Mercury in Fish: Understanding the Risks

How to enjoy the benefits of fish while avoiding hidden risks

Fish is often considered a healthy choice; rich in protein, omega-3 fatty acids, and important micronutrients. But in today’s world, pollution has changed the picture. Many fish now carry traces of mercury and other contaminants, which can build up in the body over time.

Understanding which fish are higher risk, and how to make safer choices, helps you enjoy the benefits of seafood while protecting your health.

Why Mercury Matters

Mercury is a naturally occurring metal, but industrial pollution has dramatically increased levels in rivers, lakes, and oceans. When mercury enters waterways, it is converted into methylmercury, a toxic form that accumulates in fish.

Mercury exposure can affect:

• The nervous system and brain, especially in unborn babies and young children.

• Energy and concentration, with high exposure linked to fatigue and brain fog.

• Overall health, as mercury builds up in fatty tissues, organs, and brain over time.

The biggest concern is bioaccumulation: larger, older fish that sit higher in the food chain tend to contain the most mercury.

Fish to Limit or Avoid

High-mercury fish are best avoided, especially for pregnant women, breastfeeding mothers, and children. These include:

• Shark.

• Swordfish.

• King mackerel.

• Tilefish.

• Tuna.

Even for adults, these fish are best limited to very occasional consumption.

Safer Seafood Choices

Smaller fish tend to have much lower mercury levels. Safer options include:

• Salmon (wild-caught, not farmed where possible).

• Sardines.

• Anchovies.

• Herring.

• Trout (freshwater, farmed responsibly).

These provide omega-3 fatty acids without the same mercury risk as larger predatory fish.

Alternatives to Eating Fish

If you want to reduce or avoid fish but still benefit from omega-3s, consider:

• Filtered fish oil supplements — many reputable brands test for and remove heavy metals and other contaminants.

• Algal oil supplements — a plant-based source of DHA and EPA (the key omega-3s found in fish).

• Flaxseeds, chia seeds, and walnuts — good sources of ALA, another form of omega-3 that the body can partially convert.

Supporting Your Detox Pathways

The body naturally detoxifies mercury and other toxins, but you can support this process through your diet:

• Cruciferous vegetables (broccoli, cabbage, Brussels sprouts, bok choy).

• Allium vegetables (garlic, onions, shallots).

• Green tea and black tea.

• Berries and grapes (rich in antioxidants).

• Spices like turmeric, rosemary, basil, and cumin.

These foods are rich in compounds that help the liver process and eliminate toxins more efficiently.

In Summary

Fish can still be part of a healthy diet, but choosing wisely is key. Avoid the large, high-mercury fish, enjoy smaller species in moderation, and consider high-quality omega-3 supplements if you prefer not to eat fish. Pairing these choices with a diet rich in detox-supportive foods will help reduce the impact of toxins and support your long-term wellbeing.

This post is for educational purposes only and is not a substitute for medical advice. If you are concerned about mercury exposure, please speak to your GP or a qualified healthcare professional.