Last week the news told us to be scared of our salad. The story came from food journalist Joanna Blythman, who had a lengthy feature article in the Guardian’s weekend magazine that took readers around a food manufacturers’ trade show, informing us of the unearthly sounding gunk lurking unseen, and sometimes not on the label, in our favourite convenience foods.

The article is peppered with unnatural sounding products: Glucono-Delta-Lactone, potato protein isolate, texturised soy protein, monosodium glutamate, phosphoric acid, acetone, L-cysteine, glutamate, carrageenan, acetylated distarch adipate, gelatine, lipases, proteases, permeates … The list goes on, and the yuck factor is definitively invoked – who wants their salads “sloshed” with chemicals or their meat “gassed”? But on closer inspection, it’s not too clear why we should be disgusted.

Many people equate “chemical” with “bad”, and “natural” with “good”. But as chemists are at pains to point out, natural things are made up of chemicals too and not all of them are good for you. Deadly nightshade anyone? Potatoes are in the nightshade family, and eating too many green potatoes might deliver you a toxic dose of solanine. Even the humble apple has a complex chemical makeup, including such exotic compounds as 5-hydroxymethylfurfural. So while hijacking the professional language of chemists and food technologists may sound scary, it’s not enough to put me off my salad quite yet.

But Blythman is suggesting it is the chemicals added to foods that we should be concerned about. On the face of it, it seems reasonable to approach these additives with a raised eyebrow. And that’s exactly what food toxicologists do. They work out the lowest amount of a substance that can be eaten at which there is any negative biological effect, and then set thresholds around 100-fold lower for acceptable levels in food.

Food toxicology plays a vital role in regulating what is safe to eat, and provides the basis for banning products from the food chain. Yet Blythman paints toxicology as a field stuck in the dark ages.

The foundation of modern toxicology is drawn from the 16th-century Swiss physician, Paracelsus, whose theory “the dose makes the poison” (ie., a small amount of a poison does you no harm) is still the dogma of contemporary chemical testing … [But] real world levels of exposure to toxic chemicals are not what they were during the Renaissance.

This last statement is almost definitely true. While we have new compounds to contend with, previous generations were exposed to dangerous chemicals (think lead paint, asbestos) that have been removed from everyday life thanks to, er, toxicology.

I put it to Blythman by email that she is misrepresenting the work of toxicologists, to which she replied: “As someone who believes in the precautionary principle, I would like to see those charged with ensuring the safety of our food give more weight to all the scientific researchers who, after studying a wide range of doses encountered in daily life… suggest that standard toxicology may be missing less predictable, unanticipated low-dose responses.”

It would indeed be naïve to assume that because substances do not cause immediate toxic effects they are completely benign, and among all the gross stuff, Blythman does occasionally look to science to back up some of her claims, such as:

Several large-scale studies have found a correlation between artificial sweetener consumption and weight gain. Accumulating evidence suggests that they may also increase our risk of type 2 diabetes.

It’s tough to check this without references (Blythman assures me that her book, from which the feature article is taken, is thoroughly referenced) but the type 2 diabetes link may refer to a recent study in the journal Nature which found that saccharin had an impact on the gut bacteria and blood sugar of mice, and that four out of seven people who were fed a high saccharin diet also had higher blood sugar. At the time, scientists were intrigued but urged caution over reading too much into the results. Naveed Sattar, professor of metabolic medicine at the University of Glasgow said: “Current epidemiological data in humans do not support a meaningful link between diet drinks and risk for diabetes. The findings of this study do not prove that sweeteners pose any real risk to humans. If there are any risks, we need well controlled studies in humans to find them.”

Is that enough to warn people off sweeteners? Observational studies suggest any number of substances might have negative effects, including those in traditional foods as the many, many news articles about coffee and red wine attest. But as food writer Stefan Gates found out after purposefully gorging himself on e-numbers, the evidence is much clearer that it is the salt, fat and sugar that we should be worried about.

When challenged in a follow up Guardian webchat on her scientific claims, Blythman responded: “Are you really suggesting that NO-ONE other than a scientist has the right to discuss how processed food is made?” Herein lies an old canard. When talking about science, all claims should be held to the rigorous standards of empirical research, and scientists have a monopoly on that. If the evidence doesn’t justify you making the claim, you shouldn’t make it.



On the other hand, the social, legal and ethical issues that go alongside scientific issues are absolutely up for discussion. And that’s the tragedy. There is an important story in how closed the food additive industry is to investigation and we need people to shine a light into that world. Blythman had to blag her way into that trade fair, and her investigation of the industry’s ‘clean label’ campaign is important. But then pointing at scary sounding ingredients while holding up ‘natural’ whole foods as the only alternative distracts from having any meaningful discussion.

It is no different on the other side of the Atlantic. Even the elite New York Times has published Vani Hari (aka The Food Babe), who makes bizarre statements like “I couldn’t believe there was beaver’s ass in my vanilla ice cream, coal tar in my mac and cheese, yoga mat and shoe rubber in my bread.” The online magazine Slate sassily debunked these claims, and as Hari’s influence grows she is under increasing scrutiny by both scientists and journalists.

The lurking assumption is that we can simply do away with all the food technicians and engineers and still have the food we want, when we want it. I personally bake my own sourdough, buy as fresh as possible, and have been known to refer to myself (cringily) as a demitarian. But I also rely on being able to pick up an oven pizza or prepared salad, and I’m not in the least worried that it’s going to kill me.

Robin Bisson is Director of The Genetic Expert News Service (GENeS), which provides access to scientific expertise and opinion on the latest genetics and biotechnology news in the US.

This article was corrected on Wednesday, 4th March, to clarify the role of toxicology. The original article stated “They work out the lowest amount of a substance that can be eaten before there is any negative biological effect”, when in fact it is the lowest amount that can be eaten at which there is a negative effect. This has now been corrected.