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Artificial Sweeteners: Are They Good or Bad?

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If artificial sweeteners come up in a conversation (everyone’s favorite party topic), there is almost always one person who will mention at least one potential health risk that is commonly associated with them. These health risks can range from cancer to kidney stones to increased risk of obesity. Just googling the term “artificial sweeteners” will show you numerous articles warning of a myriad of potential health concerns.

However, one thing I noticed about these articles and social media posts is that they only ever seemed to cite other articles/social media posts, if they cited anything at all. The actual amount of scientific research and studies behind these claims seemed to be lacking. Of the few studies I did see that were used to back up these claims, further review of them showed their conclusions were flimsy at best, and of those few, many had been proven to be incorrect. This did not stop them from being repeatedly used as justifications for claims.

It seemed like many of the websites and social media posts were falling for confirmation bias, where they had a preconceived notion and when they saw that others said the same thing they believed, they latched onto it without further research. This is unfortunate since many of the conclusions were based on poorly conducted research studies.

This led me to do more of my own research, starting with the scientific studies that I saw cited as proving the harmful effects of the artificial sweeteners, and then branching out into the numerous other studies on the topic. What I found surprised me and has led me to think differently on the effects of artificial sweeteners on the body. 

What follows is my summary of numerous studies on artificial sweeteners, with my sources linked at the bottom of the article. Feel free to do your own fact checking of what I found and share in the comments below. Before we jump into the research, let’s start with:

What is an Artificial Sweetener?

Artificial sweetener is a blanket term used to describe numerous low-calorie substances used to sweeten food in the same way sugar does. Some of the most common types are aspartame, sucralose, and saccharin. The official term for these sweeteners is non-nutritive sweeteners (NNS), since they provide no nutritional effect on the body. NNS is also a better term since there are no-calorie sweeteners, like Stevia, that are natural in origin.

One of the most common misconceptions about artificial sweeteners is that they are new and have not been heavily researched. I was surprised to learn that many of the most popular ones have been around for several decades. Aspartame, the primary sweetener in most diet sodas, along with many other items, has been around since 1965 and has been studied for almost as long. Saccharine, another sweetener for diet sodas and other treats, was first synthesized in 1878 and has been in use for over a century [1]. 

Some of these sweeteners are newer than others and their prevalence in what we consume varies. However, in order to be included in food and beverages, they must first achieve FDA approval.

Currently, the FDA approved NNS include saccharin, aspartame, stevia, monk fruit, acesulfame potassium (Ace-K), sucralose, neotame, and advantame. Of these stevia and monk fruit are derived from natural sources, why sucralose is derived from sugar.

To gain FDA approval for use in beverages and food, the non-nutritive sweeteners must first go through studies to prove their safety. These studies are then investigated by the FDA to prove their reliability. As a result of the many critics of artificial sweeteners, they have been scrutinized for several decades to prove their safety. Over these decades, the FDA has reviewed hundreds of studies and NNS have retained their approval due to an overwhelming amount of studies proving them to be safe. Even still, numerous critics continue to claim that there are health risks associated with artificial sweeteners. The main one being:

Do Artificial Sweeteners Cause Cancer?

The link between artificial sweeteners and cancer is mostly linked back to studies that occured in the 1970s. These studies, conducted on rats and mice, seemed to show a correlation between saccharin and cancer [1]. 

This led the FDA to require warning labels on products that contained it warning of cancer risks. However, after further reviews of the studies, it was found that they were not statistically significant, meaning the observed cancer was most likely just a chance occurrence and not because of the saccharine [1]. Furthermore, in one of those studies, the cause of the cancer in the rats due to the saccharin occurred because of a body function mechanism that only occurs in rats, not humans [1]. After disproving the results of this study, the FDA removed the warning label requirement for saccharine. However, even after being proved false, these studies are by far the most common ones that I have found cited by websites that claimed that artificial sweeteners carried a cancer risk. 

Moreover, since then, the vast majority of studies have shown no increased risk of cancer due to NNS [1]. 

Even though the majority of studies have proven them to not have a connection to cancer, I have found that many other websites have cited two other studies conducted in the early 2000’s that showed a carcinogenic effect from aspartame. These two studies were conducted by the same group of Italian researchers [2] [3]. The first study was reviewed by the European Food Safety Authority, along with the FDA, who concluded that the results were not statistically significant and that the cancer was probably just a result of chance [1]. The second study by the group has been highly controversial, with claims that it contains many flaws in its methodology. Furthermore, when the FDA tried to request the original results to verify the conclusion, the researchers refused to provide them [1]. As a result, these two studies have been discarded due to faulty methods and conclusions, but they are still cited over and over again by websites that want to show risks associated with NNS.

It should be noted that the majority of the studies on NNS have been on rats. This is not uncommon as it is much easier to study risks of substances on rats, since they have a much shorter life than humans, so the results can be seen faster. The studies that have been done on humans are limited to a short span of a person’s overall life. Plus, it is extremely hard to control for all the variables in a person’s life to determine what actually causes a certain outcome. 

The studies that have been done on humans have shown no statistically significant increased risk of cancer in the subjects, however, these studies have only looked at a few years of a person’s life [1]. Furthermore, none of these studies have followed subjects to the end of life. However, as previously stated, doing so and controlling for all variables in a person’s life are extremely difficult so we may never have a definitive conclusion one way or another. Regardless, the vast majority of research to date has shown no significant increase in the risk of cancer due to the consumption of non-nutritive sweeteners.

Do Artificial Sweeteners Cause Obesity?

Another common claim is that non-nutritive sweeteners may actually increase the chance someone becomes obese. Many of the studies that are used to back up this claim that those who drink diet soda, which contain NNS, are more likely to be obese than those that drink regular sodas [4]. For instance, one study I found mentioned on Harvard Health concluded that those who drink 21+ cans of diet soda a week are twice as likely to be overweight/obese as those who do not [5]. Many other websites cite similar conclusions. 

These claims are often grossly overstating the significance, if any, of diet soda and non-nutritive sweeteners on obesity. People interpret these studies to mean that diet soda consumption causes obesity, however, it would be more reasonable to conclude that there could be a correlation between diet soda consumption and obesity. 

There is a difference between correlation and causation. Causation means that one variable specifically causes a certain effect, while correlation means that there is a relationship between one variable and another. For instance, if you were to look at the relationship between sunglasses sold and ice cream sold, you would notice that as one increases, the other increases. This does not mean that an increase in sunglasses sold causes more people to buy ice cream, and vice versa. It is most likely just a correlation, since both items would see sales increases in the summer time due to warmer weather and more sunshine. 

Jumping back to the diet soda consumption correlations to obesity, what many of these conclusions miss is that those who are drinking excessive amounts of diet soda may also have bad diets and they are trying to use diet soda to make up for the bad food choices they are making. 

An example of this would be someone eating McDonald’s, or other unhealthy food choices, and trying to make up for it by ordering a diet coke to save on calories. Diet sodas will not cancel out the excessive calories consumed from unhealthy food choices, so many of these people will struggle with weight gain. This does not mean the diet soda caused the weight gain, rather than the other diet choices the person made. If anything, if these people consumed regular soda on top of their bad food choices, they would only be adding more calories to their diet.

To mention the study found on Harvard Health again, it is probably safe to assume that the majority of people who consume 21+ diet sodas a week do not have a good diet in the first place, especially compared to people who do not consume soda at all. Basically, Harvard Health, and many other websites, are making the common blunder of mistaking correlation for causation. Shame on you Harvard Health. I expected more responsible research analysis than this.

Now, other websites do try to provide some theory behind non-nutritive sweeteners potentially leading to obesity. Another common claim is that NNS increase the cravings to eat more [9]. The simplified reasoning behind this claim is that the body “knows” that it is not getting the calories it typically would from a sugar sweetened food or drink.

The scientific theory behind the body “knowing” could be based on the fact that the sweet taste of NNS induces an insulin response in the body, shown in a rat study [6]. This insulin response lowers blood sugar levels as the insulin guides the glucose (blood sugar) out of the bloodstream and into muscle and fat cells [6]. This is the body’s normal response when we consume and digest food. However, when we consume food and drinks with calories in them, the body digests them and adds glucose to the blood, raising blood sugar levels. 

In comparison, NNS are not broken down into glucose. So, when they are consumed, there would be an insulin response, without the corresponding increase of blood sugar. This would mean that the NNS triggering an insulin response would lower the blood sugar to a state of hypoglycemia (low blood sugar). The body would try to compensate for this low blood sugar level by causing a craving to consume food in order to balance out the blood sugar levels.

Where this claim falls apart is that NNS sweeteners in food products do contain other macronutrients, since they are more than just the sweetener. This means that there typically would be a blood sugar increase as well, potentially stopping the creation of the craving since the body does not enter hypoglycemia. This was not present in the rat studies that are often cited for these claims since they give the rats water sweetened with NNS, causing the rats to enter hypoglycemia, since they are not consuming anything else to balance out the blood sugar level.

To further this, numerous studies have shown that non-nutritive sweeteners are actually helpful in reducing cravings and have helped subjects to lose weight, such as this one [7]. Other studies have shown that NNS had similar satiating effects to foods sweetened with sugar [8]. This could likely be due to the fact that the NNS can help make food just as palatable as sugar, without adding potentially hundreds of extra calories.

To summarize non-nutritive sweeteners’ relationship to obesity, there are studies out there that claim they increase the risk of obesity. However, as we saw, many of these studies rely on flimsy conclusions without considering other variables that can easily cloud the results. And/or, the studies and websites make broad claims based on principles that would not typically apply to how NNS are consumed by the average person. There are exponentially more studies that have shown that non-nutritive sweeteners can actually be a helpful crutch for people trying to lose weight in tandem with diet/exercise changes.

Non-nutritive Sweeteners and Gut Health

So far, I have found very little definitive information from scientific studies on non-nutritive sweeteners and gut health. It is probably one of the least mentioned things in other articles/websites as well. However, I would feel remiss if I did not mention it since this is an area I believe has the most validity in a possible negative effect (not that any has been shown yet). The reason it probably does not show up on many websites is because of how limited our understanding of the gut bacteria microbiome is in its relation to our bodies overall health and function.

Our gut is home to 40+ trillion bacteria. These different types of bacteria aid us in numerous essential functions of our body. We would not be able to survive without them.

Early research has shown a healthy gut microbiome is related to our metabolism, mood, brain function, immune system function, and more. Early studies are even showing a link between depression and an out-of-balance gut microbiome health.

Therefore, anything that has the potential to throw the gut microbiome off balance could potentially be harmful. However, we do not entirely understand what a balanced gut microbiome is yet so it is hard to make conclusions based on data from the limited studies on NNS and the gut microbiome. 

So far, I have only seen studies that show a measured effect on the composition of the gut microbiome due the consumption of non-nutritive sweeteners. For instance, saccharin and sucralose have been shown to decrease the amount of certain types of gut bacteria while increasing the amount of others that researchers were measuring for in rat studies [10]. However, others, like stevia and aspartame have had studies where they have no measurable effect on the gut microbiome for the types of bacterias the researchers were measuring for [10]. It should be noted that aspartame does not actually reach the gut because it is broken down beforehand. 

Another thing to consider is that since NNS have no nutrient properties, they do not provide any nutrients to the gut bacteria. This could in theory cause the gut bacteria to starve since they cannot get any nutrients. However, we do not survive strictly off just NNS alone. We would starve. 

Now, dropping to my own speculation on the subject based on what I have read and how I interpret it. It is entirely possible that NNS could have an effect on our gut microbiome that would have negative consequences. Whether that be a direct reaction of the bacteria trying to consume the NNS, or as a result of them not gaining nutrients from them. Either way, it seems very possible that they do have some sort of effect, even ones like aspartame or stevia that did not have a measured effect in the terms of the earlier cited studies. However, at this point, we just do not know what that effect is. It could be positive for all we know. 

It should be noted that effects on the gut microbiome are limited to non-nutritive sweeteners. Everything we consume most likely has some sort of effect. That is why probiotics are a thing. Probiotics are just something that we assume (either from studies or speculation) have a positive effect on our gut microbiome. We even consume things that have been shown to have a negative effect on the gut microbiome on almost a daily basis, such as sugar. 

This section specifically is not meant to take a stance one way or another on NNS and their effect on the gut microbiome because honestly, there just is not enough information out there to make an informed conclusion. I would, however, feel irresponsible if I did not at least make a mention of the gut microbiome and how non-nutritive sweeteners could play a role in it. This is one area of general nutrition we could learn a lot from in the future as more studies are conducted and published.

Other Effects

This section is going to take a more rapid fire approach to some other common misconceptions about non-nutritive sweeteners, as well as bring up some facts that you might not know.

Can artificial sweeteners weaken our sweet taste receptors?

Technically, yes. However, this is not limited to just non-nutritive sweeteners. The same effect can happen if you consume lots of foods sweetened with sugar. Basically, the food and drink products that are much sweeter than anything we would find in nature would blunt how sensitive our taste buds are to sweetness. Therefore, if we consume overly sweet foods, we would not be able to perceive the same sweetness that we normally would from things with a more subtle sweetness, like fruits. Will this have any sort of negative effect? Eh. I think it depends on the person and how much sweeteners you consume, whether that be sugar or NNS. Taking a break from artificially sweetened items for a week or two can be a personal experiment to see if you notice any sort of change to our sweet taste receptors. Either way, as always, moderation is key. Too much of a good thing turns into a bad thing.

Allergic Reactions

It should be noted that some people do have allergic reactions to some of the types of NNS [1]. The severity of these reactions would vary from person to person. It appears that they are pretty rare but if you do think you are having an allergic reaction, it would be best to speak to your doctor.

Less Cavities

Sugar is a fuel source for the bacteria that cause cavities. However, since there is no nutritional value in NNS, the bacteria have nothing to feed on. This could actually cause them to starve to death since they may try to consume the NNS and derive no energy from them. With less sugar in your diet, you can have less of these bad bacteria in your mouth, possibly saving you some dental bills.

Less Blood Sugar Spikes

Since NNS are not broken down into blood sugar, they can be used to prevent blood sugar spikes. This can be helpful for keeping energy more constant throughout the day, since you could have less blood sugar crashes. I have also read instances of them being helpful for individuals with diabetes, since they would have a more steady blood sugar level throughout the day [1]. Please note, this is not medical advice. Please talk to your doctor before trying anything.

Aspartame and Formic Acid

When aspartame exceeds 86°F, the wood alcohol in aspartame converts to formic acid [1]. This results in metabolic acidosis, which can lead to a toxic effect. Again, this most likely comes down to moderation, as this effect would be minimal as long as consumption is kept in check. This is a reason the FDA sets an ADI level (average daily intake) for foods and vitamins, which is a consumption level deemed safe for the majority of people (>50% of the population). To exceed the ADI for aspartame, a 150 pound person would need to consume 18 cans of diet soda a day.

Sugar Alcohols: Laxative Effect

One type of low calorie sweetener is sugar alcohols. These types of sweeteners have been shown to have a laxative effect. I personally noticed this, along with some other folk on my rugby team, when we started eating Halo Top ice creams for a short stint. Dangerous? Not really. Shitty time? Yeah a bit.

Conclusion

After years of hearing other people and websites talk about the health risks of artificial sweeteners, I was hesitant to include them in my diet. I was in the camp that sugar was better for me since it was natural in origin. However, after reading over and over again about how many negative effects sugar has on our health – such as cancer, obesity, diabetes, tooth decay, to name a few – I started to reconsider. For instance, the amount of sugar we consume today and how refined it has become from its natural form, it is hard to consider it natural. At no point in human history, until recently, was it normal to be able to consume 30+ grams of pure sugar in a single meal. Plus, sugar consumption increases have correlated very closely with increases in obesity. 

As a result, I have started using NNS more often in my diet. They have been a great tool in cooking many low calorie/high protein treats and foods, like the ones I review on Munchies Monday. NNS have been a great asset to have in the arsenal to make healthy food choices taste just a bit better so they are comparable to the high calorie, sugar heavy foods. This has helped me minimize cravings while maintaining and/or losing weight.

In my opinion, non-nutritive sweeteners can be a great tool for those trying to make small changes in their diet from sugar heavy foods to healthier alternatives. Since they contain very few calories (2 calories in 0.5g, which is a lot since they are light), they can help you eliminate 100’s of calories from your diet by drastically lowering your sugar consumption and still keeping the sweetness. I do not think that they are completely harmless, but I do think that they are better than sugar. That being said, I am just some guy on the internet, so please do your own research on the topic. The numerous studies I have cited throughout this article would be a great way to start.

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[7] Wiebe N, Padwal R, Field C, Marks S, Jacobs R, Tonelli M. A systematic review on the effect of sweeteners on glycemic response and clinically relevant outcomes. BMC Med. 2011 Nov 17;9:123. doi: 10.1186/1741-7015-9-123. PMID: 22093544; PMCID: PMC3286380.

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[8] Anton, S. D., Martin, C. K., Han, H., Coulon, S., Cefalu, W. T., Geiselman, P., & Williamson, D. A. (2010). Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels. Appetite, 55(1), 37–43. https://doi.org/10.1016/j.appet.2010.03.009

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[10] Ruiz-Ojeda, F. J., Plaza-Díaz, J., Sáez-Lara, M. J., & Gil, A. (2019). Effects of Sweeteners on the Gut Microbiota: A Review of Experimental Studies and Clinical Trials. Advances in nutrition (Bethesda, Md.), 10(suppl_1), S31–S48. https://doi.org/10.1093/advances/nmy037

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