Nutrition specialist Tim Spector has advice on how our dietary choices can strengthen the body's natural defences against viruses and potentially reduce the risk of developing severe complications like long Covid. The professor of genetic epidemiology at King's College London, who founded the Zoe health app, highlights a crucial link between our immune function and digestive health - identifying inflammation as a key factor behind serious complications.
Spector stresses how a thriving gut microbiome is essential for strong viral protection - especially against threats such as Covid-19 - whilst also preventing the overactive immune responses commonly associated with persistent long Covid symptoms.
He explained: "We now know that most of our immune system is in our gut and the way it gets its signals, and it understands what's going on around it is through the gut. Microbes healthier your gut microbes." He continued: "The more diverse they are, the better you're going to be able to control your immune system. And this means it's going to react appropriately to, say, a covid virus. It's going to try and kill it, but without overreacting and killing you.
"So people eating a junk food is going to have an inflamed gut microbiome that's trying to put out fires all over the place. And so when a real virus comes along, it's not able to pin it down. So if you want to have the best immune system, you need to make sure your gut health is in the best possible way. I can't stress enough. It's plant diversity. It's fermented foods, and it also means not having ultra processed foods and getting plenty of fibre in there."
Prof Spector warned that pandemics are occurring with greater frequency and intensity, encouraging individuals to reassess their eating habits in readiness for future health crises, reports Bristol Live. The nutrition expert has advocated eliminating specific foods from both adult and children's diets, highlighting how Britain now "leads Europe in ultra-processed food consumption, with a staggering 57% of our daily food intake coming from these products".
Tim describes ultra-processed foods as "edible food-like substances" that extract components from genuine food whilst removing crucial elements like fibre, as it proves difficult to manipulate. "They take the essential extracts from food and they combine them in different ways," he explained.
"They have to add glues, chemicals and additives to stick stuff together and to make it look like food again."
Prof Spector advised that people should strive to eat 30 different varieties of plants each week and strongly advocates fermented foods such as kefir for digestive health. In his comments, first made in November 2024, he outlined the multiple advantages of these foods, explaining: "In particular, they seem to support your immune system, which is so vital to fighting allergies, infections, cancer and ageing, thanks to their interaction with your resident gut bacteria."
Nevertheless, he cautioned against consuming sweetened, additive-laden yoghurt just once weekly, stressing the importance of high-quality products eaten in modest quantities throughout the day.
He referenced an American clinical trial which discovered that people who consumed four to five small portions of fermented food daily demonstrated markedly better blood indicators of inflammation and immune response after merely two weeks.
"So, if you have one or two portions daily, you will likely also benefit."