The fish department at Whole Foods Market Kahala was bustling late last week as a steady flow of customers eyed bright-coral fillets of fresh wild sockeye salmon on ice, on sale for less than half its regular price.

This was not surprising, given that isle consumers eat three times more fish than folks in other parts of the U.S., according to Hawaii seafood researchers.

Among the shoppers was Peter Naka­sone of Hono­lulu.

"We eat sushi maybe twice a month, salmon once a month, poke once a month. We’re not big fish eaters," he said.

Still, Nakasone said, his family tries to be careful about the kind of fish they consume in light of health advisories about mercury in seafood and the benefits of omega-3 fatty acids in fish.

"We try to limit ahi because we heard it might contain larger quantities of mercury than other fish," he said. "We try to stick to wild salmon because we heard it’s better for you."

The healthfulness of fish is a complex issue for many consumers. Whole Foods seafood department employee Christian de Quevedo said many customers are like Naka­sone.

"They ask for advice all the time," he said. "They ask me if the fish has mercury, if they’re farm-raised, because those are supposed to be lower in mercury."

It’s been almost a decade since the U.S. Environmental Protection Agency and U.S. Food and Drug Adminstration released a joint recommendation in 2004 to limit seafood consumption over concerns about exposure to mercury. Though the advisory was aimed at women of childbearing age, pregnant women and young children, alarmed consumers outside the target groups have taken the guidelines to heart.

Less known is research from 2007 by a Hawaii seafood expert stating that the toxic effects of mercury in seafood are nullified by the presence of selenium, an essential nutrient with antioxidant properties.

Selenium binds to mercury at a 1-to-1 ratio at the molecular level, meaning one molecule of selenium binds with one molecule of mercury.

Hawaii’s wild ocean fish species are predominantly more rich in selenium than mercury, making them a safeguard against mercury rather than a threat, according to the research. (See chart.)

The reportrefers to naturally occurring mercury, not mercury pollutants introduced into an environment.

Though the 2004 recommendations are included in 2010 federal dietary guidelines, the FDA and EPA stated in response to an inquiry that they are in the process of updating their recommendations in light of new science and data that has emerged since 2004.

"Studies now suggest that there’s still protection at a 5-to-1 ratio of mercury to selenium, so the 1-to-1 ratio appears to be conservative," said John Kaneko, a seafood safety researcher and program manager for the Hawaii Seafood Council, a nonprofit advocate for Hawaii fisheries funded in part by the National Oceanic and Atmospheric Administration.

Kaneko and Nicholas V.C. Ralston conducted research and wrote the report "Selenium and Mercury in Pelagic Fish in the Central North Pacific Near Hawaii," published in the journal Biological Trace Element Research.

"It comes down to a risk-benefit analysis, and there are net benefits to eating most ocean fish rather than net risks."

A bigger health concern today, said Kaneko, is that people are not eating enough fish, which are rich in omega-3 fatty acids.

Rachel Novotny, a University of Hawaii nutrition professor who served on a fish consumption consultation committee with the World Health Organization, agreed.

Novotny said certain omega-3 fatty acids, namely EPA and DHA, are found in fish and shellfish and maximize brain and cognitive development and cognitive ability in children, and protect against cardiovascular disease in adults.

"Assuming that basic environmental protections are in place — and that’s generally true in the U.S. — and there are no major acute incidents (of mercury pollution), data suggest that for adults, the benefits of eating fish far outweigh the risks," she said.

"Children are perhaps an even more sensitive, delicate situation. They have windows of brain development, and the EPA/DHA fatty acids are really important for brain development. Fish is an important food source."

The 2004 recommendations warn against eating swordfish, shark, tilefish and king mackerel because of higher levels of mercury. Shrimp, canned light tuna, salmon, pollock and catfish have lower levels. The recommended serving of seafood per week is 12 ounces, or about two meals, except for albacore tuna, which has a recommendation of once a week.

Hawaii residents average three meals of fish a week, Kaneko says, while most Americans eat fish less than once a week.

That makes real Kaneko’s and Novotny’s concerns about nutrient deficiencies, because human bodies don’t make DHA and EPA. These omega-3s are formed in high quantity by marine algae. A common vegetarian source of omega-3s is flaxseed, but Kaneko says that is not effectively converted to EPA and DHA. While many folks take omega-3 supplements, fish offers protein and other nutrients.

According to Kaneko, the 2004 recommendations were a response to data showing high mercury levels in pregnant women and children of the Faroe Islands, located near Iceland and Norway. The levels were attributed to high consumption of pilot whale meat, a popular food source. Pilot whales are mammals with higher levels of mercury than selenium.

In 1989, a study began in the Republic of Seychelles, an archipelago in the Indian Ocean, where the majority of the population consumes as many as 12 meals of fish weekly. The Seychelles Child Development Study, which continues today, has focused on how mercury exposure from fish consumption affects child development. It has not found adverse impacts.

Kaneko said the U.S. recommendations did not consider the Seychelles study because the study did not detect a measurable impact from mercury, whereas the Faroe Islands data did.

"They based the recommendations on marine mammal consumption," said Kaneko. "These are not fish."

Kaneko said much of his focus now centers on sharing information about selenium’s protective properties with "trusted health communicators — those with science backgrounds, OB/GYNs, family practitioners."

"I try to get the word out on where the recommendations came from, where the science came from, why there’s a need for re-evaluation of the recommendations," he said.

"The recommendations now treat fish as solely a mercury delivery system. People need to look at fish as nutrients delivered as tasty food."

STEAMED RED SNAPPER
"Popo’s Kitchen, Volume 2," by June Kam Tong

1 pound snapper (can also use onaga, moana or kumu)
2 slivers ginger
1 small package Chinese preserved vegetables
Salt and pepper, to taste
2 tablespoons soy sauce
2 stalks green onions, for garnish
Chinese parsley, to taste, for garnish
3 tablespoons oil
1 clove garlic, mashed

Boil water in steamer. Place fish, ginger and Chinese preserved vegetables on platter, then place in steamer. Season with salt and pepper. Cover and steam on medium heat for 5 to 8 minutes or until cooked. Do not overcook.

Meanwhile, mix soy sauce with more pepper.

Remove fish from steamer. Pour soy sauce over fish and veggies, and add garnish.

Heat oil and garlic and pour over fish. Serves 2.

Approximate nutritional information, per serving (not including salt to taste): 450 calories, 24 g fat, 2.5 g saturated fat, 85 mg cholesterol, greater than 1000 mg sodium, 7 g carbohydrate, 3 g fiber, 1 g sugar, 50 g protein

CHEF CAROL’S FAMOUS AHI POKE
Carol Nardello, "A Splash of Aloha," by Kapiolani Community College

2 pounds fresh ahi
1 cup chopped Maui onion
3 stalks green onion, thinly sliced
3 cloves garlic
3/4 teaspoon freshly grated ginger
1/4 cup low-sodium soy sauce
1/2 teaspoon crushed red pepper flakes
1 teaspoon sesame oil
1 teaspoon sriracha hot chili sauce
1 teaspoon Hawaiian sea salt

Dice fish into 1/2-inch or smaller cubes and store in refrigerator.

In large glass bowl, combine onions, garlic, ginger, soy sauce, red pepper flakes, sesame oil and sriracha. Mix well and chill.

When ready to serve, combine fish with sauce. Toss well and sprinkle with salt. Serve on chilled platter. Serves 4 to 6.

Approximate nutritional information, per serving: 200 calories, 3.5 g fat, 1 g saturated fat, 60 mg cholesterol, 730 mg sodium, 5 g carbohydrate, 1 g fiber, 1 g sugar, 37 g protein

BROILED OPAH WITH TOSCANO KALE
Kevin Tate, "A Splash of Aloha," by Kapiolani Community College

2 tablespoons butter, divided
Juice of 1/2 lemon
1 tablespoon white wine
1-1/2 tablespoon garlic powder, divided
1/2 teaspoon salt, divided
1 tablespoon fresh thyme, leaves stripped and chopped fine (see note)
1 pound opah
6 to 8 cups chopped Toscano kale (about 1 large bunch)
1/2 cup sweet peppers, red, yellow or orange, short julienne
2 tablespoons extra-virgin olive oil
1 red onion, thinly sliced
1/2 teaspoon pepper

Melt butter in microwave (45 seconds at 30 percent). In zippered plastic bag, combine butter, lemon juice, wine, 1 tablespoon garlic powder, 1/4 teaspoon salt and thyme.

Cut fish into 4 even pieces and place in the bag with butter mixture; marinate 10 minutes.

Broil fish 3 minutes (do not turn). Remove from oven and let sit while preparing kale.

In large skillet or wok over medium heat, place olive oil, then add onion and peppers and toss to coat with oil.

Add kale, remaining garlic powder, salt and pepper. Stir-fry 3 minutes until kale begins to wilt. Do not overcook; kale should have a slight crispness.

Add remaining butter. When butter has melted, plate on top of fish. Serves 4.

Note: To easily strip leaves from stalks of thyme, run fingers down stalk from top to bottom; leaves will pop off.

Approximate nutritional information, per serving: 370 calories, 22 g fat, 7 g saturated fat, 75 mg cholesterol, 320 mg sodium, 19 g carbohydrate, 4 g fiber, 2 g sugar, 29 g protein