Understanding the Confusion: True Butterfish vs. Escolar
When people ask "how much butter fish can you eat," the answer depends entirely on what kind of fish they are actually consuming. The name "butterfish" is applied to several different species, leading to confusion and, in some cases, adverse health effects. The most significant source of this issue comes from the mislabeling of escolar as butterfish, especially in Asian cuisine and sushi restaurants. True butterfish, like the American Atlantic butterfish (Peprilus triacanthus) or New Zealand butterfish (Odax pullus), are safe for regular consumption and do not cause digestive problems. In contrast, escolar (Lepidocybium flavobrunneum) is a species of snake mackerel that contains a significant amount of indigestible wax esters called gempylotoxin. It is these wax esters, not found in true butterfish, that can cause unpleasant side effects.
The Health Risks of Escolar (Mislabeled 'Butterfish')
The primary health concern associated with eating escolar is a condition known as keriorrhea. This occurs when the indigestible wax esters pass through the digestive system largely unabsorbed, leading to oily, orange-colored discharge and diarrhea. Other symptoms can include nausea, abdominal cramps, and vomiting. The severity of these symptoms is highly dependent on the individual and the amount consumed, but the risk is present even with moderate portions. As a result, several countries and regulatory bodies have restricted or banned the sale of escolar or required specific warning labels. In the United States, the Food and Drug Administration (FDA) advises against consuming escolar or oilfish due to these potential side effects.
Nutritional Profile: What's the Real Difference?
While both true butterfish and escolar are protein-rich, their nutritional makeup diverges significantly, particularly in their fat content and composition. True butterfish offers a balanced nutritional profile, whereas escolar contains the problematic indigestible fats.
| Nutrient (per 100g) | True Butterfish (e.g., US Atlantic) | Escolar / Oilfish (potential mislabeling) |
|---|---|---|
| Calories | ~146 kcal | Higher, due to fat content |
| Protein | ~17g | Also high, but less critical |
| Total Fat | ~8g | Much higher, up to 20% of body weight |
| Indigestible Wax Esters | No | High, leading to keriorrhea |
| Mercury Content | Low | Low, but risk of digestive issues is higher |
| Selenium | High (~37µg) | Present |
| Vitamins (B12, B3, B6) | Good source | Present |
Recommended Consumption Guidelines
Given the stark difference in potential health effects, the consumption recommendations vary dramatically depending on the species.
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For true butterfish: This species is considered a low-mercury fish and is safe for regular consumption as part of a healthy, balanced diet. Following the FDA's general fish consumption guidelines of 2-3 servings per week for adults is a safe approach. For pregnant women and children, the recommendations also align with the FDA's guidance for low-mercury fish.
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For escolar (mislabeled 'butterfish'): Experts and health authorities strongly advise limiting or avoiding consumption. If one chooses to eat it, the recommended serving size is very small, typically less than 6 ounces per meal, to minimize the risk of digestive upset. Some individuals may be more sensitive and should avoid it entirely. It is also recommended to grill escolar, allowing some of the oils to cook off, and to discard the cooking liquid.
How to Identify and Cook Safely
Preventing a mislabeling mishap starts with being an informed consumer. First, always ask your fishmonger or restaurant server for the specific species of "butterfish" they are selling. In places where escolar is sold, reputable businesses will often provide a warning. If you are purchasing raw fish for sushi, consider ordering from a trusted source that provides transparent information about their seafood origins.
To reduce your risk, consider the following:
- Ask about the species: Specifically inquire if the fish is escolar or another snake mackerel species. If they cannot confirm it is true butterfish, proceed with caution or choose another option.
- Purchase from reputable sources: Stick to fish markets and restaurants that have a reputation for transparency and accurate labeling.
- Cook properly (for Escolar): If you are knowingly consuming escolar, opt for cooking methods like grilling that help remove some of the indigestible oils.
- Observe the texture: The oily, rich texture of escolar is a key indicator. True butterfish is tender but not excessively greasy or oily.
Conclusion
In summary, the question of how much butter fish you can eat is not a simple one, and it is largely determined by which species you are actually consuming. True butterfish, a low-mercury and nutrient-rich choice, can be part of a regular diet. However, due to the prevalence of mislabeling with escolar, consumers must exercise caution. Escolar, containing problematic wax esters, should be consumed in very small quantities, if at all, to avoid significant digestive distress. The critical takeaway is the importance of species identification and sourcing seafood from trusted and transparent providers. By being vigilant, you can enjoy the delicious, delicate flavor of genuine butterfish without any unwanted side effects. For more information on seafood species and safety, visit the National Oceanic and Atmospheric Administration's (NOAA) FishWatch website.
