Jan 27 2014

Sucralose Fearmongering

It is easier to scare than reassure. We seem to be programmed for fear – fear of the unknown, of the “unnatural,” of things over which we have little control. Humans are what psychologists call “risk averse.” While the precautionary principle is fine, as far as it goes, risk averse decision-making can often lead to irrational decisions that are not in our best interest.

Food is a particular fear trigger because we also have the evolved emotion of disgust – a negative emotional reaction to the idea of exposure to or ingestion of contaminated or foul substances. The protective effects of this emotion are obvious, but it is a crude indicator rather than a precise toxicological detector.

Artificial sweeteners are a popular topic for stoking fears about what we eat. Aspartame has been a common target over the years, based on misinformation and distortion of the evidence.  More recently sucralose has been the target. Perhaps it’s because they have the word “artificial” right in the name. The industry uses the term “non-nutritive sweeteners” but this has not caught on in popular use.

Because of the internet and social media, misinformation not only spreads quickly, it keeps coming back around again and again. All it takes is for someone to post a link to a 5 year-old article on their Facebook page, and it can be spread around as if it is news. Often I am sent such items as if they are new, because those sending the article around did not check the dates on the original source documents.

Take, for example, this bit of fearmongering about Splenda (sucralose). These claims about sucralose, that it reduces GI good bacteria by 50% and increases the pH level in the GI systems, are based upon a study from 2008, but has been spread by Mercola (a notorious health crank). Many of the mentions of this information link back to Mercola, rather than the original study.

This is an excellent example of cherry picking – you can find studies that purport to show scary things about just about anything. There are tens of thousands of studies published every year, most of which are preliminary, with varying results. It just takes a bit of searching to find studies to support whatever view you wish.

Mercola writes:

The approval was given after the FDA supposedly reviewed more than 110 animal and human safety studies, but as you’ll soon find out, out of these 110 studies, only two were human studies, and the longest one was conducted for four days!

But then he bases his own conclusions on a single study in rats. The study did conclude that intestinal flora was decreased while pH was increased. It also found increases in the activity of enzymes that metabolize certain drugs in the GI tract. If true this could reduce the bioavailability of certain drugs. (Mercola apparently missed the irony of warning about reduced bioavailability for the drugs that he so often rails against.)

Since sucralose is approved by the FDA, the new study was cause for some concern. An expert panel reviewed the study in detail, as well as previous relevant research. They found:

“The Expert Panel found that the study was deficient in several critical areas and that its results cannot be interpreted as evidence that either Splenda, or sucralose, produced adverse effects in male rats, including effects on gastrointestinal microflora, body weight, CYP450 and P-gp activity, and nutrient and drug absorption. The study conclusions are not consistent with published literature and not supported by the data presented.”

This study was published after Mercola’s article, but this is exactly why you don’t jump on one preliminary study. I also notice there is no update on Mercola’s article citing the review.

The most recent systematic review of the health effects of sucralose is from 2009. They found that sucralose is completely safe.

Another strategy of fearmongers is to ignore the whole issue of dose. Mercola reports that a study of sucralose showed: “Decreased red blood cells — sign of anemia — at levels above 1,500 mg/kg/day.” However, the “FDA Acceptable Daily Intake for sucralose is 5 mg/kg.” This is right from the abstract of the study he is presenting. So – researchers found possible toxicity at doses 300 times greater than acceptable limits. I bet pretty much everything we eat has negative effects at 300 times the recommended use.

What about the issue of non-nutritive sweeteners contributing to weight gain? You will also find this claim common among sweetener critics. The data here is still a bit muddied. 

Long term observational studies do find a correlation between non-nutritive sweetener use and obesity and diabetes. However, it is likely that such studies are confounded by reverse causality – in other words, people use artificial sweeteners because they are already overweight.

Short term experimental studies, however, find that use of artificial sweetener is associated with reduced calorie intake and better glycemic control. These beneficial effects are offset and may even be eliminated by compensatory eating.

I don’t think the final word is in yet on this issue, but the most recent reviews show there is no large effect. There may be a small beneficial effect from avoiding sugars, as long as you don’t make up for it elsewhere.


We have decades of research and hundred of studies with non-nutritive sweeteners. Not just the FDA, but multiple agencies and organizations around the world have looked at all this evidence and concluded that they are safe.

Those who make a living out of spreading fear or a particular world view (usually based around the naturalistic fallacy), however, give a distorted view of the evidence, mainly through cherry picking.

Further, the fearmongering is dependent upon accepting a conspiracy-oriented view of reality. In order for the claims about sucralose to be true, then regulatory agencies around the world are either complicit or hopelessly incompetent. In addition, professional organizations must also be on the take or ignorant of their own supposed area of expertise.

I am not, however (as will likely be the accusation) preaching mindless acceptance of authority. I simply think expert systematic reviews are more reliable than distorted or cherry picked evidence with an agenda.

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