Reviewing current evidence in light of a new systematic review by Lohner et al.
Highlights:
- Low/no calorie sweeteners do not affect glucose control and can be safely consumed by people with diabetes.
- Consumption of foods containing low/no calorie sweeteners instead of sugar cause a lower blood glucose rise after eating compared to sugar-containing foods.
- Low/no calorie sweeteners allow people with diabetes to enjoy sweet tasting foods and beverages with less or no sugar.
For people with diabetes, the reason for choosing a food or beverage sweetened with low/no calorie sweeteners instead of sugar is simple: enjoy sweet taste in the diet while decreasing daily intake of sugar and calories with no impact on glucose control. The American Diabetes Association explains that dietary changes aiming to reduce the intake of carbohydrates, including sugars, and calories could beneficially affect glycaemic, weight, and cardiometabolic control.1
At the same time, people with diabetes want to be reassured that using low/no calorie sweeteners has no adverse effect on glycaemic control or overall health. The safety of approved low/no calorie sweeteners, including for people with diabetes, has been repeatedly confirmed by food safety bodies around the world. The opinions of these agencies, based on the collective evidence from published studies, also support the assertion that low/no calorie sweeteners do not affect glucose control.
However, according to some experts, the question about the benefits of low/no calorie sweeteners in diabetes still remains open. In a newly published systematic review that was supported by the World Health Organization (WHO), Lohner et al looked at the impact of sweeteners on long-term glycaemia.2
Analysis of outcomes of Lohner et al: Are low/no sweeteners beneficial or harmful for people with diabetes?
The results of the systematic review by Lohner and colleagues published in May 2020 showed no evidence of adverse events and no different impact oflow/no calorie sweeteners’ use on glycosylated haemoglobin (HbA1c) – an index of longer-term glycaemic control-, when compared to control, placebo or sugar. The lack of effect is what should be expected for low/no calorie sweeteners which, as food additives, should not be expected to have any pharmacological type of effects. The authors, however, state that there is inconclusive evidence of clear benefit or harm from sweeteners’ use. So, the questions that emerge are: Does the outcomes of this review mean that sweeteners have no benefit? Could there be any harm from their use?
Is there any evidence of benefits? Yes, there is a benefit when low/no calorie sweeteners are consumed instead of sugars, and this is confirmed by recent systematic reviews and also by the European Food Safety Authority (EFSA).3,4 A recent systematic review of 29 studies looking at the acute impact of low/no calorie sweeteners on glycaemia concluded that their consumption does not increase blood glucose levels post-prandially (i.e. after eating), and that this effect does not differ by type of sweetener.3 Considering that sugar, like all carbohydrates, causes a rise in blood glucose levels after consumption, the absence of glycaemic impact of low/no calorie sweeteners’ makes them a useful dietary aid for people with diabetes, as explained by the researchers. Evidence indicating the benefit of low/no calorie sweeteners on post-prandial glucose levels has not been examined in the review by Lohner at al, while this has been evaluated by EFSA in 2011 who concluded that: “Consumption of foods containing low calorie sweeteners instead of sugar induces a lower blood glucose rise after their consumption compared to sugar-containing foods”.4 It is important to explain that the potential benefit of use of low/no calorie sweeteners in diabetes is to facilitate glycemic control in the context of everyday living circumstances, i.e. allowing people with diabetes to enjoy sweet tasting foods and beverages without inducing glycaemic swings.
Is there any evidence of metabolic harm from the review by Lohner et al? No, the review found no evidence of metabolic harm, e.g. no impact on glycaemic control, nor any other adverse event from sweeteners’ use. Experts explain that statements suggesting that potential harms could not be excluded relate to lack of evidence, not to evidence of harm.5 Importantly, the safety of approved low/no calorie sweeteners, including the lack of adverse metabolic impact for people with diabetes, has been repeatedly confirmed by food safety bodies worldwide including the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA), the US Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA), upon a thorough evaluation of all available evidence.
Study limitations: The study has also some limitations. From a methodological perspective, the meta-analyses group data of trials with different sweeteners in order to evaluate their effects, even if individual sweeteners have different metabolic fates, while subgroup analysis by type of sweetener and by type of diabetes is lacking.
Take-home message
Low/no calorie sweeteners offer people with diabetes an important alternative to sugar as they do not affect overall glycaemic control.6 In fact, when used instead of sugars, low/no calorie sweeteners cause a lower rise in postprandial glucose (i.e. blood sugar levels after eating).4 Maintaining postprandial glucose levels within a healthy range is critical for overall glycaemic control, which is an important goal in diabetes care. Therefore, low/no calorie sweeteners are valued by and can be a significant aid to people with diabetes who need to manage their carbohydrate intake, an important aspect of diabetes management, while still enjoying sweet-tasting foods and drinks with fewer or no calories.
