This follows a massive study released last fall from Harvard that found eating nuts decreased mortality rates by 20 percent, and it builds on Jenkins’ work done more than 10 years ago which suggested, in the American Heart Association’s journal Circulation, “Almonds used as snacks in the diets of hyperlipidemic subjects significantly reduce coronary heart disease risk factors.”

That's all wonderful, but coverage of almond-nutrition research necessarily affords a narrow vantage on health. It seems like every day someone asks me to dichotomize a health trend: good or bad. Almonds are a great example of why I'm terrible at doing that.

It was around the time of Jenkins' prior study, and amid the broader "actually, fat isn't categorically bad" movement in the U.S. that almonds really got traction. We eat about the same amounts of other nuts as we did decades ago, but almond consumption singularly soared. (Pistachios are on the rise, but they are nowhere near almonds.)

The only state that produces almonds commercially is California, where cool winter and mild springs let almond trees bloom. Eighty-two percent of the world’s almonds come from California. The U.S. is the leading consumer of almonds by far. California so controls the almond market that the Almond Board of California’s website is almonds.com. Its twitter handle is @almonds. (Almost everything it tweets is about almonds.)

California’s almonds constitute a lucrative multibillion dollar industry in a fiscally tenuous state that is also, as you know, in the middle of the worst drought in recent history. The drought is so dire that experts are considering adding a fifth level to the four-tiered drought scale. That's right: D5. But each almond requires 1.1 gallons of water to produce, as Alex Park and Julia Lurie at Mother Jones reported earlier this year, and 44 percent more land in California is being used to farm almonds than was 10 years ago.

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In Photos: The Almond's Awful Secret Emily Anne Epstein

That raises ecological concerns like, as NPR’s Alastair Bland reported last weekend, that thousands of endangered king salmon in northern California’s Klamath River are threatened by low water levels because water is being diverted to almond farms. Despite the severe drought, as of June 30, California's Department of Agriculture projected that almond farmers will have their largest harvest to date. If more water is not released into the river soon, Bland reported, the salmon will be seriously threatened by a disease called gill rot. If there's one disease I never want to get, it's gill rot.

Even as almond production increases in California, demand is driving prices ever higher. Other producers are getting into the game. In England, for example, the cost of almonds has almost doubled over the past five years, and sales of almond milk increased 79 percent in a year. "The value of each kernel has gone up dramatically, and growers are looking for the best return on their investment, so they're still planting almond trees at an alarming rate," one farmer told BBC’s Peter Bowes. "If you decided to plant an orchard right now, you would wait two years for available root stock to actually plant."