Glucose, Fructose, Sucrose: what's the difference? what's better for health? Scientific studies | PRO7fitness.com - The Honest Website About Nutrition in Sport, Supplements, Muscle Gain, Weight Loss and Health

Persistent remarks about the dangers of sugar, which are heard today from all informational outlets, make one believe that the problem truly exists.

And since the love for sugar is “embedded” in our subconscious from birth and it is not very desirable to give it up, we have to look for alternatives.

Glucose, fructose, and sucrose are three popular types of sugars that have much in common, but also significant differences.

Here and thereafter, the term sugar will be used not only to refer to the familiar table sugar but also to all the listed types of sweet substances. That is, both glucose, fructose, and sucrose are types of sugar.

They naturally occur in many fruits, vegetables, dairy products, and grains. Humans have also learned to extract them from these products and add them to their culinary creations to enhance flavor qualities.

In this article, we will discuss how glucose, fructose, and sucrose differ, and we will definitely explain which of them is more beneficial/harmful.

Main thoughts:

Sucrose, glucose, and fructose are three types of sugars that differ in absorption time (minimum for glucose and fructose), degree of sweetness (maximum for fructose), and impact on blood sugar levels (minimum for fructose)

Glucose is the basic source of energy for all cells in the body. Its consumption increases the level of the hormone insulin in the blood, which transports glucose into cells, including muscle cells, for conversion into energy. If there is too much glucose, some of it is stored as glycogen, and some can be converted into fat

Fructose, unlike glucose, does not raise insulin levels in the blood as much and does so gradually. This is an advantage for diabetics. The increase in triglyceride levels in the blood and liver, which is often cited as a greater harm of fructose compared to glucose, does not have unequivocal evidence

Sucrose (or sugar) differs from glucose and fructose in that it is a combination of the two. The health risks of such a combination (primarily concerning obesity) may be stronger than those of its individual components

All types of sugars (both table sugar and fructose) are harmful to health when consumed in large quantities. In their natural form within whole foods, they do not pose harm. For diabetics, fructose is indeed less harmful than sucrose

Glucose, Fructose, Sucrose: Differences from a Chemical Perspective. Definitions

All types of sugars from a chemical perspective can be divided into monosaccharides and disaccharides.

Monosaccharides are the simplest types of sugars in structure, which do not require digestion and are absorbed as they are and very quickly. The absorption process begins in the mouth and ends in the rectum. They include glucose and fructose.

Disaccharides consist of two monosaccharides and must be broken down into their components (monosaccharides) during digestion for absorption. The most prominent representative of disaccharides is sucrose.

What is sucrose?

Sucrose is the scientific name for sugar.

Sucrose is a disaccharide. Its molecule consists of one molecule of glucose and one of fructose. That is, the composition of the familiar table sugar is 50% glucose and 50% fructose ¹.

Sucrose naturally occurs in many natural products (fruits, vegetables, grains).

Most of what is described in our vocabulary with the adjective “sweet” is so because of the presence of sucrose in it (candies, ice cream, carbonated drinks, baked goods).

Table sugar is obtained from sugar beets and sugar cane.

Sucrose tastes less sweet than fructose but sweeter than glucose ².

What is glucose?

Glucose is the main basic source of energy for our body. It is delivered by the blood to all cells of the body for their nourishment.

The blood parameter known as “blood sugar” or “blood sugar level” describes the concentration of glucose in it.

All other types of sugars (fructose and sucrose) either contain glucose in their composition or must be converted into it for use as energy.

Glucose is a monosaccharide, meaning it does not require digestion and is absorbed very quickly.

In natural food products, it typically forms part of complex carbohydrates – polysaccharides (starch) and disaccharides (sucrose or lactose (which gives milk its sweet taste)).

Of all three types of sugars – glucose, fructose, sucrose – glucose is the least sweet in taste ².

What is fructose?

Fructose or “fruit sugar” is also a monosaccharide, like glucose, meaning it is absorbed very quickly.

The sweet taste of most fruits and honey is explained by the presence of fructose in them.

As a sugar substitute, fructose is obtained from the same sugar beets, cane, and corn.

Compared to sucrose and glucose, fructose has the sweetest taste ².

Fructose has become particularly popular among diabetics today, as it has the least impact on blood sugar levels compared to all types of sugars ². Moreover, when consumed together with glucose, fructose increases the proportion of glucose stored by the liver, which leads to a decrease in its level in the blood ⁶.

Sucrose, glucose, fructose – these are three types of sugars that differ in absorption time (minimal for glucose and fructose), sweetness level (maximum for fructose), and impact on blood sugar levels (minimal for fructose)

Glucose, fructose, sucrose: differences in terms of absorption. Which is more harmful?

How glucose is absorbed

When it enters the bloodstream, glucose stimulates the release of insulin – a transport hormone whose job is to deliver it into the cells.

There, it is either immediately “thrown into the furnace” for conversion into energy, or stored as glycogen in the muscles and liver for later use ³.

This explains the importance of carbohydrates in sports nutrition, including for gaining muscle mass: on one hand, they provide energy for performing exercises, and on the other hand, they make muscles “voluminous,” as each gram of glycogen stored in the muscles binds several grams of water ¹⁰.

Our body strictly controls the level of sugar (glucose) in the blood: when it drops, glycogen is broken down and more glucose enters the blood; if it is high and the intake of carbohydrates (glucose) continues, insulin sends the excess to be stored in glycogen stores in the liver and muscles; when these stores are filled, the excess carbohydrates are converted into fat and stored in fat reserves.

This is why sweets are so harmful for weight loss.

If the level of glucose in the blood is low and carbohydrates are not coming from food, the body can produce it from fat and protein, not only from those contained in food but also from those stored in the body ⁴.

This explains the state of muscle catabolism or muscle breakdown, known in bodybuilding, as well as the mechanism of fat burning during calorie restriction.

The likelihood of muscle catabolism is very high during body cutting on a low-carbohydrate diet: there is little energy from carbohydrates and fats, and to ensure the functioning of vital organs (the brain, for example), muscle proteins may be broken down ⁴.

Glucose is a basic source of energy for all cells in the body. When consumed, the level of the hormone insulin in the blood rises, which transports glucose into the cells, including muscle cells, for conversion into energy. If there is too much glucose, part of it is stored as glycogen, and part can be converted into fat.

We recommend: Milk: benefits and harms for the human body. Scientific facts

How fructose is absorbed

Like glucose, fructose is absorbed very quickly.

Unlike glucose, after the absorption of fructose, the blood sugar level rises gradually and does not lead to a sharp spike in insulin levels ⁵.

For diabetics, who have impaired insulin sensitivity, this is an advantage.

However, fructose has one important distinguishing property.

For the body to use fructose for energy, it must be converted into glucose. This conversion occurs in the liver.

There is an opinion that the liver cannot process a large amount of fructose, and, if there is too much in the diet, the excess is converted into triglycerides ⁶, which have known negative health consequences, increasing the risk of obesity, fatty liver formation, etc. ⁹.

This viewpoint is often used as an argument in the debate “which is worse: sugar (sucrose) or fructose?”.

However, some scientific studies suggest that the property of increasing triglyceride levels in the blood is equally present in fructose, sucrose, and glucose and only occurs when they are consumed in excess (beyond the required daily caloric intake), rather than when they replace part of the calories within the acceptable norm ¹.

Fructose, unlike glucose, does not raise insulin levels in the blood as much and does so gradually. This is an advantage for diabetics. The increase in triglyceride levels in the blood and liver, which is often cited as a greater harm of fructose compared to glucose, does not have unequivocal evidence.

We recommend: Cholesterol in chicken eggs: how many eggs can an adult eat in a day?

How sucrose is absorbed

Sucrose differs from fructose and glucose in that it is a disaccharide, meaning that for absorption it must be broken down into glucose and fructose. This process partially begins in the mouth, continues in the stomach, and ends in the small intestine.

With glucose and fructose, what happens next is as described above.

However, this combination of two sugars produces an additional curious effect: in the presence of glucose, more fructose is absorbed and insulin levels rise more significantly, which means an even greater potential for fat deposition ⁶.

Fructose itself is poorly absorbed by most people, and at a certain dose, the body rejects it (fructose intolerance). However, when glucose is consumed along with fructose, a larger amount of it is absorbed.

This means that when consuming fructose and glucose (which we have in the case of sugar), the negative health consequences may be stronger than when they are consumed separately.

In the West, there is particular concern among doctors and scientists regarding the widespread use of so-called “corn syrup” in food, which represents the mentioned combination of various types of sugar. Numerous scientific data indicate its extreme harm to health.

Sucrose (or sugar) differs from glucose and fructose in that it is their combination. The health harm of such a combination (primarily regarding obesity) may be stronger than that of its individual components.

We recommend: Cottage cheese in bodybuilding: benefits for muscle mass gain, weight loss, but NOT for cutting

So what is better (less harmful): sucrose (sugar)? fructose? or glucose?

For those who are healthy, there is probably no point in fearing the sugars that are already present in natural products: nature is wonderfully wise and has created food products in such a way that it is very difficult to harm oneself by consuming only them.

The ingredients in them are balanced, they are rich in fiber and water, and they are practically impossible to overeat.

The harm of sugars (both table sugar and fructose), which everyone talks about today, is a consequence of their consumption in excessive amounts.

According to some statistical data, the average Western person consumes about 82 g of sugar per day (not counting what is already present in natural products). This is about 16% of the total caloric intake – significantly more than is recommended.

The World Health Organization recommends consuming no more than 5-10% of calories from sugars. This is approximately 25 g for women and 38 g for men ⁸.

To make it clearer, let’s translate it into the language of products: 330 ml of Coca-Cola contains about 30 g of sugar ¹¹. This is basically all that is allowed…

It is also important to keep in mind that sugar is added not only to sweet products (ice cream, candies, chocolate). It can also be found in “savory-tasting” items: sauces, ketchup, mayonnaise, bread, and sausages.

It would be a good idea to read labels before purchasing…

For some categories of people, primarily those with impaired insulin sensitivity (diabetics), understanding the difference between sugar and fructose is vital.

For them, the consumption of fructose indeed poses less harm than sugars or pure glucose, as it has a lower glycemic index and does not lead to a sharp increase in blood sugar levels.

Thus, the general advice is as follows:

minimize, or better yet, completely eliminate from your diet any types of sugars (sugar, fructose) and refined products containing them in large amounts;
do not use any sweeteners, as an excess of any of them can have health consequences;
build your diet exclusively on whole natural products and do not fear the sugars in their composition: everything is “packaged” in the right proportions.

All types of sugars (both table sugar and fructose) are harmful to health when consumed in large quantities. In their natural form within natural products, they do not pose harm. For diabetics, fructose is indeed less harmful than sucrose.

We recommend: Phytoestrogens: questionable benefits during menopause, content in products, harm. Scientific facts

Conclusion

Sucrose, glucose, and fructose – all have a sweet taste, but fructose is the sweetest among them.

All three types of sugar are used by the body for energy: glucose is the primary source of energy, fructose is converted into glucose in the liver, and sucrose is broken down into both.

All three types of sugar – glucose, fructose, and sucrose – are found in their natural form in many natural products. There is nothing criminal about their consumption.

The harm to health comes from their excess. Despite frequent attempts to find a “more harmful sugar,” scientific research does not conclusively prove the existence of one: negative health consequences are observed by scientists when consuming any of them in excessively large doses.

It is best to completely avoid the consumption of any sweeteners and enjoy the taste of natural products (fruits, vegetables) that contain them in their natural form.

Glucose, Fructose, Sucrose: what’s the difference? what’s better for health? Scientific studies | PRO7fitness.com