The biggest problem regarding artificial sweeteners and their impact on health is that the science is misinterpreted. A recent segment on The Dr Oz Show claims that diet soda and low-calorie sweeteners lead to weight gain and negatively impact a person’s metabolism. This was not based on scientific facts, but was probably a misinterpretation of recent publications. Articles are increasingly appearing that claim that it has been scientifically proven that artificial sweeteners such as aspartame cause cancer and that sweeteners actually contribute to the development of diseases such as obesity and diabetes. But what exactly are artificial sweeteners, and what exactly do the scientific articles mean?
What are artificial sweeteners
Artificial sweeteners are synthetic sugar substitutes but can be derived from naturally occurring substances, such as spices or sugar itself. The most common artificial sweeteners are saccharin, aspartame, acesulfame K, sucralose and neotame. In addition, there are steviol glycosides, which are sweeteners extracted from the stevia plants and are used in many foods and drinks.
Artificial sweeteners are chemical compounds that are much sweeter than sugar, meaning that much less sweetener is needed and the energy contribution of these substances is often negligible. The disadvantage is that the sweet taste of these substances often differs from sugar and usually also leaves an unpleasant aftertaste.
Rebaudioside and stevioside are steviol glycosides responsible for the sweet taste of the leaves of the stevia plant, and are sometimes referred to as a natural sweetener. While there is no universally agreed upon definition of ‘natural’, the question is, is ‘natural’ always better? After all, anthrax is natural, but no one would want it added to our food supply. The big problem with stevia is that no company knows the exact chemical composition of their product, and extracting the rebaudioside from the plant requires many chemicals. However, steviol glycosides are the only ‘natural’ non-caloric sweeteners available to consumers today as a natural sugar replacement choice.
Detection of sweetness in the body
How can such different chemical compounds all taste sweet? Dr. Charles Zuker, a professor at Columbia University Medical Center, discovered in 2001 that “all sweet things in life are sensed by a single receptor.” This sweet taste receptor, a G-protein coupled receptor, is located in specific papillae at the back of the tongue. These cells then send signals to the brain. Other scientists have also shown that artificial sweeteners elicit sensory perceptions beyond sweetness. Saccharin, for example, also appears to have bitter properties, while some of the steviol glucosides have a licorice-like aftertaste.
Recently it has been shown that the gastrointestinal tract also contains sweet taste receptors, similar to those found on the tongue. The role of these receptors in the gastrointestinal tract has not yet been identified. “We are just beginning to unravel why these sweet taste receptors are present in the gut,” said Dr. Richard Mattes, professor of Nutrition Science at Purdue University. “We believe that these receptors contribute to the detection of intestinal contents and provide feedback through the secretion of hormones.”
Artificial sweeteners and obesity
The role of artificial sweeteners in body weight control remains controversial. It has been suggested that consumption of low-energy foods is followed by increased intake of energy-dense foods to compensate for the lost energy. Scientists suggest that when real sugars are consumed, hormones are released and energy expenditure increases to effectively break down the sugars. Artificial sweeteners would disrupt this process; they produce a sweet tasting signal in the mouth, but they do not have the expected energy-rich properties.
Scientists emphasize that artificial sweeteners can help with weight management, but only if people don’t overcompensate for this healthy behavior by eating extra-calorie foods, as a kind of reward for their healthy behavior. For example, if a person chooses an apple pie for dessert, which contains about 600 calories per serving, but uses artificial sweetener in the coffee or tea (16 calories) to replace sugar. Many people use artificial sweeteners incorrectly, which leads to weight gain, because they use drinking diet sodas as an excuse to eat more high-calorie foods.
Artificial sweeteners and glucose homeostasis
Glucose homeostasis is the balance between insulin, glucagon and blood sugar levels. Insulin is a hormone secreted by the pancreas that helps with the absorption of sugar into cells, but also helps to reduce the amount of sugar circulating in the blood. The amount of insulin released into the bloodstream is related to the amount of sugar in the blood. In type 2 diabetes, the pancreas is no longer able to produce enough insulin, making the cells no longer able to absorb sugar from the blood.
Artificial sweeteners can be a good alternative for type 2 diabetes patients. Unlike sugar, artificial sweeteners do not increase blood sugar levels. However, recent studies show that some artificial sweeteners can affect blood glucose and insulin levels. For example, Acesulfame K appears to influence insulin secretion, although this effect only occurs when taken in combination with glucose. In a study conducted by Dr. Pepino (Washington School of Medicine) it was shown that sucralose causes a higher peak in blood sugar levels, resulting in more insulin being secreted.
Is it bad that artificial sweeteners effectively stimulate insulin secretion? Scientists don’t think so. Artificial sweeteners are usually consumed as part of a meal. So promoting insulin secretion would then be beneficial to keep blood sugar levels steady. Another advantage of this increased insulin secretion is that insulin also provides a satiety signal after a meal and which is associated with decreased appetite and decreased absorption of energy-dense foods.
Animal versus human studies
Making direct comparisons between humans and animals is of course more complicated, but what animal studies can do is test a hypothesis directly and then refine it for humans. If there is convincing evidence from multiple animal studies, that gives more confidence in the theories, scientists say.
On the other hand, there are many studies that show that there are very clear differences between animals and humans. Cyclamate, an artificial sweetener banned in the United States but still freely available in the United Kingdom and other parts of Europe, has a sweet taste to humans, but certain strains of mice commonly used in laboratories do not take it true as sweet. Another artificial sweetener, sucralose, has been shown to stimulate secretion of hormones from the gut in mice, but the human gastrointestinal tract does not respond to this artificial sweetener unless it is combined with other foods.
Although there is already a lot of information available about the effects of sweeteners on health, the majority of this data has been obtained from animal studies. The claim that aspartame causes cancer has been scientifically proven, but only in mice, and not in humans. The amount these animals receive is many times higher than what we as humans would consume. Because this type of scientific data is misinterpreted by consumers, misconceptions and unfounded fears about certain food products arise.
The ideal sweetener
So what would be the ideal sweetener? Scientists universally agree: one that is consumed occasionally and in relatively small quantities. While sweetened drinks used to be seen as a reward, they now seem ubiquitous and consumed daily by many people, including children. Other products are also packed with added sweeteners, both sugars and artificial sweeteners. While this may make foods and drinks very tasty, this will contribute to overconsumption.
Scientists agree that it doesn’t matter whether you consume sugar or artificial sweeteners, as long as it’s in moderation. Artificial sweeteners can help with weight loss, as long as you don’t overcompensate with other high-calorie foods. Whether artificial sweeteners play a role in other health problems is still up for debate. There is no convincing evidence that sweeteners contribute to the development of health problems, but there is also no convincing evidence that they don’t.
