The bitter truth about sweeteners

In

,

By

Yassine Damil

Episode 13

TL;DR

When I order a burger and fries from a fast food restaurant, I’m quick to specify that the soda must be “diet”. The first thing I say to myself is that there’s probably something wrong with orders of magnitude, and that I’m just calming a guilty conscience. Then I think: aren’t we doing ourselves more harm than good? Today, we’re going to talk about low-calorie sweeteners. This topic reminds me of the concept of “free lunches” in the late 19th century in the United States. Indeed, saloons sometimes offered a free meal to anyone who took a drink (cheaper than said meal). But the idea was obviously to make the operation profitable with subsequent orders. In other words: nothing is “free” or “zero” consequences! Here’s an unsweetened version…

Sweeteners reduce sugar intake…

Low-calorie sweeteners are sweet-tasting substances that contain few or no calories, but have a higher sweetness intensity per gram. The 6 authorized as additives in both North America and Europe are, in order of discovery: saccharin, aspartame, acesulfame K, sucralose, neotame and advantame. We can even add certain steviol glycosides (from the stevia plant), “generally recognized as safe”.

Note that this definition excludes polyols, which are other sugar substitutes (typically derived from sugars), with reduced calorie content (by half), and which can be found in chewing gum as well as toothpaste.

I’ll leave aside their interest in preventing cavities. The other is common sense: by replacing sweet foods with those that have an equivalent (albeit distinctive) sweet taste, but are much lower in calories, it seems mechanically possible to reduce energy intake and thus more easily achieve calorie deficit. This was the conclusion reached by a 2022 meta-analysis1 of randomized controlled trials, identifying “small improvements in body weight and cardiometabolic risk factors without evidence of harm”.

These substitution strategies therefore appear to be effective, even if we don’t necessarily know their long-term repercussions. Are they a permanent solution for ‘safely’ satisfying one’s sweet tooth, or merely transitory steps towards a more genuine reduction?

… But seem to be associated with several negative effects

Now is the time to look back at the WHO’s statement2 last May on sweeteners, following on from their meta-analysis of 20223. It was rather controversial. Why was it? Because it drew some rather radical (albeit conditional) conclusions: “use of NSS does not confer any long-term benefit in reducing body fat in adults or children” and may have “potential undesirable effects (…), such as an increased risk of type 2 diabetes, cardiovascular diseases, and mortality in adults”.

In fact, these conclusions shouldn’t surprise me as a Frenchman, especially considering their methodology, given that they relied mainly on prospective cohort studies such as the NutriNet-Santé study (cited in their sources). Nearly a year ago, the latter published4 similar but quantified conclusions based on 103,388 participants: increased risk of cardiovascular diseases by 8% (hazard ratio = 1.08, CI [1.01, 1.18]) and cerebrovascular diseases by 18% (hazard ratio = 1.18, CI [1.06, 1.31]).

The limitations of this analysis, which provide an insight into those of the WHO, are that it is primarily an observational study. Several efforts have been made to reduce confounding factors, but nothing can prevent us from thinking that the correlation identified is in the end only a reverse causality: it is because people are already at risk (notably through an excessively rich diet and a lack of physical activity) that they try to reduce their energy intake by using sweeteners.

By way of comparison, another 2022 meta-analysis5 of prospective cohort studies used different statistical methods, notably to carry out substitution analyses, and this time came to similar conclusions to those of the very first synthesis cited here. Indeed, these interventional studies, in which a food is substituted by its sweetened equivalent, or sweeteners are added to the diet, appear to be more conclusive.

Bottome line: there is a correlation, but more is needed to define a clear cause-and-effect relationship. Nonetheless, we could also try to understand the phenomenon: why might sweeteners create certain disorders? Some say they may alter insulin secretion, or disrupt the gut microbiota…

The gut microbiota, the beginning of understanding

Back to the introduction and the association: zero calories means zero consequences. This is probably not true! These substances are not inert. For a start, not everyone reacts in the same way to the (over)excitement of a sweet taste with no calorie counterpart. And for some, it even increases the sensation of hunger.

But more interesting discoveries are to be found in the gut microbiota. An Israeli publication in 20226 already provided some support for this hypothesis. The study involved 120 people who did not normally consume sweeteners. The participants then added to their diet 6 sachets a day for 2 weeks. Their gut microbiota and glucose response were monitored. All sweeteners affected the composition of the gut microbiota in different ways. In addition, both saccharin and sucralose had negative effects on the subjects’ ability to regulate their blood glucose levels.

Was this simply a transient effect? More clinical trials are needed…

Remember, sweeteners are probably not inert! That’s how we should understand the WHO’s recommendations to eliminate them completely from our diet. Quite simply, they have no nutritional value. But they still seem relevant to me as a substitute for sugar for diabetics or people in transition to a healthier diet. What I’m really getting at is the need to wean off sweetness… so as to appreciate it more naturally, in fruits for example. And it’s strange, but we’ve been beating around the ‘sugar’ bush without actually talking about it, so that’s for another time… Also, I think it’s a good thing that the Nutri-Score algorithm for beverages will soon be modified, with a downgrading of the scores for drinks with sweeteners. This means that only water will be an A-rated beverage.

Here’s a personal hack: instead of turning to beverages that can desensitize your palate, make your own homemade low-calorie beverages. Naturally flavour your water (sparkling if you like) with lemon or cucumber slices, mint leaves or ginger. In short, you’ll go from ‘zero‘ beverages to ‘plus’ beverages (almost said ‘hero’ but that’s overused). I’m not there yet, but some people are going even further by making flavored ice cubes… Let’s give it a try!

Fun Fact

Saccharin, which takes its name from the Latin word for “sugar”, was accidentally discovered in 1879 by Constantin Fahlberg, a Russian chemist working on coal tar derivatives in Ira Remsen’s laboratory at Johns Hopkins University. Legend has it that, having forgotten to wash his hands, he tasted something sweet on his fingers. After a few taste tests in his laboratory, he discovered that it was benzoic sulfimide, 300 times sweeter than sugar.

Fun Fact in the Fun Fact, Monsanto started out in 1901 selling… saccharin.

By 1907, saccharin was already widely used in sodas and canned goods, but most Americans had no idea it was in their food. As part of a series of radical food and drug reforms, Harvey Wiley, head of the U.S. Department of Agriculture’s chemical division, recommended banning saccharin because of its potential toxicity. The person who objected was none other than President Theodore Roosevelt, who was on a weight-loss diet that included a dose of saccharin prescribed by his physician. The sweetener was finally banned in 1912, but the decision was reversed during World War I, when sugar rations necessitated the use of saccharin as a substitute. Once the war was over, people continued to enjoy this low-calorie sweetener.

This unusual episode of ‘I accidentally tasted something sweet’ was repeated with cyclamate (by picking up a cigarette), aspartame & acesulfame K (by licking fingers to pick up a paper) and sucralose (by confusing ‘test’ and ‘taste’), unbelievable!

Going further

References

  1. McGlynn ND, Khan TA, Wang L, et al. Association of Low- and No-Calorie Sweetened Beverages as a Replacement for Sugar-Sweetened Beverages With Body Weight and Cardiometabolic Risk: A Systematic Review and Meta-analysis. JAMA Netw Open. 2022;5(3):e222092. Published 2022 Mar 1. doi: 10.1001/jamanetworkopen.2022.2092. https://pubmed.ncbi.nlm.nih.gov/35285920/ ↩︎
  2. https://www.who.int/news/item/15-05-2023-who-advises-not-to-use-non-sugar-sweeteners-for-weight-control-in-newly-released-guideline ↩︎
  3. Rios-Leyvraz M, Montez J. World Health Organization: health effects of the use of non-sugar sweeteners: a systematic review and meta-analysis. World Health Organization; 2022. https://www.who.int/publications/i/item/9789240046429. ↩︎
  4. Debras C, Chazelas E, Sellem L, et al. Artificial sweeteners and risk of cardiovascular diseases: results from the prospective NutriNet-Santé cohort. BMJ. 2022;378:e071204. Published 2022 Sep 7. doi: 10.1136/bmj-2022-071204. https://pubmed.ncbi.nlm.nih.gov/36638072/ ↩︎
  5. Lee JJ, Khan TA, McGlynn N, et al. Relation of Change or Substitution of Low- and No-Calorie Sweetened Beverages With Cardiometabolic Outcomes: A Systematic Review and Meta-analysis of Prospective Cohort Studies. Diabetes Care. 2022;45(8):1917-1930. doi: 10.2337/dc21-2130. https://pubmed.ncbi.nlm.nih.gov/35901272/ ↩︎
  6. Suez J, Cohen Y, Valdés-Mas R, et al. Personalized microbiome-driven effects of non-nutritive sweeteners on human glucose tolerance. Cell. 2022;185(18):3307-3328.e19. doi: 10.1016/j.cell.2022.07.016. https://pubmed.ncbi.nlm.nih.gov/35987213/ ↩︎