Benefits of Eating Fish and Choosing the Best Fish to Eat

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Tsukiji fish market in Tokyo
Of all the fish caught in the world. Only about three quarters are eaten by humans. The remainder are used to make things like glue, soap, pet food and fertilizer.

The ocean pout is a fish that lives in very cold waters in the North Atlantic Ocean and stays warm and active in below freezing temperatures with the help of an anti-freeze protein in its blood. The food giant Unilever, which make several ice creams and owns Ben and Jerry’s, has harnessing the anti-freeze protein — replicating and multiplying it using genetic engineering — to lower the temperature in which ice crystals form — meaning less cream, or fat, is needed to make ice cream.

Some ethnic group in eastern Siberia have traditionally made their clothes from fish skin. In the 1920s some fashionable Western women decorated their dresses with fish scales rather than sequins.” In a 1922 article in National Geographic, author Louis L Mowbray wrote: “The writer has seen an evening gown made wholey of bonefish scales which was indeed a thing of beauty. The scales were bored and laid on a fabric base like shingle son a roof, The resultant effect was like that of the natural body of the fish.”

Consumers are encouraged only to buy fish that is known to have come from secure and replaceable stocks. Keeping fish alive as long as possible, keeping it moving quickly to its destination, and keeping it chilled are key to ensuring it is fresh and free of pathogens. A stiff body and no smell are signs of freshness. Large fish companies ensure freshness by eliminating middlemen and shipping fish directly in refrigerated truck from fish auctions to processing plants, restaurants or shops. Often microbiologist are hired to check for bacteria, toxins and parasites.

Benefits of Eating Fish

The Japanese have traditionally eaten a lot of fish and they are the longest living people in the world. In 2000, the American Heart Association recommended that people eat salmon or tuna twice a week. It was the first time the group recommended eating specific things rather than offering general guidelines. Studies have shown that eating oily fish can significantly reduce the chances of getting a stroke, developing prostrate or breast cancer, suffering from depression or being stricken by a sudden, unexpected death caused by a severely abnormal heart rhythms.

Eating fish has been linked with low cholesterol levels and low rates of heart disease. Oily fish such as salmon and tuna are in rich fish oils, which in turn are rich in omega-3 fatty acids, an essential nutrient in the human diet (See Below). According to the Mayo Clinic: Omega-3 fatty acids and other nutrients in fish may benefit heart health and reduce the risk of dying of heart disease. Some people are concerned about mercury or other contaminants in seafood. However, the benefits of eating fish as part of a healthy diet usually outweigh the possible risks of exposure to contaminants. Try to eat at least two servings a week of fish, particularly fish that's rich in omega-3 fatty acids. Doing so appears to reduce the risk of heart disease, particularly sudden cardiac death. [Source: Mayo Clinic]

A Finnish study published in the journal Neurology in August 2008, researchers found that older adults who regularly ate fish had a lower chance of developing subtle brain damage that contributed to stroke and dementia. Eating fish can reduce irregular heart beats. In a study conducted by Bingham and Women’s Hospital and Harvard Medical School, regularly eating tuna or broiled or baked “but not fried — fish reduces the risk of atrial fibrillation, a major cause of stroke and other problems. Scientists credit the Omega 3s in the fish.

Omega 3s and Their Benefits

fish market in Japan
Omega-3 and omega-6 are essentially fatty acids that work together to promote good health, The human body can not make them so it is essential that people eat diet rich in them. Omega-3 are found in fish and certain oils such as canola and flaxseed and omega-6 are found in raw nuts and seeds. Omega-3 fatty acids are found in salmon, sardines, Atlantic mackerel, cod, herring, lake trout and canned, light tuna and some kinds of tuna. Shrimp, other kinds of tuna, haddock, clams, cod, and crab are low in Omega 3s. Omegas 3s are also found in wild game, nuts like almonds and walnuts and avocados. With the absence of Omega-3s the body uses saturated fat to make cell membranes. Cell membranes made with this type of fat are less elastic and a lack of elasticity can be dangerous to the heart.

There is evidence that omega-3 fatty acids prevent iclot formation and clogging of blood vessels with fat and cholesterol and that a lack of omega-3 fatty acids may play a role in a variety of maladies, including bipolar disorder, heat arrhythmia, high blood pressure, heart disease, kidney failure, irritable bowel syndrome and rhomboid arthritis. According to the Mayo Clinic: Omega-3 fatty acids may reduce inflammation throughout the body. Inflammation in the body can damage the blood vessels and lead to heart disease and strokes. Omega-3 fatty acids may benefit heart health by: 1) Decreasing triglycerides; 2) Lowering blood pressure slightly; 3) Reducing blood clotting; 4) Decreasing the risk of strokes and heart failure; 5) Reducing irregular heartbeats. [Source: Mayo Clinic]

According to the U.S. Food and Drug Administration (FDA) most adults should eat at least 8 ounces or two servings of omega-3-rich fish a week. A serving size is 4 ounces or about the size of a deck of cards. In order to get the most health benefits from eating fish, pay attention to how it's cooked. For example, grilling, broiling or baking fish is a healthier option than is deep-frying. If you don't want or like fish, other things that have some omega-3 fatty acids are: flaxseed and flaxseed oil, walnuts, canola oil, soybeans and soybean oil, chia seeds, green leafy vegetables, cereals, pasta, dairy and other food products fortified with omega-3 fatty acids. As with supplements, the heart-healthy benefits from eating these foods doesn't seem to be as strong as it is from eating fish

Studies on the Benefits of Omega 3s

Studies have shown that eating fish rich in omega-3 fatty acids cuts the risk of stroke and cancer. A study by Dr. Mich Brown of Paterson Institute at Christie Hospital in Manchester England published in the journal Cancer in March 2006 found that eating foods rich omega-3 fatty acids could help prevent the spread of prostrate cancer.

There is also some research that suggests that mothers who eat Omega 3s while pregnant produce smarter children and that people who get angry easily can better control their tempers better if they eat them. A study by American and British researchers published in Lancet in 2007 reported that children of mothers who ate small amounts of fish when they were pregnant gave birth to children who had lower IQ and academic test scores and had more social and behavioral problems than children of mothers who ate 12 or more ounces of fish per week. Other studies have indicated that women who don’t get enough omega-3 fatty acid are more likely to deliver babies too early and at a low birth weight.

A study published in in March 2011 suggested that women whose diet was rich in omega-3 fatty acids found in fish were at significantly lower risk of developing age-related macular degeneration. The New York Times reported: The Harvard Women’s Health Study, which followed 39,876 women in midlife, had participants fill out detailed food-frequency questionnaires at the start of the study in 1993. After an average 10 years of follow-up, 235 of the women had developed macular degeneration, a progressive eye disease that is the leading cause of irreversible vision loss in the elderly. [Source: Roni Caryn Rabin, New York Times, March 17, 2011

But the analysis, in Archives of Ophthalmology, found that women who had reported eating one or more servings of fish per week were 42 percent less likely to develop age-related macular degeneration than those who ate less than a serving each month. (Researchers adjusted the data to control for other factors linked to the disease, including smoking.) Eating canned tuna and dark-meat fish like mackerel, salmon, sardines, bluefish and swordfish appeared to have the most benefit.“We know that inflammatory processes are involved in A.M.D., and the omega-3 long-chain fatty acids do have an anti-inflammatory effect,” said the lead author, Dr. William G. Christen, an associate professor at Brigham and Women’s Hospital and Harvard Medical School.

Omega 3 Fish Rankings

Top 25 Fish Ranked By Omega-3 Fatty Acids
Type of Fish — Calories Per 3.5oz — Protein (Grams) — Omega-3 (grams)
1) Mackerel (King) — 260 — 21 — 2.6
2) Sablefish — 250 — 17.2 — 2.125
3) Trout, lake — 189 — 20 — 2.0
4) Herring — 202 — 14 — 1.7
5) Tuna, yellowfin — 107 — 30 — 1.6
6) Sardines, canned — 203 — 22 — 1.5
7) Tuna, albacore — 103 — 7.7 — 1.5
8) Whitefish, lsake — 133 — 24.2 — 1.5
9) Salmon, sockeye — 216 — 27 — 1.4
10) Anchovies — 130 — 28.7 — 1.4
11) Bluefish — 123 — 19.8 — 1.2
12) Bass, striped — 96 — 17.5 — 0.8
13) Trout, brook — 147 — 20.6 — 0.6
14) Trout, rainbow — 137 — 20.7 — 0.6
15) Halibut, Pacific — 109 — 20.7 — 0.5
16) Pollock — 91 — 18.5 — 0.5

Concentrations of the Omega-3 Fatty Acids (Eicosapentaenoic and Docosahexaenoic Acid) in Multiple Fish and Shellfish (from Mahaffey, 2004)

17) Shark — 126 — 19.7 — 0.5
18) Catfish — 105 — 18.5 — 0.3
19) Ocean perch — 134 — 18.5 — 0.3
20) Cod — 105 — 23 — 0.28
21) Tilapia — 128 — 26.1 — 0.24
22) Flounder — 90 — 17.9 — 0.2
23) Haddock — 86 — 17.6 — 0.2
24) Snapper, red — 99 — 20.3 — 0.2
25) Swordfish — 155 — 25.4 — 1.05
[Source: Sources: Built Lean,,,, July 13, 2022]

This list may not be totally reliable. Many sources say albacore tuna has about three times as much omegas as skipjack or “light” tuna. With fresh tuna, the belly is fattier — and more Omega 3 rich — than the meat on either side. According to Dr. Blonz: For higher levels of omega-3 fats, use albacore (white) tuna. One 3.5-ounce serving of water-packed albacore (drained) contains 2.5 grams of fat and 706 milligrams of omega-3 fats. Yellowfin and skipjack varieties used to make light tuna contain fewer omega-3 fatty acids than albacore, sometimes called a dark tuna. [Source: Dr. Blonz, Tri-Valley Dispatch]

What are the Best Fishes to Eat

According to Consumer Reports: “Packed with protein, fish is one of the best foods you can put on your dinner plate. It's the only one that directly supplies omega-3 fatty acids, a type of polyunsaturated fat that is important for heart and brain health. Salmon, sardines, mackerel, and tuna are among the healthiest fish because they're excellent sources of omega-3s, but all fish and shellfish have some. “There’s very solid science showing that omega-3s can help reduce inflammatory factors associated with a variety of chronic diseases, including heart disease,” says Marian Neuhouser, Ph.D., R.D., of the Fred Hutchinson Cancer Research Center in Seattle. [Source: Consumer Reports, April 16, 2016]

“There is a catch: Some fish are high in mercury, which can be toxic to the nervous system. But this means making smart choices, not cutting out fish altogether. According to the Department of Agriculture’s new Dietary Guidelines for Americans, issued in 2015, “for the majority of wild-caught and farmed species, neither the risks of mercury nor organic pollutants [toxic substances that can accumulate through the food chain] outweigh the health benefits of seafood consumption.” A Consumer Reports investigation found that canned tuna is a common source of mercury and should be avoided by pregnant women. Children and women who are breast-feeding or may become pregnant should stick to light varieties. White tuna, or albacore, had much higher mercury levels.

“Seafood sustainability is another factor to consider when choosing fish to eat. Increased demand and lax fishing practices can lead to overfishing and can damage other possibly at-risk species that often get caught up in nets with the intended catch. The Monterey Bay Aquarium Seafood Watch lists options that are fished or farmed in ways that protect the environment. Your best strategy is to aim for 8 ounces per week of sustainably farmed or wild-caught, low-mercury fish. Among the healthiest fish are: Atlantic mackerel, Pacific sardines, freshwater (farmed) coho salmon and wild-caught salmon (including canned), and sablefish (black cod) from Alaska.

Mercury and Problems with Eating Fish

Mercury food chain
One of the main problems with eating fish is mercury. It turns out that many fish such as tuna that are heralded as being healthy to eat are also high in mercury, a dangerous heavy metal linked to health problems in children, birth defects and brain deformities. Fish at the top of the food chain such as sharks, king mackerel, tilefish and swordfish have the highest mercury levels. Tuna has moderate amounts. Albacore tuna has more than light tuna. The levels in salmon are low.

In 2001, U.S. government health services advised pregnant and breast-feeding women not to eat fish and seafood because of worries about mercury poisoning and reiterated the same advice in 2004. Then in 2007 the agency reversed itself and said expectant and nursing women should eat at least 12 ounces of fish and seafood per week, arguing that seafood was critical for brain development of babies and this outweighed the risks presented by mercury.

Some seafood also contains Polychlorine biphenyls (PCBs) and dioxins. PCBs are substances found in electrical goods and refrigerators, They are linked to skin problems, reproductive disorders, liver disease and neurological problems. Dioxins are produced mainly through the combustion of trash. They are linked to some cancers and birth defects. Fish and other sea creatures absorbed these pollutants from the environment and store them in their fat. Most doctors say the levels of mercury, dioxin and PCBs found in fish are so low that they should not present a problem and put people off to eating fish.

According to the Mayo Clinic: The amount of toxins depends on the type of fish and where it's caught. If you eat a lot of fish containing mercury, the toxin can build up in the body. It's unlikely that mercury would cause any health concerns for most adults. But it is particularly harmful to the development of the brain and nervous system of unborn children and young children. For most adults, the benefits of omega-3 fatty acids outweigh the risk of getting too much mercury or other contaminants. [Source: Mayo Clinic]

Environmentally-Friendly Fish Consumption

Due to concerns about health, overfishing, and other environmental concern, consumers are advised: 1) not to eat swordfish or bluefin tuna, because their stocks are dwindling as they have been overfished; 2) avoid canned tuna because of concerns about accidental catching of dolphins (although this is less of a concern than before); 3) avoid shark fin soup, because of the dwindling shark numbers and the inhumane practice of slicing off fins and throwing sharks back in the water; 4) avoid farmed salmon because of concerns that the industry is having on wild fish and poor water quality in areas with farms; and 5) avoid caught shrimp because of the damage trawling causes to the sea bottom and high amount of “by catch” (unwanted fish and creatures that often die and end up as trash) brought up with hawl.

Levels of mercury in Omega 3 fish

Consumers are encouraged to eat fish like sablefish which is taken from well-managed fisheries in Alaska and Canada rather than overfished grouper, swordfish and bluefin tuna and particularly avoid orange roughy and Chilean sea bass (aka Patagonian toothfish) which are badly overfished and take a long time to reach maturity and reproduce, meaning that reduced stocks take a long time to recover.

Eating sardines, farmed shellfish and Alaskan pollack are all okay because their stocks are large and healthy and fishing for them and their production doesn’t cause too much damage to the environment. Try to find out about farms that supply fish. Fish farms vary a lot in quality. Some generate lots of wasteful effluents and use large amounts of chemicals, antibiotics and hormones. Others don’t. As a rule the cheaper the fish is the more likely its to have come from sub-standard farms.

Fish eaters are also advised to eat low on the food chain. Eating sardines and anchovies is better than eating the fish that eat sardines and anchovies — such as tuna, salmon and swordfish — because these fish are more abundant, quick to reproduce and offer more protein to human eaters in a way that harms the ocean ecosystem less.

Perhaps the best thing you can do is eat sea urchin. There is a lot of these creatures: so many they are regarded as a pest that eat valuable kelp and other marine life. Even better is eating jellyfish. There is no shortage of them and in recent years there have been huge swarms of them, causing problems for swimmers and fishermen and other aquatic life.

Websites: Seafood watch (; Blue Ocean

Marine Stewardship Council and Sustainable Seafood Campaigns

20120521-MSC_ecolabel.png Paul Greenberg wrote in National Geographic, “There are dozens of sustainable-seafood campaigns, each of which offers suggestions for eating lower on the marine food chain. These include buying farmed tilapia instead of farmed salmon, because tilapia are largely herbivorous and eat less fish meal when farmed; choosing trap-caught black cod over long-lined Chilean sea bass, because fewer unwanted fish are killed in the process of the harvest; and avoiding eating giant predators like Atlantic bluefin tuna altogether, because their numbers are simply too low to allow any harvest at all.” [Source: Paul Greenberg, National Geographic, October 2010, Paul Greenberg is the author of “Four Fish: The Future of the Last Wild Food”]

The Marine Stewardship Council uses a third-party verification system to determine that fish sold in stores comes from fisheries run in a responsible manner. Enterprises that sell seafood can display a MSC-certified seal of approval on their products if they meet certain standards defined by the MSC.

The MSC was founded in 1996 as a joint venture between major seafood buyer Unilever and the major environmentalist group, the WWF, but is now an independent entity. Fisheries that take part agree to be regularly inspected and if they the meet the standard win the right to bear blue and white MSC-approved label. The MSC claims that every year the number of fisheries that participate in the scheme increases by 50 percent and as of 2009 about 7 percent of the fish on the global market were MSC certified, including 42 percent of the total wild salmon catch and 40 percent of the global whitefish catch.

Wall Mart, McDonald’s and MSC-Approved Fish

Wal-Mart has pledged to sell only certified sustainably-caught fresh and frozen fish by 2011. Peter Redmond, a former vice president at Wal-Mart said in the film “End of the Line”, “We sell approximately 20 million pounds [9 million kilograms] of fish a year. We had to do something that would protect us as we grow and as we need more and more product into the future.” Wal-Mart’s involvement in the scheme came when S. Robson “Rob” Walton, son of Wal-Mart founder Sam Walton, befriended Peter Seligmann, co-founder of Conservation International, on a scuba diving trip in Costa Rica and this led to a series of meetings in which Wal-Mart promised to participate in the Marine Stewardship program.

The National Fisheries Institute, the seafood industry’s principal lobby, said McDonald’s, which puts 50 million tons of Alaskan pollack,New Zealand hoko and other whitefish in its Filet-O-Fish sandwiches, the parent company for red Lobster, are climbing aboard the sustainable seafood movement.

In June 2011, Bloomberg reported, “McDonald’s Corp. (MCD), the world’s biggest restaurant chain, plans to become the first company of its type to sell fish in Europe that’s been certified as sustainable by the Marine Stewardship Council. McDonald’s will start selling MSC-certified white fish -- including in its Filet-O-Fish sandwiches -- at 7,000 restaurants in 39 European countries from October 2011, the Oak Brook, Illinois- based company said. [Source: Clementine Fletcher, Bloomberg, June 8, 2011]

The MSC certification is the “most robust and recognizable” demonstration of sustainable sourcing, Keith Kenny, senior director of supply chain for McDonald’s Europe, said in an interview. “This is really going to raise awareness” of the issue of sustainability for McDonald’s 13 million daily customers in the region, he said.

McDonald’s, which sold about 100 million Filet-O-Fish portions in Europe last year, said it won’t increase prices on fish products as a result of the switch to MSC-approved goods. The company will absorb any costs incurred as it regards the move as beneficial for the McDonald’s brand. McDonald’s said in April that it expected food expenses to rise as much as 4.5 percent in the U.S. and Europe this year.

“The main reason we take actions like this in our supply chain is to ensure we have supply in the future,” Kenny said. “It’s a serious issue.” McDonald’s also uses only free-range and non-caged eggs in 95 percent of its restaurants across Europe, and sells only coffee that has been certified as produced through sustainable methods. Europe represented about 37 percent of operating income last year, compared with the U.S.”s 46 percent.”Our customers are increasingly interested in the food they eat, where it comes from, and how it’s been sourced,” Julian Hilton-Johnson, vice president of corporate relations and McDonald’s Europe’s chief of staff, said by phone. “We talk in McDonald’s about moving from “fast food” to “good food, fast,” and making sure we differentiate ourselves to our customers,” Hilton-Johnson said.

Some scientists worry about the overall effect of the trend as Wal-Mart and other climb on the bandwagon, creating increased demand for seafood the sustainable seafood movement is trying to save. Another problem, Paul Greenberg wrote in National Geographic, “is that the oceans have reached a critical point. Simply changing our diets is no longer sufficient if fish are to recover and multiply in the years ahead.”

Image Sources: Wikimedia Commons, National Oceanic and Atmospheric Administration (NOAA); Ray Kinnane, JNTO, Andrew Gray Photosensibility

Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, Yomiuri Shimbun, The Guardian, National Geographic, The New Yorker, Time, Newsweek, Reuters, AP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.

Last updated April 2023

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