Sweeteners vs sugar – what IS the truth? Even the experts are divided…

It’s a row that’s been brewing for decades.

Fuelled by studies showing sweeteners may be linked to some cancers, anxiety and cardiovascular diseases, some experts have raised the alarm over their use.

Yet the alternative, sugar, also poses a risk of type 2 diabetes, heart disease and strokes, alongside weight gain and tooth decay.

The debate was reignited yesterday after a bombshell report revealed that the artificial sweetener aspartame would be declared a potential cancer risk to humans in the coming weeks by the World Health Organization (WHO). 

The WHO’s subsidiary body, the International Agency for Research on Cancer (IARC) is expected to rule it ‘possibly carcinogenic to humans’.

The sugar alternative is used in a multitude of soft drinks including Diet Coke and Dr Pepper, as well some juices, yoghurts and even certain over the counter medicines.

But is artificial sweetener really worse than consuming sugar? MailOnline asked the experts.

‘The main advantage of sweeteners is that they are non-calorific and can therefore provide sweet taste without sugar’, Professor Gunter Kuhnle, a professor of nutrition and food science at the University of Reading, told MailOnline. 

‘They make it possible to provide a source for sweetness that does not affect blood sugar levels and are therefore important for people living with diabetes.

‘Whether there are disadvantages to sweetener use is a difficult question: their impact on health has been assessed very carefully by various regulatory agencies and these assessments have found no evidence of an adverse effect on health at the permitted levels.’

He added: ‘That does not necessarily mean that they are unsafe at higher levels – it might well be that there are simply no data that provide evidence of safety or harm.

‘In that respect there is therefore no concern about their use. 

‘Whether they have an effect on the microbiome and whether this effect is adverse or not has been discussed in the past, but there are currently not enough data to suggest a problem.’

Sweeteners are however unable to replace the ‘functionality of sugar’ including the preservation of some foods like jam or cakes, or the texture and feel in the mouth, he noted. 

‘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. 

Current recommendations for safe daily aspartame consumption are 50mg per kg of body weight in the US and 40mg per kg of body weight in the UK. 

This puts the British recommendation at about 2800mg for a 70kg adult.

Considering the average can of Diet Coke contains 180mg of real aspartame, the British Dietetic Association outlines how an adult would need to consume 15 cans a day before being at risk of any health consequences from the sweetener. 

However, Professor Kuhnle noted that ‘aspartame contains phenylalanine’, making it unsuitable for those with phenolketonuoria – a rare but potentially serious disorder where the body is unable to break down proteins. 

According to the International Sweeteners Association, zero and low calorie sweetened foods have been linked with improved diet quality, are useful in reducing calorie intake and are ‘tooth friendly ingredients’ for they do not promote teeth decay.

Evidence from some short term trials on drinks sweetened with zero calorie sweeteners show that when they are consumed instead of sugary drinks, they can support lowering of energy intake and weight gain. 

Public health organisations around the world have also largely accepted the benefits of sweeteners. 

‘Sweeteners that don’t increase blood glucose can be used as part of a healthy diet for diabetes,’ the NHS says. 

This is because they do not affect blood glucose levels.  

All sweeteners in the UK undergo a rigorous safety assessment before they can be used in food and drink, the NHS also advises. 

All approved sweeteners are considered a safe and acceptable alternative to using sugar. 

The law determines how much sweetener can be used and in which products.

However, other experts are more worried about the effects of aspartame. 

But Professor Erik Millstone, a science policy expert at the University of Sussex, who has been studying the effects of sweeteners on human health for nearly 40 years, told MailOnline: ‘Evidence showing that we could not be sure that aspartame is safe has been available since the mid-1980s.

‘Reliable evidence that it can cause cancer in laboratory animals emerged in 2005 and has subsequently strengthened.’

He added: ‘It is sad that several large food and beverage companies, and their trade associations, have been trying to discredit the IARC. 

‘They are attacking the messenger for providing a message that they don’t welcome. 

‘IARC is more reliable that almost all other official bodies because it excludes individuals with commercial conflicts of interest, while many governments do not.’

A 2017 study published in the Canadian Medical Association Journal examined ten years of data from more than 400,000 people and found that those who drank one or more artificially sweetened beverages a day had a significantly higher risk of weight gain and obesity, and related illnesses such as type 2 diabetes. 

And in 2018, a study by George Washington University reported that sucralose increases levels of a protein called GLUT4 that promotes the accumulation of fat in our cells. 

These changes are associated with an increased risk of obesity, the scientists said. 

After the soft drinks industry levy was launched in the UK in 2018 – as part of plans to tackle childhood obesity rates – the tax charged manufacturers 24p a litre for any drink with 8g or more of added sugar per 100ml.  

Almost all the major soft drinks brands in the UK cut the sugar content of their products and replaced the missing sweetness with an artificial alternative. 

However, Dr Vicky Sibson, a public health nutritionist and director of the charity First Steps Nutrition Trust warned of the dangers of sweeteners in children’s diets.

She told MailOnline the more children consume sweeteners, the more they develop a sweet palate and crave sweetness in all its forms, with or without sugar.

She said: ‘Sugary foods and drinks cause dental decay, which is a huge public health concern, and they drive excess energy intake and weight gain. 

‘But one key reason to avoid both artificially sweetened and sugary foods and drinks – noting that many products contain a cocktail – is that in the early years taste preferences are forming and we don’t want to encourage a sweet palate.’

She added: ‘This can mean a lifelong preference for sweet foods. With that in mind it’s important to note how much sweeter artificial sweeteners are than sugar.’ 

A recent report co-authored by Dr Sibson also set out a list of recommendations over artificial sweeteners and children’s diets.  

‘Public Health England should explicitly discourage the addition of sweeteners as a part of product reformulation under the Government’s Childhood Obesity Action Plan, and sweetener use should be monitored and reported,’ read one.

A second also noted: ‘Public health messages should not promote artificially sweetened foods and drinks as “healthy” options. 

‘Messages should actively encourage minimal consumption of all sweet products, particularly among young children, to avoid creating a sweet palate.’

Meanwhile, Dr Duane Mellor, a registered dietitian and senior lecturer at Aston University told MailOnline: ‘Non-sugar sweeteners can have a place in providing an option for a low sugar alternative in drinks and foods.’

But, ‘it perhaps needs to be more clear that they are not necessarily biologically inert,’ he added.

‘There is evidence that some sweeteners like aspartame and sucralose have an effect on our gut microbiome and this may in some people influence their ability to metabolise glucose – blood sugar.

‘Sweeteners are lower in calories than sugar, although without other changes to the diet is unlikely to help support people to lose weight,’ he said.