The Best Laid Plans In Mice and Men …

I never thought I’d find myself indebted to one R. Burns, said to be Scotland’s national poet, but as a title for today’s piece it’s hard to avoid a mild bit of adaptive plagiarism. And after all, if John Steinbeck could do it …

Artificial sweeteners are wonderful things …

The next thing to do is to pass up all pretence at suspense and give the upshot of a remarkable new bit of work first. The story is of artificial sweeteners (non-caloric artificial sweeteners: NAS for short – most commonly saccharin) – among the most widely used food additives worldwide. Introduced over a century ago, they’ve long been considered great as they pander to our sweet teeth yet are low on calories – what can possibly go wrong?

Saccharin  StructureSweet'N Low

Well, according to Jotham Suez and his pals in The Weizmann Institute, Israel, quite a lot, once you get round to looking in the right places. They found that artificial sweeteners, particularly saccharin, make normal folk glucose intolerant (i.e. cause metabolic conditions – including diabetes – in which blood glucose levels are raised, aka hyperglycemia). Moreover, they do so by changing the make up of the bacteria in our gut (our intestinal microbiota – we’ve already met these guys in it’s a small world). The effects of NAS are reversed by antibiotics which, as we described in it’s a small world, can have drastic, permanent effects on our insides.

It’s a real shocker because, put another way, it shows NAS can dirDiet Coke etcectly drive the very outcomes we’re trying to avoid – diabetes and obesity.

How do they do it?

Suez & Co first showed that saccharin increases blood glucose in mice (glucose intolerance). Treatment with commonly used antibiotics (e.g., ciprofloxacin) blocks this effect. Sequencing DNA extracted from faeces revealed big shifts in the proportions of different types bacteria (taxa) – with some increasing whilst others went down. The overall effect is that the intestinal bugs (microbiota) as a whole became much more efficient at energy harvesting from food (e.g., producing more short-chain fatty acids) – an effect known to be associated with obesity in both mice and humans.

Obese miceDirect or indirect?

To show whether saccharin does this by directly acting on gut bugs they grew samples of faeces in the lab with and without added saccharin and – you’ve guessed it – the bug balance changed: Firmicutes down, Bacteroidetes up (from 89 to 79% and 6 to 22%, respectively). Transferring the saccharin-treated microbiota to germ-free (normal) mice made them glucose intolerant.

Lolli the Saccharin by Trinity FateRe-think required

The upshot of all this is that NAS may be doing the very thing we’re trying to avoid. Suez et al. note that the cult of NAS use has coincided with the epidemics of diabetes and obesity – but their results suggest very strongly that, far from being coincidence, it is yet another example of optimism and our hunger for easy solutions diverting our attention from our ignorance of the underlying science.

Grim reaperSo the message is there isn’t a short-cut to dealing with our sugar craving – if we aren’t to go on making ourselves very ill on a big scale we just have to show more self-discipline.

Reference

Suez , J. et al. (2014). Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature 514, 181-186.

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2 comments on “The Best Laid Plans In Mice and Men …

  1. Pingback: Fast Food Fix Focuses on Fibre | Betrayed by Nature: The War on Cancer

  2. Pingback: Scandinavian Somersaults … or As You Were? | Betrayed by Nature: The War on Cancer

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