What do we know about low calorie sweeteners? A Conference review (part 1)

Author(s): Vicky Pyrogianni, MSc, Dietitian – Nutritionist, Scientific Director, ISA

Take-home scientific outcomes for health-care professionals from the ISA Conference in 2018

Key speakers’ remarks:

  • Low calorie sweeteners can be part of the toolbox along with other strategies in dealing with obesity and diabetes.
  • Overall diet quality is key for individuals’ health and well-being. Low calorie sweeteners are part of higher-quality dietary patterns in population studies.
  • We tend to forget the importance of the enjoyment that food brings, and sugar reduction can go against that. Low calorie sweeteners can help people meet nutrition recommendations to limit excess sugars’ intake.
  • Contrary to how sugars affect glucose control, blood glucose and insulin levels are not affected by low calorie sweeteners in people with or without diabetes.

What we eat is increasingly becoming a priority to most people. We want to know if what we eat is good for us and which food choices can help us improve our diet quality and ultimately health. But there is often a lot of biased information out there about our food and overall nutrition. So, when scientists are called to provide answers to common questions about food or ingredients of our food is helpful, and that was the key aim of the ISA Conference in London about low calorie sweeteners that was organised by the International Sweeteners Association (ISA) on 6th November 2018. Experts from around the world with many years of research on the fields of food science and nutrition, obesity and diabetes, sweetness and low calorie sweeteners were invited to provide the latest evidence on a number of topics related to the science of low calorie sweeteners, from their safety to their role in the diet.

Safety comes first

It is often difficult for experts like toxicologists to explain simply why they are so confident about the safety of low calorie sweeteners. In a very lively presentation, Dr Rebeca López-García, an experienced toxicologist from Mexico, talked us through the long, strict and conservative process of the safety assessment followed for food additives including low calorie sweeteners. She explained that for low calorie sweeteners there is an extensive database of studies, maybe larger than for any other food additive, that has examined the safety of low calorie sweeteners and how these ingredients are metabolised within the human body. The regulatory authorities have very high standards about how these studies should be conducted, and only when well-conducted studies are available and confirm that there is no safety concern, the authorities approve the ingredient for use in food products. This process may sometimes take years. The authorities responsible for food additives’ approval are, for example, the Food and Agriculture Organization (FAO)/ World Health Organization (WHO) Joint Expert Committee on Food Additives (JECFA), the US Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA). Authorities worldwide have confirmed that low calorie sweeteners are safe for use in foods and beverages.

What has also been highlighted by the toxicologists and food scientists speaking at the conference, was that in the approval process, the authorities establish an Acceptable Daily Intake (ADI) for each approved food additive. The same applies to low calorie sweeteners. Each sweetener has a specific ADI, which is the amount of an approved food additive that can be consumed every day in the diet, over a lifetime, without risk for health. As the ADI relates to lifetime use, it provides a safety margin large enough for scientists not to be concerned if an individual’s short-term intake exceeds the ADI, as long as the average intake over long periods of time does not exceed it. The authorities monitor the population intake so that consumption does not reach ADI levels. Dr Séverine Goscinny, food chemist and researcher at Sciensano (former Scientific Institute of Public Health) in Belgium, presented data about low calorie sweeteners’ intake which confirm that intakes of low calorie sweeteners are well below the ADIs for each individual sweetener and that recent global exposure data raise no cause for concern in relation to current sweetener use.

Why current evidence and experts support that low calorie sweeteners can help in body weight and glucose control

While it would only be reasonable to expect that when you replace sugar or sugary foods in your diet, which provide calories, with a sugar substitute like low calorie sweeteners that brings no, or virtually no, calories, weight loss can be facilitated, there have been claims supporting the opposite. Presenting outcomes of published clinical human studies and of upcoming network and pairwise meta-analyses of randomized controlled trials, which provide a better protection against bias, Dr John Sievenpiper, Associate Professor at the University of Toronto, Canada, concluded that low calorie sweeteners have the intended benefit when used to replace sugars, i.e. they can help in reducing energy intake and thus in weight loss when compared to caloric sweeteners. When compared to water, low calorie sweetened beverages specifically have the same effects in relation to their impact on body weight, glucose control and other cardiometabolic risk factors. Dr Sievenpiper as well as the chair of the session, Dr France Bellisle, a French researcher and psychologist with many years of research on this area clarified that one shouldn’t expect that low calorie sweeteners will cause weight loss by themselves, but they can be useful if they are used to replace sugars leading to a reduction of energy intake over sufficient long periods of time.

So, what about claims supporting that low calorie sweeteners can actually have an opposite effect on body weight or diabetes? These usually come from findings of some observational studies, which show that people with higher body weight or with diabetes consume more often low calorie sweeteners. However, this does not mean that low calorie sweeteners caused the weight gain or diabetes, but rather that people with weight management problems or diabetes turn to low calorie sweeteners to help them reduce their sugar and calorie intake, as studies show. Prof Adam Drewnowski, University of Washington in Seattle, USA, Dr John Sievenpiper, University of Toronto, Canada, and Dr Hugo Laviada-Molina from the Marist University of Mérida in Mexico, all explained that this association can be affected by many confounding factors and that these results can be just a case of reverse causality. In fact, during his keynote speech, Prof Adam Drewnowski provided data from population studies showing that low calorie sweeteners are used by consumers as part of an overall healthier dietary pattern, including for example more fruits and vegetables, as well as by individuals in their weight loss efforts.

In relation to low calorie sweeteners’ use for glucose control, especially by people with diabetes, Dr Hugo Laviada-Molina, Marist University of Mérida, Mexico and Dr Duane Mellor, a Registered Dietitian and Senior Lecturer at Coventry University in the UK concluded that replacing sugar with low calorie sweeteners can be a helpful strategy to aid glucose control in people with diabetes. Evidence from more than 30 human clinical trials confirm that low calorie sweeteners do not affect blood glucose levels and other indexes of glycaemia, while compared to sugar they have the benefit that they do not cause a spike in blood glucose levels after consumption. In addressing the role low calorie sweeteners play in the diet of people with diabetes, Dr Mellor, stressed out that it is important to enjoy our food, but reducing intake of sugars can go against it. So, low calorie sweeteners can be a useful way to reduce sugar in the diet while maintaining sweetness with fewer or no calories.

“We have to bring the evidence to the public”

In a final panel discussion chaired by Prof Peter Rogers from University of Bristol, UK, the panel of speakers highlighted that “we have to bring the evidence to the public and to help people make informed choices”. There is a lot of conflicting information on the web and on social media, but at the same time reduction of excess sugar intake is a public health priority and any useful tool such as low calorie sweeteners can play a helpful role towards this direction. So, providing accurate information about low calorie sweeteners, based on evidence rather than unproved theories, is key if we don’t want to put at risk people’s effort to manage excess energy and sugar intake.

Please also read the ISA Conference review – Part 2: ‘Emerging research about low calorie sweeteners‘.

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