Fish is a great source of protein, and it's low in saturated fat. But not all fish is created equal. Nutrition Diva breaks down the healthiest and unhealthiest ways to get your recommended servings.
Health authorities around the globe, from the American Heart Association to to the UK’s National Health Service to the Australian Dietary Guidelines, all recommend eating 2-3 servings of fish per week.
Fish is a great source of protein and it’s low in saturated fat. It can be a good source of zinc, selenium, and omega-3 fatty acids. Fish consumption has been linked with lower risk of heart disease, depression, Type 2 diabetes, and Alzheimer’s.
But there seems to be a little more to this story, as was revealed in a meta-analysis of 14 studies, involving almost a million subjects and published in the journal Public Health Nutrition.
Will Eating More Fish Help You Live Longer?
Several studies have found that people who eat more fish live longer, healthier lives, with a linear relationship between fish consumption and life expectancy: The more fish you eat, the longer you live. (Statistically anyway; individual mileage may vary).
And yet, other studies have found no relationship between fish consumption and reduced disease risk or mortality. In other words, if you put a dot on a graph for each person, with servings of fish per week on one axis and age of death on the other, you can’t connect the dots in anything that looks remotely like a line.
[Some] studies have found no relationship between fish consumption and reduced disease risk or mortality.
Even more bizarrely, some studies have observed a J-shaped curve in the association between fish consumption and mortality. That means, you can connect all the dots in a line, but it’s not a straight line. As servings of fish increase from zero to 1 serving per week, the risk of early death goes down slightly. But then, the risk of early death starts to increase again as fish consumption increases. At 2 servings per week, your risk is the same as if you didn’t eat fish at all. From there, your risk of early death increases slightly with every additional ounce of fish that you eat.
What on earth is going on here?
You might guess that that it has something to do with mercury or other contaminants, But this does not seem to be the case. The subjects in these pooled studies with the highest intake of mercury, either because of the amount or the type of fish they ate, actually had lower risks.
Another good guess would it be that something other than the fish—some other aspect of diet or lifestyle—was responsible for the increased risk. Although it’s always impossible to completely account for these types of variables, the analysis did control and adjust the findings to account for factors such as fruit and vegetable intake and red meat consumption. Those things did not appear to explain the paradox.
In the end, there were two factors that were identified as probable culprits. Two smoking guns, as it were.
The Healthiest and Unhealthist Ways to Eat Fish
The striking difference in the shape of the association between fish consumption and mortality (linear vs. J-shaped) turns out to be a regional one. Studies on Asian populations from China and Japan showed a nearly linear association between fish consumption and mortality. Studies from the US and Europe showed a J-shaped association.
In the West, we consume a lot of the fish that are relatively low in omega-3 fatty acids—species like tilapia, catfish, cod, and haddock.
This led researchers (who, by the way, were neither Asian nor Western but Iranian) to zero in on two factors: the type of fish typically consumed and the method of preparation.
Specifically, in the West, we consume a lot of the fish that are relatively low in omega-3 fatty acids—species like tilapia, catfish, cod, and haddock. Although these fish are still good source of protein and other nutrients, and are low in saturated fats, they don’t seem to provide the same life-extending benefits as fish that are high in omega-3s, such as herring, mackerel, sardines, and wild salmon and tuna.
The other factor that seems to play a role is how we cook our fish. While Asians are more likely to steam their fish, Westerners are more likely to deep fry it. If high fish consumption is most likely high fried fish consumption, it’s not suprising that it’s not reducing our disease risks. (Check out this video for an easy and healthy way to prepare salmon.)
Along those same lines, in the Nutrition GPA app that I developed, eating fish raises your grade for the day. But eating fried foods lowers your nutrition grade for the day. So, eating fried fish is essentially a wash—it doesn’t move your grade up or down. (If you’d like to check it out, the Nutrition GPA is free and available at nutritiongpa.com)
Before you blow up my inbox, let me say that these big studies reflect average eating patterns across wide swaths of the population. And I’m pretty sure your eating habits are at the healthy end of that spectrum. But for every one of you enjoying a tin of sardines for lunch or grilled salmon for dinner, there are a lot more fried fish platters and sandwiches being served up in cafeterias and fast food restaurants, and that’s probably what’s bending that J-shaped curve up.
How to Maximize the Health Benefits of Eating Fish
I still recommend aiming for at least two servings per week. But to get the maximum health benefit, make sure that at least one serving a week is a fish that’s high in omega -3 fats. And try to avoid eating fried fish more than once a week.