ZOE Science & Nutrition - Most replayed moment: The things hiding in your food? | Professor Marion Nestle

Episode Date: August 18, 2026

Today we’re talking about food additives. Take a look at the back of some ultra-processed packaged food and you’ll see a long list of unfamiliar ingredients. Complex, sciencey sounding names that most of us can barely pronounce. These are called additives. But what exactly are they? How are they tested? And, most importantly, are they truly safe for us to eat? Food policy expert Professor Marion Nestle joins me to explore how additives became so deeply embedded in modern food production — and why, now more than ever, it’s essential for you to understand the things that are hiding in your food. 🌱 Try our science-backed and tasty wholefood supplement Daily30 Get our brand-new app and Gut Health Test designed by world-leading gut health and nutrition scientists to build healthy eating habits 👉 Join ZOE Follow ZOE on Instagram. 📚Books by our ZOE Scientists The Food For Life Cookbook Every Body Should Know This by Dr Federica Amati Food For Life by Prof. Tim Spector Ferment by Prof. Tim Spector Good Mood Food (preorder) by Prof. Tim Spector Free resources from ZOE The Hormone Harmony Guide: Tuning Your Body’s Internal Orchestra Eating for Better Brain Health: Your brain-gut blueprint How to eat in 2026 - Discover ZOE’s 8 nutrition principles for long-term health Live Healthier: Top 10 Tips From ZOE Science & Nutrition Gut Guide - For a Healthier Microbiome in Weeks  Better Breakfast Guide Have feedback or a topic you'd like us to cover? Let us know here. Episode transcripts are available here.

Hello and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today we're talking about food additives. Take a look at the back of some ultra-process packaged food, and you'll see a long list of unfamiliar ingredients. Complex, sciencey-sounding names that most of us can barely pronounce. These are called additives. But what exactly are they? How are they tested? And most importantly, are they truly safe for us to eat? Food policy expert, Professor Marion Nessel, joins me to explore how additives became so deeply embedded in modern food production. And why, now more than ever? It's essential for you to understand the things that are hiding in your food. How are they discovered and produced and how does that work?

Well, companies discovered that if they put these additives in, then the bread would stay soft and last on the shelf. And the Food and Drug Administration in the United States didn't really get involved in that until a little late night. 1930s, and all these things were in the food supply. People weren't dying on the spot. So by the late 1950s, they determined that the additives that had been around for a long time were generally recognized as safe or grass, G-R-A-S, grass, and they were out in the food supply, and the idea was if anybody could find anything wrong with them, they would take them out, otherwise they were in. And that's pretty much been the attitude. There are probably 10,000 food additives in the food supply. At least I've seen that number. I certainly don't

see 10,000 on food labels. But they have not been studied. Very, very few have undergone any kind of rigorous evaluation. And then since 1958, any new additives that came in, the companies that were using them were responsible for determining their safety and would appoint a committee. A committee would say, oh, we reviewed the research on this, these things are fine, and send a letter to the FDA saying these things are fine. But those letters were voluntary. And the FDA has other things to do besides worrying about food additives. It's concerned about, you know, general food safety, microbial food safety. And additives have never been a priority. So if I'm a company in the States and I want to add a new additive into my food,

you appoint your own committee. So basically it's like when my daughter marks her own homework and says she's done an excellent job, even though she clearly hasn't done an excellent job, And in this case, I just select my own group of people to agree that this new additive is fine. And I send a letter to the FDA saying, oh, I've done an internal inspection and decided this thing is fine. And you list all the references and send it. And occasionally the FDA has sent back letters saying, we don't think so. But there haven't been very many of those. But they do exist.

But it's not something that is looked at. with the kind of rigor that our new head of Health and Human Services, Robert F. Kennedy, Jr., thinks is adequate. I'm going to come to that maybe just in a bit and just understand more, I think, the situation here and then look a bit at the picture, I guess, across the world as well. So, firstly, the fact you're saying this with, I would say, some sense of humor suggests that you think that these additives shouldn't just be viewed as clearly all. safe and you should not worry about adding them to your foods? Well, I'll say again, people don't die on the spot from eating these things. And it's very difficult to determine how would you do the studies? If you think about it, if you wanted to rigorously evaluate every single ingredient

on the Wonderbread list of ingredients, that would be enormously difficult. You would need thousands of study subjects. These are really expensive, difficult studies to run. People eat lots of different kinds of foods with lots of different kinds of additives in them. These are very complicated scientific problems to address. They're really hard. I think everybody underestimates how difficult nutrition research is because humans are not experiment animals.

You can't lock people up. Do rigorously tested experiments in which you know exactly what people are eating and wait for 30 years to find out whether the effect show. And additives are a minor consideration. I mean, really, microbial food safety is a much bigger one in the FDA's list of things that it has to worry about. And so it's been kind of ignored. And this is, as I understand it, unlike the European precautionary principle in which the attitude is, if you don't know it's say if you don't use it. We have the attitude that we'll use it and if it causes problems, we'll get rid of it. Could you talk for a minute about the contrast, for example, in Europe

about these attitude to additives? Well, I suppose the color additives, since they're so politically important right now, would be the best example. That is the red 40, blue one and two, green, whatever, and yellow five and six that are in lots and lots of candies. frostings, and kids' cereals that are marketed to children. In Europe, these are not banned, as I understand it, but they are required to have a warning label. If you use them, you've got to say that there's some evidence that they might cause problems in some children. And in the United States, we just use them until now when our new Secretary of Health and Human Services has made it his first priority to get rid of the color additives. And again, I'm laughing because why color additives?

You know, I can think of lots of other things that will make America's children healthy again. Tell me for a minute more about the generally recognized as safe that you mentioned because it feels like. that's part of this contrast around different approaches around the world towards new additives, towards this idea that actually you need to justify in some way that this additive is safe before you're added into food versus, I think you were describing something where you sort of assume it's safe until it's proven otherwise. Could you help me to understand that? What the FDA is able to do is to revoke the grass status. And it did that for trans fats. that is partially hydrogenated salad oils that have fatty acids in a specific configuration that's different from the natural one.

And they revoked. When enough evidence had come in that trans fats were unsafe and raised the risk for heart disease, the FDA revoked grass status on that. And once you do that, then companies really can't use it without being liable to legal interventions. and that took care of it. So help me to understand a little bit whether anyone else should care. So we talked about these additives. You've already said there's a lot of them in lots of different places.

They're not well studied because it's very hard to do this research. Is there any potential risks or downsides from this? Or is this like, oh, that's sort of interesting. Don't worry about it. Carry on with your day. Well, the FDA has said that color additives are safe at the levels at which they're commonly consumed. Other people disagree. And there have been a number of clinical trials dating back to the early 1980s when a physician named Benjamin Feingold developed the Feingold diet, which was aimed at children with hyperactivity or neurobehavioral problems.

And his view was that if you took the color additives out of foods and didn't allow children to eat these diets, that their behavioral problems would resolve. And it's been very difficult to do the science. First of all, you're not allowed to do experiments on children, so that's one problem. But there are others as well. The study with which I'm most familiar, because I know some of the people who were involved in doing that study, was one done in the 1980s on six children who were given either a drink that had color additives in it or a drink that did not have color additives in it. And somehow they matched the color of these two drinks

so that you couldn't tell which was which. And neither the parents nor the children knew which was which. And what they found out was that there was one child in that study who every single time that child drank the drink with the additives in it, that child went off the wall. and develop behavioral problems, the parents could identify it every single time. But the other five children know. They didn't show any effects. So when the talk is about some children are sensitive, that's what they mean. Well, one out of six is a lot, you know, or a little, depending on how you look at it.

So the behavioral problems are there for some children, and there are animal studies that indicate that some of these additives are carcinogenic, and animals are potentially carcinogenic. Well, from my standpoint, that's enough of a reason to get rid of them. These things have no purpose in the foods other than to make people want to eat them. They're cosmetics. They don't have any safety function. they don't have a nutritional function. They are strictly cosmetic. And there are replacements.

They're vegetable replacements. And they're not used in Europe. So on and on and on. There is no reason that they should have been gone a long time ago. So I'm happy that they're going to be gone. A lot of companies have pledged now that they will get rid of the color additives by 2027. I feel like you demolished these color additives. and on the other hand, we've gone from a general description of all of these additives that were in the back of that wonder pack to suddenly talking about the color additives.

But you also said, actually, this is almost like a small part of the conversation. There were so many other additives that were in that bread and we're talking about. Why might we be concerned about all those other additives that have been put in our food? Well, we don't know what they do. You know, we don't know whether they're harmful. They're certainly there in very, very small amounts. Do small amounts make any difference with the color additives? I think the reason why the color additives come up so much is because they affect children.

And because children are not eating one at a time. They're eating combinations of them. And the idea is that combinations might be worse than eating one at a time. But, you know, the chemical additives, they're chemicals of one kind or another. What they do in the body, you know, the prediction is that they're not particularly harmful. The FDA says that they're safe at levels commonly consumed. And how much you want to worry about this depends on what you want to worry about. I worry about other things more. Got it. So what you're saying is there's a lot of different chemicals. I think you mentioned

10,000 different additives. That's what they say. That's probably each individual one, you're not saying that is really dangerous as an individual additive for me. But overall, do I want to be putting all of these different chemicals into my body that I don't understand what they do? I'd probably prefer not to. Yeah, I mean, that would be my view. And I don't usually buy foods that have lots and lots of additives in them. I could give your magic wand now and you could suddenly reset the regulations around the world. What would be the top things that you would want to change?

Oh, I would rather have kids eat real food. then packaged food, real food, the way the French did or do or still do. You know, real meals were cooked with the expectation that children will eat the food, taste the food, and get involved with the food. I think school food is enormously important because, again, in the States, there's evidence that shows that kids eat most of their calories in schools and their healthiest galleries in schools. So it's important that schools do it right.

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