Purdue Opinion Article Challenges Sweeteners, Industry Disputes Conclusions as Speculation

11 July 2013 --- More and more Americans are consuming artificial sweeteners as an alternative to sugar, but whether this translates into better health has been heavily debated. An opinion article published by Cell Press on July 10th in the journal Trends in Endocrinology & Metabolism reviews surprising evidence on the negative impact of artificial sweeteners on health, raising red flags about all sweeteners—even those that don't have any calories.

"It is not uncommon for people to be given messages that artificially-sweetened products are healthy, will help them lose weight or will help prevent weight gain," says author Susan E. Swithers of Purdue University. "The data to support those claims are not very strong, and although it seems like common sense that diet sodas would not be as problematic as regular sodas, common sense is not always right."

Consumption of sugar-sweetened drinks has been linked to obesity, type 2 diabetes, and metabolic syndrome—a group of risk factors that raises the risk for heart disease and stroke. As a result, many Americans have turned to artificial sweeteners, which are hundreds of times sweeter than sugar but contain few, if any, calories. However, studies in humans have shown that consumption of artificially sweetened beverages is also associated with obesity, type 2 diabetes, and metabolic syndrome as well as cardiovascular disease. As few as one of these drinks per day is enough to significantly increase the risk for health problems.

Moreover, people who regularly consume artificial sweeteners show altered activation patterns in the brain's pleasure centers in response to sweet taste, suggesting that these products may not satisfy the desire for sweets. Similarly, studies in mice and rats have shown that consumption of noncaloric sweeteners dampens physiological responses to sweet taste, causing the animals to overindulge in calorie-rich, sweet-tasting food and pack on extra pounds, the author claims.

Taken together, the findings suggest that artificial sweeteners increase the risk for health problems to an extent similar to that of sugar and may also exacerbate the negative effects of sugar. "These studies suggest that telling people to drink diet sodas could backfire as a public health message," Swithers says. "So the current public health message to limit the intake of sugars needs to be expanded to limit intake of all sweeteners, not just sugars."

The Calorie Control Council claims that the views put forth in the opinion piece are biased and highly speculative. “The author ignores the large body of robust scientific research that demonstrates the safety and benefits of low-calorie sweeteners,” said Haley Curtis Stevens, Ph.D. of the Calorie Control Council, whose members include manufacturers and end users of low and reduced calorie sweeteners and other ingredients. “This study adds no new data to the literature, as it is an “opinion piece,” rather than a peer reviewed study.”

This opinion piece had many flaws and limitations, the group claims, including:

•  The author presented only the studies that supported her opinion and ignored the rest of the scientific literature. For example, the author cited two studies that found a link between the use of low-calorie sweeteners and weight gain, but ignored the over a dozen studies that demonstrated that low-calorie sweeteners could be useful tools for lowering and/or maintaining body weight.2-21

•  The studies cited by the author did not prove that the consumption of low-calorie sweeteners have any undesired effects. The author alleged that consuming low-calorie sweeteners increases the risk of gaining weight and/or developing metabolic syndrome, type 2 diabetes, hypertension, or cardiovascular disease. However, individuals seeking to lose weight or manage their health often switch to low- and reduced-calorie foods and beverages. Low-calorie sweetener use might therefore simply be a marker for individuals already on weight-gain or unhealthy trajectories. This is the most plausible explanation of these findings, not that low calorie sweeteners caused a health issue. Although the author noted that many studies adjusted for baseline differences including BMI, many other factors such as age, exercise, the use of medication, etc. may have influenced the findings.

•  Many of the studies used to support the author’s views were weakly designed. Most of the studies cited were observational or cross-sectional. These types of studies cannot prove cause and effect, and their findings are often tainted by confounding variables. The studies may not have taken into account other lifestyle factors that could lead to obesity and other health problems such as a diet high in saturated and trans fats and/or a lack of physical activity.

•  The two interventional studies – the gold standard of study design – that were cited by the author showed that using low-calorie sweeteners did not lead to weight gain, metabolic syndrome, type 2 diabetes, hypertension, or heart disease.2,5

•  Many of the studies cited to support the author’s opinion were done in rodents, not humans. There are differences between rodent and human bodily processes and it cannot be assumed that the reported results of these studies would apply in humans.

•  Numerous studies in humans have shown that the consumption of low-calorie sweeteners does not lead to an increase in blood glucose levels,20,22-40 energy intake,7,9,16-18,20-24,26 feelings of hunger or body weight when controlling for other factors. In fact, a 2012 review of human studies on low-calorie sweeteners and weight management by Anderson et al in the Journal of Nutrition concluded that “there is no evidence that LCS can be claimed to be a cause of higher body weights in adults.”41

•  Low- and no-calorie sweeteners can help reduce calories consumption and aid in the maintenance of a healthy weight, a position supported by both the American Diabetes Association and the Academy of Nutrition and Dietetics.

Source:
Trends in Endocrinology & Metabolism, Swithers et al.: "Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements."

Calorie Control Council