What are the disadvantages of sole fish?

November 12, 2025 •

5 min read

According to the Food & Water Watch, sole fish is included on their "dirty dozen" list, raising serious concerns about its consumption. While often praised for its mild flavor, there are several significant disadvantages of sole fish that consumers should be aware of, including potential health risks and negative environmental impacts.

Quick Summary

This article outlines the primary disadvantages of sole fish, focusing on health concerns such as potential contamination and low omega-3 content. It also covers the ecological damage caused by its unsustainable fishing methods, helping readers make more informed dietary choices.

Key Points

Contaminant Risk: Sole fish, as bottom dwellers, can accumulate heavy metals like mercury and other toxins such as PCBs and PAHs, which pose health risks.
Low Omega-3s: Unlike oily fish, sole is low in beneficial omega-3 fatty acids, making it a less ideal choice for those seeking to maximize these nutrients for heart and brain health.
Unsustainable Fishing: The common use of bottom trawling to catch sole fish is a destructive practice that harms sensitive ocean habitats and contributes to overfishing.
Allergy Potential: Sole is a whitefish, and allergies to this category of fish are common. Improper handling can also lead to scombroid poisoning from high histamine levels.
Farmed Sole Challenges: Farmed sole often face problems with disease, slow growth, and high production costs, making it a potentially inefficient and risky alternative to wild-caught fish.
Less Nutrient-Dense: Compared to alternatives like salmon or tuna, sole is a less nutrient-dense option, providing less of the critical fats needed for optimal health.
Potential for Higher Sodium: Some reports indicate sole can have a higher sodium-to-potassium ratio, which could be a factor for individuals monitoring their blood pressure.

Contamination Risks from Bottom-Dwelling Habits

One of the most significant disadvantages of sole fish stems from its bottom-dwelling nature. As a flatfish that resides on the seafloor, it is more susceptible to absorbing pollutants and heavy metals from the sediment.

Polycyclic Aromatic Hydrocarbons (PAHs)

Studies have analyzed biomarkers of contaminant exposure and found that sole fish in some areas are exposed to high amounts of PAHs. These are toxic chemicals that can be associated with DNA damage and cancer development in humans. PCBs (polychlorinated biphenyls) and dioxins are other industrial waste products that can accumulate in sole and other flatfish, posing a risk to the nervous system and overall health.

Heavy Metal Exposure

While sole fish are typically lower in mercury compared to larger predatory fish like shark or king mackerel, they still carry a risk of heavy metal contamination. This risk is particularly concerning for vulnerable populations such as pregnant women and young children. Although the FDA considers sole a "Best Choice" for low mercury content, the accumulation of other metals in bottom feeders is a valid concern.

Low Omega-3 Fatty Acid Content

Sole is a lean fish, which means it is much lower in heart-healthy omega-3 fatty acids compared to oily fish like salmon, sardines, and mackerel.

Nutritional Comparison

While lean fish like sole offer protein without high fat, they lack the high concentration of beneficial omega-3s (EPA and DHA) found in fatty fish, which are known to improve heart health, reduce inflammation, and support cognitive function. For individuals seeking to maximize their omega-3 intake, sole is a less optimal choice.

Unsustainable Fishing Practices

Most sole is caught using demersal trawls, a fishing method that has severe negative environmental and ecological impacts.

Damage to Habitats

Demersal trawls involve large nets being dragged across the ocean floor, which can cause long-term damage to sensitive benthic habitats. This destructive practice destroys coral, sponges, and other ecosystems that are critical for marine life.

Bycatch and Overfishing

Bottom trawling is notoriously non-selective, resulting in high levels of bycatch—the accidental catching and discarding of non-target fish and other vulnerable marine species. This unsustainable method contributes significantly to overfishing and reduces overall marine biodiversity.

Allergies and Histamine Risks

Allergies to whitefish, which includes sole, are a potential health risk, and improper handling can lead to food poisoning.

Whitefish Allergy

Fish allergies, particularly to whitefish, are relatively common and can cause symptoms ranging from hives to anaphylaxis. Individuals with a known fish allergy should avoid sole fish entirely.

Scombroid Poisoning

Another risk is scombroid poisoning, which can mimic an allergic reaction. This occurs when fish is improperly refrigerated, allowing bacteria to convert amino acids into histamine. Symptoms include flushing, headache, and dizziness. Proper storage and cooking are crucial to prevent this.

Sole Fish vs. Alternative Options: A Comparison


Feature	Sole Fish	Oily Fish (e.g., Salmon)	Lean Fish (e.g., Tilapia)
Omega-3s	Low	High	Low
Contaminants	Risk from bottom-dwelling; PAHs, PCBs	Varies by source, generally lower risk than bottom feeders; higher mercury in larger species	Varies by source; farmed tilapia can carry contaminants
Sustainability	Often caught by destructive bottom trawling; potential for overfishing	Varies greatly; wild-caught and farmed options can be sustainable	Varies; some farmed tilapia has sustainability concerns
Flavor	Mild, delicate, slightly sweet	Rich, pronounced, oily	Mild, neutral
Texture	Tender, flaky	Firm, buttery	Flaky, delicate
Ecological Impact	High due to trawling methods	Varies based on fishing/farming methods	Varies based on farming methods

The Problem with Farmed Sole

While some might turn to farmed sole to avoid the issues of wild overfishing, it presents its own set of challenges, including disease and cost.

Disease Outbreaks

Farmed sole are often raised in overcrowded, intensive systems, which can lead to rapid and devastating disease outbreaks. Historically, disease problems, particularly Pasteurellosis, have forced many European sole farms to close.

Inefficient Production

Research has shown that sole farming can be economically marginal, with issues like poor growth rates and high variation in size. The industry has faced persistent challenges with reproduction in captivity and requires significant research to be consistently viable.

The Cost Factor

Another practical disadvantage is the cost. Dover sole, a popular variety, can be relatively expensive. Consumers should consider if the nutritional value and potential risks justify the price compared to more nutrient-dense and sustainably sourced alternatives.

Conclusion

While sole fish can provide protein, it is not a perfect food choice due to a number of disadvantages. Key concerns include a higher risk of contaminants like PAHs from its bottom-feeding habits, a low omega-3 fatty acid content compared to oilier fish, and significant environmental damage caused by the common practice of bottom trawling. Additionally, farmed sole presents its own set of problems, including disease risks and high production costs. Consumers can find better alternatives by choosing other types of fish that offer a richer nutrient profile, are more sustainably sourced, and present fewer health risks related to contaminants.

Dr. Axe: "Sole Fish Dangers: 4 Reasons to Avoid This Flatfish" (Last Updated: October 01, 2023) https://draxe.com/nutrition/sole-fish/ Dr. Axe: "Sole Fish Dangers: 4 Reasons to Avoid This Flatfish" (Last Updated: October 01, 2023) https://draxe.com/nutrition/sole-fish/ Dr. Axe: "Sole Fish Dangers: 4 Reasons to Avoid This Flatfish" (Last Updated: October 01, 2023) https://draxe.com/nutrition/sole-fish/ Veganuary: "The Problems with Fish and Fish Farming" (May 26, 2023) https://veganuary.com/en-us/problems-fishing-fish-farming/ OEHHA: "Benefits and Risks of Eating Fish" https://oehha.ca.gov/fish/benefits-and-risks-eating-fish OEHHA: "Benefits and Risks of Eating Fish" https://oehha.ca.gov/fish/benefits-and-risks-eating-fish WebMD: "Does Dover Sole Have Health Benefits?" (June 14, 2024) https://www.webmd.com/diet/health-benefits-of-dover-sole FDA: "Advice about Eating Fish" (March 05, 2024) https://www.fda.gov/food/consumers/advice-about-eating-fish Seafood Watch: "Healthy and sustainable farmed Alaska flounder & sole" https://www.seafoodwatch.org/seafood-basics/sustainable-healthy-fish/nutritious-alaska-flounder-sole ACAAI: "Fish Allergy | Causes, Symptoms & Treatment" (March 21, 2019) https://acaai.org/allergies/allergic-conditions/food/fish/ Mayo Clinic: "Shellfish allergy - Symptoms and causes" (July 02, 2024) https://www.mayoclinic.org/diseases-conditions/shellfish-allergy/symptoms-causes/syc-20377503 Solid Starts: "Sole for Babies - First Foods for Babies" https://solidstarts.com/foods/sole/ ResearchGate: "Sole farming: nearly there but not quite?" https://www.researchgate.net/publication/233944299_Sole_farming_nearly_there_but_not_quite ResearchGate: "Sole farming: there or thereabouts" https://www.researchgate.net/publication/233944176_Sole_farming_there_or_thereabouts WebMD: "Does Dover Sole Have Health Benefits?" (June 14, 2024) https://www.webmd.com/diet/health-benefits-of-dover-sole

Frequently Asked Questions

No, sole fish typically have lower levels of mercury compared to larger predatory fish such as shark or swordfish. The FDA lists sole as a "Best Choice" for consumption due to its lower mercury content, making it a safer option for regular consumption, including for pregnant women and children.

Sole is often caught using demersal trawls, a method known for being environmentally destructive and contributing to overfishing and bycatch. Some sole species have been placed on red lists for unsustainable practices, so it is important to check the sourcing before purchasing.

Yes, allergies to whitefish, including sole, are not uncommon. Symptoms can range from mild (hives, congestion) to severe (anaphylaxis). Individuals with fish allergies should avoid sole and seek medical advice if they experience symptoms.

Sole is a lean, or white, fish, meaning it has a lower fat content compared to oily fish like salmon, sardines, or mackerel. Since omega-3 fatty acids are healthy fats, sole naturally contains a smaller amount, offering fewer heart and cognitive benefits.

Sole, as a bottom-dwelling flatfish, can accumulate environmental pollutants from the seabed. Contaminants can include polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and dioxins, which can pose health risks.

Farmed sole can have its own disadvantages, including risks of disease outbreaks due to overcrowded conditions and inconsistent quality. The production can also be economically marginal due to issues with reproduction and growth rates.

To minimize risks, always ensure the fish is fully cooked to an internal temperature of 145°F to kill any parasites or bacteria. Check the freshness and proper storage to prevent histamine buildup (scombroid poisoning). Sourcing sole from sustainable fisheries can also reduce environmental and some contamination concerns.