James Hamblin reports on new research that shows almonds are even better for us than we thought. Eating an ounce of almonds a day is associated with lower rates of heart disease, prevention of diabetes and arthritis, lower changes of Alzehimer’s. No wonder the almond has overtaken the peanut as America’s most popular nut.

But there’s always a cost. Water from the Klamath River in California has been diverted to water almond groves, and salmon are suffering as a result. Almond-growers need bees, which have been in short supply. So the growers have hired “mercenary pollinating bees,” nearly a third of America’s colonies. But they’ve been exposed to pesticides and have been dying off.

What most impresses here is the inter-dependence of our world. You can’t even eat an innocent, healthy almond without starting some ripples that might cause harm somewhere else. That, and the alertness of someone who sees dead salmon and thinks, “Must be almonds.”