Butylated Hydroxytoluene (BHT) is a synthetic chemical widely used as a preservative in processed foods, cosmetics, and packaging materials. This additive functions to slow spoilage, extending the shelf life of consumer products. Its inclusion in chewing gum frequently leads consumers to question its safety and long-term health implications.
Butylated Hydroxytoluene: What It Is and Why It’s In Gum
BHT is a lipophilic, fat-soluble compound that serves as an antioxidant. It neutralizes unstable molecules called free radicals, preventing the oxidation of fats and oils within a product.
In chewing gum, BHT is added to the gum base, which contains elastomers, resins, waxes, and fats. These components are susceptible to degradation when exposed to oxygen. By preventing oxidative rancidity, BHT preserves the gum’s chewable consistency and stabilizes flavor compounds. This ensures the product maintains its texture, color, and intended flavor for a longer period.
The Scientific Controversy Surrounding BHT
The scientific debate centers on the difference between BHT’s function as an antioxidant outside the body and its potential effects inside the body at various doses. Research indicates that high-dose exposure in animal models can lead to adverse effects, including toxicity in the liver, lungs, and kidneys. Some studies suggest BHT may act as an endocrine disruptor, potentially interfering with hormone function and affecting reproductive health.
BHT has also shown tumor-promoting effects under specific, high-dose conditions in certain rodent studies. These adverse findings are linked to how the chemical is metabolized in the liver, where its breakdown products may contribute to localized oxidative stress.
The controversy is complicated by other studies that highlight BHT’s protective qualities. However, the findings that raise alarm are highly dependent on the dosage and the specific animal model used. The exposure levels that elicit toxic effects in laboratory settings are typically far greater than the trace amounts found in consumer products. Most regulatory bodies have concluded that BHT is not genotoxic, meaning it does not damage genetic material, which is a key factor in cancer development.
Regulatory Oversight and Acceptable Daily Intake
Major regulatory agencies maintain that BHT is safe for use when kept within strict concentration limits. In the United States, the Food and Drug Administration (FDA) classifies BHT as “Generally Recognized As Safe” (GRAS), permitting its use as a food additive under specified conditions.
Safety assessment relies on establishing an Acceptable Daily Intake (ADI), which is the amount of a substance a person can consume daily over a lifetime without posing a health risk. The European Food Safety Authority (EFSA) re-evaluated BHT and set the ADI at 0.25 milligrams per kilogram of body weight per day. This figure is derived from animal studies using a 100-fold safety factor to account for differences between animals and humans.
The maximum concentration of BHT permitted in chewing gum is 400 milligrams per kilogram of gum. Typical consumption of BHT from all food sources for the average adult is estimated to fall significantly below the established ADI. Regulatory bodies continue to monitor high-end consumption estimates for children, which have been shown to approach or slightly exceed this limit in some countries.
Choosing BHT-Free Gum and Alternative Antioxidants
Consumers who wish to avoid BHT must read labels carefully. BHT is typically listed explicitly as “Butylated Hydroxytoluene” or by its acronym, BHT, often placed near the end of the ingredient list. The similar synthetic antioxidant, Butylated Hydroxyanisole (BHA), is also commonly used and can be avoided using the same strategy.
Manufacturers increasingly use alternative compounds to achieve preservation goals without relying on synthetic chemicals. Common alternatives include:
- Mixed tocopherols, which are natural forms of Vitamin E extracted from vegetable oils.
- Ascorbic acid (Vitamin C), a widely used natural antioxidant.
- Rosemary extract, which contains potent natural antioxidants used to stabilize gum bases.