Understanding Bisphenol A (BPA) and Canned Food
Bisphenol A (BPA) is an industrial chemical that has been used since the 1950s to make certain plastics and resins. It is commonly found in epoxy resins that are used to coat the inside of metal food cans, including those used for tuna. This lining is essential for preventing the can from corroding and contaminating the food with metal, but it allows the BPA to migrate into the food, especially under heat processing during the canning process.
For decades, federal agencies like the U.S. Food and Drug Administration (FDA) maintained that the low levels of BPA exposure from food were safe. However, as more independent studies have emerged highlighting potential health concerns, consumer pressure has pushed many manufacturers to seek alternatives. While many companies have phased out BPA-based linings, reports have shown that detectable levels can still be present, even in products claiming to be "BPA-free".
The Health Concerns Associated with BPA
Research has linked BPA exposure to a range of potential health problems, primarily because it is an endocrine disruptor. This means it can mimic hormones, such as estrogen, and interfere with the body's endocrine system. This disruption has been associated with:
- Reproductive Issues: Studies have pointed to potential harm to the male and female reproductive systems and developmental issues in fetuses and children.
- Metabolic Disorders: A possible link has been suggested between BPA and an increased risk of obesity, type 2 diabetes, and cardiovascular disease.
- Other Potential Effects: Some studies have explored associations with neurological issues, immune system problems, and certain cancers.
Is BPA in Canned Tuna? The Evidence
Several studies and consumer reports have confirmed the presence of BPA in canned tuna. A 2012 Consumer Reports test found that nearly all 19 name-brand canned foods, including tuna, contained some BPA. The levels found varied significantly between brands and even between different lots of the same product.
Furthermore, an alarming 2024 Swiss test highlighted high levels of BPA in certain canned tuna products. These findings underscore the fact that despite some manufacturers' moves towards BPA-free alternatives, complete elimination has been a challenge due to various factors, including contamination during processing or from other components like lids.
What About BPA-Free Labeled Cans?
Testing has shown that even products labeled as “BPA-free” can sometimes contain detectable levels of the chemical. In some instances, the lining was not epoxy-based, suggesting contamination came from another source, like can lids or the processing line itself. This highlights a crucial point: “BPA-free” does not always mean “BPA-zero,” and it is important for consumers to stay informed. A 2016 investigation found that 67% of cans tested still used BPA-based linings, though follow-up tests showed a significant drop in its usage by 2019. However, a newer concern has emerged regarding regrettable substitutions, where alternative chemicals with similar endocrine-disrupting properties, such as Bisphenol S (BPS) and Bisphenol F (BPF), are used instead of BPA.
Making Informed Choices: BPA-Free Alternatives
To reduce BPA exposure, consumers should consider products with verified BPA-free packaging. Some companies have committed to using alternative linings like polyester or non-BPA acrylic coatings. Other options include:
- Pouches over Cans: Some brands offer tuna in plastic pouches, which often have immeasurable or much lower levels of BPA compared to their canned counterparts.
- Glass Jars: Choosing products packaged in glass jars is another way to avoid can linings altogether.
- Trusted Brands: A growing number of brands, including Wild Planet and Safe Catch, have established reputations for using BPA-free linings and regularly testing their products.
- Fresh or Frozen: Opting for fresh or frozen seafood instead of canned is an easy way to completely avoid BPA from can linings.
Comparison Table: BPA-Free and Conventional Tuna Options
| Feature | BPA-Free Canned Tuna | Conventional Canned Tuna | Tuna in Pouches | Fresh or Frozen Tuna |
|---|---|---|---|---|
| BPA Risk | Very low to negligible (can vary) | Moderate to high | Very low to negligible | None |
| Convenience | High (shelf-stable) | High (shelf-stable) | High (shelf-stable) | Low (requires preparation) |
| Cost | Typically higher | Often lower | Can be higher | Variable |
| Flavor/Texture | Consistent, dependent on pack style | Consistent, dependent on pack style | Consistent, dependent on pack style | Optimal, depends on cooking |
| Mercury Risk | Present in both depending on tuna species | Present in both depending on tuna species | Present in both depending on tuna species | Present depending on tuna species |
Reducing Overall BPA Exposure
Beyond choosing BPA-free products, there are additional steps you can take to minimize your total exposure to this chemical:
- Prioritize Fresh Foods: Incorporate more fresh or frozen produce and protein into your diet to reduce reliance on canned goods.
- Avoid Heating Plastics: Never microwave food in plastic containers, as heat can cause BPA to leach more readily. Use glass, porcelain, or stainless steel for heating instead.
- Rinse Canned Foods: While not foolproof, rinsing canned goods can help reduce the levels of BPA, as a 2020 study on canned beans confirmed.
- Use Alternatives: Store food in glass or stainless-steel containers instead of plastic ones.
Conclusion
Yes, BPA has been a common component in the epoxy linings of canned tuna, posing a potential health risk due to its endocrine-disrupting properties. While many manufacturers have moved to phase out BPA, detectable levels can still appear, sometimes even in products labeled “BPA-free,” partly due to contamination or the use of substitute bisphenol chemicals. Consumers can reduce their exposure by seeking verified BPA-free brands, opting for tuna in pouches or glass, choosing fresh or frozen seafood, and following general guidelines to avoid heating food in plastic. As regulatory standards evolve and consumer awareness grows, the industry continues to shift towards safer packaging materials, but staying informed remains the consumer's best defense against chemical exposure.
Explore more information on BPA and food safety from the Environmental Working Group.
