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  • Writer's pictureBrian Dooreck MD

Fish Consumption and Mercury Levels

Updated: Jul 24, 2023

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Fish contain omega-3 fatty acids.

Let's dive right in: fish are incredibly nutritious and are an active source of high-quality protein. This is because they contain essential nutrients, including omega-3 fatty acids (DHA and EPA), that support your digestive tract. While fish have health benefits, you must control your daily intake.

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Federal Dietary Guidelines recommend at least 8 ounces of seafood (less for young children) per week based on a 2,000 calorie diet.

How does fish consumption affect your gut health?

Fish such as salmon and tuna are excellent for your digestive tract. Omega-3 fatty acids play a significant role in healthy bowel function by working to keep digestion flowing smoothly.

In addition, the iron in fish is essential in the diets of pregnant women and women who may become pregnant. The nutrients can be passed to their baby by eating the right fish. However, remember that it's best to avoid fish known to be high in mercury.

Which fish should I eat or avoid to sustain my health?

Since salmon, sardines, and tuna are high in omega-3 fatty acids, they aid digestion and reduce inflammation in the gut. Contrarily, consuming fish high in mercury may have severe or fatal effects on your kidney, lungs, digestive tract, or cardiovascular system.

The following are the five primary fish to avoid to decrease your exposure to dietary mercury:

  1. Swordfish

  2. Shark

  3. Tilefish

  4. King Mackerel

  5. Bigeye Tuna

Here's a diagram displaying the best, suitable, and worst fish options. Which category of fish do you consume the most?

Healthy fish help your gut diversity.
Healthy fish help your gut diversity.

Traits of Spoiled Fish

How can you tell the difference between fresh and rotten fish? Firstly, spoiled fish has an unpleasant smell, is covered with sticky slime, and is grayish-brown in appearance. When inspecting food, notice that old fish does not 'bounce' and is soft to the touch. In contrast, fresh fish should be first to touch.

Beware of Salmonella

While fish can be incredibly nutritious, eating raw or undercooked fish can result in severe food poisoning. Salmonella is a prevalent food poisoning from bacteria that causes gastrointestinal distress.

The overall incidence of Salmonella was 7.2% for imports and 1.3% for domestic seafood. Nearly 10% of imports and 2.8% of domestic raw seafood were positive for Salmonella.

Check out the Office of Environmental Health Hazard Assessment (OEHHA) video, "Benefits and Risks of Eating Fish."

What if I don't eat fish but still want the omega-3 benefits?

Omega-3 fatty acids can be found in nuts, seeds, and many plant-based foods and oils. Likewise, they are not the same as the EPA and DHA found in fish and eggs.

The other source of omega-3s is the form of alpha-linolenic acid (ALA), which can be found in soybean, canola, and flaxseed oils. Green vegetables such as kale and spinach also contain ALA.

Here are some plant-based alternatives to consider:

  • Flaxseeds

  • Mixed greens

  • Canola oil

  • Walnuts

  • Soybeans and tofu

How about Omega-3 Supplements?

DHA and EPA acids are found in omega-3 fish oil and can improve cardiovascular health. Regular fish oil supplements may have health benefits, but consult your doctor to determine whether they fit you.

The American Heart Association stated that omega-3 fish oil supplements prescribed by a clinician may prevent death from heart disease.

How much Omega-3 should I take per day?

The American Heart Association (AHA) recommends taking up to 3 grams of fish oil daily to be safe. Do not take more than the considered amount without first consulting your doctor.

Bottom Line

Fish is rich in calcium and filled with omega-3 fatty acids and vitamins such as D and B2 (riboflavin). Eating fish or taking fish oil benefits the heart and digestive system. Nevertheless, be cautious of bad fish by observing the surface's thin layer.

While foods are the finest source of omega-3s, fish oil vitamins are also available for individuals who do not enjoy fish. To receive the health benefits you need, ask your doctor for the recommended dose of fish oil supplements.


I eat a high-fiber, mostly plant-based 🌱 diet, no red meat, drink 4 liters of water a day, exercise, and am focused on keeping nutrition simple. I am sharing what works for me and what I routinely recommend to my patients.

"Balance. Portion control. Keep nutrition simple. Eat Smart. Eat Healthy. 🌱 🌾 🌿"

Gut Health ➕ Patient Advocacy with Navigation ➕ Life Balance

If you were looking for information about Private Healthcare Navigation and Patient Advocacy from Executive Health Navigation

Connect with Dr. Dooreck on LinkedIn, where he focuses his sharing on Health, Diet, Nutrition, Exercise, Lifestyle, and Balance.


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