0:00 A really excellent study where they lowered cholesterol was buried for 40 years. I wonder why they buried it and what the results were. Don't you? Hi, I'm Dr. Eric Westman and welcome to my channel where I review and debunk [music] nutritional misinformation online. In this study, we're going to hear Nick Norwoods unpack the detail, do a critical appraisal of a randomized control trial with outcomes that we would love to do a study like this today. Again, this was done many, many years ago and was buried. Something called file drawer bias where you hide the study in a file drawer and you don't
0:47 publish it. So, let's see what Nick says, and be sure to wait till the end where I give my final thoughts. >> What if lowering your cholesterol increased your risk of death? >> Cholesterol. >> Well, that's what a forgotten trial from the 1970s appeared to show. And this was a gold standard study, a blinded randomized control trial testing whether swapping saturated fat, like in butter and beef, for unsaturated fat, would improve heart health and save lives. But to the astonishment of the researchers, it did the opposite. The cholesterol-lowering diet didn't save lives it took them. And what's more, the lower the cholesterol dropped, the more death occurred. But then, the study wasn't published. It was hidden on nine track tapes in some guy's basement, only on Earth decades later. Why? Says Dr.
1:35 France, I've heard the possibility that there might be some very interesting data in your father's basement. And there was a mouldering old cardboard box there that I opened up and I just immediately thought to myself, Eureka, I have found it. Was it a conspiracy? Was it an inconvenient truth that didn't fit a narrative? Or was it something else? Stick around because in this video, we're going to delve into the details and find out together. Now, to truly understand the meaning of these results, we first need to understand the methods. What did the researchers actually do? What were they aiming to find? Well, this experiment, the Minnesota Coronary Experiment, was a randomized control trial conducted between 1968 and 1973.
2:23 It included 9,423 men and women from across six mental hospitals in one nursing home. Now, to emphasize the power of this approach, though ethically questionable by today's standards, was that the researchers could truly blind and rigorously control the patients diets with remarkable accuracy. So, always consider the source. Nick Noritz is a physician who graduated from Harvard Medical School, has a PhD and super smart. And here we're going to be getting a critical appraisal of a study. To me, blinding the study is not so important when it comes to food. It might be important when it comes to subjective things. But here it was actually blinded which is
3:09 unusual in a nutrition trial. But the idea looking back that in the early 1970s there was a randomized control trial testing the hypothesis of cholesterol lowering looking at outcomes of morbidity and mortality is really kind of chilling in in that if these results were known well I won't be the spoiler here. It may have changed history. What were the researchers trying to find? Well, according to the grant proposal put forth to the NIH, the project's objective was to provide evidence concerning whether the incidence of atherosclerosis and its clinical consequences couldn't be reduced by dietary modification. So, in effect, the researchers were testing whether
3:54 swapping saturated fat like in butter for unsaturated fat in the form of vegetable oil would reduce heart disease and death. That was the hypothesis. Now another unique strength of this study which is unparalleled by any other study was that participants could be autopsied after death allowed the researchers to examine their arteries like literally go into the body look in the arteries after death to assess for changes in cardiovascular plaque progression presumably as a result of the intervention. This is a stunning level of control and rigor. I want to emphasize that. Now what about the diets themselves? Well, the intervention diet was designed specifically as a cholesterol-lowering diet. That was the objective. Butter was replaced by
4:39 margarine, rich in polyunsaturated fats, leading to a diet that was overall much lower in saturated fats and higher in unsaturated fats, particularly the omega6 linoleic acid. In fact, compared to the baseline hospital diet, the linoleic acid intake in the intervention group was increased by 288% while saturated fat intake was decreased by half, cut by 51%. Now, these dietary shifts, as I mentioned, were aimed to reduce cholesterol predicted to cause a large reduction. Specifically using the Keys equation named after the famous researcher Ancel Keys the intervention group the vegetable oilrich diet was expected to lower cholesterol by about 18%. Now speaking of Anel Keys maybe that's a name you've heard of. He's one
5:25 of the best known nutrition researchers of the era. He's best known in fact for his controversial seven country study, a very influential observational epidemiological investigation that linked saturated fat intake with cardiovascular disease. And he was also one of the lead investigators on this study. So I've been to meetings where Anel Keys's name comes up and people boo because they know that he did that first seven country study and it was observational and and cherrypicked a bit. So what we're seeing here is the juxiposition of an observational study that Dr. keys published and and pushed that showed saturated fat to be bad and cholesterol
6:12 in the blood to be bad. now juxtaposed to a randomized control trial, the Minnesota study that was buried in the file drawer for decades and it the in this information was being collected decades ago before the whole dietary guideline and and push pushing us toward low saturated fat in the diet. And it's important to know this as a background because the new dietary guideline for Americans is moving away from a saturated fat restriction. If this study had shown, well, let's see what the study showed. >> The Minnesota Coronary Experiment, that's an important detail worth noting.
6:58 And we'll turn to the history later, but in summary of the design, the Minnesota Coronary Experiment was a rigorous blinded randomized control trial. Researchers fed patients either a low saturated fat diet or a control diet, and then tracked them over the course of years for meaningful clinical outcomes, including heart disease and death. So, now comes the moment of truth. Are you ready? The lowest saturated fat vegetable oil diet group did in fact show a significant reduction in cholesterol, a 13.8% reduction, but this didn't translate into improved outcomes. On the contrary, the vegetable oil low saturated fat group actually fared far worse. Specifically, there was a 22%
7:44 higher risk of death for each 30 mg per deciliter reduction in cholesterol. >> So lowering the cholesterol by lowering the saturated fat in the food led to higher deaths, higher mortality rate. >> So in plain language, the lower the participants cholesterol fell, the more likely they were to die. I know. Now, if I were less charitable toward the researchers and the broader scientific community, the way the results were then handled could be read as excellent fodder for conspiracy theories >> remembers everyone just being baffled. And they were hoping that with some new statistical techniques that had just come out that they might be able to either understand why the results came out the way they did or perhaps after some adjustments for various explanatory
8:31 factors that maybe the results would would change. >> The results didn't change. When Brosty talked to Ivan France, France just shook his head. I heard other recounting of that history and the investigators basically said, "Well, the results didn't come out the way we wanted them, so they didn't publish it." >> Now, let's take a moment to pause. I suppose you may be wondering why you never heard of these data before and why they haven't shifted common wisdom that lowering your cholesterol is good for heart health. That's still common knowledge. Well, we'll get to that, but first I need to reveal the actual cardiovascular findings because you might be thinking at least, okay, maybe lowering cholesterol with this vegetable oil rich diet was associated with more deaths overall or cause more deaths overall. But surely it must have offered
9:18 some benefits for the heart specifically, right? Well, actually, no. As mentioned earlier, one of the unique strengths of the Minnesota coronary experiment was that the researchers could perform autopsies on a subset of patients. This allowed them to confirm the presence relative presence of plaque and confirm whether participants actually had heart attacks. However, again the vegetable oil intervention showed no benefit for heart disease coronary atherosclerosis. In fact, the vegetable oil lowsaturated fat intervention group exhibited about twice as many heart attacks as confirmed on autopsy compared to the control group with a higher saturated fat diet. 41% versus 22%. >> So yeah, you're hearing it correctly
10:03 that it's the exact opposite of what we've been told for so long. Now that the stud is not perfect and we're going to hear about some limitations to it, but the upshot is that the push or understanding against this the stream the stream was basically saturated fat in the food is bad. You know, you cut out the butter, add margarine, and and then the lower the cholesterol in the blood, the better. That was the stream, the the flood going this way. And this study actually with higher methodology, really the highest possible randomized control trial didn't find it. Now, it's not a huge study and there are some limitations. At a minimum, we need to do
10:50 this over, need to do this study again where we're changing the food. Some people will choose because they believe well ideally it would be a randomized control trial where you don't uh choose that between the different diets that probably still could be done today. But the strength with which someone says you lower your saturated fat, you lower your cholesterol, you'll have less heart disease and less death, that is not a very strong statement. In fact, it was not what was found in this randomized control trial. If this is the first time that you're hearing that saturated fat is not related or not causal for heart disease, uh it's important to go back to Gary Tabs's book, Good Calories, Bad
11:36 Calories. I think it came out in 2005 and then also Nina Tyel's book, The Big Fat Surprise. These are investigative journalists who spent years looking through the evidence that was published to see if there was randomized control trial le evidence high level to see if there was high level evidence to implicate saturated fats or even cholesterol for heart disease. And they they found what I learned in my clinical epidemiology training that that they never really proved that the fat in the food or the cholesterol in the the blood was the cause of the heart disease or increased mortality. So go back to Gary
12:23 Ta's good calories bad calories Nina Ty Schwaltz the big fat surprise. If this is new to you and you're still skeptical about it, let me know your comments below about those books. Hopefully, you've read them uh as I have multiple times. >> So, where does this leave us? The Minnesota Coronary Experiment is a reminder that science is messy and nutrition science especially. So, it can be really messy. Looking for good nutrition science is like looking for a needle in 12 hay stacks. But in this study, what we see is that lowering cholesterol with a vegetable oil rich intervention, it didn't save lives. In fact, it cost lives. And whether that was due to cholesterol lowering itself or some coincidental variable isn't actually the central point. The real
13:09 point is this. Even when the dietary intervention successfully targeted the intended marker, it successfully lowered cholesterol. The ultimate unexpected consequence was catastrophe. Death. The assumption was simple. Lowering cholesterol would improve outcomes, heart disease, and death. But by clinging too tightly to that assumption, narrowing in on it. An intervention designed to heal ended up doing harm. And that is not speculation. That is a hard truth. That is a fact. And it's a lesson we shouldn't ignore. And further, the fact that these data were buried or at least not published for decades only sharpens the cautionary tale. The lesson here is not that cholesterol lowering is inherently harmful. I never said that. Nor that we
13:56 should flip conventional wisdom completely on its head. The real lesson is one that can be summed up in one word, humility. We must resist the urge to turn limited evidence into sweeping prescriptions that may harm more than help. In fact, I love how these authors finished up this paper. To quote the authors of the 2016 BMJ paper that resurfaced the Minnesota coronary experiment, they said, "Given the limitations of current evidence, the best approach might be one of humility, highlighting the limitations of current evidence and setting a high bar for advising intakes beyond what can be provided by natural diets." So, in other words, this is the picture that's coming into my mind. While these researchers had the blade of their foot on the throat of the personified lipid heart
14:43 hypothesis, they didn't press down. They could have, but they didn't. Instead, they extended a hand and said, "Look, this is a complicated topic. Maybe rather than being prescriptive in such blunt black and white ways like saturated fat is bad, cut back on red meat, butter is evil, maybe we should pause before making sweeping recommendations to the population through dietary guidelines that could ultimately be more harmful and helpful. So, let's return to the question we began our investigation with. What if lowering your cholesterol increases your risk of death? The truth is, it might or it might not. It depends on the how. But what the Minnesota coronary experiment really teaches us is that the answer isn't nearly as simple as we'd like to believe. And until we know more, the
15:30 wisest stance is one of humility. I hope you found this thoughtprovoking, nuanced, and reasonable. Stay curious and let me know your thoughts in the comments, what further questions you have because this discussion is far from done. And I think that's a great thing. Well, a great video of going through a a study and the idea that it was suppressed or in a file drawer for 40 years is another just messy part of the nutritional research that we've seen. These studies can be redone and they can be done with much less expense, I believe, given the internet and other ways to validate food that people eat and with biomarker assessments. So, if we're really going to get to the idea of
16:16 is saturated fat good or bad, we need to do prospective randomized trials and really assess what people are eating. We can do that and it doesn't have to take a lot of time, doesn't have to take a whole lot of money. It just takes the will, the humility to reassess where we are today. Thanks, Nick, for another great video. If you like this, please like, subscribe, ring the notification bell, and look out for new content on Wednesdays and Fridays. If you enjoyed [music] this video, consider joining our YouTube membership for early access and exclusive live Q&As with me. Just click the join button below, or support us with a PayPal in the description.
