Artificial Sweeteners: Are They Safe or Healthy?

As many of us try to cut back on our sugar intake, both consumers and food manufacturers alike are turning to sugar substitutes like artificial sweeteners. You’ve likely seen artificial sweeteners on packaged, “sugar-free” foods you’ve purchased, or you may even add them to your morning coffee. If you consume them, you might have wondered if artificial sweeteners are safe, or if some artificial sweeteners are healthier than others. 

A 2017 study from the Journal of the Academy of Nutrition and Dietetics found that levels of consumption of artificial sweeteners increased by 200% (yes, two hundred) in US children and 54% in US adults since 1999/2000. The same study found that 25% of children and 41% of adults in the US report consuming artificial sweeteners, with most consuming them at least once per day. While these sugar substitutes were designed to lower energy intake, improve weight loss, and lower type 2 diabetes risk, this increased frequency of consumption has had a positive relationship with an increase in body weight and chronic disease incidence. Not exactly what we would expect, right? Could it be that these increases in body weight and type 2 diabetes are causing more individuals to swap sugar for artificial sweeteners, or could these sweeteners actually be playing a role in the development of these health issues? 

The answers to these questions isn’t clear. However, with this profound increase in artificial sweetener consumption, I think it’s important that we carefully look at the research to see how these substances can affect our health. While in grad school to become a dietitian, I actually gave a research presentation on this very topic. What I learned about artificial sweeteners was eye-opening, and while the research isn’t 100% conclusive, it’s evident that these artificial sweeteners are not metabolically inert substances as once thought.

What are artificial sweeteners?

Artificial sweeteners are sugar alternatives that provide little or no calories when we ingest them. The reason they provide few or zero calories is because these substances are many times sweeter (like 200 to 20,000x sweeter) than regular table sugar. Because they are so much sweeter than sugar, you have to use very little of them to achieve the same sweet taste in food. If you’re only taking in a very tiny amount, it’s going to contribute very little calories.

While artificial sweeteners are also known as non-caloric sweeteners, non-nutritive sweeteners, high-intensity sweeteners, or low-calorie sweeteners, we’ll use the term “artificial sweetener” for simplicity and consistency for the purposes of this post (as that’s likely the term you’re most familiar with). Artificial sweeteners can be derived from plant extracts or manufactured through chemical synthesis. These compounds elicit the same sweet flavour that we derive from sugar by binding to sweet receptors on our tongues. These taste receptors transmit messages to our brain that tell us that we’re eating something sweet. 

Artificial sweeteners that have been approved for use by the FDA (US) or Health Canada include ones like Acesulfame-K, Aspartame (Equal), Neotame, Saccharin (Sweet’N Low), Sucralose (Splenda), Stevia, Monk Fruit, and Cyclamate (Canada only). 

Sugar alcohols (like xylitol, sorbitol, erythritol, and mannitol) are a hybrid of sugar and alcohol molecules that are also used as sugar substitutes, although some are found naturally occurring in fruits and vegetables. Sugar alcohols are only partially absorbed, meaning that they do provide some calories, just less than regular sugar. The most common side effects are upset stomach, diarrhea, gas, and bloating. Because sugar alcohols are different to high-intensity artificial sweeteners, they will not be the focus of this post.

What foods are artificial sweeteners found in?

Artificial sweeteners are commonly found in packaged foods and beverages, especially those labeled as “sugar free,” “light,” or “zero calorie.” Common culprits include diet sodas (the top source of artificial sweeteners), energy drinks, sports drinks, flavoured or vitamin waters, flavoured yogurts, protein powders, protein bars, baked goods, frozen desserts, and granola. Many of these foods have been marketed to be “healthier” than their sugar-sweetened versions, but the reality is that these foods still provide very little nutritional value. 

Non-food products, like liquid or chewable medications, cough drops, gummy vitamins, chewing gum, toothpaste, and mouthwash may also contain artificial sweeteners to make them more palatable, especially ones marketed to children!

Are artificial sweeteners safe or healthy?

While artificial sweeteners have been recognized as safe and approved for use by both the FDA and Health Canada, there is conflicting research regarding their long-term effects on human health. 

Recent studies have shown that the intake of artificial sweeteners may actually be linked with weight gain, type 2 diabetes, and heart disease, while also having negative effects on the gut microbiome. In fact, Canada’s new (2019) dietary guidelines state that “sugar substitutes do not need to be consumed to reduce the intake of free sugars.” The guidelines add that there are “no well-established health benefits associated with the intake of sweeteners” and that “nutritious foods and beverages that are unsweetened should be promoted instead.” The 2015 Dietary Guidelines for Americans (DGA) share that “questions remain about [artificial sweeteners’] effectiveness as a long-term weight management strategy,” yet they neither encourage or discourage their use. It will be interesting to see if this stance on artificial sweeteners will change with the release of the 2020 DGA. 

What does the research say?

Epidemiological research has shown an association between artificial sweetener intake and increased body weight and incidence of cardiometabolic disorders. For instance, a study from the Journal of the American Heart Association looked at data from 37,716 men (from 1986 to 2014) and 80,647 women (from 1980 to 2014) to see if there was an association between artificially sweetened beverages and risk of mortality. The study found that high intakes of artificially sweetened beverages was associated with total and cardiovascular disease-related mortality (death), particularly among women. 

A 2017 review and meta-analysis looked at 7 randomized controlled trials (RCTs) and 30 prospective cohort studies that analyzed the effect of artificial sweetener consumption on cardiometabolic health. While the RCTs found little effect of artificial sweeteners on weight management (neither positive nor negative), the cohort studies found that consumption of artificial sweeteners was associated with an increase in body mass index (BMI), weight, waist circumference, obesity, hypertension, metabolic syndrome, type 2 diabetes, and cardiovascular events. Of note, the length of the interventions in the RCTs ranged from only 6-24 months, whereas the duration of the large cohort studies ranged from 1 to 38 years. This suggests that while short-term studies may not show much of a negative health outcome or benefit, artificial sweeteners may play a role in chronic health issues that develop slowly over time.

A 2019 systematic review and meta-analysis from The BMJ (British Medical Journal) also looked at the association between artificial sweeteners and health outcomes in 56 individual studies. They concluded that there is “no compelling evidence to indicate important health benefits of non-sugar sweetener use on a range of health outcomes,” and that “potential harms from the consumption of non-sugar sweeteners could not be excluded.” It is clear that more long-term studies are needed to elucidate the effects of artificial sweeteners on both positive and negative health outcomes.

With these confusing links between artificial sweetener consumption and negative health outcomes, animal research has been trying to figure out what mechanisms may be behind this link. While not conclusive, what these studies have found is fascinating.

Artificial sweeteners may weaken the cephalic phase of digestion

The cephalic phase of digestion occurs before food enters the stomach. It’s considered a “reflex phase,” in which the smell, taste, sight, or thought of food triggers gastric secretions that prepare your stomach for digestion. Our brains and bodies have learned that a sweet taste predicts caloric and glucose intake. When we taste something sweet, our digestive system prepares itself for the optimal processing of the food that it believes it’s going to receive. 

A number of animal studies by Davidson & Swithers (Purdue University) have shown that the use of artificial sweeteners weakens the ability of sweet taste to accurately predict energy and evoke the learned autonomic and hormonal responses that prepare the digestive tract for food. These animal experiments show that when rats consume diets where sweet taste does not reliably predict calories (i.e. artificial sweeteners) they are heavier, have more body fat, have a reduced thermic response to eating a novel meal, and show impaired glucose tolerance compared with rats who consume a diet in which sweet taste accurately predicts calories (i.e. regular sugar). Our brains know that sweet tastes = calories, but those calories never come with artificial sweeteners. Ultimately, there is a growing body of evidence that suggests that artificial sweeteners interfere with learned responses that contribute to normal glucose control and energy homeostasis. 

Artificial sweeteners may interfere with our gut microbiota

Artificial sweeteners have demonstrated “bacteriostatic effects,” meaning that they stop bacteria from reproducing. While this may be beneficial in some instances (e.g. to stop dental cavities), we now know that we actually want good bacteria in our gut to proliferate. As we learn more about the important role of our gut microbiota, it’s of growing concern that these artificial sweeteners appear to induce negative changes in our intestinal environments. Both animal (I, II) and human studies have shown that alterations in gut microbiota brought on by artificial sweetener intake appears to lead to increased glucose intolerance. Glucose intolerance encompasses conditions that result in higher than normal blood sugar levels, increasing one’s risk for type 2 diabetes and cardiovascular disease.

Artificial sweeteners may interact with sweet-taste receptors in our GI system

Sweet taste receptors don’t only exist on our tongues, but also in our gut and pancreatic tissue. When these receptors are activated by a sweet taste, the cells of our gut are triggered to release gut hormones that stimulate the secretion of insulin from our pancreas as well as our body’s absorption of glucose. Animal studies have suggested that the interaction of artificial sweeteners with these sweet taste receptors may alter this response system and actually lead to increased glucose absorption, body adiposity, hyperinsulinemia, and insulin resistance. 

What about “natural” sweeteners like stevia & monk fruit extract?

You may be wondering if “natural” high-intensity sweeteners derived from plants (i.e. stevia or monk fruit extract) are safer or healthier to use than the more traditional artificial sweeteners. 

Both monk fruit extract and stevia are about 200 times sweeter than regular sugar. Like other artificial sweeteners, we need much less of them to achieve a sweet taste. Most of the current research that has been done on artificial sweeteners has looked at ones like Sucralose, Ace-K, and Aspartame, so it’s difficult to say if the aforementioned negative findings extend to these natural sweeteners. At present moment, these “natural” sweeteners are recognized as safe, but more research is clearly needed in this area to come to a better conclusion.

Summary

While more human research is needed to understand the metabolic effects of artificial sweeteners, it’s clear that these sugar substitutes are not metabolically inert substances and that they may in fact cause harm to our long-term health. Artificial sweeteners may be lower in calories than sugar, but “low calorie” does not necessarily mean that something is healthier. 

It’s clear that artificial sweeteners are not helping us reduce our intake of sweet foods and drinks. These artificial sweeteners are so intensely sweet, and when you regularly consume a lot of overly sweetened foods or beverages, your taste buds will continue to crave sweets and sugar. 

However, if you begin to reduce your intake of both sugar and artificial sweeteners, you will start to increase your sensitivity to sweet tastes (a good thing). What this means, is that naturally sweet foods (like fruit) start to taste a lot sweeter, while overly-sweetened processed foods start to taste too sweet (in a way that no longer tastes good). Your taste buds will adjust, you will prefer less sweet foods overall, and thus potentially reduce your sweet cravings and intake of these foods.

As a dietitian, I would recommend limiting your intake of artificial sweeteners. The evidence suggests they contribute to very few health benefits, and possibly even cause more harm. If you do occasionally use them, it appears that ones like stevia or monk fruit may be safer options. That said, I still would not recommend consuming those too frequently or in large amounts. 

What should you do?

If you regularly use artificial sweeteners, cut back gradually. Start be reducing your intake of diet sodas, or by replacing them with sparkling water flavoured with fresh fruit, herbs or a splash of fruit juice. Swap artificially sweetened yogurts with plain yogurts and add fresh fruit, cinnamon, or a small amount (~1 tsp) of honey or pure maple syrup. 

If you’re unsure about your artificial sweetener intake, check the ingredient list of your packaged foods and beverages – particularly the ones that I listed as common culprits. You may be surprised at how many “health foods” or “diet foods” contain these sweeteners.

While excess intake of sugar has also been shown to have detrimental health effects, I believe that a small amount of naturally-occurring sugars is still healthier than using artificial sweeteners. Reducing our intake of sweet foods overall, whether from overly-refined sweets or artificially sweetened foods, should be the ultimate goal. Once again, it seems that sticking to minimally-processed, whole foods seems to be the best ticket to good health from a dietary perspective. 

If you found this article helpful or have any questions about artificial sweeteners and reducing your intake of sweet foods, let me know in the comments below!

Photo by Joanna Kosinska on Unsplash

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