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.

“Depression is a debilitating mental disorder with a severe impairment to quality of life.” The drugs don’t work particularly well, and have a bunch of side effects. So, “searching for alternative antidepressant agents with proper efficacy and safety is necessary.” Well, there is this green algae called chlorella that “has been used as a dietary supplement and alternative medicine” in Asia for centuries. Why not put it to the test?

In a randomized controlled trial of chlorella in patients with major depression, subjects were randomized to standard therapy or standard therapy plus 1800 mg of chlorella, which is about three-quarters of a teaspoon a day. And, significant improvements in “physical and cognitive symptoms of depression as well as anxiety.”

Wow! Okay, but what word is missing here? A “randomized controlled trial of chlorella.” What we want is a randomized placebo-controlled trial. Here, they compared chlorella to nothing. Half got some special treatment, and the other half got nothing; the perfect set-up for the placebo effect, especially when the measured outcomes are mostly just about how they’re subjectively feeling. Now, you could argue “Look, that much chlorella would only cost about 10 cents a day. It’s healthy for you anyway, and depression is such a serious disease. Why not just give it a try?” Okay, but I’d still like to know if it actually works or not.

This other study on chlorella I highlighted suffered from a similar problem, but at least had an objective quantifiable outcome: a “significant decrease” in liver inflammation. But, this study had no control group at all. So, maybe they would have just gotten better on their own for some reason. There’s never been a randomized, double-blind, placebo-controlled trial of chlorella for liver disease…until now.

And, not just any liver disease: “non-alcoholic fatty liver disease,” which, thanks to the obesity pandemic, now affects one in four people on Earth. Let’s see if 1,200 mg of chlorella a day will help. That’s about a half-teaspoon, closer to just a nickel a day, and significant drops in liver inflammation, perhaps because they lost significantly more weight (about a pound a week over the eight weeks), which would explain the significant improvement in fasting blood sugars. They conclude that chlorella has “significant weight-reducing effects” with “meaningful improvements” in liver function.

How about a double-blinded, randomized, placebo-controlled study of chlorella for cholesterol? “Compared with the control group, the chlorella group exhibited remarkable changes in total cholesterol.” Wow, how much? Only 1.6%. What?! And, note they said total cholesterol. If you look at what really matters, LDL cholesterol, no effect whatsoever.

Thankfully, that’s not what other studies found. A meta-analysis of 19 randomized controlled trials of chlorella for cholesterol, involving hundreds of subjects, found that those taking chlorella did drop their LDL, eight points on average, and even dropped their blood pressure a few points. Four grams or more a day for at least eight weeks seems to be the magic formula. That would be about tw– teaspoons a day. That’s a lot of chlorella, but if you can find a palatable way to take it, it might help.

This is the latest: a “dietary cholesterol challenge.” They had people eat three eggs a day with or without a few spoonfuls of chlorella. “In this double blind, randomized, placebo-controlled study, 34 participants ingested 510 mg of dietary cholesterol from three eggs concomitantly with a…dose of Chlorella…or a matched placebo for 4 weeks.” Just eating the eggs alone, a 14% rise in LDL cholesterol. But, with the chlorella, significantly less. Therefore, chlorella can play “a useful role in maintaining healthy [blood] cholesterol levels.” Another way would be to not eat three eggs a day.

That reminds me of this other study “to assess the ability of Chlorella to detoxify carcinogenic [heterocyclic amines]”—the cancer-causing chemicals created when you fry, bake, broil, or barbecue meat. The chlorella did seem to lower the levels of one of the cooked-meat carcinogens flowing through their bodies, but didn’t quite reach statistical significance.

Or, what about “polycyclic aromatic hydrocarbons”—another class of cancer-causing compounds, found particularly in smoked meats and cigarettes, that “include…numerous genotoxic [DNA-damaging] carcinogens”? And, again, chlorella did seem to lower levels, but not significantly so. Still, if you’re going to going to have ham and eggs for breakfast or something, make sure to add lots of chlorella and make them green eggs and ham.

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