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Artificial Sweeteners and the Risk of Heart Disease and Stroke

Health Letter, June 2023

By Nina Zeldes, MSc, Ph.D.

Image: Mirror-Images/Shutterstock.com

On average, adult Americans consume about 17 teaspoons of added sugar (meaning sugar that was added during the processing of food rather than sugar that naturally occurs in many foods, such as fruit, milk and grains) each day. It is well-known that consuming that much sugar is unhealthy and can lead to tooth decay, weight gain and obesity. Sugar also can increase the risk of other health issues such as type 2 diabetes and heart disease, the leading cause of death in the United States.

To address these serious health concerns, public health agencies such as the World Health Organization (WHO) recommend reducing sugar intake and making sure that added sugar makes up less than 10% of an individual’s daily calorie intake. For additional health benefits, the WHO even suggests that less than 5% of the daily calorie intake should come from added sugar — which is only about six teaspoons.

It is thus understandable that many people try to reduce the amount of sugar they consume by replacing it with artificial sweeteners. In fact, patients at risk of certain health issues such as type 2 diabetes are often even advised to replace sugary foods and drinks with artificially sweetened versions as a way to help lower their risk factors by losing weight or controlling blood sugar levels.

However, two recent studies add to the growing evidence that artificial sweeteners may not be a healthy alternative to sugar and can instead be associated with increased risks of heart disease and strokes.

What are artificial sweeteners, and are they better for you than sugar?

Sugar substitutes, also called artificial sweeteners or low/zero-calorie sweeteners, are commonly found in foods or beverages that are labeled “sugar-free” or “diet.” They are chemical-, fruit- or plant-derived substances that are used to replace regular sugar because they taste as sweet or sweeter (they can be 200 to 700 times sweeter) but contain only a few or no calories.

Some evidence suggests that when artificial sweeteners are consumed instead of sugar, they help decrease calorie intake and can lead to a small reduction in body weight in the short term. However, a systematic review and meta-analysis found that when artificial sweeteners are consumed over long periods of time, they can be associated with weight gain instead and also an increased risk of cardiovascular disease (such as heart disease and strokes), type 2 diabetes and obesity.

Although the possible long-term health effects of artificial sweeteners are not fully understood, two recent studies also support earlier evidence that artificial sweeteners may not be a healthy substitute for sugar.

The BMJ study

The first study was published in the BMJ in September 2022 and found that people who consume artificial sweeteners may have an increased risk of cardiovascular diseases, especially those who consumed large amounts of these substances.

The data for this analysis comes from a large French web-based study called NutriNet-Santé that included 103,388 adults without cardiovascular disease or preexisting diabetes. Unlike many other studies that use the number of diet soft drinks consumed in order to estimate how much artificial sweetener people use, all participants in this study completed multiple 24-hour dietary records including the names and brands of all products consumed. This allowed researchers to calculate the types and total amount of artificial sweeteners consumed from all sources, including soft drinks, food products and tabletop sweeteners. The data also contained detailed information about the participants’ health, lifestyle and sociodemographic backgrounds.

Based on this information, the researchers classified participants either as non-consumers, low consumers or high consumers of artificial sweeteners, which mainly came from soft drinks (53%) and tabletop sweeteners (30%). Those who were considered high consumers were consuming an average of 78 mg a day, which is roughly the equivalent of a 200-mL soft drink or two individual packets of tabletop sweetener.

The study found that the artificial sweeteners aspartame (Equal and others), acesulfame potassium (Sweet One and others), and sucralose (Splenda) especially may be associated with an increase in the risk of cardiovascular diseases and that those who were considered high consumers were at particular risk. For example, although artificial sweeteners overall were associated with only a 9% increase in risk of cerebrovascular events (such as stroke) compared with those not consuming artificial sweeteners, the consumption of aspartame was associated with a 17% increased risk. The consumption of acesulfame potassium and sucralose were associated with an increased risk of coronary heart disease (40% and 31%, respectively).

These results do not prove that artificial sweeteners cause cardiovascular disease. Nonetheless, they suggest that consumers trying to lower their risk of cardiovascular disease may not benefit from replacing sugar with artificial sweeteners. Moreover, the results of this study are difficult to generalize. For example, the study participants were overall relatively young (42 years on average) and predominantly women (80%) and consisted of self-selected volunteers who may be more health-conscious than the general population.

The Nature Medicine study

The second paper, published in February 2023 in the journal Nature Medicine, combined several separate studies and found that a specific sugar alcohol called erythritol, which is used as a zero-calorie sweetener but also occurs naturally in small amounts in fruits and vegetables, may be associated with a higher risk of major cardiovascular disease.

The researchers reached this conclusion after they analyzed blood samples of 1,157 adults and found that participants with high blood levels of erythritol had a higher incident risk of new major cardiovascular disease. After confirming this initial finding in two additional, independent groups of 2,149 patients in the United States and 833 patients in Europe, the researchers then investigated whether high blood levels of erythritol could increase the risk of blood clotting in a laboratory setting, which could in turn help explain why high levels of erythritol can contribute to a higher cardiovascular risk.

Based on the laboratory results, the researchers then analyzed the blood levels of eight healthy volunteers after drinking the equivalent amount of erythritol as found in a can of artificially sweetened soft drink and confirmed that the levels of the sugar alcohol dramatically increased after consumption and continued to stay at elevated levels for more than two days.

Again, it is important to note that the results of this series of tests do not prove that high blood levels of erythritol contribute to a higher risk of heart disease or stroke. For example, it is not clear whether erythritol can cause heart disease or whether people who consume artificial sweeteners are already at a higher risk of heart disease than those who do not use artificial sweeteners.

What does this mean for patients?

Although the new studies provide additional information, not enough is known about possible long-term harms of artificial sweeteners. Nonetheless, based on the overall evidence available, a guideline on the use of non-sugar sweeteners published in May 2023 the WHO “suggests that non-sugar sweeteners not be used” to achieve weight loss or as a means to lower one’s risk of type 2 diabetes and heart disease.

At the same time, it is important to remember that sugar that is added to foods has well-established negative effects on health. Because added sugar or artificial sweeteners are commonly found in unhealthy foods such as highly processed snacks or soft drinks, the WHO suggests reducing unhealthy food sources and replacing unhealthy snacks with foods that have naturally occurring sugars, such as fruit.

The best way to decrease one’s overall risk of cardiovascular disease is by adopting a healthy lifestyle that includes regular exercise and eating a well-balanced diet that is high in fruits and vegetables and low in products containing added sugars, sodium (salt) and saturated fat.