ORLANDO – A commonly used food additive can make it harder to fight the flu.
Vaccinated mice that received food containing the additive, tert-butyl hydroquinone (tBHQ), took three days longer to recover from the flu than mice that ate tBHQ-free food. The unpublished result suggests that the common additive can make flu vaccines less effective, said toxicologist Robert Freeborn of Michigan State University in East Lansing on April 7 at the Experimental Biology meeting in 2019.
The additive helps to stabilize fats and is used as a preservative for a wide range of foods, including some cooking oils, frozen meat products – especially fish fillets – and processed foods such as crackers, chips and other deep-fried snacks. Food manufacturers don't have to put the ingredient on labels, so "it's hard to know everything it's in," says Freeborn.
In separate experiments, unvaccinated mice that ate tBHQ in their food had more virus RNA in their lungs than mice that did not eat it. The tBHQ eaters also had inflammation and increased mucus production deeper in their lungs than normal, found free-borns and colleagues.
The researchers don't know exactly how the additive hinders flu fights, but it may be because it increases the activity of an immune system protein called Nrf2. Increased activity of that protein could reduce the number of virus-fighting immune cells in the mice. That possibility has yet to be tested.