Many people won’t get key nutrients without fish

To save hundreds of millions of people who depend on fish from malnutrition, scientists recommend a change in management practices.

At its heart, the problem is a simple one of supply and demand: Global fish catches peaked in 1996, while the Earth’s human population is expected to rise through 2050, from the current 7.3 billion to between 9 billion and 10 billion. But that straightforward dynamic oversimplifies a problem also affected by natural processes, economic pressures, international regulations, and human health needs.

It is important to include human nutrition, along with biodiversity preservation and economic considerations, in determining the management of fisheries, according to lead author Christopher Golden, research scientist at the Harvard T.H. Chan School of Public Health and associate director of the Planetary Health Alliance.

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The work estimates that, in the coming decades, 11 percent of the global population—845 million people—will be vulnerable to micronutrient deficiencies due to a reliance on seafood, a figure that climbs to 19 percent, or 1.39 billion people, if nutrients only found in animal sources, such as vitamin B12 and DHA omega-3 fatty acids, are included.

Coauthor Edward Allison, a professor in the University of Washington’s School of Marine and Environmental Affairs, says that although we often think of fish as a good source of protein, the micronutrients found in fish and other seafood are perhaps more important—particularly in poor nations where there many not be another source of these necessary nutrients.

“We are able to quantify for the first time what supply and availability of a major food group such as fish and seafood means for maintaining the health of populations that are vulnerable to nutrient deficiencies,” Allison says.

Fish provide often overlooked micronutrients, including vitamin B12, iron, and zinc. According to the report, published as a commentary in Nature, micronutrient deficiencies can affect maternal mortality, child mortality, cause cognitive defects, and impact immune function. Some 45 percent of mortality in children under age 5 is attributable to undernutrition.

The report says that the vulnerability of these poor, fish-dependent populations in the tropics has been underestimated and that these are the very places whose fish resources are under the most intense pressure.

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The analysis of two new databases, one from the Sea Around Us research initiative at the University of British Columbia and the other from a team led by Samuel Myers at Harvard, says that those most likely to suffer the impact of fisheries’ decline are the global poor, particularly those who eat fish as a significant part of their diet.

“We’re missing an enormous piece of this picture, because many of the consequences of the way we manage resources and conserve natural systems will have very strong and powerful downstream effects on human health,” says Golden. “It’s not just a biodiversity issue, it’s not just an economics issue. We need to be really thinking through this third dimension, human health and well-being.”

Golden says those in industrialized nations can compensate for the nutritional gap left by a decline of fish in the diet. They can afford to buy replacement foods, supplements, and vitamins, while those in developing nations often have few alternatives.

The Planetary Health Alliance officially launched in January in partnership with the Wildlife Conservation Society and with support from The Rockefeller Foundation. The study took place under the joint leadership of Harvard, the University of British Columbia, the University of Washington, and the University of California, Santa Barbara. The Wellcome Trust supported the work.

Source: University of Washington via Harvard University