The price of ‘sugar free’: are sweeteners as harmless as we thought?

 

A few months ago, I found myself standing in a cinema line behind a man with two sons eager for Tango Ice Blasts – vibrant blue frozen slushy drinks – to accompany their tubs of sweet popcorn. The father hesitated, citing the excessive sugar they'd already consumed that day. One of the boys quickly chimed in, "But it's sugar-free." That settled it, and the boys happily entered the cinema with their drinks.

In a time when sugar is often considered public enemy No. 1, sugar-free alternatives, sweetened with low-calorie additives, promise guilt-free sweetness. Some opt for low-sugar options for weight management or diabetes control, while others simply enjoy the taste. However, even if you're not actively seeking them, artificial sweeteners are ubiquitous. A study in 2021 found sweeteners not only in expected products like sugarless gum but also in surprising items like salad dressings, bread, instant noodles, and various crisps, making them a routine part of our diet. Environmental scientists even search for traces of sweeteners, particularly acesulfame potassium, as a marker for human waste in bodies of water.

The prevalence of sweeteners is partly attributed to the success of sugar taxes, implemented in over 40 countries since 2010. In the UK, the soft drinks industry levy, introduced in 2016 and fully enforced in 2018, aimed to combat childhood obesity by charging manufacturers for drinks with 8g or more of added sugar per 100ml. This led major soft drink brands to reduce sugar content and replace it with artificial alternatives. By 2019, a significant percentage of drinks from Coca-Cola and Pepsi were sugar-free. Today, even "energy drinks" like Monster Absolutely Zero and Lucozade Zero Pink Lemonade are available in sugar-free versions, a paradox considering sugar typically provides the energy in such drinks.

The term "sweeteners" encompasses a range of chemicals, most significantly sweeter than sugar by weight, with few or no calories. One approved sweetener, advantame, is 20,000 times sweeter than sugar, while others like xylitol, common in chewing gum, offer comparable sweetness.

Given the well-known health risks associated with excessive sugar consumption, many public health experts have viewed sweeteners as a potential alternative. Regular sugar intake is linked to type 2 diabetes, heart disease, stroke, weight gain, and tooth decay. Despite personal cravings for sweet treats, the three primary health claims made for artificial sweeteners – weight management, diabetes control, and oral health – have been widely accepted by public health organizations.

However, recent questions have emerged regarding the purported benefits of sweeteners. The World Health Organization (WHO), in a draft guideline on "non-sugar sweeteners" in July, presented surprising findings. Contrary to industry claims, consistent evidence suggested that high sweetener consumption was associated with an increased risk of type 2 diabetes and heart disease. Weight gain was also more likely in individuals consuming large amounts of sweeteners over the long term.

Even the supposed dental benefits of sweeteners were called into question. While some studies hinted at reduced tooth decay risk with certain sweeteners, others suggested increased toothache risk in children consuming over 250ml of artificially sweetened drinks daily, even after accounting for tooth brushing habits and socioeconomic status.

The WHO's draft guidance marked a significant reversal, stating that non-sugar sweeteners should not be relied upon for weight control or reducing the risk of non-communicable diseases. This shift raised doubts about the entire premise of sweeteners as a "healthy" alternative, although the final guidelines were still pending.

Notably, the Calorie Control Council, representing major players like Coca-Cola, PepsiCo, and sweetener giant Cargill, expressed disappointment with the WHO draft, asserting that sweeteners had proven benefits in weight and blood glucose level management. However, these claims were now under scrutiny.

Tim Spector, a professor of genetic epidemiology, long harbored doubts about artificial sweeteners' health benefits. His personal experiment with the sweetener sucralose revealed unexpected blood sugar spikes, contradicting the notion that sweeteners, being metabolically "inert," don't affect the body beyond taste. A groundbreaking study led by Prof Eran Elinav supported Spector's suspicions, challenging the foundational claim of sweeteners' metabolic neutrality.

The study, involving 120 healthy adults assigned different sweeteners, revealed that two (aspartame and stevia) had no significant effect on blood sugar, while the other two (sucralose and saccharin) raised blood sugar in all participants. This contradicted decades of public health belief that artificial sweeteners had no impact on blood sugar. Moreover, all tested sweeteners altered the human microbiome, associated with high blood sugar, challenging the idea that sweeteners are metabolically inert.

While some experts applauded the study as overwhelming evidence that sweeteners are not metabolically inert, others exercised caution, emphasizing the complexity of the human microbiome. Despite differing opinions, the study suggested that sweeteners, even the seemingly benign stevia, affect gut microbes, challenging the long-standing belief in their inertness.

The historical backdrop of sweeteners includes instances where once-celebrated substances like saccharin and cyclamate faced bans due to safety concerns, only to be succeeded by new wonder-sweeteners like aspartame. Over the years, doubts about aspartame's safety emerged, with studies suggesting links to cancer. However, regulatory bodies like the European Food Safety Agency (EFSA) declared aspartame safe for the general population.

Skepticism lingers, with concerns about industry-sponsored research downplaying risks. The sweetener industry, valued at $2.1 billion globally as of November 2022, invests heavily in lobbying and PR efforts to reassure consumers. While the WHO found no significant association between sweeteners and cancer, the focus has shifted to broader health effects, such as long-term weight gain and increased type 2 diabetes risk.

Despite uncertainties, sweeteners remain popular, especially in diet drinks providing guilt-free pleasure amid daily challenges. This cultural embrace of "pleasure without consequences" has allowed the food industry to maintain profitability and palatability, encouraging excessive consumption. Efforts to shift toward less sweetened diets have seen the rise of unsweetened sparkling waters as alternatives. However, breaking the attachment to sweeteners remains a challenge, given their role as compensatory treats in an often demanding world.

As new evidence challenges the health claims of sweeteners, there's a growing call to prioritize a less sweet diet and opt for minimally processed, unsweetened foods and beverages. The WHO's draft guidelines underscore the importance of reevaluating our reliance on sweeteners, suggesting that simply replacing sugar with artificial alternatives may not improve overall diet quality. In a world where the illusion of consequence-free sweetness is one of the last comforting beliefs, confronting the potential health risks of sweeteners is a crucial step towards healthier habits.

The impact of sweeteners on children's diets is a concern, given the absence of explicit public health guidance against giving sweeteners to young children. Research hints at potential adverse effects on children, even before birth, with pregnant women consuming sweeteners linked to a higher risk of preterm birth. Early exposure to sweeteners may influence children's palates, leading to a preference for sweetness and potentially contributing to increased overall sugar consumption.

As public health experts stress the benefits of a less sweet diet, the WHO's draft guidelines challenge the prevailing narrative about sweeteners. Whether this prompts a significant