How Safe Are Artificial Sweeteners?

by Dr. Jacob Wilson, Ph.D., CSCS*D

June 27, 2017
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What are Non-Calorie Sweeteners?

Non-Calorie sweeteners are molecules that can be similar structures to table sugar (sucrose) or include molecules such as amino acids. Non-Calorie sweeteners fall under a subclass of nutrients called Non-Nutritive Sweeteners. The broad scope of Non-Nutritive Sweeteners includes Sugar Alcohols as well as Non-Calorie Sweeteners or commonly called Artificial Sweeteners. The primary Non-Calorie Sweeteners that we are going to discuss in this article are Sucralose, Stevia, and Aspartame, but we will also touch on Saccharin and Acesulfame Potassium (Ace-K). What you will find out reading this article is if Non-Calorie Sweeteners are truly calorie free, if Non-Calorie Sweeteners have metabolic health benefits, and if Non-Calorie Sweeteners are safe.

Sucralose is one of the most common Non-Calorie Sweeteners because it has a taste that resembles regular sucrose (table sugar). This is because the molecular formula of sucralose replaces three hydroxyl groups with chlorine atoms (Tandel, 2011). For those that do not know, hydroxyl is a fancy way to say the element hydrogen and the element oxygen are bound together. Before you freak out about chlorine, continue to read and I will discuss how it is not toxic in any way.

Stevia is considered a Natural Non-Calorie Sweetener because it is produced from the Stevia rebaudiana plant. The leaves of Stevia contain a natural complex mixture of eight sweet Steviol glycosides (glycosides are sugars). These sugars are bound to steviol and of these eight steviol glycosides, stevioside and rebaudioside A (Reb A for short) are the major metabolites that are used in sweeteners (Gupta et al., 2013).

Are Non-Calorie Sweeteners Truly Calorie Free?

To answer this question, you have to consider one variable; was the Non-Calorie Sweetener purchased in its Raw or commercially produced form? If the Non-Calorie Sweetener was purchased in its Raw form, then yes, it is virtually calorie free. However, if the Non-Calorie Sweetener was purchased in its commercially produced form, then no, it is not calorie free. For clarification, when I say, “Commercially Produced,” I mean the yellow, blue, and pink packets that are sitting on the tables at restaurants.

Raw Non-Calorie Sweeteners are virtually calorie free because, in the small amounts that they are used, they yield negligible amounts of calories. For example, sucralose, which is almost identically to the molecular formula of table sugar (sucrose) is not metabolized by the body and does not yield any calories (Grotz & Munro, 2009). In addition, raw stevia also contains zero calories. However, aspartame, which is made of the amino acids aspartic acid and phenylalanine, yields four calories per gram. You will soon find out that aspartame is incredibly sweet and very little must be used, which is why it contains virtually no calories.

If you were to use the Non-Calorie Sweeteners in their commercially produced form, then they may contain calories. This is because they use sugars such as maltodextrin and dextrose to carry the Non-Calorie Sweetener. Non-Calorie Sweeteners are so sweet that you only have to use a very small amount, therefore, the carrying agent is added so that the sweetener can be conveniently added to a small packet.

Sweetness of Non-Calorie Sweeteners

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Non-Calorie Sweeteners are of interest to dieters because they replace sweetness that is normally omitted from a diet. In addition, they are overwhelmingly sweet when compared gram-to-gram with sucrose (table sugar). Sucralose is ~600 times the sweetness of sugar, stevia is ~150 the sweetness of sugar, Aspartame is ~200 times the sweetness of sugar, Saccharin is ~500 times the sweetness of sugar, and Ace-K is ~200 times the sweetness of sugar. As you can see, you do not have to use a lot of Non-Calorie Sweetener to achieve the same relative sweetness as sugar.
However, many tend to pair these sweeteners together based on the way that they affect the palate. Sucralose and aspartame do not have a strong upfront sweetness, however, the sweetness will sit on the tongue and may cause some bitterness. Saccharine and Ace-K have a strong upfront sweetness that will subside fast and leave some bitterness on the back of the tongue. This is why it is common to pair Non-Calorie Sweeteners, especially with sugar alcohols, as you will read in a future article.

The Metabolic Benefits of Non-Calorie Sweeteners

Sucralose may actually have metabolic benefits such as increasing a hormone called GLP-1. GLP-1 helps regulate blood sugar by causing insulin to be released and lowering blood sugar. This is especially pronounced in people that are at a healthy weight (Temizkan et al., 2015; Pepino et al., 2013). You can find more information on insulin sensitivity in my recent article called The Basics of Insulin Sensitivity. Aspartame has been shown to not have any effect on blood glucose and actually cause you to eat less food (Carlson & Shah, 1989; Anton et al., 2010).

Ingestion, of stevia in high doses, showed a reduction in body weight as experimented in rats (Curry and Roberts, 2008). In addition, consumption of stevia leaves and extract has been shown to reduce the craving for sweet and fatty foods (Jain et al., 2007). Furthermore, leaves of the stevia plant have antimicrobial, antifungal, antihypertensive, anti-hyperglycemic, and anti-inflammatory properties (Gupta et al., 2013). Research also supports that stevia lowers blood glucose by a number of mechanisms including enhancing the release of insulin and improving insulin sensitivity. Gregersen et al. (2004) showed that 1000mg of stevia was able to lower glucose and appeared to reduce the amount of insulin needed to lower blood glucose.

Are Non-Calorie Sweeteners Safe?

The short answer is yes, but allow me to present some of the research on the topic. Remember what I said about chlorine earlier in the article? This is where it becomes important. Sucralose is not recognized by the body as a carbohydrate due to being poorly absorbed during the digestion process. It passes through the body relatively unchanged with insignificant amounts being absorbed in the GI tract. Eventually, it is eliminated in the feces. Since it is not absorbed, a 160lb adult would have to drink 1500 12oz soft drinks sweetened with sucralose every day to consume an amount comparable to the upper tolerable limit.

Stevia is globally recognized as safe with upper limits set at ~18mg per pound, which means a 170lb adult would have to consume over 3g per day; remember that it is 150 times the sweetness of sugar. That would be the equivalent of eating about one pound of raw sugar per day. It is found that people who use stevia often consume 5-6mg per day. This is nowhere near the upper tolerable limit, which is reinforcement that it is safe (Geuns et al., 2003; Carakostas et al., 2008).

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Aspartame is among the most controversial Non-Calorie Sweeteners on the market today. It has been used since its approval in 1981 by the FDA (Tandel, 2011). The main reason for the controversy in regards to aspartame is its metabolism. Following ingestion, aspartame is broken down into its component parts; aspartic acid, phenylalanine, and methanol. Once absorbed these are used in the body just like they would be from normal food. The controversy lies in methanol. At high levels, methanol can be highly toxic because it can be converted to formaldehyde by the liver and could potentially cause blindness in high enough amounts (Butchko, 2002). So what does this mean? One liter of aspartame-sweetened soda yields about 55mg of methanol. Your body can safely handle about 2000mg of methanol. You would have to consume 36 liters of aspartame-sweetened soda in one sitting (impossible) to have any negative effects. Interestingly enough, fruit juice may contain more methanol than aspartame sweetened soda.

Conclusions

To answer the burning question, yes, sucralose, stevia, and aspartame are safe. In the case of sucralose and stevia, they may even be beneficial because of their metabolic benefits. Non-Calorie Sweeteners have been scrutinized for a very long time because we only see the bad things about them. The benefits are rarely expressed in the media because they may not be intriguing enough to catch the readers eye.

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