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Are artificial sweeteners safe? The debate is heating up

In a world increasingly concerned about the negative health effects of sugar consumption, sweeteners have been hailed by many as a healthy substitute. However, a growing collection of research suggests that artificial sweeteners may not be healthier than sugar after all. 

Numerous studies have linked sweeteners to various health concerns – from certain types of cancers to anxiety and cardiovascular diseases. As a result,  many health professionals are expressing concern about their widespread use. 

Sugar, however, is not without its own set of risks, including a higher likelihood of developing type 2 diabetes, heart disease and strokes, not to mention obesity and tooth decay.

Potential cancer risk

This ongoing debate is now back in the spotlight following a groundbreaking report stating that the World Health Organization (WHO) is set to declare the artificial sweetener aspartame as a potential cancer risk to humans. The International Agency for Research on Cancer (IARC), a subsidiary body of the WHO, is expected to classify it as “possibly carcinogenic to humans” in the upcoming weeks.

Aspartame is a common ingredient in numerous soft drinks, including household names like Diet Coke and Dr. Pepper, as well as a range of juices, yogurt, and even some over-the-counter medicines. The declaration has prompted the question of whether artificial sweeteners pose a greater health risk than sugar.

In a quest for clarification, MailOnline sought the expertise of Professor Gunter Kuhnle, a professor of Nutrition and Food Science at the University of Reading. In his view, the prime advantage of sweeteners lies in their non-caloric nature, which allows for the provision of sweetness without sugar. This feature makes sweeteners particularly beneficial for people living with diabetes, as they do not affect blood sugar levels.

Lack of evidence

Addressing the possible downsides of sweetener use, Professor Kuhnle said that while they have been scrutinized by various regulatory agencies and found to be harmless at permitted levels, there is a lack of data regarding their safety at higher levels. Thus, the absence of evidence does not equate to the proof of their safety. 

However, Professor Kuhnle went on to note that there is no current reason to worry about their use, adding that debates surrounding their impact on the microbiome have yet to yield concrete evidence of an issue. “As far as I’m aware, there is no risk associated with it as long as it is used within the recommended amounts,” he added.

Nevertheless, Kuhnle noted that sweeteners can’t substitute the “functionality of sugar, ” which includes the preservation of certain foods like jam or cakes and the texture they provide in the mouth. 

Safe consumption levels

The debate around sweeteners extends to the quantity that can be safely consumed. In the US, the safe daily aspartame consumption is 50mg per kg of body weight, while in the UK it stands at 40mg per kg. This means, for a 70kg adult in the UK, the recommended limit is approximately 2800mg. 

To put that in perspective, an average can of Diet Coke contains 180mg of aspartame, implying an adult would need to drink about 15 cans a day to risk health consequences from the sweetener, according to the British Dietetic Association.

Yet, Professor Kuhnle pointed out that aspartame contains phenylalanine, which renders it unsuitable for individuals with phenylketonuria, a rare but potentially serious disorder preventing the body from breaking down certain proteins.

Potential health benefits 

According to the International Sweeteners Association, zero and low-calorie sweetened foods have been connected with improved diet quality, can help reduce calorie intake, and do not promote teeth decay. Short term trials on drinks sweetened with zero-calorie sweeteners have demonstrated that they can help reduce energy intake and weight gain when consumed in place of sugary drinks.

Global public health organizations have largely accepted these benefits of sweeteners. As the NHS explains, “Sweeteners that don’t increase blood glucose can be used as part of a healthy diet for diabetes,” primarily because they don’t affect blood glucose levels. 

Before any sweetener can be used in food and drink in the UK, it undergoes a rigorous safety assessment. All approved sweeteners are considered a safe and acceptable alternative to sugar, with laws determining their permissible amounts and product inclusion.

Aspartame and sucralose

Despite this, there is a diverging school of thought among some experts. Professor Erik Millstone, a science policy expert at the University of Sussex who has spent nearly four decades studying the impact of sweeteners on human health, voiced his concerns to MailOnline:

“Evidence showing that we could not be sure that aspartame is safe has been available since the mid-1980s.” He further highlighted that “reliable evidence that it can cause cancer in laboratory animals emerged in 2005 and has subsequently strengthened.”

Professor Millstone criticized large food and beverage corporations and their trade associations for attempting to discredit the IARC. According to him, they are attacking the IARC simply for providing a message they don’t want to hear. Professor Millstone hailed the IARC as more reliable than most other official bodies because it excludes individuals with commercial conflicts of interest, unlike many government bodies.

Further supporting these concerns, a 2017 study published in the Canadian Medical Association Journal examined data from over 400,000 individuals over ten years and found a significantly higher risk of weight gain, obesity, and related illnesses such as type 2 diabetes among those consuming one or more artificially sweetened beverages daily.

A 2018 study by George Washington University also indicated that sucralose, a common sweetener, increases levels of a protein called GLUT4, which promotes fat accumulation in cells. This alteration is associated with an increased risk of obesity, according to the scientists.

Children and sweeteners

In the UK, a soft drink industry levy launched in 2018 – aimed at addressing rising childhood obesity rates – imposed a tax of 24p per liter on any beverage containing 8g or more of added sugar per 100ml. Almost all major UK soft drink brands cut the sugar content of their products and replaced the missing sweetness with artificial alternatives in response to this tax.

However, there’s mounting concern over the effects of sweeteners in children’s diets. Dr. Vicky Sibson, a public health nutritionist and director of the charity First Steps Nutrition Trust, warned MailOnline about the risks of children developing a sweet palate from consuming sweeteners and craving sweetness in all its forms, whether from sugar or not.

Dr. Sibson explained that both sugary and artificially sweetened foods and drinks can cause dental decay – a major public health concern – and contribute to excess energy intake and weight gain. More crucially, she warned against the formation of a lifelong preference for sweet foods due to taste preferences forming in the early years. With that in mind, she underscored how much sweeter artificial sweeteners are than sugar.


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