Fish: A Closer Look

Introduction

There are many health benefits when eating fish, but do the health benefits outweigh the health risks?

Fish carry many pollutants, especially mercury, a neurotoxin (a poison) affecting the brain and nervous system.  Ironically, fish is known as “brain food” because it is a rich source of omega-3 fatty acids—an essential amino acid that the body doesn’t produce and must be obtained in your diet.

In this blog, I review five facts about fish you should know before you decide to keep it in your diet (if you eat fish) or rethink your consumption.

If you don’t like fish but still want the health benefits, I’ve got you covered!

#1 Fish contains contaminates – mainly mercury

Mercury naturally occurs in the air, water, soil, and rock but it comes with health concerns, especially in larger amounts.  It can have toxic effects on your nervous system (particularly your brain & spinal cord) lungs, kidneys, skin, eyes, and digestive and immune systems.  That about covers everything! When you eat fish from waters that are contaminated with mercury, you’re ingesting the methylmercury accumulated from the tissue of the fish.  Hence the reason it’s recommended to eat a limited amount in a week.

Fish also absorb chemicals and pesticides in addition to mercury.   More on how mercury gets into the water sources.

Health tip:  There’s no method of cooking or cleaning fish that will reduce mercury levels.

When deciding what type of fish to eat, you should have an idea of which fish is high and low in mercury. Below are common types of fish (not an exhaustive list).

Fish with high levels of mercury

• King mackerel
• Marlin
• Orange roughy
• Seabass
• Shark
• Swordfish
• Tilefish
• Tuna (ahi, albacore, bigeye)

Fish with low levels of mercury

• Cod
• Flounder
• Haddock
• Perch
• Pollock
• Salmon

Other seafood low in mercury

• Anchovies
• Clams
• Crab
• Eel
• Sardines
• Scallops

Search the fish you eat from the Monterey Bay Aquarium Seafood Watch.  This is an excellent resource and buying guide.

Health tip:  The larger and older the fish, the more mercury. 

#2 The health benefits of fish

The Standard American Diet (SAD) lacks an adequate amount of omega-3 fatty acids.  Fatty fish (oily fish) is an easy way to incorporate this essential nutrient into your diet.

Fish is an excellent source of protein, vitamins, and nutrients and is lower in fat than meat if it’s not a fatty fish like salmon or herring.  Each fish comes with their health benefits.  For instance, salmon is known as a fatty fish that contains omega-3 fatty acids, however not all salmon are the same.

Each fish will have a different nutrient content depending on whether it’s farm-raised or from another source of water like the ocean, usually referred to as wild-caught.

Health tip: Salmon is higher in calcium and lower in fat when it comes from the ocean and is not farm-raised.

#3 Wild-caught vs farm raised fish

Before you buy fish, it’s important to know where it comes from.  There are so many conflicting sources for the “best choice” of fish to eat.  For example, canned tuna is typically albacore tuna, but “chuck light” tuna is usually skipjack tuna which is lower in mercury than albacore tuna.

Fish have different diets depending on where they originate from.

Health tip:  Salmon is the best choice of fish for low levels of mercury and high in nutrients.

Wild-caught fish are captured by fishermen in their natural environments such as lakes, rivers, and oceans.

Farm-raised fish are bred in controlled environments (lakes, rivers, oceans, tanks, or pens).

Pro tip:  90% of fish eaten comes from farm-raised conditions.

Contaminants

Both classes (wild-caught and farm-raised) of fish will ingest contaminants from the water they live and eat from. Farmed-raised fish have a higher level of impurities than wild-caught because there are rules that govern what is fed to the fish depending where they’re raised.  Different types of fish will inhibit distinct types of pollutants depending on the waters where the fish live.

Antibiotics

Farm-raised fish are given antibiotics in their feed due to the infections and diseases they’re exposed to because of high-density conditions—too many fish in the pond. You eat what the fish eats, including antibiotics!  Maybe you should eat fish soup instead of chicken soup when you’re sick. 😊

Health tip:  Avoid Atlantic salmon from Canada, Chile, Norway, and Scotland unless you can confirm it’s from a good alternative source.

True patient story:  When I taught diabetic classes years ago, I was asked why blood sugar would increase after eating fish. I didn’t know the answer because that was extremely abnormal.  The only food consumed was fish, nothing else.  It didn’t make sense because fish is a protein that shouldn’t increase blood sugar.  After further investigation, the fish found to be farm-raised and was fed corn.  Corn will increase blood sugar, not fish. So, it turns out, what the fish eat, you eat as well, and affects your health.

#4 How much fish in a week?

It’s recommended to eat fish twice a week, but how much fish is the real question. 

If you’re eating fish low in mercury, you can have 12 ounces in a week.  It’s up to you how you want to split it up.  You can have 6 ounces twice a week; 4 ounces 3 times a week or 3 ounces 4 times a week.  It’s your choice!

If you’re not sure of what type of fish you’re eating, it’s recommended to only eat 6 ounces for the week.

Health tip: Canned albacore tuna contains high levels of mercury.

#5 Fish “substitutes”

If you don’t eat fish but you’d like the benefits of the nutrients it provides, take an omega-3 supplement.

More on the many different types of omega-3 supplements in a future blog.  For now, I recommend a cod liver oil (extra virgin) supplement or fish oil (krill oil supplement).

Some plant-based foods like flaxseed or flaxseed oil and chia seeds are a good replacement for fish to obtain the benefits of omega-3 fatty acids.

Health tip: Seaweed and algae contain omega-3 fatty acids too with fewer pollutants.

Expense

It’s more expensive to purchase wild-caught fish than farm-raised, so depending on your budget you may need to buy farm-raised fish or alternate between the two.

Excreting mercury

Methylmercury can take about 70 days to leave the body mainly through feces (poop) and not so much in the urine. 

Health tip:  Urine is not a good indicator of mercury in the body.

Conclusion

So, do you think the benefits of eating fish outweigh the health risks?  Leave me a comment. I’d love to hear your thoughts.

If you’re concerned about how much mercury is in your body, ask your doctor for a mercury blood test. Before purchasing fish, check for local advisories when eating fish in your area. Once on the site, select the state where you’re eating the fish and the waterbody to find out if any safety warnings are posted.

Check out this guide in more detail about the levels of mercury in any fish so you can make an informed and educated decision regarding your health.

In optimal health,

Lisa