Do articificial sweetners alter you gut microbiome? Response to Tim Spector's Diary of a CEO appearance

Lots of claims were made on Diary of CEO with Tim Spector.

Whilst I agreed with most things, there were a few claims that weren't entirely accurate. One of those is that artificial sweetners damage your gut microbiome. Although plain water will always be your best choice of liquid zero/ low calorie artificially sweetened beverages can be a good alternative to their high sugar counterparts for a number of reasons.

They can satisfy your sweet tooth, help you to keep calories under control and take the edge off clean diet approach.

So the question is do artificial sweetners alter on Glycemia/Glucose Tolerance?

We have two opposing claims to investigate:

Do NNS (non-nutritive sweetners) actually impair glucose tolerance or cause abnormal glucose/insulin responses?

As NNS are replacing sugar, could they be of benefit for glucose control in the long-term?

Some studies have suggested that NNS consumption can alter gut microbiota and therefore induce Glucose intolerance. For example, Suez et al. (2014) wrote about this at length in their paper published in Nature.

One of their studies was a rodent study, where they dosed mice over 11 weeks with water containing saccharin, sucralose or aspartame. At week 11, the mice consuming NNS sweetened water developed marked glucose intolerance, relative to those drinking either plain water, or water sweetened with sugar.

Seemed to be down to changes in gut bacteria; the types of changes observed were “previously associated with type 2 diabetes in humans including over-representation of Bacteroides and under-representation of Clostridiales“

They then wanted to see the effect in humans: for 1 week they examined seven healthy people who do not normally consume NNSParticipants consumed the FDA’s maximum ADI of saccharin (5 mg/kg)4 out of the 7 developed significantly poorer glycaemic responses 5–7 days after saccharin consumption, compared to their individual glycaemic response on days 1–4

Note: Because of the lack of a control group, it is unclear whether some of the worsening response is simply a function of them being exposed to 7 consecutive oral glucose tolerance tests (i.e. daily consumption of 75 grams of glucose). Could this have lead to changes in glucose metabolism in the absence of saccharin in some people?

More recent evidence on this question has been published in Microbiome by Serrano et al., 2021:Double-blind RCT investigatingimpact of saccharin on gut microbiota and glucose tolerance.

Pure saccharin supp didn’t alter microbial diversity or composition of any taxonomic level in humans, no treatment effects for microbial activity – fecal metabolites or SCFAs but they did show some changes in mice.

The majority of interventions to date in this area have demonstrated no significant effect of NNS on glycaemic control (14 out of 18 trials). In contrast, a large number of animal studies have reported the effects on gut microbiota.

Pang et al., 2021 meta-analysis – no effect – The Impact of Artificial Sweeteners on Body Weight Control and Glucose Homeostasis

Alsunni et al., 2020 systematic review – no associations between AS on glucose regulation and its association with type2 DM and obesity.

Similarly, human trials have showed no impact of NNS on insulin response: Greyling et al., 2020 systematic review and meta-analysis found that there was no impact on insulin?

Moller, 1991 showed that aspartame did not affect insulin levels?

Wolf-Novak et al., 1990 found that aspartame had no effect on the insulin response in humans, whether alone or combined with carbohydrates?

Ma et al., 2009 found that sucralose caused no change in insulin levels.

If you enjoyed this detailed evidence-based explanation, like this can be found on my website and also on my Monday night live presentations that I do in my free facebook support group for high achieving busy professional desi dads who want to lose weight without cutting out rice and curry or spend hours exercising. Do check out what others are saying here: https://kaanfitness.co.uk/success-stories/