"Given the widespread and increasing use of artificial sweeteners, and the current epidemic of obesity and related diseases, more research is needed to determine the long-term risks and benefits of these products", Azad said.
The university found that new data indicates artificial sweeteners may have a negative effects on metabolism, gut bacteria and appetite.
At the same time, the 30 observational studies showed that over an average follow-up of 10 years, people regularly using artificial sweeteners tended to develop health problems associated with excess weight. Among these studies, only 7 were randomized controlled trials (the gold standard in clinical research) and those studies involved 1003 people, who were followed for an average of 6 months. In addition, the cohort studies showed that there was an association between nonnutritive sweetener consumption and increases in weight and waist circumference, as well as a greater prevalence of obesity, hypertension, metabolic syndrome, type 2 diabetes and cardiovascular events.
"Despite the fact that millions of individuals routinely consume artificial sweeteners, relatively few patients have been included in clinical trials of these products", said author Ryan Zarychanski.
Artificial sweeteners don't do anything for weight loss, a new review states, contradicting the theory that using these gives the same sweetness as sugar, but without the added calories.
"Ultimately, we found no consistent proof that the sweeteners help reduce weight", says Meghan Azad, a scientist at the Children's Hospital Research Institute of Manitoba, and the study's lead author. Some researchers speculate that the sweeteners interfere with a person's microbiome, a collection of gut bacteria crucial for the absorption of nutrients.
Researchers said scientific evidence does "not clearly support" that sweeteners help people to lose weight. A previous study found that 25% of American kids and 41% of adults reported consuming them, mostly once a day.
Azad's study didn't look into what it is about artificial sweeteners that could be triggering increased risk of so many issues, it simply points to a link.
However, it's possible this evidence review is blaming artificial sweeteners for health problems attributable to an otherwise poor diet or other unhealthy lifestyle choices, countered the Calorie Control Council.
Other hypotheses suggest they promote a preference for sweetness, leading to further consumption of sweet foods and beverages, or may lead people to indulge in other ways.
Handfuls of studies have pointed to artificial sweeteners' link to diabetes, weight gain and even cancer.
Originally developed as an alternative to sugar, artificial sweeteners are used in products such as diet soft drinks and sugar-free candies in an effort to lower sugar intake and combat obesity. Observational studies, which are a lot longer in duration can do that much better but the drawback is that they only find associations and not causation.