Not all sugars are created equal
Most people are familiar with the term sugar, generally considered something to avoid if possible due to negative health effects. However, did you know that not all sugars are created equal? Different sugars work completely differently within the body. To say that “sugar” (in its entirety) is either good or bad really is a grave oversimplification. The effect that sugar has on the body and mind can vary between beneficial or disadvantageous, depending on the specific type of sugar, the dose (meaning the amount you ingest), and the circumstances (as in what you are doing).
Sugars come in many shapes and types.
Did you know that the brain actually depends on sugar as its primary (and almost only) energy source? As hardcore nutritionists and biohackers, we don’t just think of sugar as being “sugar” – we look at the potential worth of specific types of sugars for different circumstances, and try to see if they can be used advantageously. It’s what we consider next-level nutrition and being smart about what you put in your body.
As many people know, sugars are carbohydrates (or simply “carbs”). Fibers, starches and plain table sugar are all carbohydrates and made up of different sugar molecules. A single sugar molecule is also called a saccharide and can work as both energy/fuel and as a building block. All saccharides consist of single saccharide molecules called monosaccharides (mono- meaning “one”). Larger saccharides are therefore just two or more monosaccharides linked together.
Foods high in carbohydrate / sugar.
In the context of human physiology, the monosaccharide glucose holds a special place amongst sugars as the body’s preferred energy source. Your “blood sugar” actually refers to the level of glucose in the blood stream, and thereby how much glucose is readily available to be used as energy for the cells of your body.
Glucose is not only the preferred energy source of the body, but also the only sugar that can reach the brain. Between the blood stream and the brain there is something called the blood brain barrier (BBB). The BBB acts as an extra security system that makes sure that only very specific molecules can access the brain. Since glucose can get through this BBB, the brain runs on energy from glucose and the brain actually uses ~20% of all glucose-derived energy in your body even though it only accounts for ~2% of your total body weight. The availability of glucose in the blood is therefore especially important for normal brain function.
Does that then mean that glucose in itself is great nutrition?
Not necessarily. It really depends on the circumstances. Since it is the body’s preferred fuel, refined glucose is so quickly digested and metabolized that it can easily “spike” your blood sugar and basically provide much more energy than needed much too quickly, unless you are burning through calories (and depleting your blood sugar) at a VERY rapid rate. As a rule of thumb, if you are sitting still, and working hard with your brain, refined/added glucose will simply provide energy too fast. There are even studies suggesting that for sports like football/soccer, glucose and maltodextrin (longer chains of glucose that are digested pretty much equally as fast and very commonly used in sports products) are absorbed too quickly and can lead to unwanted insulin secretion. But as we stated from the beginning, not all sugars are created equal, and there are other types of sugars than glucose, and not all of them are digested/released as quickly. Whenever you eat “carbs” (including starches, fibers, or fruit) they are broken down into glucose as well as other monosaccharides.
Fructose / fruit sugar – a better alternative?
Fructose is very often found in beverages.
Another important monosaccharide is fructose, more commonly known as fruit sugar. It is important because it is found in many foods both naturally occurring (e.g., in fruits – surprise ), but also frequently added in refined/concentrated forms to many food products, not least various beverages. Many food producers prefer to add fructose because of its low price and very high sweetness level. If you compare the digestibility of fructose with glucose (and thus how readily it can act as fuel for the body), you will find that it has a much lower GI-value – 100 (super high) for glucose vs 19 for fructose (super low).
The glycemic index measures the relative rise in the blood glucose levels.
GI-value is a measure that was created to show how much and how quickly a given food affects blood sugar. You might think that due to this low impact on blood sugar, fructose might be a good fuel source for the human body … Well, unfortunately that is not the whole story. While glucose is metabolized in all cells of the body, fructose and other monosaccharides are only metabolized in the liver. In order for the body to “process” fructose, the fructose is transported to the liver where it is (relatively) slowly metabolized. The issue here is that if you try to use fructose for fuel, and simply ingest it for energy, the liver ends up being a bottleneck, and this can actually end up damaging the liver. Lower amounts of fructose, such as those found in fruits are simply much easier for the liver to cope with. This is in part because fruits also contain fibers that further slow down the uptake of fructose and the speed at which it hits the liver.
Disaccharides, polysaccharides, and glycosidic bonds
The story of how sugars affect the body becomes even more complex when we go beyond the simple monosaccharides. Disaccharides (di- meaning “two”) are sugar molecules made up of two monosaccharides linked together. As an example, sucrose (table sugar) is one glucose linked to one fructose.
“Table sugar” is an example of a disaccharide – two monosaccharides linked together.
Polysaccharides (poly- meaning “many”) are made up of 3 or more monosaccharides linked together and include dietary fibers and starches. The linkage between one monosaccharide and another (as in how they stick together) is called a glycosidic bond. How fast a consumed sugar is digested and further metabolized in the body depends on the kind of glycosidic bond linking the monosaccharides. This is one of the reasons why dietary fibers are healthier than other sugars; While starches and sucrose have glycosidic bonds called α-linkages, which are broken by digestive enzymes in the small intestine, dietary fibers have another type of glycosidic bonds called β-linkages which cannot be broken by the enzymes in the small intestine. A slower breakdown of a sugar results in a more stable blood sugar as the energy within is dispersed more evenly over time. That is why glycosidic bonds are super important when aiming to secure a stable blood sugar and energy level throughout the day.
Another example of this is seen for the disaccharide called isomaltulose which at first glance resembles sucrose. The only difference is that isomaltulose has a different type of glycosidic bond than sucrose, making isomaltulose more slowly digested. This ultimately results in a more stable blood sugar level upon ingestion than common sugars (like sucrose and glucose). The thing about blood sugar is that you generally want it to be in the sweet zone as much as possible – not too high and not too low, unless for instance you are trying to gain or lose weight.
Not all sugars are created equal: Palatinose™ (isomaltulose). Image by beneo.
If you end up “spiking” your blood sugar, which is very easy to do with foods containing refined sugars, especially the high GI ones, it generally triggers a signal in the body to release insulin. Insulin in turn tells the body to start storing that excess energy (excess blood sugar), which means that 1) the body initiates a “resting state” and starts converting energy into fat and glycogen (the body’s “sugar storage”), and 2) blood sugar starts to quickly decline as the body stores much of that energy for a rainy day. So, being mindful of not elevating your blood sugar too quickly is a pretty low-hanging fruit in terms of being smart about nutrition. Especially since it has so many implications for both body and mind, not least including weight management, mood and the subjective feeling of energy.
Conversely, whenever the blood glucose level is low, a hormone called glucagon is released from the pancreas. Glycagon tells the body to release glucose from its glycogen stores. Glycogen stores can contain enough glucose to sustain the bodies energy needs for about a day (depending on your activity level). If the stores are depleted and the body does not receive new sugar molecules (e.g., during starvation or fasting) our cells can instead “feed” on amino acids (from proteins). This is done by breaking down muscle mass to generate molecules for glucose metabolism, a process called gluconeogenesis. However, amino acids, protein, and muscle mass are essential for the body to work normally and optimally in many ways. Therefore, the body eventually starts using triglycerides (fat) for energy instead, by breaking down adipose tissue (fat stores).
Glucose Homeostasis – the release of insulin and glucagon.
The breakdown of adipose tissue results in molecules called ketone bodies – a process commonly known as ketosis. Acetone, being one of these ketone bodies, can often be smelled from the breath of people with diabetes or people on a ketogenic diet who are producing lots of ketone bodies. An important point about ketone bodies is that they, like glucose, can cross the BBB to reach the brain. Therefore, they are usable as emergency fuel for the brain. The shift from glucose- to ketone-derived energy is however a rather long process where many experience mental fatigue.
So, as you can clearly see – not all sugars are created equal. Bottom line, if you care about functional nutrition, you should also care about what exactly a given type of sugar does to your body (and mind).
You can find more information about Palatinose™ (Isomaltulose) here.
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