I've heard that salmon is high in dangerous PCBs. So what are PCBs and what risk do they pose?

Answer From Jennifer K. Nelson, R.D., L.D.

Polychlorinated biphenyls (PCBs) are industrial chemicals that were manufactured from 1929 until 1979 when they were banned. PCBs have been shown to cause adverse health effects, including potential cancers, and negative effects on the immune, nervous and endocrine systems.

PCBs can pose serious health risks to people who frequently eat contaminated fish. They can be transferred from a mother to her unborn baby, increasing the risk of preterm delivery and low birth weight. They may also be transferred from mother to baby through breast milk, and exposure has been associated with learning defects.

PCB remnants still cycle between air, water and soil, and traces are found all over the world. They settle into water and sediment, where they are taken up by small organisms, and increasingly accumulate in fat and organs such as liver in fish and animals (including humans) that eat fish. Small amounts are found in meat, dairy products and drinking water. Fish are the major dietary sources of PCBs, especially fish caught in contaminated lakes or rivers.

Level of PCBs found in fish will vary with region and the type of fish native to that region. So if you eat fish caught by family or friends, check for local advisories. In general, bottom-feeding fish (striped bass, bluefish, American eel, sea trout) and larger predator fish (bass, lake trout, walleye) caught in contaminated waters contain higher levels of PCBs.

Farmed salmon that are fed ground-up fish have been found to be higher in PCBs, compared with wild-caught salmon.

The Food and Drug Administration sets PCB residue limits for foods, while the Environmental Protection Agency sets limits for lakes, streams and drinking water. They recommend the following measures to reduce exposure to contaminants such as PCB:

  • Trim away fatty areas (belly, top back and dark meat along the side)
  • Remove skin before cooking to allow fat to drain off
  • Grill, bake or broil fish and allow fat to drain off
  • Do not fry or deep-fry fish because frying seals in any chemical pollutants in the fish's fat

Two other groups, Physicians for Social Responsibility and the Association of Reproductive Health Professionals, suggest limiting your intake of fish containing high levels of PCBs, such as salmon and bluefish. With respect to salmon, their guidelines say:

  • Canned Pacific salmon can be eaten twice a week
  • Fresh or frozen wild Pacific salmon can be eaten up to twice a month
  • Fresh or frozen farmed Atlantic salmon can be eaten once every two months

The bottom line: Eat a variety of fish twice a week and keep the portion size at 4 ounces (113 grams). When you eat fatty fish such as salmon, make sure it is prepared using the above guidelines. When you catch your own fish, follow local and state fish advisories for restrictions.

May 22, 2019 See more Expert Answers

See also

  1. MIND diet may cut Alzheimer's risk
  2. 3 diet changes women over 50 should make right now
  3. 3 key changes in the new Nutrition Facts label
  4. Healthy-eating habits
  5. Reduce sugar in your diet
  6. Acai berries
  7. Added sugar
  8. Alcohol use
  9. Alkaline water
  10. Are energy drinks bull?
  11. Artificial sweeteners and other sugar substitutes
  12. Autism spectrum disorder and digestive symptoms
  13. Bad food habits at work? Get back on track in 5 easy steps
  14. Best oil for cooking?
  15. 2015-2020 Dietary guidelines
  16. Boost your calcium levels without dairy? Yes you can!
  17. Breast-feeding nutrition: Tips for moms
  18. Caffeine: How much is too much?
  19. Is caffeine dehydrating?
  20. Calorie calculator
  21. The role of diet and exercise in preventing Alzheimer's disease
  22. Can whole-grain foods lower blood pressure?
  23. Carbohydrates
  24. Chart of high-fiber foods
  25. Cholesterol: Top foods to improve your numbers
  26. Coconut water: Healthy drink or marketing scam?
  27. Coffee and health
  28. Diet soda: How much is too much?
  29. Dietary fats
  30. Dietary fiber
  31. Prickly pear cactus
  32. Does soy really affect breast cancer risk?
  33. Don't get tricked by these 3 heart-health myths
  34. Don't go cuckoo for coconut water
  35. Make healthy snack choices
  36. Eat more of these key nutrients
  37. Eggs: Bad for cholesterol?
  38. Energy drinks
  39. Fat grams
  40. For a healthy gut, feed the good bugs
  41. Fiber: Soluble or insoluble?
  42. Fit more fiber into your diet
  43. Get to know the new Nutrition Facts label
  44. Grape juice health benefits
  45. Guidelines for a good ileostomy diet
  46. Is chocolate healthy?
  47. Healthy heart for life: Avoiding heart disease
  48. Healthy-eating tip: Don't forget fiber
  49. High-fructose corn syrup
  50. High-protein diets
  51. Alcohol during the holidays: 4 ways to sip smarter
  52. Holiday weight: How to maintain, not gain
  53. How the right diet can help an overactive bladder
  54. Takeout containers
  55. Is there more to hydration than water?
  56. Juicing is no substitute for whole foods
  57. Juicing
  58. Depression and diet
  59. Limit bad fats, one step at a time
  60. Make food labels required reading
  61. Monosodium glutamate (MSG)
  62. MUFAs
  63. Multigrain vs. whole grain
  64. Need a snack? Go nuts!
  65. Need more fiber? Take 3 steps
  66. Nutrition Facts label
  67. Nutrition rules that will fuel your workout
  68. Nuts and your heart: Eating nuts for heart health
  69. Omega-3 in fish
  70. Omega-6 fatty acids
  71. Phenylalanine
  72. Play it safe when taking food to a loved one in the hospital
  73. Protein: Heart-healthy sources
  74. Healthy eating plans
  75. Raw water: Risky fad?
  76. Reduce sugar in your diet
  77. Health foods
  78. Portion control
  79. Planning healthy meals
  80. High-fiber diet
  81. Social eating can be healthy and enjoyable
  82. Sodium
  83. Sodium: Look beyond the saltshaker
  84. Stevia
  85. Tap water or bottled water: Which is better?
  86. Taurine in energy drinks
  87. The best foods for healthy skin
  88. Time to cut back on caffeine?
  89. Time to scale back on salt?
  90. Trans fat
  91. Underweight: Add pounds healthfully
  92. Want a healthier dinnertime? Science says change your eating space
  93. Daily water requirement
  94. Functional foods
  95. What is clean eating?
  96. What's considered moderate alcohol use?
  97. What's the difference between juicing and blending?
  98. Why does diet matter after bariatric surgery?
  99. Working out? Remember to drink up
  100. Yerba mate