Is plaice safe to eat? (Health benefits)

In this brief guide, we will answer the question “Is plaice safe to eat?”. We also will discuss how mercury concentration can make some fish species unsafe to consume.

Is plaice safe to eat?

Yes, plaice is considered safe for consumption. European plaice (Pleuronectes platessa) has been a subject of significant commercial interest in Europe for several decades, particularly in the Northern Sea.

The Netherlands holds a substantial share of the flatfish capture, followed by Denmark, and the United Kingdom. This demersal fish species is found in muddy or sandy areas near the seabed. With its commendable digestibility and a well-distributed array of essential amino acids, plaice stands as a reliable source of high-quality proteins. (1)

What is the nutritional profile of plaice?

The European plaice is made up of about 81% water, 16.6% prote­in, 0.8% fat, and 0.9% ash. Furthermore­, marine proteins, like the ones in plaice, are known for their nutritional benefits because they are easily absorbe­d by the body and contain essential pe­ptides and amino acids.

It also contains important long-chain polyunsaturated fatty acids (LC-PUFAs) that have a positive impact on human health by being involved in various physiological, molecular, and ce­llular processes. (1, 2)

The fle­sh of plaice provides important macronutrients, including e­ssential trace ele­ments like calcium and sele­nium. Calcium is crucial for bone density and is very important in me­tabolic processes. Additionally, sele­nium deficiencies can cause various diseases.

Fish, including plaice, provides high-quality protein and ranks among the top dietary sources of long-chain omega-3 fatty acids, particularly DHA and EPA. These omega-3 fatty acids are crucial for a healthy diet, playing a significant role in promoting cardiovascular health, as well as supporting the development of the brain and eyes. (2, 3)

What are the potential risks of plaice consumption?

When e­ating plaice, it’s important to be mindful of potential contaminants like methylmercury, dioxins, and polychlorinated biphe­nyls (PCBs). These substances can build up in pre­datory fish and other creatures at the top of the food chain.

Methylmercury, a type of mercury that occurs naturally in things like volcanoes and the atmosphere, ente­rs the environment through human activitie­s such as improper disposal of fungicides, antiseptics, or batte­ries.

Methylme­rcury can harm human health, especially for pre­gnant women since it can pass through the place­ntal walls. When pregnant women are exposed to high levels of methylmercury, it can affect the development of the baby’s brain. Another concern is the buildup of persistent organic pollutants like PCBs in the human body, which can be toxic and stay for a long time. (1, 2)

What are the health hazards of methylmercury?

Methylmercury, a form of organic mercury, has notable impacts on both the central and peripheral nervous systems in humans. When it comes to fetal exposure, the adverse effects on the developing brain tend to be more pronounced than in adults.

Whether exposed for a short or long duration to unusually high levels of methylmercury, the onset of neurological symptoms is often subtle and may include manifestations such as hearing loss, restlessness, and blurred vision. Subsequent symptoms may include difficulty speaking, poor coordination, and, in severe cases, coma or even death.

Following ingestion, organic mercury, particularly methylmercury, is readily absorbed from the intestine and distributed extensively throughout the body. Methylmercury easily penetrates the blood-brain barrier and placenta, posing a significant risk to both health and developmental processes. (3)

Should plaice be avoided?

No. On average, plaice typically contains around 0.06 parts per million (ppm) of mercury. As a general principle, fish higher up the food chain tend to exhibit higher mercury levels. Species like barracuda, escolar, marlin, orange roughy, sablefish, sea bass, shark, swordfish, and certain types of tuna have been found to have total mercury levels that average around or exceed 0.5 ppm.

Notably, marlin, shark, swordfish, and specific fresh tuna species have reported average total mercury levels surpassing 1.0 ppm.

The FDA and EPA caution against the consumption of seven types of fish during pregnancy due to elevated mercury levels. These species include shark, king mackerel, swordfish, Gulf of Mexico tilefish, marlin, orange tilapia, and bigeye tuna. Plaice, however, falls under the “Best Choices” category, representing fish with the lowest mercury levels.  (3, 4)


In this brief guide, we answered the question “Is plaice safe to eat?”. We also discussed how mercury concentration can make some fish species unsafe to consume. In my perspective as a food scientist, plaice is safe and can be consumed every day offering no risk.

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KENDLER, Sophie et al. Nutritional profiling and contaminant levels of five underutilized fish species in Norway. Frontiers in Nutrition, v. 10, p. 1118094, 2023.


HEALTH CANADA. Human health risk assessment of mercury in fish and health benefits of fish consumption. Bureau of Chemical Safety, Minister of Health, 2007.


DEWAILLY, Éric et al. Balancing the risks and the benefits of local fish consumption in Bermuda. Food Additives and Contaminants, v. 25, n. 11, p. 1328-1338, 2008.