Artificial sweeteners taste sugary, but may be causing more harm than good.
Australia, with much of the western world, has embraced sugar substitutes. A skinny latte with an Equal has become a common (even accepted) coffee order. Soft drinks such as Coca Cola Zero and Pepsi Max are just as popular as their sugar containing siblings. While undesirable a couple of decades ago, the idea of a synthetically made artificial sweetener as a replacement of natural sugar is now accepted and sought after by many. They are now one of the most widely used food additives.
Why? They are a supposed quick fix, easy weight loss alternative. They also provide a sweet change for diabetics. But what if these substitutes could be causing more problems than we thought, such as an increase in glucose intolerance and diabetes?
Life looks sweet.
Non-caloric artificial sweeteners (NAS), such as aspartame in Equal, are synthetically produced substitutes for sugar. The strongest sweeteners can be 20,000 times sweeter. There are approximately 16 calories of energy in a teaspoon of sugar, the equivalent amount of sweetener contains 0 calories. Compared over a can of cola, that can be as significant as 160 calories difference.
This is the origin of their use for weight loss. Sweeteners cannot be digested by our gut, and therefore provide no nutritional consequence to our system. Head down to the supermarket and you will find them everywhere, especially in products like drinks, cereals and deserts. They are also used as type 2 diabetic sugar substitutes, as they do not affect or alter insulin production.
Sweeteners have been exposed to serious scrutiny for decades surrounding their safety. Several studies have highlighted negative health effects, leading to significant re-assessment. The Food and Drug Administration (FDA) in America, however, has said that all non-caloric artificial sweeteners have “reasonable certainty of no harm to consumers”, under the approved conditions of use.
Sounds sweet, doesn’t it!
Type I or II?
Glucose intolerance is one of the highest risk factors for diabetes. New studies published in Nature are linking the continued use of synthetic artificial sweeteners in mice with a significant increase in glucose intolerance. Subsequently, this could have grave impacts on type 2 diabetic levels. So, is this happening in humans too?
“The most shocking result is that the use of sweeteners aimed at preventing diabetes might actually be contributing to and possibly driving the epidemic it aims to prevent”, says Dr Elinav of the Weizmann institute.
Elinav and co-workers were interested in a casually observed link between sweetener use and both weight gain and diabetes. To explore this, they spiked drinking water of mice with the three most commonly used sweeteners; saccharin, aspartame or sucralose. The dosage was set at the relative maximum outlined by the FDA. After eleven weeks, the mice were given high glucose drinks. Those given the sweeteners were found to have higher blood glucose levels and took significantly longer to return levels to normal compared to control mice.
So what? In normal conditions, there should be an initial blood-glucose spike and gradual decrease. This process is instructed by the hormone insulin. When this is inefficient, as seen in the sweetener treated mice, glucose intolerance occurs and a strong link to type 2 diabetes is found.
How does this happen?
Because artificial sweeteners pass through the gastrointestinal tract without digestion, they directly interact with the gut bacteria. What we eat changes the bacterial make-up of our gut, and therefore the glucose intolerance may be caused by the change in digestive bacterial composition. Our gut may learn to become become not used to glucose. The mice showed significant glucose intolerance “at levels comparable to metabolic disease”.
When analysed, these bacterial changes mirrored closely the changes found in humans when associated with obesity and diabetes. When other bacteria was transferred from the healthy control mice, the levels of glucose intolerance decreased significantly. This significantly supports the observed changes in mice.
From mice to men.
How do these effects relate to humans? While mice are very similar in some ways, they are not exactly the same. The team probed this by examining a group of people. While there was a clear correlation between sweetener use and glucose intolerance in a group of 381, proving the cause of metabolic disease was harder.
They then asked seven healthy people to take the daily maximum allowed amount of saccharin (approximately four sachets). Interestingly, after just five days, four of the volunteers had a increased intolerance to glucose. The composition of their gut bacteria also changed. Those that didn’t respond to sweeteners had a different gut bacteria makeup, showing people may be more disposed than others.
The International Sweeteners Association (ISA) says it refutes the evidence, claiming the body of evidence does not support the conclusions. Still, many are calling for another investigation into the widespread use of sweeteners with the European Food Safety Authority considering providing the evidence to a panel for review.
“We are by no means thinking that based on this study we could deduce direct recommendations for artificial-sweetener consumption,” says Elinav. “We want to be very cautious about that”. If probed further, though, this may have lasting impacts. The use of artificial sweeteners must be carefully considered for the health of everyone.