Unsweetened sweeteners are not much better than sugar or at least there is no proof of that. It is the main conclusion of a review of what science knows about these substances. The report, commissioned by the World Health Organization (WHO) has not found significant evidence that these non-caloric (or low calorie) compounds have beneficial effects on health beyond a slight weight loss. The authors of the study and other experts remember that unsweetened foods and water are the best substitutes for sugar.
The demonization of sugar has gone hand in hand with the deification of unsweetened sweeteners. The sucrose of the first has been related to obesity, dental caries, type 2 diabetes and alterations in heart rhythm, among other diseases. Therefore, the health authorities recommend reducing their intake, especially among the smallest and specific risk groups. The withdrawal of sugar has given way to a dozen long sweeteners, including artificial and natural, such as saccharin, which a few decades ago was a drug for diabetics, aspartame, acesulfame K or stevia (extracted from the plant Stevia rebaudiana). All these substances are between 100 times (the Luo Han Guo plant) and 20,000 times sweeter (the advantamo, a new high intensity sweetener) than sucrose, according to data from the US FDA. Most have zero or very few calories.
These two realities have meant that while the consumption of sugar has been reduced, that of unsweetened sweeteners has exploded. In the United States, for example, the number of people who have gone over to the latter has increased by 54% since the beginning of the century. In the case of children, the percentage has gone up 200%. A figure related to soft drinks. However, there is no consensus among scientists and doctors about the long-term effects of these alternatives to sweeten life.
The demonization of sugar has gone hand in hand with the deification of unsweetened sweeteners
WHO is preparing a guide on unsweetened sweeteners and, as a starting point, has asked a group of scientists for a state of the art. Researchers have screened publications and scientific studies that have analyzed the effects on different aspects of the health of all or some of these sweeteners, either by comparing them with sugar or with placebo substances. Among the works included those focused on healthy people, adults and children, and those with overweight population. In total, they found 56 investigations and their results and conclusions have just been published in the journal British Medical Journal.
"There is not enough evidence to definitively assess the benefits and, in particular, the possible long-term effects of unsweetened sweeteners," says the researcher at the Institute for Evidence in Medicine at the University of Freiburg (Germany) and principal study author, Joerg J. Meerpohl. "There may be a small effect on weight in the short term, but we do not have high-quality data to confirm it in the long term," he adds. Of course, "we do not have consistent evidence of significant negative impacts on health", he adds.
The scientific review looked for impacts on weight, blood glucose level, dental health, cardiovascular diseases, liver diseases and even cancer. He also reviewed studies on the effects on mood, behavior or eating habits. Although not all studies faced sweeteners and sugar, in general terms the supposed beneficial effects of sweeteners are very scarce. In studies with adults focused on weight, for example, the average loss among those taking sweeteners was not greater than 1.3 kilograms. Perhaps the most contrasted effect is the reduction of blood pressure in overweight adults. Among the dozen studies with children, two of them even showed a slight gain in body mass index among those who took two artificial sweeteners, sucralose or acesulfame K.
In studies with adults the average weight loss among those taking sweeteners was not more than 1.3 kilograms
Meerpohl clarifies that more studies are needed before the WHO publishes its recommendations on sweeteners, scheduled for the end of the year. As to whether, despite everything are better than sugar, recognizes that it is a difficult question to answer, whose response depends on the result we are measuring and the amount of sweetener. And the long-term effect of combinations of two or more sweeteners is not known either, which is common in soft drinks, for example, to achieve or approach the characteristic sweetness of sugar.
"The results of this study are not surprising and confirm the idea that artificial sweeteners are not the magic wand with which to prevent obesity," Tom Sanders, professor of nutrition at King's College London, said in a note. "Replacing sugary drinks with artificial sweeteners helps prevent children from gaining weight, but it does not exceed the ideal alternative, water," he adds.
Purdue University researcher Susan Swithers has spent years studying the relationship between nutrition, metabolism and the brain. "So far, science is showing that sugar substitutes do not really help much and that people who consume them in the long term end up with less healthy results than people who do not use them." We do not know exactly why that is, but it can There's more than one reason why sweeteners are not necessarily healthy choices, "he explains.
"Sweeteners activate the brain differently than sugar does"
Susan Swithers, researcher in metabolism and brain at Purdue University
Among the possible explanations could be the alteration of the balance of the intestinal microbiota, which have indicated some studies. They may also be interfering with the signals that link sweet flavors and energy in the brain. Or, they could simply be making people make bad decisions about how much to eat.
"Sweeteners activate the brain differently than sugar does," Swithers recalls, unrelated to the current study. "The specific mechanisms that produce these changes are not yet well understood, but it seems that our brain has different routes to detect if something tastes sweet or if it provides energy." Normally, these routes can be activated together, but sugar substitutes activate some, but not others, "he adds.
The International Sweetener Association, which brings together a good part of this industry, has reacted to the study highlighting the part that confirms the connection between sweeteners and weight loss or dental hygiene. He also questions that the review commissioned by the WHO excludes some studies on soft drinks and young people that would indicate a weight loss, and its maintenance, in the long term among the kids who drank soft drinks without sugar compared to those who drank them with sugar.