How Foods Are Tested for Depression

What is the science behind the marketing of foods for antidepressant effects?

If you go online, you can see claims about “coconut water being beneficial for depression,” and studies are even cited. You can see it yourself in black and white—“Young coconut water ameliorates depression”—as shown at 0:16 in my video Flashback Friday: Coconut Water and Depression. Did they just make that up? No, if you click on the related link, 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 the study, but why waste your time? It says it right there in the title: “Young coconut water ameliorates depression…” Might as well spend that 40 bucks buying some coconut water to boost your mood! Anyway, I’m reading all the studies, so you don’t have to. That’s my job!

So what does the study actually say? It starts out saying that “plants are frequently tested for its [sic] antidepressant potential.” So far, so good. “Therefore young coconut water, a commonly used plant based beverage, was selected to explore its antidepressant potential.” Okay, still with you. So, “rodents were selected for this study and forced swim test was conducted to explore antidepressant activity.” What?!

The forced swim test is “one of the most widely used test to explore antidepressant activity.” A transparent cylinder is filled with water to a level over a mouse’s head, so they’re forced to swim. Then you drop a mouse into the water and see how long they struggle to keep from drowning before they simply give up and float to the top. Lo and behold, if you feed them some coconut water first, they hold out a bit longer before giving up, “demonstrate[ing] antidepressant activity.” Therefore, “findings from this study can be taken as a lead to use young coconut water in 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 Seventies to model “behavioral despair.” That reminds me of the Harlow experiments, which involved vertical chamber confinement that he called “the pit of despair.” It was essentially a metal contraption with sloped sides, as you can see at 2:15 in my video. If you lock a baby monkey inside of it for 45 days, you can produce “profound and persistent behavioral abnormalities of a depressive nature in monkey subjects.” They end up curled up in the fetal position, hugging themselves, as you can see at 2:24 in my video. After ten weeks alone in the chamber, they exhibit behaviors like the “contact cling,” 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] studies are now underway,” so don’t you worry. I’ll spare you the similar research that’s been conducted on puppies.

I can see why you’d want to test out new antidepressant drugs, but if you want to figure out if pomegranates have anti-depressant effects, why not just feed people some pomegranates, rather than throwing some mice into the deep end in a forced swimming test? There are literally thousands of published studies on food or food products using this forced swim test. They allow the egg industry, for example, to say things like “whole egg may be an excellent food for preventing and alleviating the conditions of major depression.” Why? Because rats struggled longer after being fed eggs before they were forced to swim? In people, however, removing eggs from the diet improves mood—though, the researchers also removed meat from their diet, so it’s not clear which did what. It’s also possible the subjects were just eating more healthful plant foods, like soy. In fact, the soy industry is happy to tell you soy “decreases depressive-related behavior”…in postmenopausal rats, who were fighting for their lives in yet another forced swim test.

In people, though, the best soy products may be able to do is simply work as well as drugs like Prozac and Zoloft, as you can see at 3:57 in my video, and we all know how little that actually says. 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, and human depression reflects a chronic subjective emotional state rather than a reaction to an individual stimulus. Most importantly, depression is…[an] internal emotional state and, to date, the subjective internal emotional state of nonverbal species is not knowable.” 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 is impossible to conclude with certainty that the FST [forced swim test] is a measure or a test of depression, or a ‘depression-like’ state.” The “ease” with which thousands of scientists do that, however, is “disquieting” in that it makes an assumption that “discourages critical thought.” In fact, “floating has been a criterion in the past to judge the witchcraft outcome of forced swim, but today it is in use to label a rodent as being depressed.”

Isn’t that unbelievable? Now you know why I try to stick to human studies on NutritionFacts.org.

What about Coconut Water for Athletic Performance vs. Sports Drinks? Watch the video to learn more.

KEY TAKEAWAYS

Coconut water has been touted as being beneficial for depression, but studies cited to back up the claim not only were performed on rodents instead of humans, but they were the forced swim test in which researchers see how long animals struggle to keep from drowning before they simply give up.
Researchers claim that when mice are given coconut water before being forced to swim for their lives, they are able to survive a bit longer before giving up, “demonstrate[ing] antidepressant activity.” Therefore, “findings from this study can be taken as a lead to use young coconut water in depressive disorders” in people.
Other questionable animal experiments include the Harlow experiments, which use “the pit of despair”—a metal contraption with sloped sides. Researchers found that locking a baby monkey inside for 45 days can produce “profound and persistent behavioral abnormalities of a depressive nature,” with the animals curled up in the fetal position, hugging themselves.
Thousands of published studies on food or food products have used the forced swim test. The egg industry, for example, claims whole eggs may be helpful with depression because rats who had been fed eggs before they were forced to swim struggled longer in the water. In humans, though, mood has been shown to improve by removing eggs from the diet, though meat was also removed, so it’s unclear which did what. The soy industry also claims soy decreases behavior related to depression–albeit in postmenopausal rats who were also used in a forced swim test.
Soy products may be able to work as well as pharmaceuticals like Prozac and Zoloft in humans, but that doesn’t say much.
The forced swim test is “a reaction to the acute stressful stimulus of being placed in a container without an escape route, and human depression reflects a chronic subjective emotional state rather than a reaction to an individual stimulus. Most importantly, depression is…[an] internal emotional state and, to date, the subjective internal emotional state of nonverbal species is not knowable.”
“[I]t is impossible to conclude with certainty that the FST [forced swim test] is a measure or a test of depression, or a ‘depression-like’ state.” In fact, “floating has been a criterion in the past to judge the witchcraft outcome of forced swim, but today it is in use to label a rodent as being depressed.”

What about coconut oil? Check out:

I mentioned my video Do Antidepressant Drugs Really Work?.

How can we boost mood naturally? See:

In health,

Michael Greger, M.D.

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