns.
The harmful effects of excess fructose
According to (Gunnars, K., 2018, April), eating a lot of fructose in the form of added sugars may:
Impair the composition of your blood lipids. Fructose may raise the levels of VLDL (very-low-density lipoprotein) cholesterol, leading to the accumulation of fat around the organs. It may potentially cause heart disease, as it may alter how the body breaks down fats and carbohydrates, and lead to atherosclerosis (the build-up of plaque in the arteries which can block blood flow to the heart and other vital organs).
Increase blood levels of uric acid, leading to gout (a common and complex form of arthritis, characterized by sudden and severe attacks of pain, swelling, redness, and tenderness in one or more joints, most often in the big toe) and high blood pressure. Uric acid is a chemical created when the body breaks down substances called purines. Purines are normally produced in the body and are also found in some foods and drinks. Foods with high content of purines include liver, anchovies, mackerel, dried beans, peas, and beer. Generally, uric acid dissolves in blood and travels to the kidneys. It is processed by the kidneys and is passed out in urine. If your body produces too much uric acid or does not remove enough of it, you can get sick. A high level of uric acid in the blood is called hyperuricemia
Cause deposition of fat in the liver, potentially leading to non-alcoholic fatty liver disease as discussed above.
Cause insulin resistance, which can lead to obesity and type 2 diabetes. Some studies found that excess amounts of dietary fructose seemed to cause inflammation that could lead to insulin resistance. We will go into more detail about insulin resistance later!
Fructose does not appear to suppress appetite as much as glucose does. As a result, it might promote overeating. When a person consumes glucose, the chemical structure of that compound triggers the pancreas to release insulin, a hormone that allows cells to use glucose for energy. Fructose does not appear to trigger insulin release or the release of hormones such as leptin which tells the brain that a person is full. It also does not inhibit hormones that tell an individual’s body that they are hungry. As a result, fructose may lead to weight gain because it may contribute to overeating. Look out for more information on leptin next week as we discuss the hormones involved in hunger and satiety!
Again, to clarify, not all of this can be proven in controlled studies. However, the evidence is still there, and over time with more human studies conducted, this will likely become more evident.
So, do I need to give up all foods that contain fructose?
The important takeaway here is to realize that all of this does not apply to foods that have naturally occurring fructose, like whole fruits, vegetables, some whole grains, and even having a little bit of good quality sugars like cane sugar, honey or maple syrup. Essentially all healthy carbohydrates that are recommended on The Livy Method food plan!
Fruits, veggies, and heavier carbohydrates like quinoa, darker rices, potatoes and squashes, although containing fructose, are real food packed with nutrition, water and lots of fiber. These foods give your body what it needs, and allow you to feel satisfied with less. This makes them hard to overeat and you would have to eat very large amounts to reach harmful levels of fructose.
Hopefully this helps with the understanding of how our bodies process carbohydrates in order to utilize them for energy! The old adage, you are what you eat really holds true and hopefully as we are progressing through the program, eating better quality carbohydrates, you can all feel the difference this is making.
Here is a good video that briefly describes the monosaccharides in more detail:
For those that want to look at the chemical structures of these sugars in more detail, check out this video!
What about protein and fat? Does our body also convert these into glucose for energy if we need it?
Great question, and the answer is yes it does! Fats are used for energy after they are broken into fatty acids and glycerol and protein can also be used for energy, but its primary role is to help with making hormones, muscle, and other proteins.
Now we are ready to talk about insulin
Now that we have reviewed the basics of glucose and the various pathways that the body uses to utilize the different simple sugars, protein, and fat for energy, let’s talk about how the body stores this energy.
When a person consumes glucose, the chemical structure of the compound triggers the pancreas to release insulin, a hormone that allows cells to use glucose for energy.
The pancreas
To recap our discussion from the science post on The Basics of Digestion, the pancreas is an organ which is located behind your stomach in the upper left part (quadrant) of your abdomen, surrounded by other organs of digestion including the small intestine, liver, gallbladder and spleen. Although the pancreas has an important role in digestion by secreting pancreatic juice rich in digestive enzymes, it also has the critical role of regulating blood sugar!
The body is designed to keep the level of glucose in your blood constant. The human pancreas contains one to two million pancreatic islets (also called endocrine pancreas cells and islet of Langerhans cells) housing different endocrine cells, primarily insulin-secreting beta cells, glucagon-producing alpha cells, and somatostatin-secreting delta cells (which serve to block the secretion of both insulin and glucagon from adjacent cells). Interestingly, although islets compose only 1–2% of the human pancreas, they receive up to 10% of the total pancreatic blood supply (Rahman, M. S., Hossain, K. S., Das, S., Kundu, S., Adegoke, E. O., Rahman, M. A., Hannan, M. A., Uddin, M. J., & Pang, M. G., 2021).
The beta cells in your pancreas monitor your blood sugar level every few seconds. When your blood glucose rises after you eat, the beta cells release insulin into your bloodstream. Insulin acts like a key, unlocking muscle, fat, and liver cells, so that glucose can penetrate them. Once inside, the cells convert glucose into energy to use right then, or store it to use later.
As glucose moves from the bloodstream into the cells, blood sugar levels start to drop. The beta cells in the pancreas can tell this is happening, so they slow down the amount of insulin they are making. At the same time, the pancreas slows down the amount of insulin that it is releasing into the bloodstream. When this happens, the amount of glucose going into the cells also slows down. Interestingly, insulin also helps our bodies store fat and protein.
After you have not eaten for a few hours your blood glucose level drops, and your pancreas stops producing insulin. Alpha cells in the pancreas begin to produce glucagon, signaling the liver to break down stored glycogen and turn it back into glucose. This glucose then travels to your bloodstream to replenish your supply until you are able to eat again. Although, as discussed earlier, your liver can also make its own glucose using a combination of waste products, amino acids, and fats.
The big takeaway here is that by following The Livy Method as designed, you are providing your body with a steady supply of energy over the day from healthy nutrient rich sources. As you are eating to satisfaction, you are no longer overeating to the state of being full, which would stimulate your beta cells to secrete a larger amount of insulin to process and store all that glucose being digested! Smaller amounts of food over time means smaller amounts of insulin being produced, feeling more satisfied with less, decreasing stress on the body!
Here is a great video that discusses the role of the pancreas.
Here is a video that discusses glucagon and its role in glucose release.
Here is a great video that discusses the role of insulin in a little more detail.
Issues with insulin
Without enough insulin, glucose cannot move into the cells and the blood glucose level remains elevated. This condition is called hyperglycemia. Prolonged hyperglycemia can damage the blood vessels that carry oxygen-rich blood to your organs, and can increase your risk for heart disease, heart attack, stroke, kidney disease, nerve damage, and an eye disease called retinopathy.
What causes hyperglycemia?
Typically, hyperglycemia is a symptom and can be caused when there is an issue with the body’s cells not responding to insulin (insulin resistance), or there is an issue with the beta cells not producing adequate insulin (prediabetes and diabetes).
Other hormones that can raise the blood sugar level include epinephrine (also called adrenaline)and cortisol which are released by the adrenal glands, and growth hormone which is released by the pituitary gland. This is again why it is vitally important to manage stress levels, as chronic stress can have an impact on blood sugar levels.
What is insulin resistance?
Insulin resistance is when cells in your muscles, fat, and liver do not respond well to insulin and are not able to easily take up glucose from your blood. As a result, your pancreas increases the production of insulin to help glucose enter your cells, a condition called hyperinsulinemia. However, as long as your pancreas can produce enough insulin to overcome your cells’ weak response to insulin, your blood glucose levels should stay in the healthy range.
What is prediabetes?
Prediabetes means your blood glucose levels are elevated, but not elevated enough to be diagnosed as diabetes. Prediabetes usually occurs in people who already have some insulin resistance or whose beta cells in the pancreas are not making enough insulin to keep blood glucose in the normal range. Without enough insulin, extra glucose stays in your bloodstream rather than entering your cells. Over time, you are at increased risk for developing type 2 diabetes.
What causes insulin resistance and prediabetes?
According to the National Institute of Diabetes and Digestive and Kidney Diseases, researchers do not fully understand what causes insulin resistance and prediabetes, but they speculate excess weight and lack of physical activity are major factors.
Excess weight
Many experts believe obesity, and especially visceral fat (the accumulation of fat in the abdomen and around the organs) are the main cause of insulin resistance. Having a waist measurement of 40 inches or more for men and 35 inches or more for women is linked to insulin resistance. This is true even if your body mass index (BMI) falls within the normal range. However, research has shown that Asian Americans may have an increased risk for insulin resistance even without a high BMI. (The discussion of BMI is used in reference to this study, although the concept of BMI is problematic as a measure of obesity).
Studies have also shown that belly fat produces hormones and other substances that can contribute to chronic or long-lasting inflammation in the body. Inflammation may play a role in insulin resistance, type 2 diabetes, and cardiovascular disease. Since excess weight may lead to insulin resistance, this also is a contributing factor in the development of fatty liver disease.
Physical inactivity
Not getting enough physical activity is linked to insulin resistance and prediabetes. Regular physical activity causes changes in your body that help with glucose regulation. When you participate in moderate exercise that increases your heart rate and breathing, your muscles use more glucose from the body. Over time, this can lower your blood sugar levels and also allows the insulin in your body to work better. You will also receive these benefits for hours after your activity or workout.
However, very intense or strenuous exercise can cause the body to produce more stress hormones, which can lead to an increase in blood sugar as well as stress on the body. This can also help explain one of the reasons why overexercise is not a good weight loss tool!
As you can see by following The Livy Method, and incorporating the food plan and eating nutrient rich foods, including heavier carbs when needed, eating to satisfaction, incorporating stress management strategies, with a focus on getting quality sleep, you can greatly improve your state of health and wellness. By losing weight and following The Livy Method which can decrease abdominal visceral fat over time, health issues can be reversed! Many of our Livy Losers have shared their amazing health related NSVs, and are great reads to tap into motivation if you need to! Finally, incorporating exercise will also help with blood sugar regulation and can be a great stress reliever too! So, if you are feeling it, move that body.
Now that we understand more about the role of insulin in the body and some of the hormones involved in digestion and weight loss, join us for our next science post where we discuss some of the issues with digestion.
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