The Perfect Protein: The Fish Lover's Guide to Saving the Oceans and Feeding the World - Hardcover

Über die Autorin bzw. den Autor

Andy Sharpless is the CEO of Oceana, the world's largest international organization dedicated to ocean conservation. Previously he began Discovery.com and helped launch RealNetworks. He lives in Maryland.

Suzannah Evans is a North Carolina-based journalist and Oceana's former editorial director.

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CHAPTER 1

A Short Natural History of Seafood

Fish, amphibian, and reptile, warm-blooded bird and mammal—each of us carries in our veins a salty stream in which the elements sodium, potassium, and calcium are combined in almost the same proportions as in sea water. This is our inheritance from the day, untold millions of years ago, when a remote ancestor, having progressed from the one-celled to the many-celled stage, first developed a circulatory system in which the fluid was merely the water of the sea.

—RACHEL CARSON, THE SEA AROUND US

IN THE SUMMER of 1935, the Inuit people of eastern Canada's remote Arctic inlets were still living a subsistence lifestyle. Clad in sealskin leather, they moved with the weather and the walruses, seals, and whales that they hunted. The only plants they ate were the blueberries that grew during 2 months of the year and sometimes the half-digested contents of caribou stomachs.

The fact that this nomadic hunter-trapper lifestyle persisted into the 20th century in one of the world's harshest environments is incredible. Perhaps even more unfathomable is the notion that the Inuits' restricted diet made them among the healthiest people in the world. But in the early 1930s, the Inuits had made contact with the modern world through the fur-trading Hudson's Bay Company, and the word was out that these tough Arctic people did not appear to suffer from diabetes, cancer, or arteriosclerosis.

Israel M. Rabinowitch, a chemist with McGill University, joined the Canadian government's annual supply trip to the Inuit communities in the summer of 1935 to find out if the stories about the hardy Inuits were true. Sailing aboard the HMS Nascopie, he traveled to four Arctic islands-- Southampton, Devon, Ellesmere, and Baffin—and made dozens of visits to towns that were nothing more than temporary assemblages of a few sealskin tents.

In total, Rabinowitch examined 389 Inuits. While the population wasn't quite as disease free as reputation had it, they were remarkably healthy. He found no diabetes. Only one possible case of cancer. A few calcified arteries. Teeth worn down by chewing leather to make clothes and tents. "If there was a serious health problem amongst the Eskimos, [I] was not aware of it," Rabinowitch noted in a report published in the Canadian Medical Association Journal in 1936. He didn't even mention heart disease.

How could a people living in such harsh conditions not report a single heart attack?

During flush times, the Inuits ate 5 to 10 pounds of meat a day. Rabinowitch estimated that an average person ate 30 to 40 grams of carbohydrates, 250 to 300 grams of protein, 400 to 600 milligrams of cholesterol, and about 150 grams of fat per day. One hundred fifty grams of fat is the amount in 33 Twinkies.

Of course, not all fat is created equal. Inuit people weren't eating Twinkies. They were eating fresh, usually raw meat from marine mammals, fish, and occasionally caribou with their bare hands, sometimes ending meals covered in blood and blubber. At the time of Rabinowitch's study, science had not yet discovered why this high-fat, low-carbohydrate diet was good for their health.

Later studies would confirm the incredible vitality of the Arctic peoples. In 1980, Danish scientists compared rates of myocardial infarction, asthma, diabetes, multiple sclerosis, and other health problems among Greenland's Inuit with those of Danes. The data cleaved neatly, with the healthier Inuits showing little to no instances of the diseases compared with the "civilized" Danes.

The scientists didn't take into account one of the oldest uses of seafood—treatment of disease—because knowledge of the techniques had been lost to history for more than a century. In 1770, a woman suffering from severe rheumatism arrived at the Manchester Royal Infirmary in England. At the time, the standard treatment for rheumatism included "rubbing of her joints with cod-liver oil," as reported by Maurice Stansby in the seminal text Fish Oils in Nutrition. The poor woman received no relief, and after a year she inquired whether she could ingest the oil instead. She was brave: In the 1700s, the oil was obtained by pressing rotting cod livers, and it was an opaque, vile-tasting liquid. "Although the hospital had no confidence that this would have any effect, she was allowed to [ingest the oil]," Stansby wrote. Her symptoms disappeared.

Unfortunately for the woman, her doctors ascribed her good health to the changing seasons, and she wasn't given any more cod-liver oil for a year—during which her rheumatism flared more severely than before. The hospital relented and gave her more oil, only to see her symptoms disappear yet again.

After that, the Manchester infirmary regularly prescribed 1 to 3 tablespoons of cod-liver oil taken up to four times a day to treat rheumatism. A Dr. Thomas Percival wrote up the case for the London Medical Journal in 1783. But the difficulty of obtaining the oil, coupled with the truly revolting flavor (sometimes it was mixed with peppermint, although it's hard to imagine that helped), caused fish oil to fall out of favor, and it was forgotten.

Seafood's role in heart health was discovered only after those early-20th-century studies on Arctic peoples. Soon, other indicators emerged suggesting that seafood was helpful in avoiding heart disease. Norway experienced a steep decline in fatal heart attacks during the German occupation of 1941 to 1945. In these years, Norwegians could not obtain much in the way of meat, eggs, or whole milk, and instead began eating more fish, skim milk, and cereals. After the war, Norwegians returned to their red-meat diet, and the rate of heart attacks rose again. Similarly, scientists began to notice that the Japanese, who eat up to 13 times as much seafood as Americans, had much lower rates of heart disease as well. One study found that the Japanese were 20 times less likely than Germans to die of heart attacks.

One of the landmark studies on seafood consumption and heart health took place in the Netherlands from 1960 to 1980. Over those 2 decades, scientists tracked a group of adult men from the town of Zutphen who ate a consistent amount of fish throughout their lives. The result? The more fish the men ate, the less likely they were to die of heart disease.

After the results of the Zutphen study were published in 1985, the knowledge of seafood's role in heart health went mainstream. Now, just about every authority from the American Heart Association to the World Health Organization recommends eating seafood at least twice a week.

So what is it that makes seafood so healthy?

It has to do with its molecular structure. Seafood is the premium source for essential omega-3 long-chain fatty acids. The human body cannot generate these fatty acids by itself, so they must be consumed.

Since the 1980s, "omega-3" has been a nutrition buzzword, found everywhere from margarine labels to fad diet cookbooks. It's usually mentioned along with its relatives, the omega-6 fatty acids, which are derived from plant oils like soybean, corn, palm, rapeseed (canola), and sunflower. Omega-3 fatty acids are found in some plants, like walnuts, but the best sources are fish and seafood. They, too, ultimately derive their omega-3s from plants--the phytoplankton that support all ocean life.

THE ABCS OF OMEGA-3S

Omega-3 fatty acids are made of a string of carbon and hydrogen atoms. "Saturated" fatty acids hold all the hydrogen atoms their structures allow. Sometimes certain enzymes can remove pairs of hydrogen atoms. "Monounsaturated" fatty acids have one fewer pair of hydrogen atoms than the saturated versions. The loss of the hydrogen pair creates a double bond between the adjacent carbons. When more than one pair of hydrogen atoms...