When it comes to choosing the healthiest and cleanest fish to eat, there are many factors to consider. Some key things to look for are levels of mercury and other contaminants, sustainability of fishing practices, and overall nutrition profile. The good news is that most fish and seafood can be part of a healthy diet if you make informed choices. This article will break down the types of fish that are lowest in contaminants and highest in health benefits. We’ll also explore sustainability issues and provide tips for choosing the best seafood options when shopping or dining out.
Why Eating Fish is Good For You
Fish is widely recognized as a healthy form of protein. Here are some of the top benefits of adding more fish to your diet:
- High in lean protein – Fish is an excellent source of complete, lean protein. Protein is essential for building and repairing muscles and tissues.
- Full of key nutrients – Fish provide important nutrients like iodine, selenium, vitamin D, calcium, zinc, iron and omega-3 fatty acids. These nutrients support heart health, brain function, growth and development, and more.
- May reduce heart disease risk – Eating fish 1-2 times per week is linked to lowered risk of heart attack and stroke.
- Good for brain health – The omega-3s in fish may boost memory, focus and brain function, especially DHA omega-3s.
The American Heart Association recommends eating fish (particularly fatty coldwater fish) at least twice a week for optimal health. The key is choosing sustainable fish that are lower in contaminants.
Most Common Contaminants in Fish
While fish can be very healthy, some types contain higher levels of contaminants like mercury, PCBs and dioxins that can build up in the body over time. Here are some of the most concerning contaminants found in certain fish:
Mercury
Mercury is a heavy metal that is released into the environment through pollution. It’s most concerning for children and women who are pregnant or may become pregnant due to potential effects on brain development. Long-lived, predatory fish tend to accumulate the most mercury.
PCBs
PCBs (polychlorinated biphenyls) are industrial chemicals that have been banned but still persist in the environment. They may disrupt hormone function and have other adverse effects in the body.
Dioxins
Dioxins are also industrial byproducts that tend to collect in fatty tissues. They are carcinogenic and linked to reproductive issues and problems with growth and development.
Other contaminants
Additional concerning contaminants that may be found in some fish include lead, arsenic, cadmium and toxaphene. However, mercury, PCBs and dioxins tend to be most common.
Low Contaminant Fish Choices
To limit exposure to heavy metals and other concerning contaminants, it’s best to choose fish that are lower on the food chain. These fish do not accumulate as many toxins in their tissues. Here are some of the top low contaminant choices:
Salmon
Wild Alaskan salmon is one of the best fish choices, providing a powerhouse dose of healthy omega-3 fats. It’s sustainably fished and low in contaminants. Atlantic farmed salmon may have more contaminants but is still a better choice than high mercury fish.
Sardines
Small oily fish like sardines, anchovies and herring tend to be very low in mercury and high in omega-3s. Canned sardines are one of the most sustainable protein sources.
Rainbow Trout
Farmed rainbow trout is another healthy option that’s raised in a sustainable manner and contains lower mercury levels.
Atlantic Mackerel
Mackerel is an excellent source of omega-3s, protein, niacin, selenium and vitamin B12. It generally has low mercury levels though some larger, longer-living mackerel may have moderately higher amounts.
Mussels
Farmed mussels are another sustainable choice that filters and cleans the surrounding water. They are very low in mercury and rich in healthy fats, zinc, iron and B vitamins.
Oysters
Farmed oysters are an eco-friendly choice packed with zinc, iron, copper, manganese and selenium. Mercury levels are very low in oysters.
Tilapia
Tilapia is a commonly consumed farm-raised fish that feeds on plant-based foods. It has low mercury levels and provides niacin, vitamin B12 and selenium.
Cod
Pacific and Alaskan cod are whitefish with very low mercury levels. They are rich in lean protein, vitamin B12 and selenium. Cod from the Atlantic Ocean tends to be more sustainable.
Catfish
In the U.S., catfish is mostly farm-raised in a sustainable manner. It has low contaminant levels and offers vitamin D, niacin, selenium and lean protein.
Pollock
Alaskan pollock is a tasty, mild whitefish that’s low on the food chain. It contains omega-3s, B vitamins and low mercury levels.
Shrimp
Shrimp harvested from U.S. waters is generally low in mercury and provides beneficial omega-3 fats. Opt for wild-caught or sustainably farmed shrimp.
Clams
Farmed clams are eco-friendly, low in mercury and rich in iron, zinc, selenium and vitamin B12.
Fish to Avoid Due to High Contaminants
On the other end of the spectrum, there are some fish that tend to be higher in mercury and other contaminants. It’s recommended that children and pregnant/nursing women avoid or limit consumption of these options:
King mackerel
King mackerel is one of the fish highest in mercury, containing around 0.73 ppm according to FDA data. It’s recommended that sensitive groups avoid king mackerel.
Marlin
Marlin is another large predatory fish that tends to accumulate high mercury concentrations. Levels above 1 ppm have been found, making it risky for children and pregnant women.
Orange roughy
Orange roughy lives a very long time, allowing it to build up higher mercury levels. It’s also often fished in an unsustainable manner from vulnerable habitats.
Chilean sea bass
Chilean sea bass is a popular fish, but it has been overfished in certain areas. Mercury levels are also moderately high, so aim to limit intake.
Bluefin tuna
Prized bluefin tuna has also suffered from overfishing. As a large predatory fish, it’s higher in mercury and should be eaten sparingly.
Grouper
Larger, older grouper fish tend to contain elevated mercury levels. It’s best for sensitive groups to avoid grouper.
Tilefish (Gulf of Mexico)
Tilefish caught in the Gulf of Mexico often have very high mercury concentrations, regularly testing above 1 ppm.
Swordfish
As a huge predator fish, swordfish accumulates very high amounts of mercury. FDA data shows average mercury concentrations around 1 ppm.
Shark
Various shark species also have very high mercury levels. They are apex ocean predators, leading to bioaccumulation of mercury in tissues.
Bigeye tuna
Bigeye tuna is another variety of tuna that tends to contain elevated levels of mercury compared to skipjack or yellowfin tuna due to its large size.
Crevalle jack
Crevalle jack is a common game fish found in warmer waters. It has moderate-to-high mercury concentrations, so limiting intake is wise.
Tips for Choosing the Cleanest Fish
Follow these tips when shopping and eating out to help identify the cleanest, healthiest fish options:
Check advisories
Consult local fish advisories that alert consumers about mercury, PCBs or other contaminants in certain fish species from specific waterbodies.
Buy sustainable
Look for sustainable fishing certification from organizations like the MSC (Marine Stewardship Council). This ensures healthy populations.
Choose smaller, younger
Larger, older fish accumulate more mercury over their lifespan. Opt for smaller, younger varieties.
Vary fish choices
To limit exposure to any one contaminant, vary the types of fish you eat from week to week.
Purchase fillets
Contaminants often concentrate in fatty parts of the fish. Buying filleted fish helps remove some of these sections.
Remove skin, fat
When preparing fish at home, slice off the fatty belly area, skin, and any visible fat deposits.
Limit fried fish
Fried fish absorbs and concentrates oils, increasing the potential for exposure to accumulated contaminants.
The Bottom Line
There are plenty of nutritious fish in the sea that can be part of a healthy diet. Just be sure to choose sustainable options that are lower on the food chain and avoid fish known to accumulate higher mercury levels and contaminants. This allows you to reap the nutritional benefits of fish without the unwanted toxins. Following seafood guides and advisories can make it easier to identify the healthiest and cleanest fish choices for you and your family.