Why ultra-processed foods are not a healthy choice

Tegan Taylor: And it’s increasingly clear that ultra-processed foods, things like candy, packaged soups, nuggets, sweetened cereals, aren’t great for your health. But is that because ultra-processed foods are often high in fat, sugar and salt? Or is there something in the processing? Yet another new study is pointing towards the latter, showing that higher intake of ultra-processed food is associated with a greater risk of dying from any cause. So what could be driving this? And should the level of processing be included as a warning label on foods, along with the nutritional information that we already get? I’ve been speaking to researcher Marialaura Bonaccio.

Marialaura Bonaccio: We wanted to compare how these two ways of looking at foods agree or if they say something different in relation to health outcomes. In the case of our study, it was mortality, all-cause mortality and cause specific mortality. And we found interesting stuff.

Tegan Taylor: Well, let’s talk about it. Let’s start with the top line. What effect did ultra-processed food intake have on dying of any cause?

Marialaura Bonaccio: We just confirmed what has been seen by others; a diet rich in UPF, so ultra-processed food, is associated with increased risk of dying from any cause, but also from cardiovascular and specifically ischemic heart disease and cerebral vascular disease.

But it was also true when we look at diet by a traditional approach, that means we use the dietary score that basically evaluates the nutritional content of the diet, it’s emphasised the consumption of fibre, vitamins, all the good things that we know we have to eat every day. And in some way, it scores in a negative way foods that are rich in saturated fat, salts and so on. Diets that are not nutritionally adequate, as reflected by this score, are also associated with risk of all-cause and cardiovascular mortality.

But what happened is that when we analysed these two dimensions of foods together, we basically saw that the risk, the risk associated with the traditional way of looking at food is almost completely explained, or at least for a greatest proportion, by the fact that these unhealthy foods from a nutritional point of view are also ultra-processed.

Tegan Taylor: Right, so there are some foods that are naturally high in saturated fats, but what you’re saying is the foods that seem to confer the most risk on that measuring stick were also tending to be the ones that were ultra-processed.

Marialaura Bonaccio: Exactly. So what counts most, the fact that the nutritional balance is not ideal or optimal, or the fact that these foods are ultra-processed. In our study, a greatest proportion of the risk associated with this unnutritional diet is explained, I mean, it goes away or reduced a lot when you account for the fact that these foods are also ultra-processed. While the opposite, the other way around, is not true.

I mean, the risk associated with the UPF is still there after adjustment for the fact that these foods are also nutritionally unbalanced. The point is that when you look at a diet, especially in this time, where all the food that we put on the table comes mostly from the supermarkets are highly processed, it’s important to consider when you analyse the nutritional content of foods also to account for the fact that they may be ultra-processed.

So researchers start to ask themselves, if there are any other explanation, there are many actually, one is that these foods are packaged in mostly plastic-based package. So the plastic contains some chemical that have the ability to migrate from plastic to food. So if you are exposed every day to huge amounts of these foods, you are also exposed in an indirect way to the contamination of these chemicals. And this is one hypothesis, but there are also other hypotheses that maybe point to the fact that these foods, for example, result from a long process of deconstruction of the food matrix. It’s not whole food, what you eat, but it’s just a result of several processes that basically destroy the food matrix. And this makes, for example, the absorption of some nutrients more available in the body. If you destroy fibre, and then you recompose it, it’s not the same way that having fibre in the original version.

There was a third that points to the fact that these foods are also enriched with many, many food additives that you generally don’t have in domestic kitchens, for example artificial sweeteners instead of sugar, or you have the task of preserving the food so they can have a long shelf life, maybe all these pathways interact in some way. So you have like, you know, a cocktail effect. And by now it’s difficult to disentangle because you have several hypotheses, but none excludes the others. So maybe it’s all the stuff that may contribute to what we see in large, large population cohorts worldwide. Also in a population who has a relatively low consumption of this food, like Italy, you can see these huge differences in mortality, and it’s very, you know, alarming, worrying.

Tegan Taylor: What are the policy implications for this research? Because a lot of people rely on ultra-processed foods for their food supply, especially people who are living with lower incomes,

Marialaura Bonaccio: Yes, because they are cheaper, yes. Well, this paper that we are talking about was conceived in the framework of a strong debate at the European level now, looking for the adoption of a front-of-pack label system, common to all EU countries. Now in Europe it’s an option, but it’s not mandatory. But the EU wants to choose one mandatory front-of-pack nutrition labelling system. The one that has gained more support in these last years is the Nutri-Score. I don’t know if you are…

Tegan Taylor: We have different versions of it.

Marialaura Bonaccio: Yes, but you know, the concept is very similar, because also the one that you have in Australia are based on the fact that just the nutritional quality is taken into account. They say this food is good for you because it’s balanced from a nutritional point of view. But the point is that we are not against this system, but we just say that this information deriving from an assessment of the nutritional quality should be complemented. So our proposal at the end of the study is to place, together with the nutritional warning, also the processing warning, you know, diet sugar-sweetened beverages which have very low calories, they get an A, a green light, but they are ultra-processed.

Tegan Taylor: Are you saying that what you need is to take it in concert, the nutritional information, but in addition to that, the level of processing?

Marialaura Bonaccio: Yes, you know, a double dimension of considering food.

Tegan Taylor: Marialaura, thanks for making time for us.

Marialaura Bonaccio: Thank you.

Tegan Taylor: Dr Marialaura Bonaccio is in the Department of Epidemiology and Prevention at the Neuromed Institute in Italy.