What is Flake Fish?
For many, especially in Australia, the term 'flake' is a familiar name for the mild-tasting, boneless fillets used in traditional fish and chips. However, flake is not a specific species of fish, but rather a marketing term for the flesh of various sharks, most commonly the gummy shark. Other species sold as flake can include whiskery shark, school shark, or sawshark. Given sharks are apex predators, their place at the top of the marine food chain is the key factor determining their mercury content.
The Health Concerns of Mercury in Seafood
Mercury is a naturally occurring element, but industrial pollution has increased its presence in aquatic environments. In water, microorganisms convert inorganic mercury into methylmercury, a highly toxic organic compound that is readily absorbed by marine life. The concentration of methylmercury in fish is governed by a process known as bioaccumulation, where the toxin builds up in the tissues of organisms faster than it can be expelled.
Fish higher up the food chain, such as sharks, consume many smaller fish that already contain trace amounts of mercury. This results in the mercury becoming more and more concentrated at each trophic level, a process called biomagnification. When humans eat these top-level predators, they ingest these concentrated levels of mercury. Chronic exposure, even in small amounts, can lead to serious health problems, particularly neurological damage. The developing nervous systems of unborn babies and young children are especially sensitive to its toxic effects.
Official Guidance on Flake Fish Consumption
Due to the elevated mercury levels in shark species sold as flake, health authorities around the world have issued specific dietary advice. The advice often varies for the general population versus more vulnerable groups. For example, Food Standards Australia New Zealand (FSANZ) and other health bodies recommend limiting consumption.
- For the general population: Consumption of shark (flake) should be limited, with some guidelines recommending no more than one portion (150 grams) per week.
- For pregnant women, women planning pregnancy, and young children (under 6 years): These groups are advised to limit shark (flake) consumption even further, often to no more than one portion per fortnight, with no other fish consumed during that period. Some health authorities, like the NHS in the UK, simply advise these groups to avoid shark altogether.
Making Safer Seafood Choices
While high-mercury fish should be limited, the nutritional benefits of consuming fish are substantial. Fish is an excellent source of protein, vitamins (like D and B2), and minerals, and is particularly prized for its omega-3 fatty acids, which support heart and brain health. The key is to choose low-mercury options for regular consumption.
- Choose smaller, shorter-lived species: These fish have had less time to accumulate mercury. Examples include sardines, anchovies, and Atlantic mackerel.
- Opt for farmed fish: In some cases, farmed fish can have lower mercury levels due to enhanced growth rates and a shorter lifespan, reducing the opportunity for bioaccumulation.
- Vary your fish intake: As recommended by the FDA and EPA, consuming a variety of fish is a good way to balance nutritional benefits while minimizing exposure to any one contaminant.
Comparison: High vs. Low Mercury Fish
Understanding the difference in mercury content across various species is crucial for dietary planning. Below is a comparison table using data from the FDA's monitoring database.
| Fish Species | Mercury Concentration (Mean PPM) | FDA/EPA Category | Notes |
|---|---|---|---|
| Shark (Flake) | 0.98 | Choices to Avoid (Highest Mercury) | Apex predator, bioaccumulates mercury. |
| Swordfish | 1.00 | Choices to Avoid (Highest Mercury) | Large, long-lived predator. |
| Tuna (Canned Light) | 0.13 | Best Choice (Lower Mercury) | Uses smaller skipjack tuna. |
| Salmon (Fresh/Frozen) | 0.02 | Best Choice (Lower Mercury) | Lower mercury levels, rich in omega-3s. |
| Sardine | 0.01 | Best Choice (Lower Mercury) | Small, oily fish, very low mercury. |
| Tilapia | 0.01 | Best Choice (Lower Mercury) | Mild-flavored, low-mercury white fish. |
The Role of a Balanced Nutrition Diet
Incorporating fish into a balanced diet is highly recommended for its numerous health benefits, but it requires mindful selection. A healthy eating pattern, as promoted by organizations like the American Heart Association and Dietary Guidelines for Americans, advocates for 2-3 servings of fish per week, with a focus on those lower in mercury. Opting for diverse, low-mercury fish options like salmon, sardines, or tilapia is a strategic way to gain essential omega-3s while managing potential risks from contaminants. For those who frequently eat fish, particularly local catches, it's wise to check for local advisories, as some specific waterways may have higher contamination. Ultimately, a well-rounded diet that includes a variety of nutrient-dense foods, including low-mercury fish, vegetables, and healthy fats, can help mitigate risks while maximizing nutritional intake.
Conclusion
In conclusion, flake fish is high in mercury and is classified by health authorities as a type of fish that should be consumed with caution and in limited quantities. For the general public, moderation is advised, while pregnant women, women planning pregnancy, and young children should severely restrict or completely avoid it. Given the significant health benefits of other seafood, individuals should focus on incorporating a variety of low-mercury fish into their nutrition diet, such as salmon, sardines, and tilapia. This approach allows for the enjoyment of seafood's nutritional value while effectively managing the potential health risks associated with mercury contamination.
For more detailed recommendations on safe fish consumption, consult the FDA and EPA's Advice about Eating Fish guidance.
