America’s sweet tooth is huge, and it’s satisfied by both sugar and, increasingly, low-calorie sweeteners, according to research out this month.
A large body of evidence links sugar-sweetened beverages, one of the main sources of the sweet stuff in Americans’ diet, to tooth decay, weight gain and type 2 diabetes. (Added sugars include high-fructose corn syrup as well as sucrose, or table sugar.)
You might think that switching to low-calorie sweeteners is a good thing, and, indeed, more Americans are consuming them than ever. But evidence about their long-term health effects--even, believe it or not, whether they can help people lose weight--is lacking.
The National Center for Health Statistics (NCHS), part of the Centers for Disease Control and Prevention, this past week released two reports about Americans’ consumption of sugar-sweetened drinks from 2011 to 2014. One report focused on adults, the otheron children and teens.
Using data from the National Health and Nutrition Examination Survey (NHANES), the NCHS scientists found that about half of U.S. adults age 20 and older drank sugar-sweetened beverages--soft drinks, teas, coffees, energy drinks--on a given day. About 8.5% of men and 6.5% of women drank at least three sugary drinks on a given day.
In men, sugar-sweetened drinks accounted for an average of 179 calories, or about 7% of their total calories, each day. In women, sugar-sweetened drinks accounted for an average of 113 calories, or about 6% of their total calories, each day. To put that in perspective, a 12-ounce can of Coca Cola contains 140 calories.
Among children and teens age 2-19, nearly two-thirds drank sugar-sweetened beverages on a given day. On average, boys consumed 164 calories worth of sugar-sweetened drinks each day, while girls drank 121 calories worth. For both boys and girls, sugar-sweetened beverages accounted for a little more than 7% of their daily calories.
While Americans still get a sizeable portion of their calories from sugar-sweetened drinks, more and more of them are consuming beverages and foods containing low-calorie sweeteners, according to a study out this month in the Journal of the Academy of Nutrition and Dietetics.
The researchers used NHANES data to compare the intake of low-calorie sweeteners in the years 2009-2012 to intake in the years 1999-2000. They found that the percentage of children and teens 2-17 who consumed the sweeteners had tripled, while it had increased by about half in adults.
“We were surprised at the magnitude of the increase,” lead author Allison Sylvetsky, an assistant professor of exercise and nutrition sciences at George Washington University, told me.
In the more recent period, a quarter of children and teens and four out of 10 adults reported consuming low-calorie sweeteners, six different kinds of which are approved by the Food and Drug Administration. As previous studies had found, beverages accounted for the majority of low-calorie sweetener consumption in adults and children.
While many youths and adults consumed low-calorie-sweetened products, such items represented only a small percentage of total food and drink intake, Sylvetsky's study found. For example, only 1% of beverages consumed by children and 5% consumed by adults contained low-cal sweeteners.
The heavier the adult, the more frequently they consumed low-calorie sweeteners, the researchers found. Sure, it makes sense that replacing your daily regular Coke with Diet Coke might help you shed a few pounds over time, said Sylvetsky, who has maybe one diet soda a month. "But," she said, "a lot of people are going to have that diet soda and say, 'Okay, now I can have French fries or that cookie.'"
However, relatively few studies have examined the effect of low-cal sweeteners on weight and disease risk, Sylvetsky said.
Because of the dearth of evidence, artificially sweetened beverages "should not be promoted as part of a healthy diet," an international team of scientists concluded in a paper published this month.
In response to that paper, the Calorie Control Council, which represents the low- and reduced-calorie food and beverage industry, issued a statement emphasizing that it was an opinion piece, not a a study. The group cited a review article, published by European scientists last March, that concluded that replacing sugar with low-calorie sweeteners resulted in reduced calorie consumption and body weight in children and adults. However, I should note that several of that paper's coauthors either received funding from or worked for companies that marketed products containing low-calorie sweeteners.
Researchers have yet to determine how long-term use of low-calorie sweeteners might impact taste preferences, dietary patterns and the microorganisms that inhabit the gut. That's a pressing issue, considering how consumption has grown among children and teens, Sylvetsky said.
"I wouldn't advise against them" for young people, she said, "but I wouldn't encourage parents to run out to the store to pick up the next diet product."
Studies in cell cultures, animals and humans have provided intriguing clues that low-calorie sweeteners aren't inert substances, as previously thought:
Research conducted by Israeli scientists in mice and humans suggested that the artificial sweeteners saccharin (Sweet'N Low), sucralose (Splenda) and aspartame (NutraSweet and Equal) could raise blood sugar levels more than sugar could by changing the makeup of the microorganisms that live in the gut.
In a small study of healthy adults published in October, Sylvetsky and her coauthors found that drinking a diet soda before an oral glucose tolerance test--used to check how the body breaks down sugar--led to consistently higher levels of insulin and a hormone involved in insulin secretion and the sensation of feeling full.
In a study published in November, researchers randomly assigned Mexican nursing students, whose average age was 22, to one of three beverage groups for six months: no sweetened beverages, only beverages with non-caloric sweeteners, or whatever kinds of beverages they usually drank. At the end of the study, the students in the first group, who drank neither sugar-sweetened nor artificially sweetened beverages, had lost the most weight.
As Sylvetsky told me, "We definitely need funding for well-controlled, better-designed research studies."