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If you look at Avocado Board-sponsored reviews, they like to brag that “[a]vocados are the richest known fruit source of phytosterols,” which are cholesterol-lowering nutrients found in plant foods. The operative word, though, is fruit.

Yes, there are more phytosterols in avocados compared to other fruit, but the reason that’s such a misleading statement is that phytosterols are fat-soluble substances; most other fruits hardly have any fat in them at all. So, of course, avocados are going to come out on top, compared to other fruit. But, let’s compare phytosterol content of avocados to nuts and seeds. One avocado has about a hundred milligrams of phytosterols. But, on the same scale, sesame seeds and tahini have 400; pistachios, pumpkin seeds, and sunflower seeds have about 300; and almonds and almond butter, flax seeds, and macadamia nuts have around 200. Even chocolate has about twice as many phytosterols as avocados.

Even though nuts and seeds have the highest levels overall, the studies that have been done on lowering cholesterol—lowering LDL (bad cholesterol) with phytosterols—have used supplements, starting at 600mg up into the thousands. So, yeah, you can lower LDL cholesterol about 8% at up around 2,100 milligrams, but that would be twenty avocados a day. That would also be a lot of nuts. But, you can get an 8% drop in LDL just eating a palmful of nuts a day—a single ounce.

So, phytosterols are not the only components of nuts responsible for driving down cholesterol; there must be other components in nuts—like maybe the fiber, or other phytonutrients—that are contributing to the cholesterol-lowering effects. Hmm; I wonder if avocados have such components, too? You don’t know, until you put it to the test.

There are studies dating back more than a half century that appear to show that if you add an avocado to people’s daily diets, their cholesterol drops, and then goes back up when you remove the avocados, then goes back down again. Pretty convincing data—until you see how the study was done. They didn’t just add an avocado, they swapped out animal fat. No wonder their cholesterol went down! So, this may have just as well read: on lard, off lard, on lard, off lard. And, that’s what nearly all avocado cholesterol studies are like.

Ten studies involving hundreds of people, and put them all together. And, it looks like adding avocados led to a significant drop in cholesterol and triglycerides—an average of about a 17-point drop in bad cholesterol. But, these were nearly all strictly substitution studies, where they removed saturated fat from people’s diets, and substituted in avocados. Well, of course, if you cut down on saturated animal fat, your cholesterol is going to drop.

You can tell this review was not funded by the avocado industry, because they point this out: “it is important to note that substituting avocados for saturated dietary fats as opposed to adding avocado to an already established baseline diet poses the greatest benefit.” Just adding avocado may confer no cholesterol benefits at all.

So, yeah, the avocado industry is right in saying that avocados are “a healthy substitute for butter/margarine, cheese, [and] cream cheese”—but that’s a pretty low bar.

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