Sweeteners are something we get asked about a lot on the Diabetes WA helpline. Our dietitian Dr CHARLOTTE ROWLEY looks at the evidence.

Aspartame, Stevia, sucralose… these words are becoming familiar as we see more products offering sugar-free or low-sugar alternatives. While they seem like a fantastic option for people looking to reduce sugar intake, a common question I get asked on our helpline is, “are they safe?” Let’s look at the evidence.

What are sweeteners?

Sweeteners are food additives that provide a sweet taste without high energy content. These may be natural, such as erythritol or xylitol, or artificial, such as aspartame or sucralose. They may contain the same number of calories as sucrose (4cal/g) but have a much sweeter taste, meaning recipes need a significantly smaller amount, therefore adding fewer calories. Other sweeteners are naturally low in energy.

Where do you find sweeteners?

Sweeteners are found in a variety of foods. Aspartame, for example, was found in more than 6,000 foods worldwide in 2022, and this has only increased since then. They are commonly used in diet products, such as diet soft drinks and cordials, diet desserts such as jelly, and are also available as standalone ingredients for baking.

Do they affect blood glucose levels?

Given that some of these sweeteners contain hardly any energy, and others are used sparingly, the simple answer is that they have no impact on blood glucose levels. However, the body is a strange and mysterious thing and sometimes works in ways we don’t understand. I’ve had some clients tell me their blood glucose levels went up after sugar-free drinks. Everybody is different, so it’s worth checking your own blood glucose levels after consuming these foods or drinks.

Aside from blood glucose, do they affect the body in other ways?

A few studies have been conducted to examine the impact of these foods on the body, and the results are worth a look.

Some studies indicate that some artificial sweeteners can alter the excretion of hormones in the gut. A common impact is an increase in a hormone called GLP-1 (the same pathway that Ozempic works on) which may indicate increased insulin production and improved glucose levels.

However, don’t rush out and stock up on diet products just yet. There is also some evidence that artificial sweeteners may affect ghrelin production, a hormone that regulates hunger, meaning consuming sweeteners may make people feel hungrier. The impact of sweeteners on blood glucose levels is also a messy space, with contradictory and confusing results, although the predominant theme appears to be that there is no impact on short- or long-term blood glucose results.

So, are sweeteners harmful?

A large-scale study examining artificial sweeteners in more than 100,000 people indicated an association between a high intake of artificial sweeteners and overall cancer risk. The “high intake” group was consuming an average of 79.43mg/day. To give you some perspective, a standard 355ml can of Diet Coke contains approximately 146mg of artificial sweetener, so if you were drinking one of these per day, you would be considered part of the “high intake” group.

If you had a Diet Coke once per fortnight instead, you would be close to the average of the “low intake” group, of 7.62mg/day. This group did not have an increased risk of cancer.

Another group, the Joint Expert Committee on Food Additives, has set the daily acceptable intake of aspartame at 40mg/kg of body weight. This means for a 60kg person, the maximum recommended intake is no more than 2400mg per day – that’s quite different from the first study!

However, not all sweeteners are the same. The cancer risk in the above study only examined artificial, not natural, sweeteners. Within the artificial group, the highest risk seems to be associated with aspartame or acesulfame-K.

One way these sweeteners might affect the body is through the gut microbiome, which is the collection of bacteria living in your bowels. Health gut bacteria promote good overall health, while disturbances in the bacteria leading to increased “bad” bacteria, can lead to poor health outcomes. However, this is an area that needs much more research.

So, what’s the takeaway?

This is an emerging area of nutrition science, and it is likely that we cannot lump all sweeteners together when it comes to their impact on our health. It is important to be aware that the World Health Organisation does classify aspartame, one of the artificial sweeteners, as being a possible carcinogen.  With that being said, it is better to keep your intake of artificial sweeteners on the lower end of the scale – include them occasionally but avoid daily intake They may not affect your blood glucose level, but they may have some longer term impacts we want to avoid.

Do you have a question about food, medication or anything diabetes-related?

Call our free helpline on 1300 001880 to speak with one of our diabetes educators today.