Saturated fat…here is part three, where we will discuss the research on the topic.

Recap

In part one I discussed the problems with relying on science in general. Some people like accepting the “scientific consensus” on something because it seems safe to go along with majority opinion. The problem with this strategy is that you don’t end up doing the research yourself. When you do, you may find something the majority did not. Also, the conventional point of view regarding all public health related matters is not always based on evidence. We could debate that all day.

In part two I described the idea of food synergy, and why this is a missing link in nutrition science research.

In this final segment I will share what the actual research shows regarding saturated fat intake and cholesterol intake on your health. In addition, I will show you how to find this research easily.

What is the research question?

We will shortly go to pubmed to search for studies on saturated fat and cholesterol consumption. Before we go to pubmed, let’s first clarify our research question. The research question I am answering in this post is “what is the effect of saturated fat and cholesterol intake on cardiovascular disease (CVD) and all-cause mortality?” This is a specific question. “Is saturated fat bad for you” is NOT a specific question. In the research world you need specific questions for a few reasons.

For one, a specific question is easier to study and the results are easier to draw a conclusion from. If we were to design a research study to answer if saturated fat was good for you in general we would probably be answering a lot of other specific questions. We could assess if it’s good for your health, which leads to more specific questions about health. But we could also ask if it makes you feel good to eat it, which is an entirely different question. If we didn’t ask specific questions, and say just designed a survey that asked people if they thought saturated fat was good for you, and they could answer in an open ended way, our data would be quite jumbled and not as meaningful to interpret.

The effect of saturated fat, if any, on cardiovascular disease outcomes and all-cause mortality asks two different questions. The first question is looking at saturated fat and cardiovascular disease outcomes. We could define those outcomes as total heart attacks, deaths from heart attacks, number of strokes, deaths from stroke, and diagnosis of cardiovascular disease.

The second question asks if there is a relationship between saturated fat intake and all-cause mortality. All-cause mortality means death from any cause. Smoking, being sedentary, and eating a standard American diet (high sugar, high amount of processed foods, low antioxidant intake) increases your chances of dying in general from any cause. Generally, unhealthy things make you die sooner, so that is the idea this question is getting at.

Death from a specific cause or any cause is arguably the most important outcome from a medical standpoint. I personally care about all the things leading to death (because we may be living somewhat longer in modern times but it’s questionable if we are healthier), but getting wrapped up in the details sometimes isn’t very fruitful. Drugs for example may reduce risk factors for a disease but make you die sooner from that disease through some unknown mechanism or from some other disease, making the drug pointless.

The other research question is the same, but we will replace saturated fat with cholesterol to get this: “what is the effect of cholesterol intake on cardiovascular disease and all cause mortality?”

What is cardiovascular disease…

The next point I want to make before discussing the research is that cardiovascular disease is sometimes interchanged with heart disease and neither are a single entity. There are a multitude of afflictions affecting the heart, including coronary artery disease (CAD), peripheral artery disease (PAD), ischemic heart disease (IHD), angina pectoris, stroke, arteriosclerosis, hypertension, cardiomyopathies, aortic aneurysm, congestive heart failure, and valvular disorders. Many of them may involve atherosclerosis (plaque build up inside arteries, impeding blood flow). Cardiovascular disease affects the heart, either due to a dysfunction with the heart itself, plaque buildup in the coronary artery, or plaque buildup throughout the vasculature, making it harder for the heart to do its job.

So what is heart health?

In general, if something improves heart health it helps the heart do its job better. If you have lower extremity artery disease (LEAD), something good for promoting blood flow in the lower extremity arteries may improve the return of blood to the heart which could help it pump more effectively. In congestive heart failure, depending on what is causing it, treating that root cause will help the heart pump blood better, reducing stress on the myocytes (name of the cells composing the heart). Off the top of my head, I’m thinking maybe beet juice could help with this, as it promotes blood flow and nitric oxide signaling (many things do this), which dilates the arteries, enhancing blood flow. This might work. It depends on the type of CHF and cause, along with the individual person.

What is mostly true is that many heart diseases can be prevented by not smoking, limiting alcohol intake, exercising regularly, and eating a varied diet rich in antioxidants and nutrients. Most of the diseases that kill people most likely can be prevented this way.

Finding the research

Let’s go to pubmed now and look for some research. I’ve learned a few things from my research classes about getting a good search result here. It takes practice. So watch first what happens when I type in “saturated fat” in the search box.

Not bad actually, when you have “best match” chosen (circled). If you chose instead “most recent” you would get less relevant results. Try it out yourself. We will definitely look at articles 2 and 4 (check marked).

The thinner circles at the bottom bring up the next subject. Instead of pouring through individual studies, we can look for systematic reviews or meta-analyses. Dr. Uman defines these two terms in her article as follows:

“Systematic reviews, as the name implies, typically involve a detailed and comprehensive plan and search strategy derived a priori, with the goal of reducing bias by identifying, appraising, and synthesizing all relevant studies on a particular topic. Often, systematic reviews include a meta-analysis component which involves using statistical techniques to synthesize the data from several studies into a single quantitative estimate or summary effect size (Petticrew & Roberts, 2006).”

Reviews just review what’s out there, and a meta-analysis takes a bunch of studies, pools their data, and performs a new statistical analysis.

Refining the search

We will now search “saturated fat intake cardiovascular disease all cause mortality,” checking just systematic reviews and meta analyses. 13 results show up.

Not bad. Now we will go one step further and go to the advanced search. Click “advanced” below the search box. We are now going to tell the search feature to look for all studies matching two different search phrases. You can simultaneously search for two things at once with one search by using the phrase OR. My search query is now “saturated fat intake AND cardiovascular disease OR saturated fat intake AND all cause mortality.”

17 results! WOW. Just kidding…the 4 additional studies here aren’t really answering our question. So in this case the advanced search wasn’t necessary.

Now let’s compare this to google searching. To my surprise, there is one article (circled below) that did not show up in my pubmed search results. I’ll have to ask my professor about that. One of the other articles that shows up was in my search results.

We will talk about the article shortly. Next, let’s click on “scholarly articles” (where the arrows are pointing). To my surprise, most of the articles on the first page aren’t answering my question.

I’m not interested in flavonoid intake google! Well atually I am but not right now. I am drinking some pour over coffee I made myself and there are flavonoids and polyphenols in there.

Article discussion time

One of the articles google found was not in my pubmed search. This article is titled “Food Sources of Saturated Fat and the Association With Mortality: A Meta-Analysis.” The researchers here set out to answer a few different questions. They were interested in whether or not a high consumption of foods containing saturated fat increased all cause mortality, cardiovascular disease mortality, or cancer mortality. They found a slight inverse association with milk, a low positive association with meat, and a moderately positive association with processed meat consumption. In general they said the evidence is too weak to support the idea that eating meat promotes mortality from all causes. They reviewed 26 different studies. That study deserves a separate post. I will keep it brief here as we still have to talk about cholesterol after this.

The second study I want to discuss is titled “Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies” (it’s a free article). They answered the same questions I want to answer (we can decide if their answer is definitive or not) and a few more. They look for an association with saturated and trans unsaturated fat with all cause mortality, CHD mortality, CVD mortality, CVD incidence, ischemic stroke, and diabetes incidence. They found no association with saturated fat and all cause mortality or cardiovascular disease. For trans fat though it’s a different story; they differentiated between natural trans fats (the ones found in grass fed meat and milk) and industrial trans fats (products of hydrogenation of vegetable oils commonly found in processed foods). Total trans fat intake was associated with a statistically significant increase in all cause mortality. Ruminant trans fats were inversely associated with diabetes (but no association was seen with cardiovascular disease). This association was the strongest out of any other association in the study, and warrants a future post.

There are plenty of other articles like these you can find from the pubmed search we went through. In general it seems as if there is no association whatsoever with saturated fat intake and cardiovascular disease or all cause mortality. In part four we will discuss the strength of these findings and come to a conclusion on whether or not we should agree with this.

Cholesterol intake

Using the methods above, I searched for “cholesterol intake cardiovascular disease.” I found a paper titled “Dietary cholesterol and cardiovascular disease: a systematic review and meta-analysis.” This paper answered many questions. One of them was if cholesterol intake had an effect on VLDL (very low density lipoprotein). This is one of the “bad” cholesterols, but it’s not so simple. They evaluated three different trials to answer this question and basically found no association. They also didn’t find much association with cholesterol intake and other serum lipids in general.

They found six different trials investigating cholesterol intake on coronary artery disease (CAD). Only one (a study in a Japanese population) found a statistically significant association. For the rest no positive association was found. Cholesterol intake also had no effect on death from CAD, except in one study where an effect was seen in men who consumed about 430 mg of cholesterol per day. This study had more vegetarians than omnivores, so there could be something else mediating this relationship. 430 mg of cholesterol a day is about a few eggs worth. This may sound alarming but it’s not, as it was just one study, and many other factors could have potentiated this positive relationship. I will have to look into that study separately.

Other studies they evaluated found no association with cholesterol intake and any CVD. Whether its CAD or CVD the results are pretty consistent that there is no positive relationship between cholesterol intake and those diseases. I don’t think they answered all cause mortality so we will just skip over that for now and say don’t worry about it!

Conclusion: In general when studies are discussed we should look at their methods, the population studied, and the outcomes they assessed, in more detail. Here I am just sharing the overall conclusions from some of the most robust analyses on the questions we chose to answer. If there was a huge effect of eating more saturated fat, which is naturally found in milk, cheese, butter, meat, and coconuts, on your heart health, we would expect to see its effect in such large studies where tens of thousands of people are evaluated. There is strength in numbers; the larger the population size the stronger the conclusion from statistical analyses one can draw.

The downside is that individuality is lost. What about meat eating among those who follow a paleo diet versus meat eating in those who follow a standard American diet versus those who eat meat in moderation and try to be healthy but aren’t strict about following a diet? Those are all different populations and I’d have to do more digging to see if studies have been done on these populations. For now, it’s settled. Saturated fat won’t kill you. Eating cholesterol doesn’t cause heart attacks and likely has no relationship with all cause mortality. Emphasize whole food once again and try to connect to nature as much as you can. Choose grass-fed meat whenever possible. Choose pasture-raised eggs. Be proactive about what’s going in to your dinner plate. I know I could even improve in that with my busy lifestyle! I have a quiz tomorrow morning I have barely studied for!

In part four I will talk more about statistics and how to draw conclusions from studies like the ones we analyzed. Hope you learned something.

Stay tuned!

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I read the blood type diet years ago. I then read the Genotype Diet, an updated version of that book. In the latter one, naturopathic physician Dr. Peter J. D’Adamo devised a litany of physical measurements to determine what type of diet is best for one’s health in addition to the detailed reasons he outlined supporting his Blood Type Diet book published years before.

His work, based off of years of research and experimentation, was deemed debunked. People read about it online in press articles and decided that it wasn’t worth looking into. The BTD was now unscientific, just like all naturopaths apparently! Dr. Michael Greger, a highly biased vegan-diet-promoting doctor who cherry picks scientific studies and who I have even found to manipulate data to support his viewpoints published a critique. There was one on quackwatch too which is not a site I find trustworthy, to say the least.

As I have outlined in previous posts, like in a recent one about the saturated fat myth, science is often unable to study the complexities of reality. The study that “debunked” the blood-type diet did not really use the blood type diet. Dr. D’Adamo’s response to it addressed this and much more. His critique included that skeptics tend to never express curiosity. They come from a place of dismissiveness.

This was part of his response:

“A look at the core data used in the PLOS Study [1] debunking the Blood Type Diet (BTD) finds support for the researcher’s conclusions that if your experimental subjects eat potato chips, sandwiches, pizza, ‘beans,’ mac-and-cheese, French Fries and processed meat products while doing 13.7% of the Blood Type Diet, their final cardiometabolic markers will probably not vary much by blood type.”

If you want to learn about the blood type diet one day and read about how it was debunked but never do any research beyond that yourself, you have not honored your curiosity. You have not followed the scientific method. You have relied on “science” that someone else did to arrive at your conclusion about how things work. And you are wrong.

End of story.

I am not going to provide a detailed explanation on why I like the blood type diet. The main reason is that it is idividualized and based on trial, error, and lots of experimentation. Although I have no idea why some types can eat manchengo cheese and others cannot, I am open to the idea that some types may be more sensitive to certain proteins. I think that was his theory but I’ll have to save this discussion for a future post. There may be flaws to it but unlike other diets, it was devised by someone who seemed to put in more time and effort into it than people usually do it diet books. Based on these observations I do not think that the blood type diet debunking study came anywhere close to debunking the success stories people have had with it.

 

On a recent instagram post about red meat, where I suggested that meat is not bad for you, someone commented that I was a charlatan and that the science was in consensus about the health dangers of red meat consumption.

Now I’ve received comments like this before, from having a youtube channel and discussing non-mainstream views on health. Calling naturopaths quacks and charlatans is done without thought by those who get their medical education from the internet or spend too much time believing what they learned through conventional routes of medical education.

What I did find interesting was the term he used–“scientific consensus.” It reminded me of the scientific consensus that climate change is happening.

Without reading the literature on climate change I am inclined to believe that the scientific consensus is onto something. I’ve heard many times that the sea level is rising, glaciers are melting, and animals are going extinct because of climate change. I can believe that. I’ve watched planet earth on netflix and short films by National Geographic that have clearly shown me that there is a change in the climate. Beyond that, I have no idea as I have not studied the details. I just recycle and aim to reuse what I can.

But is there a scientific consensus that red meat consumption is bad for your health? Well, I am going to break down the science for you, without citing it, because it’s a huge waste of time. If I cite research for you, I will have you making the same mistake the Instagram commenter did. Instead of talking about science that has been published, we are going to think about our own unique scientific experiment (in part two especially). If I cited research that shows no association between saturated fat consumption and all-cause mortality, you might be more likely to believe me, but would you keep reading and be stimulated to construct the big picture as we will do now? I doubt it. Most likely, people will say, “okay cool I can eat red meat” and move on. Well yes you definitely can but here’s why.

Why people think red meat is bad

The two bad things in red meat that are mistakenly attributed to be the cause of its alleged negative health effects are saturated fat and cholesterol. Since pharmaceutical companies have successfully spent billions of dollars convincing patients that cholesterol is a bad guy and that lowering it will improve cardiovascular disease outcomes, red meat seems like a bad idea. It’s mind-boggling that all of this is a huge lie.

The other day a middle-aged gray-haired male was reading side effects of a statin his doctor was interested in him taking at an Indian restaurant where I indulged in a buffet after fasting. This man was also seeing a naturopath, since we were in Oregon where a lot of insurance companies cover naturopathic primary care (they do what MD’s do, and prescribe some herbs along the way depending on how naturopathic they are; unfortunately many have compromised their values but that is another discussion). I started a conversation with him.

“Have you heard of red yeast rice (RYR)?”

“Ah yes, I have! What are your thoughts on that?”

“Well, I recommend it. It actually contains lovastatin. 40 mg of RYR will contain about 10 mg lovastatin, while working just as well as 40 mg of lovastatin. You also get other compounds in there so instead of just one that blocks the crap out of one enzymatic pathway you have more than just one mechanism of action. Furthermore, since you use less statin, you have less muscle cramping and more CoQ10, an important mitochondrial factor that aids in energy production and declines with age. See if you’re on a statin you might have less exercise tolerance because of your reduced CoQ10. It’s just a theory as there aren’t a whole lot of studies on this but exercse is very good for heart health so it’s ironic to me that being on a statin can inhibit your ability to derive the benefits of something you should be doing for your health.”

This individual was very happy I spoke with him.

People who like listening to the “scientific consensus” tend to place too much trust in published research and don’t seem to investigate the matter on their own. They hope that things are right but there are always missing pieces of information. They will say that statins have shown reduced risk of major adverse cardiovascular events and that the benefit of treatment outweighed the risks. It sounds wonderful, but they don’t think holistically, as I attempted to demonstrate above in my conversation with this man. If we are interested in health, we need to go beyond outcome measures and look inwards.

That should answer whether or not saturated fat is bad for you. The research shows X, or Y, or Z, but doesn’t consider everything in between. Research may have shown in the past that a high fat diet fed to mice led to increased aortic plaques and a reduced lifespan. Substitution of the saturated fats with polyunsaturated fats diminished this increased adverse effect. Although compelling, we don’t eat the way mice and rats do in these studies. And that’s why the large studies have found no effect from saturated fat consumption and heart attacks (to be discussed in part three).

Studying a real diet is often too complicated for research purposes. Research must have clearly defined outcome measures, interventions, populations, and control groups. What goes on your plate is not as clearly defined as a saturated fat.

In part two of this segment, I will begin the discussion on why red meat actually isn’t bad for you with an emphasis on holistic thinking. This post was meant to I guess get the thinking process started. Stay tuned!