Seafood is very healthy to eat – all things considered. Fish and shellfish are an important source of protein, vitamins and minerals, and they are low in saturated fat. But seafood’s claim to fame is its omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), all of which are beneficial to health. The U.S. Dietary Guidelines for Americans strongly suggest that adults eat two servings of seafood, or a total of eight ounces, per week.
Omega-3s are today’s darling of the nutrition world, and many observational studies have indeed shown them to benefit a range of conditions such as high blood pressure, stroke, certain cancers, asthma, Type 2 diabetes and Alzheimer’s disease. However, there isn’t complete scientific agreement on the health benefits of omega-3s, especially when considering the lack of strong evidence from randomized clinical trials.
The strongest evidence exists for a cardiovascular health benefit, and from consuming seafood (not just fish oil), which is significant because heart disease is the leading cause of death in the U.S.
So the solution might seem simple: Increase public health messaging along the lines of: “Seafood is healthy. Eat more of it.” But it’s a bit more complicated than that.
Complication #1: Omega-3 fatty acids vary from fish to fish
Here’s the catch: If you are dutifully eating your two servings a week, but it’s from tilapia, shrimp, scallops or catfish, you won’t actually be getting much of the health benefits from the omega-3 fatty acids.
Canned tuna is an okay source, but it’s a bit of mixed bag (white tuna has more omega-3s than light tuna).
Meanwhile, the other top seafood products – shrimp, tilapia and Alaskan pollock – are all fairly low in omega-3s.
In short, we’re not eating a lot of fish to begin with, and much of the fish we do eat is not actually that high in omega-3 fatty acids.’
Complication #2: Mercury
A naturally occurring heavy metal in rock, mercury is released into the environment primarily through human processes, such as the burning of fossil fuels.
Consuming mercury is definitely not a good thing. A little bit here and there is probably not going to harm the average adult, but with high exposure, mercury can damage key organs. Fetuses, infants and young children are vulnerable to mercury toxicity, as high exposure can cause serious, irreversible developmental and neurological damage.
For optimizing the health benefits, the best seafood choices are those high in omega-3s and low in mercury. ChooseMyPlate lists several seafood options that fit nicely in both categories, including salmon, trout, oysters, herring and sardines, and Atlantic and Pacific mackerel.
Complication #3: Sustainability
Let’s again take the case of tuna. For certain species, the method of harvest and the location of harvest matter a great deal. Here’s an example from the Monterey Bay Aquarium’s Seafood Watch guide: If you purchase a can of light tuna that’s trawl-caught in the East Pacific – that’s a Best Choice.
Pacific sardines, farmed mussels, farmed rainbow trout and Atlantic mackerel (not trawled) are some other “win-win-win” options.
How can I make an informed decision?
Making informed choices about seafood isn’t easy, and it is complicated by seafood fraud. But there are some resources to help.
Additionally, the new Seafood Import Monitoring Program, a governmental program that goes into effect this year, will help to combat the problem of seafood fraud. But you should still always be vigilant for prices that seem too good to be true.
When making food choices, sometimes we’re fortunate and the health and sustainability goals line up. Eating less red and processed meat, for example, is a choice that’s good for your health and better for the environment. Unfortunately, with many seafood choices, these three important considerations – omega-3s, mercury and sustainability – sometimes, but don’t often, align as we might like them to.