The Core Culprit: Indigestible Wax Esters
At the heart of the problem with escolar is its unique physiology. As a deep-water fish belonging to the snake mackerel family, escolar ( scientifically Lepidocybium flavobrunneum) cannot metabolize the wax esters found in its diet. Instead, it stores these waxy oils in its flesh, which can account for up to 20% of its total body weight.
When humans consume escolar, our digestive systems are also unable to process these wax esters. The indigestible oil, known as gempylotoxin, passes through the digestive tract undigested. This triggers a potent laxative effect, resulting in a condition called keriorrhea, or "flow of wax".
The Unpleasant Symptoms of Gempylotoxin Poisoning
Keriorrhea is characterized by a distinctive, oily discharge from the rectum, which is often orange or yellow in color. The onset of symptoms is typically rapid, occurring anywhere from 30 minutes to 36 hours after consumption. While the condition is generally not life-threatening, it can be extremely distressing and embarrassing for those affected.
Common symptoms include:
- Severe, oily diarrhea
- Stomach cramps and abdominal pain
- Nausea and vomiting
- Headache
Susceptibility to these side effects varies significantly among individuals, and there is no reliable way to predict who will be affected. Pregnant women, people with bowel problems, or those with malabsorption issues may be at higher risk. Critically, cooking the fish does not break down or remove the wax esters, meaning that preparation methods offer no guarantee of safety.
The Dangerous Practice of Escolar Mislabeling
Compounding the health risks of escolar is its frequent misrepresentation in the seafood industry. To increase profits, less reputable restaurants and markets often substitute the cheaper escolar for more expensive, desirable fish.
Common Mislabeling Schemes
- White Tuna / Super White Tuna: This is one of the most common mislabels. Authentic "white tuna" refers to albacore, which has a pinkish flesh. Escolar, with its stark white color and buttery texture, is an easy and deceptive substitute. A study by ocean conservation group Oceana found that 84% of "white tuna" samples tested were actually escolar.
- Walu: While walu is another common name for escolar, it is often presented ambiguously on menus to hide its identity.
- Butterfish: The term "butterfish" can refer to several different edible fish, but is also commonly used to disguise escolar.
- Sea Bass, Codfish, Orange Roughy: Escolar is sometimes passed off as these other white fish to deceive consumers into thinking they are getting a safer, higher-quality product.
Comparison Table: Escolar vs. True Tuna
| Feature | Escolar (Mislabeled as 'White Tuna') | True Tuna (e.g., Albacore) |
|---|---|---|
| Indigestible Content | High levels of indigestible wax esters (gempylotoxin) | No indigestible wax esters; safe for consumption |
| Potential Health Effect | Keriorrhea (oily discharge), stomach cramps | No risk of keriorrhea; other food poisoning possible with improper handling |
| Appearance | Bright, opaque white flesh | Pinkish flesh |
| Texture | Distinctly rich and buttery due to high oil content | Firm and meaty |
| Cost | Less expensive, making it a target for mislabeling | More expensive than escolar |
| Legality | Banned in countries like Japan and Italy | Widely consumed and legally sold everywhere |
Regulations and Consumer Awareness
In countries like Japan and Italy, the sale of escolar is banned outright due to the public health concerns surrounding its consumption. In other regions, such as Canada and parts of Australia, regulations primarily focus on accurate labeling and consumer warnings. However, the continued practice of mislabeling, especially in restaurants, proves that these regulations are not always sufficient to protect consumers.
As a consumer, your best defense is awareness and vigilance. When dining out, especially at a sushi restaurant, be wary of ambiguous menu items like "white tuna". Ask the chef or server directly what type of fish is being served. Furthermore, always purchase fish from reputable sources that guarantee proper labeling. Since no cooking method effectively eliminates the risk, moderation is key for those who choose to consume it, with many experts recommending a portion size of no more than 6 ounces.
Conclusion
The problem with escolar is twofold: it contains indigestible wax esters that cause distressing gastrointestinal symptoms in many people, and it is frequently mislabeled, deceiving consumers and posing an avoidable health risk. The risk of keriorrhea cannot be eliminated through cooking, and individual susceptibility is unpredictable. By understanding the dangers and being proactive in questioning menu descriptions and purchasing from trustworthy sources, consumers can protect themselves from this unpleasant food-related issue. Ultimately, the safest approach for those with concerns is to avoid escolar entirely and opt for properly identified, safer seafood options.
This article provides information for educational purposes and is not a substitute for professional medical advice. Individuals who experience severe gastrointestinal symptoms after eating fish should consult a healthcare provider.
