Smithsonian.com

I’m presently touring New Zealand under the blazing summer sun. In the absence of dependable refrigeration, I have been surviving on a tremendous number of tinned sardines, livened up by the occasional can of tuna. I take comfort in imagining how many heart-healthy Omega III fatty acids I am eating.

Unfortunately, scientific studies abound to temper my enthusiasm. Yes, the yummy fish oils are great for me, but it’s hard to avoid eating whatever else the fish has soaked up. Big, long-lived fish tend to have stored up a fair amount of toxic mercury, but even smaller, less pricey fish carry cancer-causing PCBs, best represented by the infamous pesticide DDT. Most PCBs are now illegal in the U.S. and many other countries, but they keep returning to land in the form of seafood.

So how about a nice daily capsule of concentrated fish oil from the vitamin store, instead? It’s a great way to avoid the contaminants in the rest of the fish, but another study found varying levels of manmade contaminants had found their way in – enough to recommend keeping an eye on production processes.

A Finnish study concerned about the rate at which that nation puts away herring noted another difficulty: those of us who like fish tend to be habitual about it. In a model, regulating the national herring catch led to little actual change in how much anyone ate. Presumably the burgeoning global trade in herring came to the rescue.

It’s almost enough to make a tramper switch to cheese for calories. For the record, I recommend the hard cheeses during summer. Brie, though delicious, has one major liability: runaway goopiness.

(New York State Dept. of Environmental Conservation)