Is It Unhealthy to Eat Too Much Fish?

Sheri Cyprus

Although fish is an extremely healthy, low calorie protein source that contains nutritious omega-3 fatty acids, it is possible to eat too much of it. The first thing to consider is that since healthy eating means a balanced, portion-controlled diet, eating too much fish or any other food is not recommended. Beyond that, high mercury levels are the main reason for not consuming large amounts of fish.

It is possible to eat too much fish.
It is possible to eat too much fish.

Many health experts warn that eating too much fish can create a toxin build up of mercury in the body. Mercury is a metallic element that is toxic in high doses. It gets into the water supply from traces of medical waste or power plants. Fish swimming in that water then become contaminated with mercury.

Chunk light tuna tends to contain less mercury than albacore tuna.
Chunk light tuna tends to contain less mercury than albacore tuna.

Fish can be a good part of a balanced diet. Avoiding fish is thought to place individuals at risk for brain, nerve, and heart problems. Most health experts recommend avoiding too much fish, due to the mercury risk, but to consume it weekly in limited amounts. The recommended amount of most fish and shellfish per adult per week is a maximum of 12 ounces (340 g). Larger fish such as tuna, shark, golden bass, swordfish, and king mackerel should be limited to 6 ounces (170 g) weekly at the most.

Farmed fish can contain antibiotics.
Farmed fish can contain antibiotics.

Pregnant women, nursing mothers, and young children should avoid larger fish varieties. Instead, they should eat other types of fish and seafood in small quantities. Toxic levels of mercury are said to be found mostly in the larger species of fish. Babies, young children, and women of child-bearing age are especially susceptible to the possible harmful effects of mercury. If a person from a lower risk group is going to eat tuna, it's generally considered best to choose chunk light, water pack types rather than albacore or oil packed versions.

Mercury poisoning, possibly from sources such as too much fish, may cause birth defects or brain damage. Symptoms of mercury poisoning in adults or children include pink or red cheeks and fingertips, as well as loss of hair, teeth, and nails. Skin rashes and organ damage are also thought to be caused by high mercury levels such as those from too much fish. Vision, speech, and hearing disorders have also been linked to mercury poisoning.

Another problem that may be caused by eating too much fish involves the ingestion of antibiotics in the fish. Antibiotics are medicines given to fish to control bacterial diseases. While wild fish may still absorb antibiotics from toxic waste in the water, traces of the drugs are most likely to be found in farmed fish. Further complicating the problem is the lack of antibiotic dosing regulations in the fish farming industry in some parts of the world. Fish farming involves raising food fishes in a limited area; antibiotics are used to keep bacteria from spreading throughout the stock.

Fish should be part of a balanced diet, but too much of it can create a buildup of mercury.
Fish should be part of a balanced diet, but too much of it can create a buildup of mercury.

You might also Like

Readers Also Love

Discussion Comments


When I decided to cut back on red meat, I started eating a lot of baked fish, mostly salmon filets and tilapia. I can see where eating nothing but fish as a protein source at every meal would get old, but I don't know that it would be unhealthy. I think when you talking about unhealthy fish, it's mostly those deep ocean fish like swordfish and tuna that pick up all of those poisons. Farm-raised catfish or rainbow trout probably doesn't have all of those contaminants in them.

I will say that fresh fish can be a lot like raw chicken. You had better handle it right and cook it before it has a chance to get funky. The problem with sushi is that if it stays out on a buffet bar too long, it can make you sick. A typical fried fish sandwich with tartar sauce from a fast food place may not be any healthier than a hamburger, either.


Several of my friends have actually had food poisoning from sushi. I like sushi too but have never been a big fan of raw fish, so I have vegetarian sushi with avocado and cucumber.

Raw fish has to be eaten really fresh or it can spoil. My friends have sushi for lunch or dinner three or four times a week. It's a really healthy meal but you have to make sure that the restaurant you are eating at is very particular about using fresh fish. Otherwise, food poisoning will be inevitable.

Post your comments
Forgot password?