Flashback Friday: Coconut Water and Depression

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

If you go online, you can see claims that coconut water may be “beneficial for depression.” And, they even cite studies. There it is, in black and white: “Coconut water ameliorates depression.” Did they just make that up? No, click on it and there it is in PubMed, just like they said. And, for a limited time offer of just $39.95, the publisher will let you read it. But, why waste your time—it says it right there in the title: “coconut water ameliorates depression.” Might as well spend that 40 bucks buying some coconut water to boost your mood! And, anyway, reading all the studies, so you don’t have to—that’s my job!

If you look at the study, it starts out saying that “plants are frequently tested [these days] for [their] antidepressant potential. Okay, sounds good. “Therefore coconut water a commonly used plant based beverage was selected to explore its antidepressant potential.” I’m with you so far. So, “[r]odents were selected for this study and a forced swim test was conducted.” What?

The forced swim test is one of the “most widely [used] test[s] to explore antidepressant activity.” You fill up a “transparent cylinder” with water over the mouse’s head, so it’s “forced to swim.” And then, you drop a mouse in and see how long it struggles to keep from drowning before you see it simply give up and just float to the top. And, lo and behold, you feed them some coconut water first, and they hold out a bit longer before giving up—demonstrating an antidepressant effect. Therefore, we should use coconut water to treat “depressive disorders” in people. What?! It depresses me to even read such wasted research opportunities. Where did they even get this idea?

It was invented by a group of French scientists in the 70s to model “behavioral despair.” Reminds me of the Harlow experiments with “vertical chamber confinement” that he called “the pit of despair,” which was basically just a metal contraption with sloped sides. Lock a baby monkey in it for 45 days, and you can produce “profound” behavioral changes. They end up just kind of hugging themselves in a fetal position. And, afterwards, after 10 weeks alone in the chamber, they exhibit behaviors like “contact cling[ing],” where they just come together and hug each other for long periods of time. “It is not yet clear why confinement in the vertical chamber is apparently so effective in producing abnormal behavior.” But, not to worry; they’ve got lots more studies to do. I’ll spare you the research on puppies.

I can see why you’d want some model to test out new antidepressant drugs. But, if you want to figure out if pomegranates have antidepressant effects, why not just feed people some pomegranates, rather than chucking some mice off the deep end? There are literally thousands of published studies on food or food products using this forced swim test, allowing the egg industry to be like, see, “eggs may be an [egg]cellent food for preventing and alleviating the conditions of major depression.” Why? All because rats struggled longer? Whereas in people, removing eggs from the diet improves mood, though they also removed meat. So, it’s not clear which did what, or maybe they were just eating more healthy plant foods, like soy—which the soy industry is happy to tell you “decreases depressive-related behavior” in postmenopausal rats, who were swimming for their lives.

In people, though, the best soy products may be able to do is just work as well as drugs like Prozac and Zoloft, and we all know how little that’s actually saying. I mean, the forced swim test is just “a reaction to the acute stressful stimulus of being placed in a container without an escape route,” whereas “human depression reflects a chronic subjective emotional state”—an “internal emotional state.” And, to date, we haven’t been able to ask animals how they’re feeling. You can’t even just look at human behavior and tell if someone has a depression diagnosis.

So, “it’s impossible to conclude” that the swim test is some test for human depression. “The ease with which” thousands of scientists do that, however, “is disquieting,” in that it makes assumptions “that discourage…critical thought.” In fact, the whole thing has been compared to some Monty Python skit, where you see if the witch floats or not. “[B]ut today it is in use to label a rodent as being depressed.”

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Image credit: Gadini via Pixabay. Image has been modified.

Motion graphics by Avocado Video.