tBHQ, the Food Ingredient that May Cause Cancer?

June 15, 2018

Has anyone else noticed that the FDA sometimes approves ingredients without really understanding how they might affect the human body? The preservative known as tBHQ is no exception.

tBHQ — or tertiary butylhydroquinone, also referred to as tert-Butylhydroquinone or t-butylhydroquinone — got press a few years ago when a popular natural health blogger began exposing the very large number of foods in which it can be found and some of the more concerning possible dangers it might cause. In fact, McDonald’s even decided to remove it from their McNuggets after all the negative feedback (but don’t worry, they’ve left in several other unsavory ingredients). Cheez-Its, Teddy Grahams and Reese’s Peanut Butter Cups also took a PR hit for their tBHQ content.

But is tBHQ really that controversial? The Environmental Working Group (EWG) rates it as only a “3,” meaning they don’t consider it to be extremely safe or extremely dangerous based on available information. (1) The FDA and USDA categorize tBHQ as “may be safely used in food.” (2) It’s also legal in the European Union and many other countries as a food additive. (3)

On the other hand, The Center for Science in the Public Interest recommends avoiding tBHQ whenever possible because of the potential it has to promote cancer formation.

Let’s look at what the science does (or does not) say about tBHQ and what to do about it in terms of your own diet and lifestyle. You want to read this, particularly if you struggle with food allergies or desire a healthy immune system.

What Is tBHQ?

The National Institute of Health’s (NIH) official definition of tBHQ is:

t-Butylhydroquinone is a white to a tan, crystalline powder. It has a very slight odor. t-Butylhydroquinone is very soluble in water. t-Butylhydroquinone is used as an antioxidant in food (EAFUS) and cosmetics and as a chemical stabilizer. It is also an inert ingredient in some ant and roach insecticides. (4)

The term “antioxidant” here might be a little confusing — but tBHQ isn’t found in blueberries, folks. It serves to stop the oxidation of molecules in food, basically stopping them from going rotten or rancid.

Like most legal synthetic food ingredients, tBHQ has never been extensively studied in a human population. “Safe” limits of tBHQ were determined by mostly short-term animal research studies.

tBHQ by the Numbers

The acceptable daily intake (ADI) of tBHQ, according to the FDA, is .7 mg/kg/day. (5) Basically, that means someone who weighs 150 pounds should be able to have 48 milligrams of tBHQ each day without adverse health effects.
About 90 percent of people in the U.S. hit the ADI of this synthetic antioxidant on a daily basis, according to the World Health Organization. People in Australia and New Zealand often have up to 180 percent of the ADI each day. (6)
The more unhealthy fats you eat, the more tBHQ you’ll consume. People on low-carb diets that consume lots of fats with minimal nutritive value probably consume the most tBHQ. (5)
The FDA limit for tBHQ in foods is set at .02 percent for most foods. That means that a food product can have no more than .02 percent tBHQ in the finished product. You may also see this number listed as 200 ppm (parts per million) or 200 mg/kg. (2)
In frozen fish products, tBHQ may be present in quantities as high as 1000 mg/kg. (6)

What is tBHQ made of?

tBHQ is a man-made compound that starts as hydroquinone (an agent used in photographic development and for reducing silver) and then has a tertiary butyl group added to its molecular structure.

That’s a lot of technical jargon to explain that tBHQ is not naturally occuring and shares some molecular structure with other butyl molecules, like those found in lighter fluid. But, no, tBHQ is not actually butane, or even found in butane. It also shares some molecular structures with the fatty acid butyric acid, which is a great natural anti-inflammatory and might even help with diabetes.

Because of the way it’s created, tBHQ is technically a vegan food preservative.

What foods are the tBHQ preservative in?

The FDA allows tBHQ both on its own or in conjunction with other synthetic preservatives like butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Some loopholes in labeling laws mean that food labels do not always have to list tBHQ as an ingredient.

Foods that contain tBHQ include: (6)

Processed fats and oils like canola oil
Frying and cooking oil at many restaurants (particularly fast food)
Most non-organic, packaged foods
Frozen, non-organic fish products
Soft drinks
Some soy milk brands

It’s not just food that contains tBHQ, though. This antioxidant is used in manufacturing in many places to stop degradation of things that would otherwise go bad, even if those things are lacquers or your lipstick color. Other products with tBHQ are:

Some pet food varieties
Cosmetics like hair dye, lipstick and eyeshadow (probably not listed on a label)
Lacquers, resins and varnishes

6 Dangers

1. Might Damage Immunity

Concerned about your immune health? tBHQ may be one culprit to blame. In amounts correlated with what an average person might consume each day, tBHQ inhibits some of the immune responses that help your body fight disease. (5)

One mechanism by which this seems to work is that the preservative activates Nrf2, a protein that controls antioxidant function. While many stimuli that activate Nrf2 cause it to boost antioxidant activity, tBHQ actually causes Nrf2 to negatively interact with proteins that control immune responses such as white blood cell function. (7, 8) Some evidence suggests that the antioxidant dysfunction caused by tBHQ is sometimes independent of Nrf2. (9)

Regardless of the exact pathways in which it works, tBHQ (again, in levels comparable to what humans consume) may inhibit immune-supporting processes in the body. (10, 11) It’s possible this damages the function of your immune system and possibly causes you to be more susceptible to illness or disease.

2. Potentially Promotes Cancer

As an antioxidant, it seems counterintuitive that tBHQ might possibly promote the growth of cancer cells. However, it interacts with various genes in the body and could do just that. (12)

It’s not a clear correlation, however. It seems true that tBHQ does cause some cancerous or pre-cancerous effects in animals. (13, 14, 15) It may also increase resistance to chemotherapy drugs and help cancer cells live longer. (16)

Other evidence seems to suggest the opposite. In some lab and animal studies, tBHQ inhibits or slows the growth of some cancer cells (including lung and colon cancers). (17, 14, 15) It may also not cause any type of cancerous lesions in certain animal subjects. (18)

Basically, the jury is still out. On the other hand, something that may or may not cause cancer still seems like an unnecessary risk, considering the alternatives are often foods that are known to reduce cancer risk.

3. Could Cause Neurological Symptoms

The National Institute of health has recorded instances of various neurological symptoms related to tBHQ consumption. These include vision disturbances, convulsions and medullary paralysis (a stage of paralysis in which the medulla, the part of the brain that controls breathing and vital bodily processes, is slowed). (19, 4)

4. May Cause Damage to Red Blood Cells

It’s possible for tBHQ to damage the structure of red blood cell membranes. (20) While it’s not clear what long-term issues this might cause, the researchers in this lab study said in their conclusion that “deleterious effects on other biological membranes are also likely to occur.”

5. Could Lead to Food Allergies

Possibly one of the most recent (and most pronounced) dangers of tBHQ is its potential to induce or worsen food allergies. Cheryl Rockwell, PhD, a researcher at Michigan State University, has been conducting research in immunology and, specifically, how tBHQ interacts with immunity.

She was on the team who discovered many of the immune-damaging effects I’ve already covered. Subsequently, her team has found that these immunity-related pathways could potentially promote food allergies. (21)

As they state in one abstract, “Overall, these studies suggest that low doses of the food additive, tBHQ, increase IgE response to food allergen and exacerbate clinical signs of immediate hypersensitivity.” (22)

Again, the doses being studied are not very high — they’re correlated with what an average person might consume.

6. Can Cause Allergic Contact Dermatitis

Since tBHQ is found in many cosmetics and other products you may touch or use topically, it’s important to note that it can cause issues with skin. Various case reports have found that people have developed allergic contact dermatitis from tBHQ, specifically in cosmetics. This reaction may also be related to cross-reactions with BHA and BHT. (23)

How to Avoid It

If you’re concerned about tBHQ, I’ve got three pieces of good news for you.

First, tBHQ is water-soluble. Why is that good? Water solubility of this antioxidant means it doesn’t bioaccumulate (build up in your body). Once you stop being exposed to it, you can reduce any problematic symptoms it might have caused.

Second, there are tons of effective, natural substitutes to use instead of tBHQ — or, as I like to think of them, better choices that don’t require a laboratory first. Not only do these substances exist, they often have more antioxidant activity than tBHQ. Plus, they don’t carry side effects like their synthetic counterparts. (24)

Some of the natural antioxidants to use instead of tBHQ include:

Green tea extracts
Olive extracts
Sesame oil extracts
Sunflower oil extract
Chinese cinnamon extract
Rosemary oil and rosemary extract
Broccoli sprout extract
Citrus extract
Clove oil
Cinnamon oil

And the final piece of good news — eliminating foods that are known to contain tBHQ would be good for you, even if the tBHQ wasn’t a factor. Getting rid of processed foods, unhealthy oils/fats, sodas and fast food will bump up your overall health!

If it feels overwhelming to make many changes all at once, start by making easy substitutions. For high-heat cooking at home, use coconut oil, avocado oil or ghee oil. Instead of soda, treat yourself with kombucha or sparkling water. Fill your plate with more whole, non-packaged foods and opt for organic when you can feasibly do so.

Final Thoughts

tBHQ is a synthetic antioxidant and preservative that is considered by most major organizations to be safe for use in food. It is found in many packaged foods, most fast food products, soft drinks, frozen fish products and certain brands of soy milk. You will also find tBHQ in some lacquers, varnishes, paints, cosmetics, dyes and pet foods.

The research on tBHQ has mostly been conducted in animal subjects. There are some dangers of tBHQ that pop up regularly in research, including that tBHQ:

Might damage immunity
Potentially promotes cancer
Could cause neurological symptoms
May cause damage to red blood cells
Could lead to food allergies
Can cause allergic contact dermatitis.

There’s good news, though! tBHQ doesn’t bioaccumulate, so it’s easy to detox your body of it by simply not continuing to eat foods containing it. There are several cost-effective, natural preservatives that perform just as well or better than tBHQ in preserving food for a reasonable amount of time. Finally, getting rid of tBHQ from your diet will inherently have to improve the quality of what you’re eating, so it’s truly a win-win situation.