Dramatic headlines and scaremongering on social media… but what is WHO really saying in their report about artificial sweeteners like aspartame, and what should we be advising our patients and clients? Rebecca Gasche, RD, considers the WHO report and examines the evidence.

I recently had a patient ask if they should be consuming sweeteners.

“I thought I was doing the right thing to manage my diabetes, but after reading the headlines, am I wrong?” they asked, a hint of panic in their voice.

Reassurance was provided, that, yes, they may continue to use some sugar substitutes, and another happy customer was on their way.

Admittedly, I had not yet seen the then very recent headlines regarding this, and it, therefore, prompted me to look at this further and, in true NHD blog style, tell you all about my findings. I started with the news headlines that my patient (and many others) would have read:

‘NOT SO SWEET: Drinks like Diet Coke don’t help you lose weight – and could actually INCREASE risk of heart disease, WHO warns’ – The Sun¹

‘Replacing sugar with sweeteners does not affect weight control in long term, WHO says’ – The Guardian2

‘WHO: Artificial sweeteners linked to diabetes, death’ – Politico3

Some quite striking headlines, I think you’d agree.

WHAT DOES WHO SAY?

So, what does the 90-page document from the World Health Organisation (WHO)4 actually say? Don’t worry – I’ll summarise for you!

It looked at recent systematic reviews and meta-analyses of randomised controlled trials (RCTs), prospective observational studies and case-control studies.5

• The RCTs found that short-term outcomes suggested that higher sweetener consumption by adults led to lower body weight and body mass index (BMI), compared with those not consuming sweeteners or consuming lower amounts.
• Significant effects were not observed on intermediate markers of disease such as fasting glucose, fasting insulin, or blood lipids when assessed in short-term RCTs.
• The observational studies gave a longer-term outlook and found that increased BMI and risk of incident obesity were associated with consumption of sweeteners
• The observational studies also found that long-term sweetener use was associated with increased risk of type 2 diabetes, cardiovascular disease (CVD) and mortality.
• Evidence from studies conducted in children and pregnant women was more limited.

THE RECOMMENDATION:

WHO suggests that non-sugar sweeteners should not be used as a means of achieving weight control or reducing the risk of noncommunicable diseases (conditional recommendation).

POINTS TO NOTE

As always, the advice behind the headlines is not exactly straightforward:

• The recommendation does not apply to those with pre-existing diabetes.
• The recommendation is conditional (as opposed to strong) due to a lack of certainty about the overall balance of desirable and undesirable effects associated with long-term sweetener use for reducing disease risk.
• Evidence of minor weight loss or reduced BMI over several months or less was observed in the RCTs. WHO felt that without additional evidence of long-term impact, this does not represent a health benefit, and therefore chose to include and advise more heavily on the observational study findings.
• There is a possible risk that reverse causation may have contributed to one or more of the associations observed in the prospective observational studies. An example of reverse causation could be that the individuals in the studies were likely already heading towards obesity/diabetes, rather than there being a direct link between consuming sweeteners and developing disease. It was noted that many studies did recognise this risk and attempted to remove any data that contributed to reverse causation – for example, excluding patients with risk factors for disease.
• The report emphasised the importance of reducing overall free sugars and maintaining a healthy diet.
• The report noted that as free sugars are often found in highly processed foods and beverages with undesirable nutritional profiles, simply replacing free sugars with sweeteners means that the overall quality of the diet is largely unaffected.
• Therefore, replacing sweeteners in the diet with sources of naturally occurring sweetness, such as fruits, as well as minimally processed unsweetened foods and beverages, will help to improve dietary quality, and should be the preferred alternative to foods and beverages containing free sugars.

MY TAKE

I feel this report from WHO should be used to emphasise the importance of a healthy balanced diet and its associated outcomes, rather than scaremongering over sweeteners. Swapping out sweet processed foods for similarly sweet processed foods just without the sugar is of course going to have fewer health benefits than swapping sugar for whole foods, and this is the message that should be relayed to the public.

The fact the recommendation is conditional as opposed to strong should be better highlighted and explained, as the evidence, particularly found in the observational studies, does not warrant the media headlines.

Sweeteners can still play a part in replacing certain ingredients, particularly for those with established diabetes, but like anything should be used in moderation; for that cup of tea you really can’t take without a sweet fix.

For patients wishing to achieve and sustain weight loss long term, focusing on the whole balance of their diet rather than swapping like for like will achieve better outcomes. Some swaps to sweeteners may help with weight loss in the initial period but should not be the only focus.

Rebecca Gasche, RD
Clinical Lead Dietitian, Countess of Chester Hospital NHS Trust

Rebecca is a Clinical Lead Dietitian for
gastroenterology services and is a Primary Care
Network dietitian based in Chester

References

1. The Sun (2023). NOT SO SWEET. Drinks like Diet Coke don’t help you lose weight – and could actually INCREASE risk of heart disease, WHO warns. Retrieved from: https://www.thesun.co.uk/health/22364689/drinks-sweeteners-wont-lose-weight-risk-heart-disease/
2. The Guardian (2023). Replacing sugar with sweeteners does not affect weight control in long term, WHO says. Retrieved from: https://www.theguardian.com/society/2023/may/15/replacing-sugar-with-sweeteners-does-not-affect-weight-control-in-long-term-who-says
3. Politico (2023). WHO: Artificial sweeteners linked to diabetes, death. Retrieved from https://www.politico.eu/article/who-artificial-sweeteners-linked-to-diabetes-death/
4. Use of non-sugar sweeteners: WHO guideline (2023). Geneva: World Health Organisation. Licence: CC BY-NC-SA 3.0 IGO
5. Rios-Leyvraz M, Montez JM (2022). Health effects of the use of non-sugar sweeteners: a systematic review and meta-analysis. Geneva: World Health Organisation