In a recent study, researchers at APC Microbiome, University College Cork. found that the western diet reduces the bodies natural ability to fight infections –making it more susceptible to food borne pathogens and incidences of food poisoning.
The western diet – typically characterized by a high intake of red meat, refined sugars and saturated fat – while lacking in fiber and variety – has been linked with a large number of chronic health conditions including obesity, diabetes and heart disease.
As part of the study, the research team conducted a series of experiments on rodents, feeding them on a diet high in saturated fats and low in fermentable fibre. This – as with a number of similar studies – was found to affect both the immune system and the make up of the rodents gut microbiome – the bacteria and microbes that reside in our intestines.
One food born pathogen that was identified as the immune system became increasingly vulnerable to was the common bacteria Listeria monocytogenes. This is a human pathogen found in contaminated foods that can cause serious disease, particularly in pregnant women, the elderly and people with a weak immune system.
In addition to this an interesting finding of the study was that even a relatively brief period of consumption of a ‘western’ high-fat diet was found to increase the number of “goblet cells” in the gut, which are the target for infection by Listeria, as well as causing profound changes to the microbiota composition and immune system.
Short-term consumption of a high-fat diet was found to increase the levels of Firmicutes bacteria together with Listeria strains in the gut. Firmicutes are naturally occurring bacteria however they are found in higher proportions in people with obesity.
Vanessa Las Heras, part of the research team, added that “The effects of diet were also seen beyond the gut, with reduced levels of immunity throughout the body, local alterations to gastrointestinal cell function and changes to the gut microbiota that enhanced the progression of Listeria infection”
“This has important implications for human health, especially during pregnancy, in old age and in immuno-compromised individuals. It also has more general implications for research on infectious disease,” said Dr Cormac Gahan, leader of the study.
Their results support health advice dating back millennia – that diet is a significant factor in the bodies ability to fight and protect from infectious disease – through its beneficial or detrimental effects on the gut microbiota and immune system. The study was funded by the EU Horizon 2020 programme and Science Foundation Ireland.