Smart Seafood Choices: Navigating Mercury and PCB Levels
Are You Feeding Your Family the Right Fish?
You’re committed to a healthy lifestyle—choosing nutritious meals, avoiding harmful chemicals, and making the best decisions for yourself and your family. But when it comes to fish, things can get tricky. You’ve heard about the benefits of omega-3 fatty acids, but you’ve also heard warnings about mercury and industrial contaminants. How do you know which fish are truly safe and nourishing?
This guide takes the guesswork out of seafood choices by helping you balance maximum nutrition with minimal toxins.
The Best (and Worst) Fish Choices for Your Health
Some fish pack a powerful punch of omega-3s while carrying low levels of contaminants like mercury and PCBs. Others, unfortunately, come with a side of heavy metals and toxins.
Top Choices (High Omega-3, Low Contaminants)
- Anchovy (2055 mg omega-3, <0.05 ppm mercury)
- Herring (2014 mg omega-3, <0.05 ppm mercury)
- Mackerel (Atlantic) (1203 mg omega-3, 0.05 ppm mercury)
- Wild Salmon (1043 mg omega-3, <0.05 ppm mercury)
- Sardines (982 mg omega-3, <0.05 ppm mercury)
These fish deliver all the brain-boosting, inflammation-fighting benefits of omega-3s without the toxic burden.
Fish to Eat in Moderation (Moderate Mercury Levels)
- Halibut (465 mg omega-3, 0.25 ppm mercury)
- Tuna (Light/Skipjack) (270 mg omega-3, 0.12 ppm mercury)
- Trout (935 mg omega-3, 0.07 ppm mercury)
- Snapper (321 mg omega-3, 0.19 ppm mercury)
While these options have some nutritional benefits, it’s best to limit them to occasional meals.
Fish to Avoid (High Mercury and PCBs)
- Shark (689 mg omega-3, 0.99 ppm mercury)
- Swordfish (819 mg omega-3, 0.98 ppm mercury)
- King Mackerel (401 mg omega-3, 0.73 ppm mercury)
- Tilefish (not listed but known for high mercury levels)
- Lobster (84 mg omega-3, 0.31 ppm mercury)
These varieties may be delicious, but their toxic load outweighs their benefits.
This is a reference table to help us choose fish that has the highest Omega 3 fatty acids, along with the lowest toxic contaminants.
Looks like the winners are Anchovy, Herring, Mackerel and Wild salmons.
Omega-3 fatty acids and industrial contaminants in commonly eaten fish and shellfish.
| Type | EPA + DHA (mg/serving) (oz) | EPA + DHA (mg/100 g) (3.5 oz) | Mercury (µg/g) (ppm) | PCBs (ng/g) (ppb) |
| Anchovy | 1165 (2) | 2055 | < 0.05 | |
| Catfish, farmed | 253 (5) | 117 | < 0.05 | < 50 |
| Cod, Atlantic | 284 (6.3) | 158 | 0.10 | |
| Fish burger (fast food) | 337 (2.2) | 546 | < 0.05 | 8 |
| Fish sticks, frozen | 193 (3.2) | 214 | < 0.05 | |
| Halibut | 740 (5.6) | 465 | 0.25 | |
| Herring, Atlantic | 1712 (3) | 2014 | < 0.05 | |
| Mackerel, Atlantic | 1059 (3.1) | 1203 | 0.05 | |
| Mackerel, King | 618 (5.4) | 401 | 0.73 | |
| Mahimahi | 221 (5.6) | 139 | 0.15 | |
| Pollock, Alaskan | 281 (2.1) | 468 | < 0.05 | |
| Salmon, farmed | 4504 (6) | 2648 | < 0.05 | 15–51 |
| Salmon, wild | 1774 (6) | 1043 | < 0.05 | 0.5–5 |
| Sardines | 556 (2) | 982 | < 0.05 | 22–57 |
| Shark | 583 (3) | 689 | 0.99 | |
| Snapper | 546 (6) | 321 | 0.19 | |
| Swordfish | 868 (3.7) | 819 | 0.98 | |
| Trout | 581 (2.2) | 935 | 0.07 | 11 |
| Tuna (light/skipjack) | 228 (3) | 270 | 0.12 | 45 |
| Tuna (white/albacore) | 733 (3) | 862 | 0.35 | 100 |
| Clams | 241 (3) | 284 | < 0.05 | 2–3 |
| Crab | 351 (3) | 413 | 0.09 | 6 |
| Lobster | 71 (3) | 84 | 0.31 | |
| Mussels | 665 (3) | 782 | < 0.15 | 0.8–7 |
| Oysters | 585 (3) | 688 | < 0.05 | 0.8–17 |
| Scallops | 310 (3) | 365 | < 0.05 | |
| Shrimp | 267 (3) | 315 | < 0.05 | 0.2–2 |
DHA: Docosahexaenoic acid; EPA: Eicosapentaenoic acid; PCB: Polychlorinated biphenyls; ppb: Parts per billion; ppm: Parts per million.
Making Safe, Smart Seafood Choices
Fish can be a powerful superfood—or a hidden source of toxins—depending on what you choose. By selecting cleaner options, you’re protecting your health, supporting your body’s natural detox pathways, and ensuring that what’s on your plate is truly working for you.
Hi, I’m Dr. Onna Lo. I’m an Ivy League-trained, board-certified Family Medicine, Integrative and Functional Medicine doctor and founder of the Vitality Renew Program. I help smart, powerful women reclaim their vitality, joy, and balance through integrative and functional medicine. I don’t believe in “just managing” symptoms or staying stagnant. Imagine being empowered and championed in your health journey so you can thrive. This is Unstuck Medicine—real answers, real transformations.
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We are a virtual and in-person Integrative Medicine Clinic helping women break free from exhaustion, brain fog, and burnout with a clear way forward—so you can reclaim your energy, clarity, and live your fullest potential. I’m Dr. Onna Lo. I’m an Ivy League-trained, board-certified Family Medicine, Integrative and Functional Medicine doctor and founder of the Vitality Renew Program.
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References:
1. O'Keefe JH, Torres-Acosta N, O'Keefe EL, et al. A Pesco-Mediterranean Diet With Intermittent Fasting: JACC Review Topic of the Week. Journal of the American College of Cardiology. 2020
2. Weinberg RL, Brook RD, Rubenfire M, Eagle KA. Cardiovascular Impact of Nutritional Supplementation With Omega-3 Fatty Acids: JACC Focus Seminar. Journal of the American College of Cardiology. 2021.
3. Ginsberg GL, Toal BF. Quantitative Approach for Incorporating Methylmercury Risks and Omega-3 Fatty Acid Benefits in Developing Species-Specific Fish Consumption Advice. Environmental Health Perspectives. 2009.
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Disclaimer:
This information is for educational purposes only and is not intended as medical advice. Consult a qualified healthcare professional before making any health-related decisions. Individual results may vary.