Dear 48res,

Firstly, I would like to thank you all for your support and looking at the ever growing number of 48ers on our Facebook page is really overwhelming! We at 48 Fitness always work to give out the correct and unbiased advice based on the principles of scientific and critical thinking.

Having said that, one of our dear members on the page; Amit Sawant has commented not to have the egg yolk under one of the recent post on this page on including eggs in the breakfast as they are really nutritious. I’ve come across this ideology many a times when individuals have come to me for diet consultation and they generally have told me how they avoid egg yolks and red meat because of their fear of it causing heart diseases. Fortunately, the scientific knowledge of nutrition at 48 Fitness has helped many with right counseling and advice, whilst clearing the myth that has been into existence for over 50 years in the health and fitness fraternity.

I am glad to share the scientific facts behind this myth for the benefit of all 48ers on this page. Trust this helps all..

The egg yolk contains the amino acids that are not present in the egg white which by removing, we are giving those aminos up and which are essential for the growth and maintenance of the lean tissues, collagen, organs and other structural proteins like skin, hair, etc. Over and above this the egg yolk also has higher quantities of vitamins & minerals required for optimal health. Therefore, by not consuming them we are throwing all those vitamins & minerals too.

The fear of the cholesterol in yolk causing heart disease came into existence due to scientists researching the subject of dietary fats and cholesterol; namely Ancel Keys being the pioneer of this erroneous idea, believing that fat and cholesterol in our diet causes us to accumulate plaques and lesions in the arteries which leads to heart diseases such as acute myocardial infarction (heart-attack). Therefore, in his studies he only measured total cholesterol to assess the risk of heart disease of his subjects because of his false understanding of the true relation of diet with heart disease.

Before we get into the truth of the matter and the science the true association of dietary fats and cholesterol is explained, it is important for us to understand the role of cholesterol in the body. Cholesterol is an essential molecule and without it there would be no life. Every cell in the human body is capable of synthesizing it. Among other duties of cholesterol in ensuring optimal functioning of the body. It is responsible for the production of bile acids, vitamin D and steroid hormone such as testosterone & progesterone. It is also a major structural molecule, a framework on which other critical substances are made. The tissues that produce the lion share of the cholesterol in the blood are produced by the liver tissue and remaining is absorbed from the diet.

In fact lower total cholesterol in the blood has been shown to be a risk factor for cancer!

In 1974, the principal investigators of six ongoing population studies including Keys, Stamler, William Kannel of Framingham, and the British epidemiologist Geoffrey Rose reported in The Lancet that the men who had developed colon cancer in their populations had “surprisingly” low levels of cholesterol, rather than the higher levels that they had initially expected. In 1978, a team of British, Hungarian, and Czech researchers reported similar findings from a 1600 men clinical trial of a cholesterol-lowering drug. By 1980, this link between cancer and low cholesterol was appearing in study after study. The most consistent association was between colon cancer and low cholesterol in men. In the Framingham Study those men whose total cholesterol levels were below 190 mg/dl were more than three times as likely to get colon cancer as those men with cholesterol greater than 220 mg/dl; they were almost twice as likely to contract any kind of cancer than those with cholesterol over 280 mg/dl. This finding was met with "surprise and chagrin," Manning Feinleib, a National Heart, Lung, and Blood Institute (NHLBI) epidemiologist, told Science.

Now having understood the importance and function of cholesterol in our body, now let us understand the science of cholesterol and fat metabolism. Cholesterol is a substance in the blood that is transported in its carriers known as the lipoproteins. The lipoproteins are classified as amongst others; HDL (high-density lipoprotein), LDL (low-density lipoprotein) and VLDL (very low-density lipoprotein. HDL is the type of cholesterol termed as the “GOOD” cholesterol and LDL is termed as bad cholesterol. Now this erroneous terminology and over simplification of science of dietary cholesterol is the reason why cholesterol is so misunderstood! This is partly due to the state of science and tools and technology available in 1950s and 1960s to assess the impact of carbohydrates and fats in the diet.

Now let us understand what are these lipoprotein and the things that it carries:

The lipoprotein particles mainly carry blood fats known as the Triglycerides and Cholesterol.

The lipoprotein that is richer with TGs will be of very lower density, hence a VLDL particle. And lipoprotein particles richer with cholesterol are of higher density, hence are Low Density Lipoprotein (LDL). These lipoproteins of varying densities are particles in the blood possessing a balloon like structure. These lipoproteins carry and shuttles the cholesterol and triglycerides throughout the body, and into the cell where it is needed. Out of the three classes of lipoproteins (HDL, LDL & VLDL); LDL and VLDL are made up of three things:

1) A single particle of LDL/VLDL has a single protein known as the Apo B that serves as the structural foundation of the balloon and holds the balloon together.

2) It has an outer membrane that is composed of cholesterol, and

3) Fats, known as the phospholipids.

Then inside the balloon inflating it are TGs and more cholesterol. The two entities present in lipoprotein particles are triglycerides and cholesterol. The cholesterol carried in lipoproteins particles is heavier than the triglycerides. Therefore, the lipoprotein particle carrying more triglycerides than cholesterol in them float on the surface of the blood stream making it highly susceptible to damaging the inner artery lining, and the lipoproteins carrying more cholesterol than triglycerides are the particles that sink into blood plasma having lesser susceptibility of causing damage to the artery wall.

Now having understood the complication involved in the science of dietary cholesterol and fats. The over simplification of the science by Keys (which I will get into in the coming section and decode), is why doctors generally advise their patients to reduce their LDL count through a vegetarian, carbohydrates and fiber rich diet and through regular exercise because a vegetarian diet causes the LDL count to lower and exercise increases the HDL count which improves our cholesterol profile. But this advice is only based upon half the story of how carbohydrates, cholesterol and fats impact upon our cholesterol profile. And there is a better way to do that purely through good diet. Read on to know the TRUTH!

While keeping a check on the LDL count is important because higher LDL count is indeed a risk factor for heart disease; it is also important for us to make sure that our HDL count is also at a greater level; 60 mg/dl of blood and above.

It was theorized by Ancel Keys in 1950s that total fat and cholesterol in the diet causes an increase in LDL level in the body which leads to heart disease in humans. A higher level of LDL is indeed a risk factor for heart disease. Patients having severe arteriosclerosis often have a total cholesterol level of 1,000 mg/dl, and if higher cholesterol seems to associate with higher risk of heart disease among rest of us. Then cholesterol is the cause of heart disease, and elevating cholesterol by any amount in these individuals will increase their risk of heart disease.

Having said that, Keys oversimplified the science drastically, and the true relationship of cholesterol and heart disease is simply misconceived. And researchers who believed in Keys’ fat-cholesterol hypothesis jumped the gun and easily and wrongly assumed that a higher LDL count means the subject is more likely to face the ill fate of developing heart disease, again an untrue assumption! Because it is a well document fact that individuals with a higher cholesterol count of 300 mg/dl, never develop heart disease, while a person with a cholesterol profile of as low as 140 mg/dl develop them. When scientists were confronted with such data the observation could not be explained because the explanation for what causes us to develop heart disease was never correctly analyzed. Moreover when confronted with such observation, researchers in this field explained it by concluding that the heart disease is a genetically developed one and something that runs in the family. It is something like if one wants to understand what causes lung cancer by taking smokers only in the sample group. Then the result and conclusion of it would inevitably be that lung cancer is a genetically developed disease.

However coming back to how the myth of dietary cholesterol and heart disease developed, Ancel Keys, in his later study, the Seven Countries study, which holds a legendary status among the dietitians who believe in his theory. Keys discovered that monounsaturated fats didn’t have an impact on total cholesterol, and therefore he considered it to be neutral as far as causing heart disease is concerned. And polyunsaturated fats actually reduced total cholesterol. But the apparent neutrality of monounsaturated fats on total cholesterol is actually because of its ability to increase HDL and reduce LDL levels in the blood.

So, then Keys understood that not all fats is responsible for increase in LDL cholesterol in our body, only saturated fats increases LDL, leading to arteriosclerosis. And at this time he also observed that monounsaturated fats protected against heart disease, and this explained him the observation of why Finnish lumberjacks and Cretan villagers could both eat diets that were almost 40% fat but still have such dramatically different rates of heart disease.

While by this time the science of cholesterol, fats and heart disease started to complicate, yet it is an simplified version and fails to explain the data from the 22 countries that Keys conveniently ignored because by allying his theory data could not be explained, hence, he chose to select only seven countries in his study that explained his theory of the connection of dietary cholesterol and heart disease. Hence, this study was biased to say the least.

Now to understand the further complication in the science; LDL particles in the blood are of heterogeneous nature, while Key’s considered it to be a single entity that leads to heart disease, and this is where he simplified the science and went wrong with his interpretation of the relation of heart disease to diet in various populations.

Researchers in the 1970s have discovered that there are seven grades of LDL found circulating in the body. These grades of LDL, when put into a spectrum then on one end we have LDL that are small and dense, and on the other end there is LDL that is large and fluffy, and there are 5 grade of it in between of the LDL spectrum. These LDL have different properties with respect to its atherogenesity. The SCIENCE of Heterogeneity of LDL was worked out by Krauss in 1980. There are seven gradations to LDL particles that were identified by him.

In his study, he further discovered that the cholesterol inside these lipoproteins particles is not harmful, i.e. it does not cause heart disease. But it is the particles itself (the LDL/VLDL) that carry the cholesterol which is deemed dangerous and one that causes arteriosclerosis because these LDL particles gets oxidized and stick into the artery walls leading to the formation of plaques in them.
Researchers in this field of subject have developed a reliable technique through which they have identified the LDL particles that oxidizes easily to form plagues to be identified. It involves quantifying the concentration of Apo B protein in the blood sample. By identifying the concentration of Apo B, it makes for a better marker of heart disease risk than measuring the total cholesterol, and/or the total LDL cholesterol.

This implies that for the same level of total cholesterol and/or LDL level, in two individuals. One with higher Apo B number has a greater chance of developing plaques and lesions in the arteries that leading to a blockage in the arteries, and therefore death from heart attack.

Therefore, total cholesterol is NOT a risk factor for heart disease, and LDL cholesterol is a “MARGINAL RISK FACTOR” for heart disease. In fact, the level of HDL is the best predictor of heart health! A Higher HDL implies the heart is in good health, and LOWER HDL LEVEL is BAD NEWS..

The small and dense LDL particles are the ones that are TGs rich and stay longer in the system, and cholesterol rich large and fluffy LDL have a shorter life span and therefore,

1) They are less likely to oxidation that results in formation of atheroma.

2) They are less likely to stick to the damaged areas of arteries as they are LARGER and FLUFFIER, so difficult to get into the artery wall.

This was another simplification of SCIENCE by Keys! He assumed all LDL cholesterol to be of a homogeneous nature… When now we know that is NOT the CASE…

Krauss, in his study discovered the appearance of two patterns of LDL in the population he studied, which he called pattern A and pattern B of LDL cholesterol profile. Pattern A is dominated by large, fluffy LDL and implies a low risk of heart disease. Pattern B is discovered to be the dangerous one, with predominantly small, dense LDL. Pattern B is inevitably accompanied by high TGs, low LDL and HDL. Pattern A is not, it is accompanied by low TGs, higher larger and fluffier LDL and HDL. In his study he also reported that heart-disease patients were three times more likely to have pattern B than pattern A.

The pattern A LDL profile is a result of an increase in TGs level (coming from the conversion of abundant amount of blood glucose getting into the system due to higher carbohydrates in diet) is the prime cause of formation of plagues in the arteries that leads to heart blockage…

It is easier to understand this; i.e., the impact of TGs on elevating the total LDL particles in the blood , if we picture what is happening in the liver when large amount of carbohydrates are consumed in the meal.

After we eat carbohydrates and the bloodstream is flooded with glucose. To deal with this flood of glucose in the blood stream, the liver takes this glucose, at least some of it if not most, and transforms it into fat, i.e. TGs for temporary storage in our fat cells.

These TGs are nothing more than oil droplets circulating in our system. This increase in TG leads to reduction in total cholesterol, reduction of the HDL and the LDL cholesterol. Reduction in HDL tracks with the increase in triglycerides in the body.

Reduction in HDL is the first reason why low fat and high carbohydrates diets are bad for heart health. Because it reduces our levels of HDL, and HDL levels are far better, in fact the only predictor of heart disease that matters!

Secondly, in the liver all the LDL in the body began its life as VLDL. Due to lots of carbohydrates, they are converted to TGs. It increases the production of VLDL in the liver (not the cholesterol in VLDL, but the number of VLDL particles) to carry the TGs throughout the body. This increase in VLDL particles eventually leads to an increase in LDL particles in the blood. Because VLDL particles are like ship floating in the blood stream, eventually they get filled with more cholesterol and TGs, ending their lives as LDL. These TGs rich LDL particles are the arteriogenic ones because of the following reasons!

1) Small, dense LDL find their way easily into the damaged areas of arteries to form incipient plaques that leads to formation of atheroma in the inner artery walls.

2) They circulate in the system for longer and so are more susceptible of oxidizing by free radicals and forming advanced glycation endproducts (AGEs) that lead to the thickening of artery walls.

It is also important to note that, all the circulating LDL particles in the system are NOT of one size and density. LDL particles circulating in our system are of heterogeneous nature with respect to their size and density.

Large, fluffy LDL is a result of consuming animal fats and EGG YOLK…

Small, dense LDL particles are the result of food that increases blood sugar…

Therefore, summing up the knowledge contained within this post.

Consuming EGG YOLKS and animal meat doesn’t lead to an abnormal elevation of TGs, and LEADS TO:

i) Increase in HDL Level (Good Cholesterol).

ii) The Liver releases lesser VLDL (therefore lesser VLDL particles in the blood)

iii) The VLDL released will eventually blossom into larger and fluffier LDL, and no abnormal elevation of SMALL, DENSE LDL particles!

iv) Lesser TG level means lesser small, dense LDL particles.
All of this will lead to IMPROVEMENT of our cholesterol profile that will decrease the risk of heart disease!

OUR CHOLESTEROL PROFILE IMPROVES WITH CONSUMPTION OF EGG YOLKS, AND NOT THE OTHER WAY AROUND!

- Vijay Thakkar