What to do when safety studies smell a rat

Studies performed with rats and mice form a key component of any ingredient’s safety record, people’s views of animal testing aside. But promoting their validity when the news is good, and dismissing it when the news is bad does not constitute a level scientific playing field.

Like with the Pied Piper, all the rats should dance to the same tune.

The issue was highlighted last week when we reported on results from a new rat study performed by scientists from Duke University in North Carolina. A 12-week feeding study with rats revealed one or two concerns over the safety of the Splenda sweetener, and its main ingredient sucralose. When these findings came to light, McNeil Nutritionals, the company that markets Splenda, issued a statement dismissing the study, its relevance, the methodology used, and the conclusions drawn.

The company quoted a judge in an ongoing legal battle between McNeil and the Sugar Association, which co-sponsored the study, dismissed the findings as “irrelevant”​ because they were performed on rats and thereby not applicable to humans.

There are two separate questions here. First of all, since the study was performed in rats can it be applied to humans? The second regards the science – are the methodology, data and conclusions valid?

The company did provide a fact sheet with what it considered flaws in the science of the Duke study. But an official statement from the company led with the judge’s ruling that the study is irrelevant because it was performed in rats.

The FDA approval for Splenda was achieved, in part, on the back of many positive rat studies. Does dismissing the new rat study as irrelevant solely because it was done on rats, also, by association, dismiss the earlier safety data as irrelevant?

Taking the stance of “it was done on rats” is not the way to foster trust in food additives, which – by dint of being added – are likely to be viewed with some suspicion by natural-loving consumers. If the methodology, analysis and conclusions do not stack up, then that is another thing, but discounting the relevance of the study because it is performed in rats is simplistic.

A more appropriate response is to acknowledge the study, state that the findings will be considered, but then emphasise that the current body of science overwhelmingly supports the safety.

I do not want to fan the flames of a conspiracy theory. Indeed, the current body of science does​ overwhelming support the safety of sucralose – it has received regulatory approval across the globe, and it is used as an ingredient in over 4,000 products worldwide.

Everyone who has ever been involved in science knows it is a field in constant motion – new results come to light, methodological breakthroughs allow us to study systems in new and novel ways, and we have to be flexible to deal with these advances.

Safety data from a decade ago should not be the be all and end all – new studies are constantly emerging and these should be given credit where credit is deserved.

In their new book, The Atlas of Food​, Professor Erik Millstone from the University of Sussex and Professor Tim Lang from London’s City University put it perfectly. They write: “The food additives industry often treats the results of [animal] studies as valid when they show no adverse effects, but questions their relevance when they do suggest adverse effects.”​

It is a no-brainer that studies investigating the toxicity, mutagenicity, carcinogenicity and so on of a compound or ingredient cannot be performed on humans. It is simply unethical to feed a human a compound at a dose of 100-times that consumed in the diet and wait to see if something nasty happens.

Animal studies, regardless of what you may feel about animal testing, are an integral part of the regulatory and scientific process.

The Pied Piper got the rats to follow his lead, and act in unison. The same should happen in science.

Stephen Daniells is the science editor for NutraIngredients.com and FoodNavigator.com. He has a PhD in chemistry from Queen's University Belfast and has worked in research in the Netherlands and France. ​

If you would like to comment on this article, please email stephen.daniells'at'decisionnews.com​