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News from CRIS: New Research - Preservative tBHQ

March 10, 2025

Top Takeaways:

  • In mice, this common food preservative was shown to increase allergic sensitization and worsen anaphylaxis when exposed to an allergen.
  • In mice, a diet containing relevant quantities of tBHQ had more severe allergic reactions compared to a diet without tBHQ.
  • Other preservative antioxidants didn’t have the same increased allergic responses.
  • A mouse is not the same as a human; we need human studies to confirm whether tBHQ has the same impact on human immune responses to allergens.

What is tBHQ?

Tert-butylhydroquinone (tBHQ) is a synthetic antioxidant used as a food preservative.

It helps prevent oils and fats from oxidizing, which keeps food fresh for longer.

Where do we find tBHQ?

We find tBHQ in many different oils and foods including

  • Packaged snacks (e.g., chips, crackers, popcorn)
  • Frozen foods (e.g., pizza, processed meats, fish sticks)
  • Fast food (e.g., some fried items use oils containing tBHQ)
  • Cooking oils & margarine (e.g., canola, palm oil)
  • Certain cosmetics & pharmaceuticals (used to stabilize ingredients or as a preservative)

Why do we use tBHQ?

We use tBHQ because it extends shelf life and prevents spoilage by stopping fats and oils from going rancid. It helps food manufacturers maintain product freshness and quality over time. It also helps to prevent food borne illnesses.

Additionally, manufacturers only need to use a tiny amount of tBHQ to achieve its powerful antioxidant effect, making it both cost-effective and widely accessible.

What does the study show?

In this study, mice that consumed tBHQ had stronger allergic reactions when exposed to a common food allergen (ovalbumin, a protein in egg whites).

Compared to mice on a diet with no tBHQ, those on a diet with tBHQ had:

  • Higher levels of IgE: an antibody responsible for triggering some types of allergic reactions.
  • More severe anaphylaxis: measured by changes in symptoms and body temperature.
  • Increased mast cell activation: a key driver of some allergy symptoms.

These findings demonstrate that tBHQ worsens allergic responses in mice.

Why does tBHQ seem to worsen allergic reactions in mice?

There is a protein called Nrf2 that helps cells respond to stress, by turning on protective pathways. However, in this study, researchers found that when Nrf2 was turned on by tBHQ, it also increased

  • IgE levels (antibody that triggers some types of allergic reactions)
  • Mast cell activity (cells that trigger allergic reactions and inflammation)
  • Th2 immune response (linked to allergies)

In mice genetically modified not to have Nrf2, mice did not experience worsened allergic reactions, even when exposed to tBHQ. This suggests that tBHQ’s impact on allergies depends on Nrf2 activation.

Does tBHQ cause food allergies in mice, or worsen existing allergies?

Current research suggests that tBHQ worsens food allergies in mice, increasing immune hypersensitivity and allergic reactions. However, there is no evidence that tBHQ directly causes food allergies, only that it may intensify existing responses.

Did other preservatives have the same response in mice?

To see if other preservatives had the same response as produced by tBHQ, scientists also tested two other antioxidants:

  • BHT (another synthetic preservative)
  • 3-hydroxytyrosol (a natural compound found in olive oil)

Neither of these increased allergic responses like tBHQ did. This suggests that tBHQ may have a unique effect on the immune system, which needs further investigation.

However, neither of these preservatives are as potent at a low concentration as tBHQ, meaning they aren’t a good fit as a preservative for many foods and products.

What don’t we know about tBHQ in humans?

Human immune systems are similar but different from the immune systems of mice. While mice are a good model for studying immune responses, they don’t perfectly mimic human immunity. For example, certain immune cell types and pathways differ between species.

We don’t yet know if humans will have the same immune response in the presence of tBHQ as mice.

Additionally, human exposure levels likely differ from those of the mice in the study. While the researchers used dietary tBHQ at levels comparable to human exposure, actual human intake varies depending on diet, metabolism, and other lifestyle factors.

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To continue reading the entire blog post, visit: https://cris.msu.edu/news/tbhq/.