“Whatever the calories, sugar should be consumed in moderation,” warn researchers, as a new study shows the effect of eating artificial sweeteners on metabolism and glucose regulation.
We have been hearing a lot in the media recently about the dangers of consuming sugar. Added sugar increases the risk of obesity, cardiovascular disease and type 2 diabetes, not to mention addictive brain effects.
Therefore many people turned instead to low-calorie sweeteners in an attempt to avoid sugar. Artificial sweeteners provide none of the side effects to the sweet taste, so it seems to be a welcome and healthy “trick.”
So, many people have bought into the idea that, according to some estimates, about a quarter of children in the United States and over 40 per cent of adults are currently consuming low-calorie sweeteners.
But, do artificial sweeteners seem as harmless as people think? A couple of years ago research suggested that artificial sweeteners can still promote diabetes and obesity. And now, a new study adds evidence of undeniable metabolic effects from sweeteners.
In fact, the latest study suggests that simply degusting something sweet might alter our metabolism and control of glucose.
M. The lead author of the new paper, which appears in the journal Nutrients, is Yanina Pepino, a professor of food science and human nutrition at the University of Illinois, Chicago.
The hypothesis that Prof. Pepino and her colleagues set out to test was that sucralose, or the artificial sweetener used in low-calorie sweeteners, would differently affect the metabolic reaction of moderate-weight people and that of those who are obese.
Testing sucralose’s effect on metabolism
The researchers asked 21 participants— “10 with normal weight and 11 with obesity” — to take oral glucose tolerance tests (OGTT) after glucose and sucralose ingestion to check their hypothesis.
Neither researcher had diabetes or routinely ate artificial sweeteners. Next, after they had drunk distilled water, the participants took an OGTT.
Instead, a week apart, they took the test again after drinking water with 48 grams of sucralose in it— the size of a standard soda can — and eventually, a third test when they drank the same quantity of sucralose for 5 seconds but did not swallow.
We did the OGTTs after consuming a solution containing 75 grams of glucose, as well. After one of the three substances above we took the glucose for 10 minutes.
Prof. Pepino and his team obtained blood samples from participants’ at 40, 30, 20, 10, 8, 6, 4 and 2 minutes before and at 0, 10, 20, 30, 40, 50, and 60 minutes upon glucose ingestion, and then every 20 minutes for an additional 4 hours’ to analyze the reaction of the body to glucose.
The scientists looked at blood levels of sucralose, insulin, glucose, and C-peptide in the participants.
Among people with “normal weight,” swallowing sucralose resulted in a small decrease in insulin levels within the first hour and an improvement of about 50 percent in insulin sensitivity, the authors say.
People should consume sweetness in moderation
By contrast, when sweeteners were consumed by people with obesity, their insulin levels increased much more compared to when they drank distilled water or just tasted the sweetener.
“Although insulin responses were comparable in those of normal weight to either eating or swallowing sucralose, those responses were very different in people with obesity,” says Professor Pepino.
“We hypothesize therefore that any post-ingestive effects of sucralose can only occur in people with obesity.”
Nevertheless, the researcher warns that different sweeteners have different chemical structures, so the findings of this study, about the “post-ingestive effects,” can only refer to sucralose. The effect of sweet taste alone may however be more generalizable.
Intriguingly, and contrary to what the researchers expected, the study also found that mere sweetener degustation also had a metabolic effect.
“Interestingly, we found that there was a decrease in the insulin response to the glucose tolerance test in both groups of people— those with obesity and those of normal weight— when they only tasted sweetness before drinking the glucose solution.”
“It was the most surprising finding, and in a new study we are following up on that,” Prof. Pepino explains.
“The most important take-home message is that sweet taste in itself may have an impact on carbohydrate metabolism and glucose control.”
– Prof. Yanina Pepino
Researchers accept the limitations of their results, stating, “What our data indicate is that there are processes that we don’t understand clearly about how the human body controls glucose, and the possible physiological effects of consuming something sweet beyond a sense of pleasure.”
Nevertheless, they emphasize the importance of eating sweet foods in moderation.
“Although the sample population in our study was small, the findings contribute to a body of evidence suggesting that sweetness should be consumed in moderation, regardless of the calories,” Prof. Pepino adds.
