Is fish good for you? Here are the pros and cons

Choosing to put fish on your dinner plate might seem like a smart, healthy, even responsible choice. But surrounding these creatures is a roiling sea of controversy: Is the mercury in fish harmful? Are farmed fish as healthy as wild? Each new study seems to bring more confusion. We weight the evidence on whether fish deserves to be on your shopping list.

Sushi Plate, courtesy Getty and Sullivan Images

PROS: serving up omega-3s

Fish oils are the best source of omega-3 fatty acids going. That’s crucial, as our bodies can’t manufacture this good fat from scratch, and we cannot live without omega-3s. They promote homeostasis throughout the body, helping our system return to normal if it gets out of whack, says University of Toronto associate professor Richard Bazinet, an expert in fatty acid metabolism.

Studies show omega-3s lower our risk of dying of a heart attack by 9 per cent, Bazinet says. They reduce inflammation, regulate the heartbeat, decrease blood pressure, relax the artery walls, and make blood less likely to clot. Research is also starting to show that this fatty acid may reduce our risk of depression, dementia, cognitive decline, arthritis and schizophrenia. And it’s vital for fetal and infant brain development.

Some people are concerned about fish because it contains mercury, a poison that has been associated with short attention spans and delay in infants learning to walk and talk. But there’s a difference between mercury poisoning and the low levels of mercury in all fish, says Bazinet. There’s no official limit to the amount of fish we are supposed to consume. But most people stick to no more than 150 g a week of large fish with long lifespans, such as orange roughy, shark, marlin and fresh tuna, according to Health Canada. Pregnant women and breastfeeding mothers should limit themselves to 150 g per month. “Just don’t eat shark seven times a week,” Bazinet says “and you’ll be OK.”

CONS: Something’s fishy There just aren’t enough fish in the sea. If we continue to consume fish at our current rate “we’ll run out by 2050,” says University of Toronto professor Dr. David Jenkins, Canada research chair in nutrition and metabolism. Jenkins points to the near loss of Canada’s east coast cod in the 1990s as a wake up call, but says it failed to resonate around the world. The “halcyon days of fish are over,” he says. “Are there other things we can do in our lives to make us healthy that don’t involve endangered species?” Health Canada recommends at least two servings of fish a week, but that doesn’t take into account the ecological impact, Bazinet says.

Buyer beware: If you’re eating fish for health reasons make sure you know where it comes from. Farmed fish may be prone to disease, and they can have dramatically reduced levels of omega-3s, because they are likely fed fishmeal instead of algae, Bazinet says. Take farmed tilapia. It barely has any omega-3s, he says. “We joke and call it the chicken of the sea.”

Another disadvantage: Fish can be very expensive. Fiesta Farms grocery store in Toronto’s west end is selling halibut for $21.99 per pound.

Bottom Line

Not all fish are created equal.

Larger fish that have longer life spans and are higher up the food chain, such as sea bass, shark and cod, have higher mercury levels than small fish, such as sardines, mackerel and anchovies, which mainly eat algae. They are also more likely to end up on the endangered species list.

So, no matter who you are — a pregnant woman, lactating mother, small child or average adult — if you stick to the small, wild caught, coldwater fish that replenish themselves quickly by reproducing often, you really can’t go wrong nutritionally, or ethically. “I have a hard time thinking of a healthier source of protein,” Bazinet says. Registered dietitian Shauna Lindzon agrees. She says to meet the weekly Health Canada recommendations we should consume between 1,400 and 3,500 milligrams of omega-3s a week. That amounts to a lot less than you might think: about one serving, or 75 grams, of wild caught Atlantic salmon (1,920 milligrams of omega-3s) twice a week.

When you’re choosing fish, remember that pink-fleshed fish, like salmon and trout, tend to be higher in omega-3s than white-fleshed varieties. We can also get omega-3s from plants, such as leafy greens, flax, walnuts and soybean, but they’re not as good a source of the fatty acid. And, at $6.99 per pound of Atlantic salmon at Fiesta, it won’t break the bank either.

Source: Metro News Canada 

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