Sugar substitutes for people with diabetes – can you have your cake and eat it too?

Healthy foods from the food groups image

By Adele Mackie - Accredited Practising Dietitian, Diabetes Victoria


The idea that people with diabetes need to completely avoid added sugar and use alternatives is one of the most persistent myths in the dietary management of diabetes. ‘Do I need to cut out sugar?’ and ‘are sugar substitutes safe to use?’ are two of the most common questions people with diabetes ask dietitians.  

Sugar substitutes have existed for many years and have traditionally taken the form of what we call ‘non-nutritive sweeteners (NNS)’ or ‘artificial sweeteners’ and sugar alcohols (polyols). NNS, such as aspartame, saccharin, sucralose and stevia, do not contain carbohydrate and have very few calories. They are often referred to as high-intensity sweeteners, as they are many times sweeter than sucrose (i.e. table sugar). (1) Polyols, such as Xylitol, Sorbitol and Erythritol still contain carbohydrate, however, they are poorly absorbed in the intestines and therefore provide fewer kilojoules than other sugars and have little effect on blood glucose levels. (2)

NNS are not a necessity to help manage diabetes. The latest American Diabetes Association nutrition therapy guidelines recommend “monitoring carbohydrates by carbohydrate counting, or experienced based estimation to achieve glycemic control. Choosing NNS instead of nutritive sweeteners is one method to assist with moderating carbohydrate intake” (3). People with diabetes can still use regular sugar to sweeten foods without having an adverse effect on blood glucose levels (BGLs), as long as it is used in small amounts and generally eaten as part of a meal. An example of this might be one teaspoon of sugar sprinkled over a hot bowl of porridge or a thin spread of regular jam on some grainy toast. This is the same advice that would be given to someone who does not have diabetes, in accordance with the current Australian Dietary Guidelines to limit foods and drinks that contain added sugars (4), and the latest World Health Organization (WHO) guidelines to limit added sugar to 5-10% of total energy intake.(5) 

There has always been a lot of debate about the safety of NNS, however, Food Standards Australia New Zealand (FSANZ) has approved all NNS available in Australia as safe for consumption. All NNS have a recommended Acceptable Daily Intake (ADI) which have safety margins built into them. For example, Aspartame (NutraSweet, Equal, Sugarless) has an ADI of up to 40mg/kg of body weight per day. This is equivalent to a 60kg person having 12 cans of artificially sweetened soft drink containing aspartame a day. Despite this, there is some emerging evidence to suggest that regular consumption of NNS may alter metabolic pathways, causing people to overeat to make up for the lack of kilojoules that usually come with sweetened foods, and weakening the hormonal responses that occur when an actual glucose load is consumed (6). More research is certainly needed to confirm this. 

In recent times, there have been a number of alternative sweeteners gaining popularity because they are thought to be ‘healthier’ than sucrose. With the exception of stevia, many of these new popular sweeteners are in fact, ‘nutritive’ sweeteners, meaning that they still contain carbohydrate, have the potential to raise BGLs, contribute energy to the diet and contribute to the development of dental caries. Even stevia is often blended with polyols or maltodextrins in powdered form, so may still provide some energy. They may claim to have a lower glycaemic index (GI) or contain more micronutrients, such as small amounts of calcium, potassium and magnesium.

However, many of these claims may be misleading, depending on the context. For example, as these alternative sweeteners can be used in relatively small amounts in hot drinks for example, the GI is arguably irrelevant. One teaspoon of any of these sugars is going to have a negligible impact on BGLs, so it doesn’t matter if it is high GI or low GI. If they are used in larger quantities as part of a recipe, however, the GI of the alternative sweetener may have a clinically significant effect on BGLs. 

The micronutrient content of these alternative sugars is also insignificant given that these are not usually a major dietary component. These claims are potentially misleading for consumers, who would be much better off reaching their vitamin and mineral requirements by eating the recommended number of serves from each of the five core food groups.

The choice of sweeteners on the supermarket shelves has expanded rapidly over the past few decades. All types of sweeteners (both nutritive and NNS) do little to enhance the nutritional value of foods, however, they can be used in small amounts to enhance the flavour of nutritious meals. The newer nutritive sweeteners on the market contain just as much carbohydrate as sucrose and in most circumstances, will have a similar impact on blood glucose levels. Nutrition professionals will generally recommend that people with diabetes limit the consumption of all nutritive sweeteners to less than 5-10% of energy intake and account for their use by carbohydrate counting. NNS can be used out of personal preference, but are not necessary to help manage diabetes. 

Table 1: Properties of nutritive and non-nutritive sweeteners. (2)

  • NNS, such as Equal or Stevia are not necessary to manage diabetes.

  • Sugar is not a health food and never will be. All types of added sugar should be limited to small amounts in accordance with the Australian Dietary Guidelines and the WHO guidelines. Additional nutrients present in some sugar alternatives are negligible in these small portions.

  • Most of the new alternative sugars contain just as many kilojoules and as much carbohydrate as regular sugar, therefore, the end result on BGLs is going to be similar.

  • Sugar alternatives tend to be much more expensive.

  • People can choose any form of sweetener that suits their recipe or meal the best. Just use them in small amounts to reduce the impact on BGLs and weight.

References

1. Fitch C, Keim KS, Academy of Nutrition and Dietetics. Position of the Academy of Nutrition and Dietetics: use of nutritive and non-nutritive sweeteners. J Acad Nutr Diet. 2012 May; 112(5):739-58.
2. Sandall P, Barclay A, Shwide-Slavin C. The ultimate guide to sugars and sweeteners: discover the taste, use, nutrition, science and lore of everything from agave nectar to xylitol. The Experiment; 2014 Dec.
3. Evert AB, Boucher JL, Cypress M, Dunbar SA, Franz MJ, American Diabetes Association, et al. Nutrition therapy recommendations for the management of adults with diabetes. Diabetes Care. 2013 Nov; 36(11):3821-42.
4. National Health & Medical Research Council (NHMRC). Australian Dietary Guidelines. Canberra: NHMRC; 2013.
5. World Health Organization (WHO). Sugars intake for adults and children. Geneva: WHO Press; 2015.
6. Swithers, SE. ‘Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements’. Trends in Endocrinology and Metabolism. 2013 September; 24(9):431-41.