Like all sugars, both glucose and fructose are carbohydrates. But not all carbohydrates are the same. In this case, we are talking about monosaccharides, carbohydrate molecules in the simplest form.
The body’s preferred fuel source is glucose. Glucose is made by breaking down disaccharides which are larger sugar molecules. Instead, fructose is found in its simplest form in fruits and vegetables like beets, corn, and potatoes. Read on to learn more about the main differences between glucose and fructose.
What is glucose?
Glucose is a monosaccharide found in food products (mainly sweets and fruits) and is obtained from carbohydrate foods during digestion.
During the passage of food through the esophagus and stomach, enzymes and an acidic environment convert carbohydrate foods into (more minor) glucose molecules. They are then absorbed in the intestines (or liver) and used as an energy source.
Glucose serves as the primary source of energy for the nervous system (in particular, it is needed by neurons for successful communication), as well as a structural element for the formation of glycogen deposits in the muscles. In the human body, approximately 100 g of glucose is stored in the liver, 400 g in the forces, and only 4 g in the blood. 5
The hormone insulin is necessary for glucose absorption; When this system does not work well, blood glucose levels can rise dangerously. Insulin opens the way for cells to store energy. Chronically high blood glucose levels disrupt average insulin production, known as insulin resistance, the first step in triggering type 2 diabetes and an even higher rise in blood sugar.
What about fructose?
What is Fructose? It is also a monosaccharide found in fruits. Fructose changes blood sugar levels much more gradually than glucose and does not affect insulin levels. Unlike glucose, which is processed throughout the body, fructose is almost entirely metabolized by the liver. Over time, excessive consumption can cause fatty liver and visceral fat around essential organs.
A diet rich in fructose is associated with the development of nonalcoholic fatty liver disease. This condition can trigger insulin resistance and type 2 diabetes.
Also, although glucose stimulates the fullness hormone, there is some evidence that fructose can do the opposite. For this reason, some experts believe that high-fructose diets contribute to overeating patterns. Put, if you are not satisfied, you will keep eating.
So does this mean that we should stop eating fruits because they are high in fructose? The answer is (mostly) no. Like most things in nutrition, there are more factors to consider than just one unit of measurement, namely the fructose content. Unlike junk food and nutrient-poor high-fructose sodas, fruits contain many other healthy components. They are loaded with water and fiber, which means their fructose is released slowly. In stark contrast, foods like candy and soda immediately overload the liver with fructose.
Additionally, studies show that diets rich in fruits and vegetables are associated with lower rates of heart disease, diabetes, and stroke. They are even linked to better psychological health.
Most of your carbohydrates should come from vegetables rather than fruits. And while fructose in fruits may be refined for most, people with diabetes should be more cautious. Consult your doctor about the proper amount of fructose that is safe for your consumption. Because ultimately, sugar is sugar.
What is the difference between glucose and fructose?
Both fructose and glucose are simple carbohydrates. In its pure form, its glycemic index is very high. In other words, they provide their energy excessively quickly.
The main difference between glucose and fructose is how they are processed within your body.
Fructose is not absorbed through insulin; Instead, it is assimilated in the large intestine and then transferred to the liver by a different enzyme system, the fructose transporters. This system is less developed, and less is known about it.
Since the liver regulates the processes of carbohydrate and fat metabolism, excess fructose in the diet (and therefore its excessive accumulation in the liver) can be associated with a set of unwanted fats, as well as with an increase in the level of “bad cholesterol in the blood.”
Researchers believe that even the body of a completely healthy person cannot assimilate more than 25 to 50 g of fructose at a time. What is associated with adverse changes in metabolism?
However, remember that glucose (and fructose) molecules can bind to proteins and fats in the human body, causing structural damage to them. In particular, excessive glucose consumption can accelerate the aging process of the skin and internal organs. 2
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Recommended amounts for adults and children
Current recommendations of nutritionists boil down to not exceeding 10% of the proportion of simple carbohydrates in the daily calorie intake. Otherwise, it has been seen that in the long term, the excess of this type of carbohydrate leads to the development of a series of serious chronic diseases (obesity, diabetes, hypertension) ³.
In practice, we are talking about 30-50 g of glucose and fructose in their pure form (that is, in the form of sugar and fruits), while the average Russian consumes about 110 g of sugar per day. Among children, due to sweets, snacks, and sugary drinks, the figure can reach 200-250 g of sugar per day.
Regarding the total amount of carbohydrates in an adequate diet, the World Health Organization recommends limiting carbohydrates to 55% of the daily caloric value (approximately 250-300 g), including at least 18-25 g of fiber in the diet 4.
Glucose is the primary source of energy for the human body, necessary to maintain the performance of the muscles and the nervous system. Fructose is a very close relative of glucose. However, the body processes them differently. Excess glucose, fructose (and other simple carbohydrates) can negatively affect metabolism, increasing micro-inflammation and accelerating the aging process.
The critical point here is to eat food in its most diminutive processed form, like a serving of fruit that contains all the fiber from the plant or brown rice instead of refined grains. This will allow the body to obtain the sugars it needs for energy while also providing thread, an essential tool for healthy eating.