From ready-meals to chewing gum, sweeteners have been the food industry’s answer to an all-important question – how can food be made palatable to the world’s perpetual sweet tooth, without the negative health effects that come with sugar?

Sweeteners come in a variety of forms, with some of the most well-known including aspartame, saccharin and sucralose. Global demand for natural sweeteners, such as stevia, has increased as beverage and food companies come under pressure to dro calorie counts and sugar from their products.

However, as the world has continued to shift towards sweeteners, concerns have been raised about whether sweeteners are actually safe and provide substantial health benefits. A recent study into ‘non-sugar sweeteners’ conducted by scientists alongside non-profit research group Cochrane found that ‘no evidence was seen for health benefits from non-sugar sweeteners and potential harms could not be excluded.’

Could sweeteners be worse than they seem? And what further studies are needed into sweeteners to determine whether they are actually having any detrimental effect on health?

Are sweeteners safe?

Georgia Head, a nutritionist from UK food delivery service Fresh Fitness Food, says that as sweeteners have grown more prominent, there has been a growing need to explore the effects they have on certain health outcomes. These include Type 2 diabetes, cancer, obesity and dental health.

In some cases, this has led to controversy. The artificial sweetener aspartame has received flack ever since it was first approved by the FDA in the 1970s, with critics claiming that initial research had not suitably determined the sweetener safe to consume. In the years since, numerous scientific projects have proven otherwise; in 2013, the European Food Safety Authority (EFSA) released a report saying that aspartame posed ‘no toxicity concern for consumers at current levels of exposure.’

Nutritionists and GPs we spoke to told us that sweeteners have been generally found to be safe when consumed in non-excessive quantities. Several pointed to rigorous safety assessments that sweeteners are required to undergo before they can be used in food and drinks. In the EU, the EFSA allocates each sweetener with an e-number and an ‘acceptable daily intake’ (ADI) – the amount of a food additive that can be ingested daily over a lifetime without incurring health risks.

Indeed, sweeteners have been found to cause side effects in the past when consumed in excess. It’s been determined, for example, that Xylitol, a sweetener that is produced naturally in fruit, vegetables and mushrooms, can cause water retention leading to diarrhoea.

James Collier, nutritionist and Huel co-founder, says that artificial sweeteners have had some bad press, but the negativity seems to be based merely on how people feel about the word ‘artificial’.

“There have been numerous scientific studies which have indicated no adverse health effects from using the common sweeteners in levels below the regulated amounts,” he says.

Health effects of sweeteners: a mixed business

While sweeteners are generally seen as safe, nutritionists are still engaged in a wider debate over whether it actively provides health benefits.

One potential benefit is weight loss due to sweeteners lower calorific content compared to sugar. A meta-analysis paper published in The American Journal of Clinical Nutrition found that across 14 randomised controlled trials, low-calorie sweeteners were found to significantly reduce body weight, body fat and weighted circumference.

Another widely appreciated benefit is sweeteners’ reduced impact on dental health. Unlike sugars, sweeteners can’t be broken down by oral bacteria, so don’t lead to the same levels of tooth demineralisation. According to nutritionist and consultant Dr Emma Derbyshire, a number of studies show low-calorie sweeteners can reduce impact on blood sugar levels, and that it can help reduce and regulate daily glucose and insulin levels.

However, Dr Abby Hyams, a GP at private health services provider Medicspot, says that evidence of sweeteners being safe does not necessarily mean that they are healthy, and points out that there is some research to suggest that sweeteners may have a stimulating effect on appetite and play a role in weight gain and obesity. In 2016, researchers from the University of Sydney’s Charles Perkins Centre and the Garvan Institute of Medical Research found that a sucralose-only diet contributed to animals consuming more food.

“More evidence from long-term studies into the effect of sweeteners on appetite is required before conclusions can be drawn on whether sweeteners lead to increased energy intake and contribute to an increased risk of obesity,” says Hyams.

The aforementioned Cochrane report looked into the association between the intake of non-sugar sweeteners and health outcomes in generally healthy or overweight/obese adults and children. It found that there was no significant difference in those on non-sugar sweetener diets across any health outcomes. Nevertheless, the reporters did say the studies were limited, had few participants and often were carried out over a short duration.

“Studies should be carried out over longer periods of time and consist of greater sample sizes of participants,” agrees Head. “When it comes to health outcomes such as obesity, diabetes and cancer this is even more crucial.”

“The research to date shows there is potential for prospective developments on the topic. I think the review provides indications of methodological changes that should be considered by researchers for future projects in order to improve the quality of the findings.”

Cleaning up the medical mess

When it comes to the long-term benefits of sweeteners, more studies are required to clear up confusing, conflicting and poorly proven information. In particular, studies will need to continue to explore the stimulating effect that sweeteners play on appetite, as this has a correlation to weight management. It also remains clear that individual sweeteners should be treated differently, with the impact of certain sweeteners not tarring the rest with the same brush.

Derbyshire says that good evidence does exist to support the three strongest areas wher sweeteners are helping – weight management, dental health and blood sugars – but looking closely at other dimensions of health beyond these three areas will be important in the future.

She highlights that one major issue has been pinpointing the impact that one sweetener has over another. Such ‘confounders’ make it more difficult to have randomised controlled trials wher only one sweetener is the focus. “You have to rigorously develop a study that’s got a stringent inclusion/exclusion criteria,” she says.

Another suggestion from the Cochrane report is that more studies should consider the effects of a combination of sweeteners, so as to better reflect products on the market – a suggestion that Head says is ”extremely valid” and ”should be considered going forwards”.

Collier says that the next batch of studies should look at the benefits in relation to specific health outcomes, comparing people who consume products with artificial sweeteners to those that consumer comparative high-sugar versions. “As with anything, further studies are always useful to better our insight,” he adds.

Sweeteners hitting the mainstream

Levels of sugar are still very high amongst consumers. The UK’s Scientific Advisory Committee of Nutrition recommends that intakes of free sugars should be limited to no more than 5% of daily calories – equivalent to about 30 grams or a teaspoon of sugar daily. However, Derbyshire reveals that teenagers in the UK on average regularly consume over triple this target (17%), while adults consume over double (12%).

Nevertheless, she says that the food and drinks market will continue to see a shift away from sugars and towards sweeteners in the future. Taxes placed by countries on sugary beverages, for example, are causing soft drink manufacturers to move towards sweeteners. Food and drink manufacturers have been under pressure from Public Health England to reduce the sugar content of their products to help tackle the obesity crisis.

According to a report published in January by Research and Markets, the global non-sugar sweeteners market is expected to be valued at $13.85bn by 2026. The stevia market in particular is looking to carry on with significant growth, alongside new sweeteners continuing to emerge.

“We need to keep studying intakes of sweeteners to make sure they are maintained below the ADI,” says Derbyshire. “What some organisations recommend is that people have a mixture of sweeteners so you’re not having an intake of one sweetener.”

Otherwise, nutritionists have advised against avoiding sugar completely and replacing all sugar sources with sweeteners, but recommend eating smaller amounts of sugar as part of a healthy balanced diet.

“We need to educate parents and children not necessarily to not have a sweet tooth, but in cases wher it is already established – educating them that sweeteners have a place and they can swap over,” says Derbyshire.

The consensus on the long-term detrimental effects of sweeteners is still muddled. However, what’s clear is that further, more comprehensive studies will be required in the future as sweeteners increasingly appease our sweet tooth in years to come.