What's the deal with seed oils?

Emily Oster (0:00)

Hi, Perry.

Dr. F. Perry Wilson (0:01)

Hi, Emily.

Emily Oster (0:02)

Perry, did you know that avocado oil is a seed oil because it comes from the seed of the avocado?

Dr. F. Perry Wilson (0:08)

Oh, actually, no, and I probably should have because we're doing an episode on seed oils. But I thought, I assumed it came, because avocado like meat is pretty oily. I thought it just came, I thought you just squeezed the meat.

Emily Oster (0:22)

Is meat the right term? It's not the right term. But also I have another fun fact about avocados. This is a good cocktail party fact for you.

Avocado seeds are very large, and plants that require being reseeded require animals to eat them and poop them out, like that's how plants work. And when avocados first existed in the Mesoamericas, there were these giant animals, like 15-foot-tall animal megafauna. They have names like Megatherium, and they had these giant digestive tracts, and they could poop out the whole avocado seeds. They could just eat the fruits and poop out the seeds. But then those went extinct, like 13,000 years ago. And avocados almost went extinct.

Dr. F. Perry Wilson (1:03)

Right around the time that homo sapiens showed up, just pointing that out.

Emily Oster (1:06)

I'm not sure that it was totally our fault, but I think we played a role. And then avocados almost went extinct before people discovered how delicious they were and started cultivating them. That was like 8,000 years ago.

Dr. F. Perry Wilson (1:19)

Oh, amazing. Thank you, ancestor humans, for keeping avocados going.

Emily Oster (1:24)

We almost have no avocados.

But instead, we have a lot of avocados. So there you go. And you can make them into seed oil, which is the topic of today.

Dr. F. Perry Wilson (1:33)

I love when a good plan comes together.

Emily Oster (1:39)

I'm Emily Oster. I'm an economist and a data expert.

Dr. F. Perry Wilson (1:42)

And I'm Perry Wilson. I'm a medical doctor.

Emily Oster (1:44)

It's Thursday, September 10th, 2026 And this is Wellness, Actually.

Dr. F. Perry Wilson (1:49)

Because you're getting a staggering amount of health and wellness information nowadays from every source imaginable. And some of it is awesome.

Emily Oster (1:57)

And some of it is, well, actually bullsh**. Fortunately, we're both people who know how to read studies, how to parse the data, and can tell you what's worth thinking about and what you can safely ignore.

Dr. F. Perry Wilson (2:10)

But before we dig in, a note that this podcast is for educational purposes and should not be construed as medical advice. We don't know your unique situation, so talk to your doctor for personal health decisions.

Emily Oster (2:22)

This week, we're asking, what's the deal with seed oils? Perry and I will give the official smash or pass, and then we'll get to your question of the week. But first, let's do the health news roundup after the break.

And now for the health news of the week. Perry, there are a bunch of articles about how a promising heart drug has failed in clinical trials. What happened, and is it something we should have predicted?

Dr. F. Perry Wilson (3:00)

I mean, this is actually really has sent a shock wave around the cardiovascular community. So the story here is that cholesterol has many different subtypes. And some of them, like LDL cholesterol, we know are both associated with heart disease, like heart attacks and strokes, and that if you reduce them, then the risk of heart attack and stroke goes down. So like that's true of LDL cholesterol. It is causally associated with cardiovascular disease, therefore reducing it changes your risk of cardiovascular disease. That's why statins work.

There is another subtype of cholesterol called lipoprotein A, sometimes referred to as Lp little a. And the data is completely unambiguous that people with higher levels of Lp little a have a higher risk of heart attack and stroke, just like LDL. It's like looks very, very similar. But it was really a problem because unlike LDL, which can be influenced by lifestyle factors such as diet, Lp little a seemed to be entirely genetically determined. It was just like you rolled the genetic dice, that's your Lp little a, sorry.

So obviously the race was on to develop a drug that can reduce Lp little a. And Novartis did have one called Pelicarsen. And in phase two trials, when they did randomized trials of this drug versus placebo, people's Lp little a went down by 80% on this drug. Slam dunk, reducing this level of subtype of cholesterol.

But that doesn't matter, right? What matters is, does taking the drug actually reduce your risk of heart attack and stroke, not, you know, does it change this surrogate marker? And of course, we all assumed, of course it will, because we know that Lp little a is very strongly associated with these outcomes, just like LDL was. And if we can reduce it, we'll reduce the risk of these outcomes. And you probably see where this is going. In a phase three trial of 8,383 people, all of whom had high Lp little a and history of heart disease, they were randomized to get this drug, which is a monthly injection versus a placebo injection. And all we know so far is that there is no difference in the subsequent rate of major adverse coronary events, which was the primary outcome of the trial. Like, really, a type of, like people were so confident in this. And I'll tell you, this enters the wellness space because a lot of direct to consumer testing labs will tell you your Lp little a level. They'll be like, ooh, it's the new hot biomarker of cardiovascular risk. Like a lot of people listening who have done that testing will know what their Lp little a is. And it turns out, like, does it even matter? So Emily, like this is sort of your area here, right? We have a clear correlation between a level and an outcome, but changing the level doesn't change the outcome.