Having some understanding or awareness of how our bodies metabolize and regulate glucose levels is essential if you are living with diabetes mellitus.
By having a grasp on some of the fundamental principles, you can:
- Learn to control your blood glucose levels better
- Manage your weight (if you are aiming to do so)
- Potentially reduce your risk of developing serious diabetes complications
In this article, we will discuss how our bodies store and regulate glucose. We will cover how the food that we eat influences blood glucose levels, as well as some lesser-known ways you can improve control!
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How your body makes glucose
Firstly, it is important to remember that for people with diabetes, their metabolism differs.
The key difference is that the volume and/or effectiveness of insulin produced are different for people living with diabetes.
In this informative diabetes blog, you can read more about type 1 and type 2 diabetes, as well as view some guidance on how and why to test your blood sugar levels.
For now, let’s get back to our guide to glucose metabolism and regulation. Before we look at specifically how the body makes and stores glucose, we must understand a bit about the basics of glucose metabolism.
Metabolism refers to the chemical reactions that take place inside the cells of living organisms, which are essential for life.
Aside from the food that you eat, other processes affect glucose metabolism and determine circulating glucose levels. The following processes both occur in the liver (1,2).
- Glycogenolysis: the release of glucose into the systemic circulation, from previously-stored glycogen.
- Gluconeogenesis: the formation of glucose during periods of fasting, mainly from lactate and amino acids. Lactate is an organic molecule that is produced by muscle cells, red blood cells, brain, and other tissues during anaerobic (not in the presence of oxygen) energy production. Amino acids are the building blocks of protein.
As humans, our unique ability to store and release glucose, even when we are not eating, is crucial to our survival.
When it comes to food specifically, there are important things to be aware of when it comes to how our body utilizes and stores energy. The amount primarily determines circulating levels of glucose in the blood, and timing, of the carbohydrate we eat (7).
When we eat carbohydrates, it is converted to glucose for the body to use for energy. In fact, energy production is one of the primary functions of dietary carbohydrates.
The carbs that you eat are mostly broken down into glucose (except fiber, but more on that later), before entering the bloodstream.
Once in the bloodstream, glucose is taken into the cells in your body. It is there that it is used to produce something called adenosine triphosphate (ATP). This occurs through a complex process called cellular respiration. The cells in the body can then use ATP for a variety of metabolic jobs.
Yet, as we have just discussed, it is not only carbohydrates that turn into glucose for our cells to use for energy. Amino acids from proteins can also be converted to glucose via gluconeogenesis (2).
So while it is important to understand the impact of diet on our blood sugar levels, carbs are not to be feared! Essentially, all the food we eat has the capability of turning into glucose. However, glucose is the body’s preferred energy source.
Much more important than swearing off carbohydrates completely, is focusing on the amount, and type that you eat. You can read more about a healthy diet for those with diabetes, here.
Which hormones regulate glucose levels?
Two key hormones regulate glucose levels in your blood. The first is insulin, a growth hormone, which you may have already heard of. The second, arguably less well-known hormone, is glucagon (8). When you eat a food containing carbohydrates, the digestive system breaks down the digestible ones into sugar, which enters the blood.
The pancreas produces insulin in response to this rise in sugar levels in the blood as this sugar is used by the body’s cells, the levels in the blood fall. This is followed by the pancreas making glucagon, which sends a signal to the liver to start releasing stored blood sugar.
This relationship between these two key hormones ensures that the body and the brain have a supply of blood sugar so that they can function effectively (8).
Understanding carbohydrate metabolism is important as part of improving your knowledge when you have diabetes. When you have type 2 diabetes, the body is either not producing enough insulin or is not using the insulin it has effectively. Usually, type 2 diabetes develops gradually over several years, starting with the progression of something called insulin resistance.
Over time, as blood sugar levels stay consistently high, (known as hyperglycemia) there is a high demand for the cells that produce insulin. Eventually, this causes them to wear out, and insulin production stops.
What factors affect blood glucose?
You will have all heard that famous phrase – ‘you are what you eat.’ Whilst there are arguments against this (as your health is also heavily influenced by genetics, environment, and your social situation) – diet and nutrition, of course, are important.
When it comes to your blood glucose levels, diet is the main factor to consider for gaining good control.
Dietary carbohydrates are broken down by the liver into sugar, which then enters the bloodstream to be used by the body as a source of energy. The exception to this rule is fiber – a type of non-digestible carbohydrate.
Fiber is essential for good gut health and general wellbeing – so (for most people), you certainly don’t want to be limiting your intake! Fiber can also help to regulate blood glucose levels, as it slows the absorption of sugar into the bloodstream.
Soluble fiber has also been shown in numerous studies to lower cholesterol levels, thus having the potential to reduce the risk of cardiovascular diseases.
There are two types of fiber – soluble and insoluble. The following foods are good sources of fiber, and whilst most foods contain a mix of both soluble and insoluble fiber, they usually contain more of one type.
Soluble fiber is found in:
- Oats and oat bran
- Fruits and vegetables
- Beans, pulses, and lentils
Insoluble fiber is found in:
- Wholemeal bread
- Wholegrain cereals
- Some fruit and vegetables
The take-home message when it comes to fiber is (for most people) – eat more! As living with diabetes can increase your risk of cardiovascular disease (9), this is particularly important if you have the condition.
Thinking back to the carbohydrates that we eat and drink that are digested, we have already discussed how they are all broken down into sugar (or glucose). Carbohydrates are an important part of a balanced and healthy diet and are the brain’s preferred energy source.
Yet, you should be aware of the most nutritious types, as the type and amount you consume can make a big difference to your blood glucose control and your diabetes management (7).
Carbohydrates can be split into two broad types – those that contain mostly starches, and those that contain sugars primarily.
Carbohydrates that contain mostly starches include:
- Bread and pasta
- Other grains, e.g., bulghar wheat, and couscous
- Starchy vegetables like yam and plantains
Carbohydrates that contain mostly sugars include:
- Sweets and confectionery
- Dairy (contains the intrinsic sugar lactose)
- Sugary drinks
- Many desserts
- Fruit (contains the intrinsic sugar fructose)
It is widely agreed that eating fewer refined carbohydrates, less added sugars, and more fiber are good nutritional principles for healthy people to follow.
What’s more, when you are living with diabetes, they can contribute to far better blood sugar control and a reduced risk of complications. In this recent review study, a large body of research on insulin resistance and diabetes was evaluated.
Amongst the conclusions were that where necessary, weight loss remains the cornerstone of management strategies for type 2 diabetes.
What lifestyle changes can improve glucose levels?
Nutritional quality is also continuously cited as being very important. Many authors conclude that the importance of dietary changes should not be overlooked. The main ones to consider for many people are:
- Reducing intake of added sugars, particularly from drinks, e.g., fizzy drinks and other sugar-sweetened beverages
- Eating complex carbohydrates, rather than simple ones
- Consider eating a low GI diet
- Eat plenty of non-starchy vegetables and some fruit
- Include some omega-3-fatty acids in your diet (oily fish such as mackerel and salmon are the best source)
Aside from your diet, several other factors can cause your blood glucose to rise. Included in these various lifestyle factors are how much exercise you do, your stress levels and how much sleep you get.
By making some lifestyle changes like getting more sleep, managing your stress more effectively, and being more active, you may be able to make a notable change to your blood sugar levels.
Whilst lifestyle factors that can cause your blood sugar to rise are largely modifiable; there are factors that can impact our blood sugar control that we have less control over.
Some commonly prescribed medications can also harm your blood glucose. Of course, you should not make any changes to your prescribed medication without checking with your doctor first. Yet, if you are concerned about the impact your medications are having on your blood glucose levels, it is worth mentioning this to your specialist diabetes team.
If you take medication to help manage your diabetes, your healthcare team can advise you on the best choices and when you may need to adjust your dose.
They will be guided on this by your blood sugar results. They will look at a combination of readings from before eating, after you have eaten, and, most importantly, over a longer time period (usually over three months). This test is called hemoglobin A1C, or HbA1c.
What are normal blood glucose levels?
For the majority of people without diabetes, normal blood sugar levels are as follows:
- Between 4.0 to 5.4 mmol/L (72 to 99 mg/dL) when fasting (5)
- Up to 7.8 mmol/L (140 mg/dL) 2 hours after eating
When you are living with diabetes, knowing what ‘normal’ blood glucose levels are is very important. It can help guide you toward better glycaemic control and to prevent hypoglycemia.
It can also help you understand more about how your own body responds to certain foods and certain situations.
Whatever your situation, your dedicated healthcare team will work with you to tell you what your targets for good blood sugar control are. Be sure to request a blood glucose meter for checking your results, if you do not already have one.
Optimum control will look different for everyone. It will depend on individual factors such as age, health status, medications you take, and how active you are.
Yet, there are general targets that you may wish to be aware of, to help get you started with self-management (3):
- Before meals: 4-7 mmol/l (72-126mg/dl)
- Two hours after meals: less than 8.5mmol/l (less than 153 mg/dl)
The only reliable way to measure your long-term blood sugar control when you have diabetes is by knowing what your HbA1c is.
Your specialist diabetes team should be keeping an eye on this for you, with a blood test at least once per year. It will help them to look at your average blood sugar levels, and also any emerging patterns.
Try and aim to get your HbA1c within the recommended limits to avoid increasing your risk of serious complications (4):
• Equal to or below 48mmol/mol (equal to or below 6.5%).
Best supplements for managing glucose levels
There are various supplements available that are aimed at those wishing to gain better control of their blood sugar levels. Some examples include cinnamon supplements, bitter melon supplements, and magnesium supplements.
While not taken in supplement form, apple cider vinegar is also a popular natural remedy for those living with diabetes.
There is evidence supporting its use for improving glucose metabolism and promoting lower fasting blood glucose levels. However, many agree it should be taken with caution. For instance, it is highly acidic and if taken undiluted, can cause damage to your tooth enamel, and possibly to your esophagus, too.
If you do choose to take supplements for your diabetes, there are some things you should be aware of before deciding on your approach:
- Always check with a healthcare professional first.
- Some supplements can interfere with prescribed medications, so be sure to chat with your dedicated diabetes team about which supplements you wish to take.
- Supplements are not a replacement for a balanced diet and a healthy lifestyle! The benefits of eating a healthy diet and staying active should not be overlooked. Both can have a positive impact, not only on your diabetes control but on your overall health and mood.
Always check the recommended dose and any contraindications on the supplement packaging
The most substantial evidence for the use of supplements for diabetes management appears to sit with cinnamon supplements and magnesium supplements (6). Studies have shown that if you are deficient in magnesium, supplementing can lead to better blood sugar control.
How our body metabolizes and regulates glucose is complex. There are various strategies you can focus on, to help yourself improve your blood glucose control. These range from the more obvious, to approaches you may not have considered.
Dietary modification has a pinnacle role to play, as well as several other lifestyle factors. Supplements are an interesting area of research. As always, it is best to check with your healthcare professional before making any decisions about which to use.