Researchers don't know why a plant-based diet seems to have a protective effect, but one likely reason is the nutrient profile of vegetarian diets, which tend to be higher in fiber and lower in saturated fat.

WSJ: Vegetarians Live Longer Than Meat-Eaters, Study Finds

"Today everyone is focused on reducing nutrient inputs to the sea in order to reduce eutrophication (the effect of excessive nutrients) in the Baltic, but by helping nature itself to deal with the phosphorus that is discharged we can create a turbo effect in the battle against eutrophication, " said Anders Stigebrandt, of the University of Gothenburg's Department of Earth Sciences.

CNN: Can oxygen pump breathe life into ocean 'dead zone?'