An additive – Tertiary Butylhydroquinone (TBHQ), also known as E319 – which can be found in many common foods may worsen your flu. Commonly found in products such as frozen and dehydrated meat and processed food, it suppresses the body’s immune response to infection.
Not only does it increases the severity of flu symptoms, but it also reduces the effectiveness of the flu vaccine, according to the US researchers who presented these results April 7 at the American Society for Pharmacology and Experimental Therapeutics (ASPET) annual meeting during the 2019 Experimental Biology meeting in Orlando, FL.
Lead author Robert Freeborn, a Ph.D. candidate at Michigan State University, said:
“If you get a vaccine, but part of the immune system doesn’t learn to recognise and fight off virus-infected cells, then this can cause the vaccine to be less effective.”
The connection may help explain why seasonal influenza continues to pose a major health threat worldwide with an estimated 290,000-650,000 people globally dying from flu-related respiratory problems each year.
According to a new study in mice by Michigan State University scientists, E319 suppresses the immune response the body mounts when fighting the flu and it also reduces the effectiveness of the flu vaccine through its effects on T cells.
Freeborn said:
“Our studies showed that mice on a tert-butylhydroquinone (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.”
Helper And Killer T Cells
Helper T cells direct other parts of the immune system and help coordinate an appropriate response when a person is infected with influenza virus; while killer T cells hunt down infected cells and clear them from the body. Through their experiments, Freeborn and colleagues 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.
Freeborn said:
“Right now, our leading hypothesis is that TBHQ causes these effects by upregulating some proteins which are known to suppress the immune system. Expression of these proteins, CTLA-4 and IL-10, was upregulated in two different models we use in the lab. However, more work is necessary to determine if upregulation of these suppressive proteins is indeed causative for the effects of TBHQ during influenza infection.”
Memory Response
Through a second phase of experimentation, they re-infected the mice with a different but related strain of influenza. Those mice on the TBHQ diet were ill for longer and lost more weight.
Freeborn said:
“This suggests that TBHQ impaired the ‘memory response’ that typically primes the immune system to fight a second infection. Since the memory response is central to how vaccines work, impairment of this function could potentially reduce the efficacy of the flu vaccine. T cells are involved in the immune response to a variety of diseases, so TBHQ could also play a role in other types of infectious diseases.”
Conclusion: Eat Healthily
The scientists believe the link may help explain why flu worldwide has not been eradicated. To avoid this, be cautious of what you consume. The best way to avoid it was by having a low-fat diet and cutting down on processed snacks.
It is estimated that some U.S. consumers eat almost double the maximum allowable amount of TBHQ suggested by the joint FAO/WHO Expert Committee on Food Additives and that people in other parts of the world may consume up to 11 times the maximum allowable amount.
E319 is most common in high-fat foods, for which it is used as a preservative. It is banned in Japan but not in most other parts of the world. In Europe for example, it is allowed in milk powder for vending machines; fats and oils for processed heat-treated foods, frying oil and lard, fish oil, beef, poultry, and sheep fat, frying fat, processed nuts, nut-butters and spreads, dehydrated potatoes, cake mixes, heat-processed dehydrated meat, dehydrated soups, and cereal-based snacks. In the US, it can be in frozen fish, ice cream, microwave popcorn, and chicken nuggets.
Freeborn said:
“It can be hard to know if you are consuming TBHQ, as it is not always listed on ingredient labels. The best way to limit TBHQ exposure is to be cognizant about food choices. Since TBHQ is largely used to stabilize fats, a low-fat diet and cutting down on processed snacks will help reduce TBHQ consumption.”
Of course, getting a yearly flu shot remains the best way to prevent influenza infection. However, it is possible to contract the flu after getting the vaccine, being vaccinated has been shown to significantly reduce the length and severity of the illness.
The researchers plan to use human blood samples next to further investigate how E319 affects T cell activity.
