Fructose is a simple sugar. “It has the same chemical composition and the same molecular mass as glucose, but different properties,” says Prof. Patrick Tounian, head of the pediatric nutrition unit at Armand Trousseau hospital (Paris). by a twice as sweetening power, a lower glycemic index (19 against 100), an independent metabolism of insulin and almost exclusively hepatic, and a more fat production. ”
By using it instead of classic sugar, you can put less for a identical taste result, but also to avoid hypersecretion of insulin and the sudden rise in the level of sugar in the blood (glycemia). This is, in particular, the reason why it has long been recommended for people with diabetes and / or overweight.
Where is fructose found?
This is a common sugar in our diet ! “It is naturally present in fresh and dried fruits, vegetables, honey, sweet wines, agave syrups, maple syrups … we then speak of ‘free fructose’, explains Professor Tounian.
Then, it constitutes, in equal proportion with glucose, sucrose, a common sugar obtained from beet or sugar cane.
Finally, it is frequently found as glucose-fructose syrup in most processed products with added sugar (sodas, ice cream, dairy specialties, candies, cookies, breakfast cereals, chocolate bars), even savory (pizzas, aperitif cookies, surimi ..). ”
Some dietetic brands offer crystallized fructose and fructose products (jams, chocolate, etc.) intended for type 2 diabetics and people wishing to limit their sugar consumption.
Why is fructose singled out?
According to an English study carried out by researchers at the University of Bristol and Francis Crick Institute from London, a diet high in sugar fructosecould prevent the proper functioning of the immune system. While fructose is already associated with obesity and type 2 diabetes, its impact on the immune system was not yet well known. The findings of this study were published in the journal Nature Communications (source 1). Researchers have proven that fructose is responsible for a inflammation of the immune system. The study’s authors point out that inflammation of this type can continue to damage cells and tissues. It can also cause organs and bodily systems to not function as they should and could lead to the development of certain diseases. Thanks to this study, researchers also gained a better understanding of how fructose could be linked to the onset of diabetes and obesity. “Researching the different components of our diet can help us understand what could contribute to inflammation and disease and what could be best exploited to improve health and well-being,” says Dr Nick. Jones of Swansea University School of Medicine.
Gout and diabetes
If it has qualities, fructose also has deleterious effects when it is consumed in excess. “Due to its particular metabolism, it has the undesirable effects of inducing a insulin resistance , antechamber of diabetes, to raise the level of triglycerides in the blood and to promote the production of uric acid responsible for gout “, continues the specialist.
In predisposed people, it could also promote metabolic syndrome and obesity, giving food a pleasant texture on the palate, conducive to overeating.
“These side effects are not new, says Professor Jacques Delarue, professor of nutrition at the University Hospital of Brest. The problem is that we could tend to consume too much fructose, in particular because it is present in many processed products. “
Is industrial fructose more dangerous?
In processed products, fructose is present in the form of glucose-fructose syrup. This syrup is obtained by hydrolyzing an inexpensive basic ingredient, corn starch, through various industrial processes.
It can be scary, but in fact, it does not change anything: “Whatever the food or the product of origin, a fructose molecule remains a fructose molecule, insists Professor Tounian. The body does not make the difference!”
It is rather his “hidden” presence which should encourage vigilance, although an American study has shown that the consumption of fructose increased by only 15% between 1970 and 2006, while that of added fats, starches and other calories have, at the same time, respectively increased by 54, 42 and 24%.
How much fructose per day?
“The threshold from which these risks become significant has been set at 100 g of fructose per day, specifies Professor Tounian. This is equivalent to 2 liters of cola or 1.5 liters of apple juice. ”
As this sugar is already naturally present in many foods such as fruits for which consumption is recommended, it is advisable, in order not to exceed this limit, not to over-sweeten your diet and not to abuse processed products of any kind.
“Be careful especially with liquid forms!, warns Professor Delarue. This is the most problematic, because gastric emptying is very fast, which speeds up the metabolism of fructose. Drink soda or juice occasionally, yes. Chronically, no! ”
Is fructose still recommended for diabetics?
“Yes, but on condition of do not abuse it, always for the same reasons, continues Professor Delarue. When you have type 2 diabetes and / or are overweight, it is better to learn to reduce your overall consumption of sugar and sweet products. ”
“Or use synthetic sweeteners”, as Professor Tounian reminds us.
Source 1: Fructose reprograms glutamine-dependent oxidative metabolism to support LPS-induced inflammation, Nature Communications, February 22, 2021