I’ve recently been much more focussed on looking at the ingredients of everyday food. While I tend to eat fairly healthily overall, when it comes to convenience and snack foods, it’s easy to overlook just how many extra additives they contain.
Even a seemingly healthy salad I recently picked up contained several emulsifiers. The same goes for supermarket sandwiches and flavoured nuts (no surprise there…)
Over the past few weeks I’ve been speaking to numerous researchers about ultra-processed foods and our diet. It’s a topic which many of us worry about, from what to feed ourselves, which snacks to reach for or what to feed our children.
In a piece for the BBC, I looked into how the additives added to processed food to keep it fresher for longer might also be having an unexpected effect on the health of the microbes in our guts - a condensed version of the piece is below:
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Inside all of us there’s a bustling community of trillions of cells that influences numerous aspects of our health. We call it our “microbiome”.
“You can think of gut diversity as like a forest. The more microbes that you have and the different types of microbes in your forest, the greater resilience you have to any perturbations,” says Melissa Lane, a nutritional epidemiologist at Deakin University.
Science long ago confirmed that a healthy and diverse microbiome is key for our overall wellbeing, as it influences everything from our mood to our metabolism and even our brains.
Those who have lower bacterial diversity in their gut are more prone to sleep problems, poorer gut health and greater inflammation, whilst a high diversity is even linked to a longer life.
“It’s this whole ecosystem. It’s like an extra organ that we have in our body,” explains Sarah Berry, a professor of nutrition from Kings College London.
But some of the foods we commonly eat could be harming this ecosystem, evidence suggests. Ultra-processed foods (UPFs) in particular can disrupt and alter the microbes in our gut.
And one of the reasons is increasingly being attributed to the numerous additives in our food. It made me wonder what these additives do to our gut.
Look at any ingredient list as you next browse the supermarket and you’ll quickly note just how many dietary emulsifiers, artificial sweeteners and food colourings are added to our food.
They do everything from making food tastier or increasing its crunch, to changing texture and extending shelf life.
The texture of your favourite melt-in-the mouth ice cream? That is down to emulsifiers. They also extend its shelf life. Emulsifiers help supermarket bread stays spongy for so long and are also why a shop-bought cake will stay moist for longer than a homemade one.
Evidence suggests these additives may negatively affect our gut microbiome
So why is this of concern? Evidence suggests these additives may negatively affect our gut microbiome, and have been linked to inflammatory bowel disease, irritable bowel syndrome and colorectal cancer.
Research carried out on both animals and humans appears to pinpoint a direct link between emulsifiers and ill health.
Kevin Whelan, a professor of dietetics at Kings College London and Benoit Chassaing have recently collaborated on a clinical trial on individuals with Crohn’s disease. The trial found those on a restricted emulsifier diet were three times more likely to experience reduced symptoms, compared to those who ate a regular intake of emulsifiers as part of their diet.
They were never tested in the past for the direct effect on the microbiome
Despite the health concerns over their use, there is no public guidance over whether we should avoid emulsifiers. One reason is because there are simply so many additives in our food and scientists don’t definitely know how many are toxic, or whether it’s the combination of them that’s harmful, Whelan says.
In addition, how food is processed could also matter for gut health, beyond nutrient content alone.
In a randomised control trial, Lane and colleagues found that a diet high in ultra-processed food resulted in lower gut microbe diversity. The team compared two groups over three weeks; both ate low calorie diets, and the diets contained comparable nutrients.
Crucially, one group consumed a diet based mainly on highly processed meal-replacement products like shakes, soups and bars, and the other followed a low-UPF diet made up of minimally processed, freshly prepared food.
While the two groups experienced similar weight loss levels, the gut bacteria in each group dramatically differed. Those on the low-UPF diet had a more diverse gut microbiome whilst those on the high-UPF diet had lower diversity.
Cooking from scratch
Another important point to consider is that many UPFs are low in the nutrients we need, which could also affect the gut. It’s already well understood that a diet rich in fibre and polyphenols nourishes our gut bacteria, and polyphenols are known to have anti-inflammatory properties.
With the evidence mounting up, I asked those I spoke to what the public should to look out for to minimise some of these harmful effects of emulsifiers.
The best thing, says Berry, is to cook from scratch using fresh ingredients as much as possible. It’s unrealistic to avoid ultra-processed foods altogether, she says.
Whelan agrees: “I wouldn’t want to be saying to the general public, ‘never eat anything that has a food additive in it’, I certainly don’t do that and I’m not recommending people do it.” What we can all do, he says, is think about eating more healthily. “Food is a really precious thing in our lives and we should celebrate it.”
Clearly, moderation is key and rather than only focussing on what to take away, we can also consider what to add to our diet, Berry says, especially when it comes to snacks, as they account for a significant portion of our daily calories.
Ultimately, a good rule of thumb is to eat much fresh produce as possible. When we do so, our health – and our microbes – only benefit.
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Breadwinners is packed with research, real-life stories, and practical advice for navigating the power dynamics at play in our lives. Buy it for a friend, or consider leaving a review or rating here.
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