Seafood Consumption, Climate Stability, and Human Health

Is it time to eat fewer burgers and more salmon? Scientists have learned that replacing land-based animal protein with seafood holds promise for improving the health and nutrition of humans worldwide while reducing greenhouse gas emissions and stabilizing Earth’s climate.

Presently, seafood accounts for only 1/6 of humans’ global intake of animal protein.1 Concern about toxic contaminants, such as methylmercury, in some seafood products partly explains this low ratio. However, selective consumption of seafood should allay that concern.

Health Benefits of Seafood
Several studies establish the health benefits of seafood consumption.2 Seafood is rich in omega-3 fatty acids. These fatty acids support the development and maintenance of the brain, eyes, and nerves, especially in young children.3 Studies show that they help lower blood pressure, heart rate, and blood triglyceride levels, which improves blood circulation, lowers inflammation levels, and reduces the risk of stroke and varicose veins.4 Seafood is also exceptionally rich in peptides, amino acids, vitamins D and B12, and the micronutrients selenium, zinc, iron, iodine, and phosphorus. The health benefits of these seafood nutrients far outweigh the health risks.5 Furthermore, only a few seafood species harvested from a few marine regions pose any significant risk and, thus, can be avoided.

A recently published review shows that aquafoods (which include seafoods) substantially enhance the immune response systems of human consumers.6 Compounds in aquafoods enhance both immunocompetence (ability to produce a normal immune response) and immunomodulation (change in the body’s immune system). The three reviewers demonstrated that increased consumption of seafoods would reduce the severity and frequency of infectious diseases worldwide, especially of influenza and other viral infections. They noted, too, that the nutrients in aquafoods suppress the growth of tumors and, therefore, could play a major role in the fight against cancer. They argue that these health benefits would significantly boost the world economy and that such economic benefits need to be considered in the development of aquaculture projects and businesses. Finally, the team advocates for educating people around the world about the health benefits of aquafoods.

Assessing Seafood Nutritional Diversity
In another study, an interdisciplinary research team led by Marta Bianchi undertook a comprehensive analysis of seafood consumption and production. They sought ways to improve human health through increased seafood consumption while managing seafood production and harvesting with the goal of lowering greenhouse gas emissions.7 In their words, they propose a “blue shift” in the human diet (a shift to marine foods) as a means to achieve a “green shift” (a lowering of global greenhouse gas emissions).

Bianchi and her colleagues began by comparing the nutritional scores of different seafood sources. Their nutrient density scores were based on data for 24 different nutrients and the results broadly affirmed the conclusions of previous studies.8

Bianchi’s team demonstrated that crustaceans (shrimp, crabs, lobsters, etc.), both farmed and wild-caught, have lower than average nutritional scores, with farmed crustaceans scoring 10–15% less than wild-caught crustaceans. Wild-caught whitefish species had the lowest nutrient density scores of all seafood groups considered in the studies, with scores about 45% less than average. Salmonids (pink, coho, king, sockeye salmons) followed by small pelagics (herring, anchovies, pilchard, capelin, mackerels, etc.) had the highest nutrient density scores. Wild-caught salmonids, farm-raised salmonids, and small pelagics scored 50%, 35%, and 25% above average respectively. Large pelagics (tuna, albacore, hairtail) were just slightly behind small pelagics at 15–20% above average. Bivalves (clams, mussels, scallops, cockles, and oysters) manifested slightly below-average nutrient density scores. Farm-raised whitefish had superior nutritional scores, slightly above average, than did wild-caught whitefish, partly due to higher vitamin D content.

Bianchi’s team then compared the nutritional scores of seafood with land-based animal protein sources. Chicken scored only slightly better than wild-caught whitefish (45% less than average). Pork had the same score as farmed bivalves (below average). Beef scored between farmed bivalves and wild-caught crustaceans. However, when compared to individual seafood species, chicken, pork, and beef only registered higher nutrient density scores than some wild-caught whitefish species and Japanese carpet shell.

All animal seafood protein sources deliver minimal quantities of sodium and saturated fat. Bivalves are the only animal seafood source in which sodium can be regarded as nonnegligible. However, all land-based protein sources deliver sodium and saturated fat levels at potentially unhealthy levels. The most popular cuts of beef, lamb, and pork yield sodium and saturated fat well above unhealthy levels. Seafood’s exceptionally low levels of sodium and saturated fats is reason enough to replace land-based animal protein in one’s diet with seafood animal protein.     

Climate Impact of Seafood Harvesting
The main focus of the Bianchi team’s research was the impact of animal protein sources on global warming. They assessed the relative greenhouse gas emissions by current means of animal protein production.

By far, the worst performer was beef. Beef scored about 12 times above the average score. Pork was double the average score. Chicken came in right at the average score.

The only poor performer among seafood sources was wild-caught crustaceans at nearly three times the average score. The reason for this poor score is that fishing boats require fuel combustion to harvest wild crustaceans. Some farmed whitefish and salmonids and some wild-caught tunas were about 100% above the average score. The reasons for these high scores included the energy required for fish feed composition in the case of the farmed fish, and fuel combustion needed to capture wild tuna. A compensating factor for farmed salmonids and trout is that they need the least land and water.9

The best performers were small pelagic fish and farmed bivalves at just 20% the average score. Wild-caught salmonids were at 30–35% the average level. Wild-caught whitefish were at 70% the average level. All other animal seafood protein sources, with the exception of wild-caught crustaceans and cephalopods (squid, octopus, cuttlefish), performed markedly better than beef and pork. However, wild-caught crustaceans and cephalopods account for less than 0.3% and 4% of the total annual seafood harvest respectively. Thus, the environmental impact of harvesting them is minimal.

Strategies for Improving Human Health
Bianchi and her colleagues hope that the combination of the clear health benefits of substituting seafood protein for land-based animal protein and the major contribution that increased seafood consumption could potentially make toward reducing greenhouse gas emissions will be enough to induce major population groups to consume more seafood protein and much less land-based animal protein. The one issue they did not adequately address is cost. Currently, the most popular seafood protein sources are more expensive than most land-based protein sources.

I spent most of my childhood years in Vancouver, British Columbia. At that time, herring for human consumption was priced at just 10 cents a pound. Most herring was sold for much less and used as fertilizer. During salmon runs, salmon could be purchased for as little as 15 cents a pound. Cod was so abundantly caught on the Grand Banks east of Newfoundland (known as one of the world’s richest fishing grounds) that it was the protein of choice for all Canadians and Americans who could not afford beef, lamb, pork, or poultry.

Demand for the roe of herring and salmon as a food delicacy and overfishing has markedly reduced the availability not only of herring, salmon, and cod but nearly all fish species consumed by humans. It is now difficult to purchase salmon for less than $10 a pound.

Fortunately, it’s possible to restore edible fish species populations to what they were six and seven decades ago. It will require international agreement on adequate conservation measures and a willingness to prosecute cheaters. However, the economic and health benefits should be sufficiently great to motivate such actions.

As I have explained in two of my books, restoring the world’s whale populations to what they were previous to 1600 AD would vastly increase marine fish stocks.10 Whale populations had been increasing recently, but they’re now threatened. Orcas, as apex predators, are turning to other whales as food sources since there are no longer sufficient fish, seals, and sea lions to sustain them. It will take international agreement on adequate conservation measures for both edible fish species and whales for the world’s oceans to permit a doubling or tripling of human seafood consumption.

Bianchi’s team did point out that more economic means exist to cultivate and harvest seafood. For example, changes in fish feed composition and use and the timing of the harvest could produce increased yields at lower cost.

I agree with Bianchi and her colleagues that doubling human consumption of animal seafood protein while halving the consumption of beef would yield tremendous health benefits worldwide. However, for that goal to be realized the cost of animal seafood protein will need to be reduced much lower than the cost of beef.    

Strategies for Mitigating Global Warming and Climate Change
Bianchi’s team explained that changes in management strategies for harvesting wild-caught fish, and especially for farm-raised seafood, can yield substantially greater reductions in greenhouse gas emissions than current management practices. They recommend replacing high-emission technologies with low-emission technologies11 and replacing seafood farms that require importing feed products with those that do not. They also call for replacing feed products requiring high fossil fuel consumption to produce and/or transport with feed products that need less fossil fuel to produce and/or transport.12 They also point out that significant greenhouse gas emission reduction can be achieved through better assessment and management of the life cycles of the fish being caught or farmed.13

The nearly exponential reduction in wild fish stocks that has occurred over the past half-century means that catching wild fish requires a nearly exponential increase in fossil fuels. Restoring the wild fish stocks to the levels they attained a century ago would dramatically reduce greenhouse gas emissions by fishing vessels. Also, fish caught by purse seine nets (used to target dense schools of fish) require considerably fewer fossil fuels than fish caught by hooks and line gears.   

Huge reductions in greenhouse gas emissions are possible with seafood harvesting and farming. But only minor greenhouse gas emission reductions are possible with land-based animal proteins. Bianchi’s team concludes, therefore, that every effort should be made to substitute land-based animal protein and fat with seafood protein and fat.

Biblical Implications
In the opening creation account in the Bible, God assigns responsibility for managing Earth’s resources to the humans he created. He commands them to manage Earth’s resources for their benefit and the benefit of all Earth’s life. This biblical mandate implies that God has designed Earth and its resources such that humans will not need to choose between solutions that benefit them and solutions that benefit the rest of Earth’s life. There will be solutions that simultaneously benefit both. Thus, humans should diligently search for win-win solutions.

Another crucial biblical principle is that all humans are sinful. In their sinfulness, they will express selfish tendencies. Such selfishness implies that the only workable management solutions will be those that enhance the well-being and wealth of humans. That is, management solutions need to enhance the world economy and world health. The recommendations by Bianchi and her colleagues, with some significant tweaks, will achieve both and at the same time help restore climate stability.

Endnotes

Food and Agricultural Organization of the United Nations, The State of World Fisheries and Aquaculture 2020—Sustainability in Action (Rome, Italy: FAO, 2020), doi:10.4060/ca9229en.

Elizabeth K. Lund, “Health Benefits of Seafood; Is It Just the Fatty Acids?” Food Chemistry 140, no. 3 (October 1, 2013): 413–420, doi:10.1016/j.foodchem.2013.01.034; Carlo Agostoni et al., EFSA (European Food Safety Authority), “Scientific Opinion on Health Benefits of Seafood (Fish and Shellfish) Consumption in Relation to Health Risks Associated with Exposure to Methylmercury,” EFSA Journal 12, no. 7 (July 14, 2014): id. 3761, doi:10.2903/j.efsa.2014.3761; Sofie Theresa Thomsen et al., “Human Health Risk-Benefit Assessment of Fish and Other Seafood: A Scoping Review,” Critical Reviews in Food Science and Nutrition 62, no. 27 (May 6, 2021): 7479–7502, doi:10.1080/10408398.2021.1915240.

Government of Canada, Canadian Food Inspection Agency, “Health Claims on Food Labels: Function Claims,” modified October 31, 2019.

Javier Delgado-Lista et al., “Long-Chain Omega-3 Fatty Acids and Cardiovascular Disease: A Systematic Review,” British Journal of Nutrition 107, Supplement S2 (June 2012): S201–S213, doi:10.1017/S0007-11452001596; Paige E. Miller, Mary Van Elswyk, and Dominik D. Alexander, “Long Chain Omega-3 Fatty Acids Eicosapentaenoic Acid and Docosahexaenoic Acid and Blood Pressure: A Meta-Analysis of Randomized Controlled Trials,” American Journal of Hypertension 27, no. 7 (July 2014): 885–896, doi:10.1093/ajn/hpu024; Trevor A. Mori et al., “Docosahexaenoic Acid but Not Eicosapentaenoic Acid Lowers Ambulatory Blood Pressure and Heart Rate in Humans,” Hypertension 34, no. 2 (August 1999): 253–260, doi:10.1161/01.HYP.34.2.253; Howard S. Weintraub, “Overview of Prescription Omega-3 Fatty Acid Products for Hypertriglyceridemia,” Postgraduate Medicine 126, no. 7 (November 2014): 7–18, doi:10.3810/pgm.2014.11.2828; Lindsay E. Robinson and Vera C. Mazurak, “N-3 Polyunsaturated Fatty Acids: Relationship to Inflammation in Healthy Adults and Adults Exhibiting Features of Metabolic Syndrome,” Lipids 48 (April 2013): 319–332, doi:1-.1007/s11745-013-3774-6; Kelei Li et al., “Effect of Marine-Derived N-3 Polyunsaturated Fatty Acids on C-Reactive Protein, Interleukin 6 and Tumor Necrosis Factor ⍺: A Meta-Analysis,” PLOS ONE 9, no. 2 (February 5, 2014): id. e88103, doi:10.1371/journal.pone.0088103.  

Agostoni et al., “Scientific Opinion on Health Benefits of Seafood”; Thomsen et al., “Human Health Risk-Benefit Assessment.”

Sharmin Suraiya, Mirja Kaizer Ahmmed, and Monjurul Haq, “Immunity Boosting Roles of Biofunctional Compounds Available in Aquafoods: A Review,” Heliyon 8, no. 5 (May 25, 2022): id. e09547, doi:10.1016/j.heliyon.2022.e09547.

Marta Bianchi et al, “Assessing Seafood Nutritional Diversity Together with Climate Impacts Informs More Comprehensive Dietary Advice,” Communications: Earth & Environment 3 (September 8, 2022): article number 188, doi:10.1038/s43247-022-4.

Elinor Hallström et al., “Combined Climate and Nutritional Performance of Seafoods,” Journal of Cleaner Production 230 (September 1, 2019): 402–411, doi:10.1016/j.jclepro.2019.04.229.

Jessica A. Gephart et al., “Environmental Performance of Blue Foods,” Nature 597 (September 15, 2021): 360–365, doi:10.1038/s41586-021-03889-2.

Hugh Ross, Hidden Treasures in the Book of Job: How the Oldest Book in the Bible Answers Today’s Scientific Questions (Grand Rapids, MI: Baker Books, 2011), 65–68; Hugh Ross, Weathering Climate Change: A Fresh Approach (Covina, CA: RTB Press, 2020), 211–213.

John Driscoll and Peter Tyedmers, “Fuel Use and Greenhouse Gas Emission Implications of Fisheries Management: The Case of the New England Atlantic Herring Fishery,” Marine Policy 34, no. 3 (May 2010): 353–359, doi:10.1016/j.marpol.2009.08.005.

Gephart et al., “Environmental Performance of Blue Foods.”

Frederike Zeigler et al., “Expanding the Concept of Sustainable Seafood Using Life Cycle Assessment,” Fish and Fisheries 17, no. 4 (December 2016): 1073–1093, doi:10.1111/faf.12159.