Fish, explained.
Nov 30, 2020
Fish can be healthy. The American Heart association recommends twice weekly fish consumption, and several populations around the world, including several blue zones have successfully integrated limited amounts of fish into their diets.
My view is that most nutritional benefits from fish, can be obtained from plant foods, without any downsides (saturated fat, arachidonic acid, mercury, pollutants). However, if fish is replacing other types of meat in your diet, then it’s probably not a bad choice.
When Choosing Fish, you want:
1. High Omega 3 ratio: Fish that eat lots of plants, plankton
2. Low Mercury: Low-food chain-fish (not fish that eat other fish…. that eat other fish)
3. Low environmental pollutants: Favorable geography, good sourcing, hyper-selective farming techniques
4. Good preparation: Typically fried fish decreases the omega-3 ratio
A quick note about farmed fish: industry standards are generally quite low, resulting in poor quality meat. While there have been advances in this field, overall, there is no consistent standard. Inexpensive corn-based feeds yield short chain omega-6s and arachidonic acid in the meat of fish. Unless the farming methods are evidently known to the consumer, making an educated choice about farmed fish, is a near impossible task. .
The best types of fish are:
Sardines & Anchovies- Even the canned variety have high levels of Omega 3 (higher than salmon) with low levels of omega-6 and arachadonic acid (2-4%). These smaller fish also have low mercury content.
Wild Alaskan Sockeye Salmon- Sockeye salmon feed on more plankton, resulting in higher omega 3, and lower mercury levels when compared to their Atlantic counterparts. Wild caught varieties also have lower saturated fat content.
Herring/ Kippers/ Shad- Spawn in fresh water and eat high plankton diet (high omega 3 content, low mercury)
Atlantic Mackerel (Not king or Spanish variety)- Atlantic Mackerel swim in distinct, closely-packed formations to feast on mostly plankton (their wide, open mouths act as miniature tow-nets). In contrast, King Mackerel and Spanish Mackerel, feast mostly on other fish, and have higher mercury content with less favorable ratios of anti-inflammatory fatty acids.
Lake/Rainbow Trout- One of the few farmed fish that can be high in omega and low in mercury. Freshwater farms in the US produce the best quality meat, low in contaminants, utilizing very safe methods. However, Avoid Lake Superior’s Wisconsin waters, and Washington’s Chehalis and Hoh Rivers.
Pacific Halibut from Alaska and Canada (Not California)- Good fishing practices, high omega 3, low-medium mercury. Avoid the California and Atlantic varieties, which have high mercury content.
The bottom line: I like vegetables, a lot, for many reasons; but if you MUST eat fish, choose from the list above; fish is a good alternative to other types of meat, due to beneficial omega 3s. As always, get educated about the food you eat.
Chanu Dasari MD
Always be true, and surround yourself with people who affirm your wellbeing. Find a doctor who will slow down and listen; find one who carefully considers your concerns; find one who cares.
I found the following sources helpful:
https://www.seafoodwatch.org/ Good resource from Monterey Bay Aquarium. I would recommend saving the link into your phone for reference. My only criticism is that they place more emphasis on environmental impact over nutritional profiles (eg. there is more information about fishing practices and mercury, rather than the omega-3 content)
https://www.seafoodhealthfacts.org/seafood-nutrition/healthcare-professionals/omega-3-content-frequently-consumed-seafood-products/ This article discusses the omega-3 content of common seafood. It leaves out information about mercury however.
Other articles referenced in this post (no particular order):
Easton MDL, Luszniak D, and E Von der Geest, 2002. Preliminary Examination of Contaminant Loadings in Farmed Salmon, Wild Salmon and Commercial Salmon Feed. Chemosphere (46) 1053-1074.
Gardner J and DL Peterson, 2003. Making Sense of the Salmon Aquaculture Debate: Analysis of Issues Related to Netcage Salmon Faming and Wild Salmon in British Columbia. Pacific Fisheries Resource Conservation Council.
Hites RA, Foran JA, Carpenter DO, Hamilton MC, Knuth BA, and SJ Schwager, 2004. Global Assessment of Organic Contaminants in Farmed Salmon. Science (303) 226- 229.
Mazurek R and M Elliott, 2004. Seafood Watch, Seafood Report: Farmed Atlantic Salmon (PDF). Monterey Bay Aquarium.
Nash CE (editor), 2001. The net-pen salmon farming Industry in the Pacific Northwest. U.S. Department of Commerce, NOAA Technical Memorandum NFMS-NWFSC-49, 125 p.
Waknitz FW, Iwamoto RN, and MS Strom, 2003. Interactions of Atlantic salmon in the Pacific Northwest. IV. Impacts on the local Ecosystems. Fisheries Research 62 (2003) 307-328.
https://www.ncbi.nlm.nih.gov/pubmed/28800114
https://www.sciencedaily.com/releases/2008/07/080708092228.htm
https://www.healthline.com/nutrition/optimize-omega-6-omega-3-ratio#section6
https://www.healthline.com/nutrition/omega-3-6-9-overview#section6