A recent study by American scientists has found a connection between a common food additive and the body’s defences against influenza, with research showing that it may increase the severity of symptoms – as well as potentially affecting the effectiveness of the flu vaccine.

Tertiary butylhydroquinone (TBHQ), also known as E319, is found in food products like processed foods and frozen and dehydrated meats. It’s derived from petrol, and is also often used as a varnish. It’s banned in some countries, including Japan, but in Europe it can be found in nut butters and spreads, cake mixes, cereal-based snacks, dehydrated soup and frying oils, among other products.

However, experts and snack manufacturers have said that there are few items on the UK market which contain E319 – and if they do, the “minimal additive” was a listed ingredient. The ingredient works as a preservative, most commonly found in high-fat foods, and is more often found in food in the USA, including ice cream and chicken nuggets.

The study at Michigan State University found that the additive suppressed the body’s immune response to infection, as well as potentially reducing the effectiveness of the flu vaccine.

 

The impact

The researchers in the US tested the additive on mice, which gave interesting results. “Our studies showed that mice on a TBHQ diet had a weakened immune response to influenza infection. In our mouse model, TBHQ suppressed the function of two types of T cells, helper and killer T cells. Ultimately, this led to more severe symptoms during a subsequent influenza infection,” explained one of the scientists.

When a person gets the flu, helper T cells direct parts of the immune system and help “coordinate an appropriate response”, while killer T cells go on the hunt for infected cells and get rid of them. The experiments found that “mice eating a tBHQ-spiked diet were slower to activate both helper T cells and killer T cells, resulting in slower clearance of the virus”.

TBHQ, or E319, also seems to affect the vaccine’s memory of how to fight off a virus.

When the mice involved in the study were later re-infected with a “different but related strain of influenza”, those who had received the tBHQ diet during the first study had a longer illness and lost more weight. One researcher suggested that it “impaired the “memory response” that typically primes the immune system to fight a second infection”, which could potentially reduce the how effective the flu vaccine is over time.

 

Looking to the future

The team behind the study say the connection may provide some explanation around why “seasonal influenza continues to pose a major health threat worldwide” – with stats showing that up to 650,000 are estimated to die from flu-related respiratory problems each year across the globe.

Experts including the World Health Organisation have gone on record as saying a flu pandemic is “only a matter of time”, so taking steps to protect yourself is essential. “The best way to limit tBHQ exposure is to be mindful about food choices. Since tBHQ is largely used to stabilise fats, a low-fat diet and cutting down on processed snacks will help reduce tBHQ consumption,” advise scientists.

The team went on to emphasise the importance of the yearly flu vaccine, and how it is still the best way to prevent an influenza infection. At FluCamp we’re working hard to find ways to protect people from common cold and flu viruses, but we need your help to do so. Find out more about taking part in one of our trials, or get in touch for more information.