Fructose is the most popular sugar substitute that was first discovered in fruit. In any large supermarket, you can find supposedly dietary sweets in which the usual table sugar is replaced with fructose. It would seem that this is happiness for diabetics, because with such a wide selection of delicious products, it is much easier to follow a diet. But there is no reason for joy here – fructose is harmful to the body and at certain stages of metabolism is even more dangerous than sugar. Let’s find out why foods containing fructose should be avoided not only by diabetics, but also by healthy people.
The metabolism of fructose
All the nutrients that enter our body must go through a certain path of transformation. Some of them go to the needs of the body, providing nutrition to the cells and covering energy costs. And some stock up on a “rainy day”. Fructose is no exception. It is a simple sugar, most of which is absorbed in the intestine. About a quarter of the fructose is converted to glucose, and the rest is absorbed.
Fructose absorption is a passive process that does not require energy expenditure. Through diffusion, it penetrates into the cells of the intestine,and then into the blood. Further, with the blood flow, fructose enters the liver, where it enters into various biochemical reactions.
Fructose does not need insulin to be metabolized, so it is considered an alternative to sugar for people with diabetes.
In the liver with fructose, many transformations occur. We will not analyze complex reactions in detail, we will only announce the most important end products.
Differences in fructose and glucose metabolism
Fructose under the influence of enzymes of the liver is converted into pyruvate. This compound is necessary for the synthesis of fatty acids, which combine with glycerin to form the so-called triglycerides. Next, the triglycerides leave the liver and are carried throughout the body by special transport proteins with the blood. Adipose tissue cells capture fatty acids, while increasing their volume. This is why foods containing fructose lead to weight gain.
It should be noted that glucose is also converted to pyruvate. But there is a significant difference between the metabolism of glucose and fructose. The fact is that for the conversion of glucose, other enzymes are needed, the activity of which depends on the concentration of the final product. That is, the more pyruvate is synthesized, the less glucose reacts. With fructose, the situation is much worse – despite the amount of pyruvate, the enzymes remain active, and fructose will undergo transformations until its amount is completely exhausted.
Due to uncontrolled metabolism, fructose leads to obesity much faster than glucose.
And then the effects of excess fatty acids appear. The volume of adipose tissue increases, the secretion of its hormones increases. They have different effects – an increase in blood pressure, the manifestation of insulin resistance (insulin resistance), impaired kidney function, stimulation of inflammation, etc .The only hormone of adipose tissue, the activity of which decreases is adipokinin. Normally it regulates the level of sugar in the blood. Accordingly, the deficit adipokines, the glucose level increases. Insulin resistance and increased blood sugar levels lead to type II diabetes. Now you can answer the question – is fructose possible for a diabetic.
Fat deposition occurs in all body tissues, including the liver. Fructose causes fatty liver disease, the frequency of which is steadily increasing in modern society.
If you collect all the negative properties of fructose, you will get a very impressive list:
- Causes obesity of the liver and disruption of its work. Such changes can lead to cirrhosis. The effect of fructose on the liver is practically no different from the harmful effects of alcohol.
- Increases the level of triglycerides and cholesterol, which under certain conditions can lead to the development of atherosclerosis.
- Leads to general obesity.
- Disrupts carbohydrate metabolism. Increases blood sugar and insulin levels.
- It blocks the production of leptin, the hormone responsible for satiety. This means that you can eat much more fructose than glucose without noticing it.
- Disrupts the work of the kidneys.
Characteristics of fructose
Fructose is 1.5-2 times sweeter than sugar and has a slightly lower calorie content. In 100 g of sugar 400 kcal, and in 100 g of fructose – 380. As you can see, the difference is not significant. But if we take into account the fact that it takes almost 2 times less fructose to give a sweet taste, then indeed, products with this sweetener are less caloric.
As we already know, some of the fructose in the intestine is converted into glucose, which means that after taking it, the blood sugar level will increase. Of course, the glycemic index of fructose is lower than that for sugar. GI of fructose – 22, GI of sugar-75.
The amount of carbohydrates in fructose is almost 100 g, and naturally it does not contain proteins with fats.
What conclusions can be drawn? Fructose is a fairly high-calorie sweetener, and it increases the level of glucose in the blood. However, slightly slower than regular table sugar. Of course, it can not be called a dietary product. Therefore, if you follow a strict diet and have replaced sugar with fructose, you can draw conclusions why the extra pounds still do not leave your body.
The World Health Organization (WHO), taking into account the harm of fructose, excluded it from the list of dietary products.
Modern style of nutrition – daily overdose of fructose
Obesity and related diseases are considered almost the main problem of modern humanity. This, of course, must be fought. In the beginning, a war was declared on fats, which were expelled in every possible way even from those products where they should be. No one will be surprised by low-fat dairy products. Even the oil, which by definition should consist of fat, managed to make fat-free. However, as time went on, the number of people with diabetes, obesity and cardiovascular diseases clearly did not decrease. Rather, on the contrary. It became obvious that a low-fat diet is not a panacea, and the reason is different.
It’s time to seriously think about how to reduce the amount of sugar consumed, and in particular fructose. By the way, table sugar is 50% fructose. And since fructose is cheaper and sweeter than sugar, it is most often added to food and drinks. At the same time, fructose can be found not only in sweets, but also in the most unexpected products – bread, sauces, meat semi-finished products.
Defenders of fructose claim that it is impossible to demonize fructose, considering it an absolute evil. They are partly right – fructose is necessary for the body, but in very small doses. And this is incommensurable with the amount that we consume daily!
The American Heart Association and the World Health Organization are calling for reducing fructose intake to 40 mg per day.
The leaders in fructose content are corn syrup, honey, figs, raisins and sugar.
What about the fruit? — you may ask. Fresh fruit does not contain as much fructose as it seems – only 5-10%. And there are a lot of vitamins and useful substances, so you can not exclude them from the diet. In addition to fructose, fruits are rich in fiber, which regulates the absorption of sugar. Therefore, fructose comes from fruits much less than from food sweeteners. But do not forget that as a result of breeding, new varieties of fruits are produced that have a greater sweetness compared to their natural relatives. Therefore, it is better to give preference to seasonal, well-known varieties. It is advisable to choose less sweet ones.
All modern dietary recommendations come down to one thing – to reduce the consumption of sugar, primarily fructose. But it’s not as easy as it sounds. First, fructose is associated with fruit, and therefore with health. Secondly, for several decades in a row, fructose was positioned as a mega-dietary supplement, and people are not so easy to convince. In addition, fructose is quite tasty, and the peculiarities of its metabolism do not allow you to control saturation.
Defenders of fructose urge not to accept information about the dangers of fructose-they say many studies were conducted on laboratory animals, not on humans, and not all studies involved a sufficient number of people, and not all of them have a sufficient evidence base, etc. You can criticize anything, but the fact is obvious – the more people consume fructose, the more often they get sick.
To sum up. Fructose is not a dietary product. Only those who benefit from it can talk about its benefits. Despite the prevailing stereotypes, foods containing fructose should be excluded from the diet. Alternatives to fructose and glucose are sugar substitutes-stevia and inulin. The consumption of such sweets will reduce the risk of obesity and diabetes.
Eat right and take care of your health!