The additives added to processed food to keep it fresher for longer might be having an unexpected effect on the health of the microbes in our guts.
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.
For instance, a seemingly “healthy” chicken salad I picked up recently contained a high-risk additive according to an app I use to scan the nutritional quality of food.
It included several emulsifiers, substances which allow oils and water to mix, which are commonly found in UPFs. The texture of your favourite melt-in-the mouth ice cream? That is down to emulsifiers. They also extend its shelf life. (Read more about the ice cream that doesn’t melt.) Emulsifiers help supermarket bread stays spongey for so long and are also why a shop-bought cake will stay moist for longer than a homemade one. (BBC)
And they are extremely prevalent. One analysis found that 6,640 different food products in UK supermarkets contain emulsifiers, which amounted to about half the products analysed.
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.
In a study on mice, led by Benoit Chassaing at Institut Pasteur in Paris, France, low doses of two widely used emulsifiers caused gut bacteria to move closer to the gut wall, leading to inflammation and signs of disease. Mice already prone to gut problems experienced more severe inflammation.
Normally our gut microbes are kept at a safe distance from the gut wall by a layer of mucus that lines the intestine, which helps prevent inflammation. It’s when bacteria erode into our protective mucus layer that can trigger chronic inflammatory diseases, Chassaing says. (BBC)