Understanding Cholesterol and Diabetes

Dr. Jedha, Host

Hello wonderful people, Dr Jedha here and welcome to episode 42. 

September is National Cholesterol Education Month in the US. The last day of the month, 30th September, is LDL cholesterol Awareness Day. So it seemed like a perfect time to cover the topic of cholesterol. 

1:00 

When it comes to cholesterol, well, there are quite a number of myths surrounding the topic, along with quite a lot of controversy about it too. Some say it’s the cause of one of our deadliest conditions in the world–heart disease. While some say it doesn’t matter whatsoever. The truth probably lies somewhere in the middle. Why is this? Well, much of the research shows contradictory results, some of the research during the 50s established inaccurate hypotheses that became the status quo, other research over the years has been distorted, there is frequently research bias and poor interpretation of results, and in most cases, large population studies are used that may show associations, but an association does not prove causation, so many studies can’t be said to provide actual proof of anything. In addition, we hear a lot of propaganda from the media about cholesterol. We also see common narratives perpetuated. And there are pharmaceutical companies with vested interests in maintaining common narratives. Yes, there’s a lot tied up in it. The reality is, many of the messages we’ve all come to believe are true are over simplistic and the truth is, for the most part, cholesterol is widely misunderstood. 

We could go down the rabbit hole trying to dissect this but creating more confusion is not what we want to do. When I sat down to plan this podcast, I wanted it to be about the practical steps you can take to bring high cholesterol levels back on track. But, I had a feeling we may have to do a part one and part two on the topic of cholesterol because it’s difficult to say: “It’s okay to eat eggs even though they’re high in cholesterol” without first diving into the myths and misunderstandings about cholesterol. It’s only when you get a better understanding of cholesterol and your body, that you can leave common narratives and perpetuating outdated myths behind, and move forward in a sensible way that will support better cholesterol and improvements in your health overall. Without the contextual background, it’s easy to stay stuck in those perpetuating myths. So, what we will endeavor to do today is chat about what cholesterol actually is and its role in our body. Plus, bust a few of the predominating myths. In our next segment on cholesterol, coming soon, we’ll chat about practical nutrition strategies to bring high cholesterol levels down. 

As with all things here on Type 2 Diabetes Talk, it’s all about evidence over opinion. We are not here to perpetuate these myths and common narratives but to share the facts of real science and try to get to the bottom of the real truths about what really works – that’s what we’ve been focused on for over a decade, as there is way too much propaganda and dominant narratives that are just inaccurate or grossly disproportionate. The information shared here comes from peer-reviewed research or from medical doctors and researchers who are experts in the area of cholesterol and metabolic health. As always, you can find this information and further resources on our website at Type2DiabetesTalk.com alongside episode 42. For our members, you can find all our cholesterol info inside the members library. 

5:30 

It makes sense that we should start at the beginning, by answering the question: what is cholesterol? 

Many people might say that cholesterol is a type of fat in your blood that can build up in our arteries, leading to plaques that cause heart attacks and strokes. That’s a very over simplified version of something that is quite complex. 

Cholesterol is a lipid, a fat synthesized by every cell in our body. While we often think of cholesterol as bad, the fact that it is synthesized by every cell in our body indicates how important it is. In fact, without cholesterol there would be no life, we would die. 

Cholesterol is essential for the creation of cells. Cholesterol forms the basis of all our cell membranes. Cholesterol allows transporters to cross the cell wall, for example, transporters that provide nutrients. Cholesterol is the precursor to hormones like vit D, cortisol, estrogen, and testosterone. Cholesterol is essential for bile acids that aid in the digestion of foods. Cholesterol is crucial for brain function. We absolutely need cholesterol for many essential physical functions. 

Even though all cells make cholesterol, all cells are not capable of creating the cholesterol they need so our liver synthesizes cholesterol. The issue is, cholesterol needs a method of transport, as it is a lipid or fat, so it’s insoluble in our bloodstream. The vehicle that transports cholesterol around the body is called a lipoprotein. Basically, cholesterol is a molecule that travels through the bloodstream on proteins called “lipoproteins.” Despite commonly held assumptions, there is no good or bad cholesterol, only cholesterol. The name of a lipoprotein purely explains its density. LDL stands for Low Density Lipoprotein. HDL stands for High Density Lipoprotein. 

Think of lipoproteins as the courier responsible to carry various cholesterol packages around the body to where they are needed. To emphasize, the lipoproteins carry cholesterol molecules, they are not actually cholesterol, even though we call them that. The mechanisms by which the lipoproteins act, or some of the things they do is different. For instance, LDL couriers a lot of packages from the liver, moving them around the body to provide the building blocks to the body so the body can do its job. As one example, hormones are built from a cholesterol backbone so a courier might drop off packages to help with hormone production. HDL is the reverse transport courier, picking up packages, excess cholesterol from tissues for example, and HDL transports them back to the liver for processing or excretion. 

9:23 

The next question to answer is, why would LDL be labeled as “bad” cholesterol?

Firstly, the mechanism by which LDL acts has placed it as a “bad” player, after all, it’s the one dropping off packages into our cells and arteries, while HDL is the one picking them up and cleaning up any mess. 

Secondly, the concerns have arisen from data that’s come out of large population studies that have shown an association between higher LDL and heart disease, that can’t be denied, the association is there. But population studies can’t prove anything, as association does not mean causation. And it’s an overly simplistic way to look at LDL because we now know there are different types of LDL, some of which are neutral, others which are harmful. A single snapshot from a lab test saying your LDL is high, doesn’t tell you anything about the functionality of that LDL or your cardiovascular risk. 

Among other things, what’s needed is to evaluate the risk of your LDL load, through an extended lipid panel, which may include apoB or Apolipoprotein B, which can show the total number of atherogenic particles; particle number and size, which can provide insights on the functions of LDL and HDL lipoproteins; and Lp-a or lipoprotein levels, which measures a specific type of LDL particle. Yet, that’s not something most GPs will assess, basing most of their decisions on a single snapshot view. But, you can request an extended lipid panel and there are many labs that provide these tests. 

11:27 

Coming back to LDL, not all LDL is created equal. With LDL there are large buoyant particles and small dense particles. Large buoyant particles are neutral for cardiovascular health. If your LDL is high but your profile shows large buoyant particles, there is no cause for concern. Small dense LDL particles are the concern. Since these are dense, these are the ones that can get under the cells in the lining of arteries, they can become oxidized and spark an inflammatory response that may lead to plaque formation and eventuate in heart disease or stroke. 

HDL, on the other hand, is thought of as the “good” cholesterol because it is the reverse transport courier, picking up packages and retransporting them back to the liver for processing or excretion. Basically, HDL helps clean up any mess. Higher HDL means your body is efficient at recycling molecules your body doesn’t need. And it is agreed that having higher HDL levels is beneficial, more protective. 

It’s also important to know your fasting triglyceride level. Triglyceride level is more predictive of heart disease because if triglycerides are high then LDL is likely to be small dense. In simple terms, the liver turns sugar into fat (triglycerides) and creates packages for a courier called VLDL (very low density lipoproteins). As the VLDL travels around the body delivering packages, the VLDL eventually converts to LDL, and a large majority of these will become small dense LDL particles. Hence, higher triglycerides usually means more small dense LDL particles. That’s the evolution. These small, dense LDL particles are more prone to oxidation and are more likely to penetrate the arterial walls, contributing to plaque formation and increasing the risk of cardiovascular disease.

Some interesting food for thought to throw in here is that pharmaceutical companies were able to come up with a drug that supposedly lowers LDL cholesterol. They’ve never been able to come up with a drug that lowers triglycerides. 

While blood tests are certainly important, the numbers always need to be considered in the context of everything else. In the context of other tests and in the context of your overall metabolic health. For instance, your blood glucose, your fasting insulin levels and assessing your level of insulin resistance, among other things. Numbers are indicators that give us pieces of a puzzle, on their own they mean very little, it’s only when we connect the dots that we’re able to see the picture clearly. 

15:31 

The third question to answer is, why is high cholesterol so common among people with prediabetes and type 2 diabetes?

In previous episodes you’ve probably heard me talk about the fact that pre and T2Diabetes are conditions of altered metabolism – high blood glucose, high insulin levels and insulin resistance all play havoc in the body. For this reason, it is common to see altered cholesterol levels, which frequently looks like high triglycerides, low HDL and either normal or elevated LDL. Because of an altered metabolism – your body has changed the way it metabolizes and uses nutrients, and that includes metabolizing and utilizing fats. We need to address the underlying issues and correct and reverse the altered metabolism. As we often speak about, everything is connected – the high glucose, the high blood pressure, the high cholesterol – they’re not independent of each other, they are all connected.

Okay, the next thing we need to chat about are some of the pervading dietary myths about cholesterol. 

16:47

Myth #1: Dietary Cholesterol Directly Increases Blood Cholesterol

For many years, it was believed that eating foods high in cholesterol, such as eggs and shellfish, would directly increase blood cholesterol levels, so we’d commonly see people limiting eggs or only eating the egg whites. Fast forward and there is now extensive research that has shown, for most people, dietary cholesterol has little impact on blood cholesterol levels. Or in other words, cholesterol in foods does not automatically equate to more cholesterol in your body – that is a myth. The body tightly regulates cholesterol production, and when you consume more cholesterol, the liver typically produces less. And foods such as eggs, which do contain a high amount of cholesterol, have no negative impact on cholesterol and if anything, they can help to boost HDL levels. We covered eggs in episode 13 so go back to listen to that. 

17:59

Myth #2: Cholesterol In The Diet Is A Concern

Over the years the dietary recommendations said we shouldn’t eat more than 300mg of cholesterol each day. Hence the reason many people avoided eggs, as they contain 180-200 mg of cholesterol per egg. As we just established in myth one, dietary cholesterol does not directly increase blood cholesterol. The guidelines to limit cholesterol were never based on solid evidence. Subsequently, back in 2015, the American Dietary Guidelines Committee had to remove the concern about cholesterol from the dietary guidelines, stating: “Cholesterol is not a nutrient of concern for overconsumption.” Subsequently, we’ve seen guidelines across the globe change in terms of their view of dietary cholesterol. We do not have to worry about the amount of  cholesterol in foods – that’s a myth, period. 

19:10 

Myth #3: All LDL Cholesterol is “Bad”

I think we’ve busted this myth already but I wanted to highlight it here again. There is no good or bad cholesterol, only cholesterol. LDL is often labeled as “bad” cholesterol because in large population studies, high levels have been associated with an increased risk of heart disease. However, as we established, not all LDL is created equal. There are different subtypes of LDL, with small dense LDL particles being more atherogenic (more likely to cause plaque formation) than large buoyant LDL particles. Simply measuring total LDL cholesterol doesn’t provide the full picture of cardiovascular risk, and it’s essential to understand the particle size and number for a more accurate assessment. 

20:09 

Myth #4: Eating Fat Raises Cholesterol Levels

This myth stems from the idea that fats are bad for heart health. However, not all fats are created equal. Now, the topic of fats is a big one and we’re going to reserve going into this in detail for another episode. But, let’s just put a few facts straight so we can get past this myth. 

Over the years we’ve all been led to believe that eating fat is bad, and as a consequence, we’ve been pushed toward eating low fat diets. And in particular, something that gets pushed a lot is that saturated fat is bad and polyunsaturated fats are good. Briefly, research does support monounsaturated fats as being some of the best fats for us, we’re talking foods like avocados and olive oil. These can help improve your cholesterol profile by helping to increase HDLand changing LDL from small, dense particles to larger, more benign particles.

Saturated fats have long been demonized, unnecessarily. Overall, there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of coronary heart disease or cardiovascular disease. I have a colleague who has been evaluating the science in this area for years, and she has always been open to finding evidence that saturated fat raises LDL-cholesterol. She still hasn’t found any. This makes sense since saturated fat comes from natural food sources that are nutrient dense and is not something to be feared. That’s all we’ll say on that until another time, as there’s a lot to debunk on this too. 

One of the major issues with fat is intake of unhealthy fats, but no, we’re not talking about saturated fats, we’re talking about trans fats and omega-6 polyunsaturated fats. Trans fats, well, guess where these come from – man-made foods and lots of the low fat foods we were told were healthier to eat. Trans fats come from partially hydrogenated oils found in margarines and spreads, baked goods like cookies, cakes, and pastries, fried foods, snack foods and other processed foods.  

Another thing is the excessive amount of omega-6 fatty polyunsaturated fats that are used in processed foods – low quality oils like soybean, corn, safflower and cottonseed. These play a role in inflammation and LDL oxidation that can negatively impact cholesterol levels. It’s this imbalance of fats, particularly the overconsumption of omega-6 fatty acids and trans fats, that contributes to cholesterol issues.

22:59

Myth #5: Low-Fat Diets Are the Best for Lowering Cholesterol

For decades, low fat diets were recommended to lower cholesterol and reduce heart disease risk. However, evidence has shown that low fat diets are not necessarily the best approach. In many cases, reducing dietary fat leads to an increased intake of carbohydrates, particularly refined carbs, which can raise triglycerides and lower HDL cholesterol. In addition, when people substitute low fat products, they frequently consume more sugar, more carbs, more trans fats and more omega-6 fats – all of which are not best practice for a healthy cholesterol profile or a healthy metabolism. 

A low carbohydrate nutrition plan, such as we’re always discussing here on Type 2 Diabetes Talk, is more effective for lowering cholesterol. The common outcomes we see in people are dramatic improvements in their cholesterol profile, with lower triglycerides (that’s good, because remember these are carried around the body by VLDL and then can turn to small dense LDL); higher HDL (that’s great as it means you metabolism has improved and is becoming more efficient at recycling molecules your body doesn’t need); and lower LDL, with LDL particle size frequently increasing to those large, fluffy buoyant particles, which is great because these are neutral and don’t pose cardiovascular risk. 

24:42

Being that we’ve covered a lot today, let’s just go over this in summary again. 

Cholesterol is an essential molecule that plays a crucial role in many bodily functions, from forming the basis of cell membranes to aiding in hormone production and digestion. Despite its importance, cholesterol has been widely misunderstood, leading to the perpetuation of myths that have shaped dietary guidelines and public perception for decades.

We’ve explored how cholesterol is transported in the body by lipoproteins like LDL and HDL, and how the simplistic labels of “good” and “bad” cholesterol don’t capture the full picture. LDL isn’t inherently bad; it’s the small, dense LDL particles that pose a higher risk for cardiovascular disease, while large, buoyant LDL particles are generally neutral. On the other hand, HDL’s role in reverse cholesterol transport makes it protective against heart disease.

We’ve also debunked several common dietary myths, such as the belief that eating dietary cholesterol directly raises blood cholesterol or that all fats are bad for your heart. The truth is more involved and complex than that. Saturated fats from natural sources aren’t the villains they’ve been made out to be, while trans fats and an excessive intake of omega-6 fatty acids from processed foods are the real culprits in cholesterol-related issues.

As we conclude this episode, the key takeaway is that understanding the complexities of cholesterol and how it functions in your body is essential for making informed choices – when it comes to diet and nutrition and when it comes to medication too. 

For our members, remember you can head down to the members library to search for cholesterol resources, and there are several resources available there, and also look for the resources alongside episode 42. And we will be doing a follow up segment on cholesterol sometime in the future, where we’ll cover the practical nutrition strategies to help manage cholesterol levels effectively.

Again, thank you so much for joining me today. 

Until next week, take care. 

Dr Jedha, over and out.