Science of Dietary Fats

A breakthrough in science & knowledge of dietary fats, carbohydrates & proteins and their association with heart diseases!

Do dietary fats cause heart diseases? Do dietary carbohydrates protect the heart from life threatening diseases such as myocardial infarction? The traditional dogma says that all fats are bad for health and are responsible for heart diseases. But did you know that the traditional knowledge has been misleading and new research has debunked this idea.

This article will bring forward the new science on nutrition & dietetics, which confirms that saturated fats have got little or no role to play in the development of artery inflammation, leading to plaque and blockage. It is largely due to the consumption of carbohydrate rich diet including refined ingredients such as table sugar & refined flour, which eventually leads to heart disease. So guys, put your thinking cap on! Here’s the uncensored truth and updated good science on the dietary causes of heart disease!

The Background:

Post World War II, the US experienced a strong boom in agricultural technologies and productivity, subsequently increasing the international trade of food items. During this period, the US population also observed a relatively steep rise in the rates of obesity & heart diseases. To understand the root cause of this epidemic endangering the lives of millions of US citizens, the US government hired a team of scientists to conduct research on the problem & find solutions to it. An extensive research for almost 56 years went on in understanding the lifestyle and dietary causes of heart disease & obesity.

Dr. Keys’ Seven Countries Study

In 1950, Dr. Ancel Keys along with other prominent scientists led the charge & pioneered in the study of dietary fat, cholesterol and heart disease. However, their was study was limited by the lack of advanced scientific tools. As a result, their research conclusions were heavily reliant on just the observations of obesity patterns and heart disease rates and how this broadly correlated with the staple constituents of the diet of the population they studied.

Dr. Keys’ original research study on this subject, popularly known as “Seven Countries Study”, concluded that the total dietary fats intake in one’s diet led to an increase in total blood cholesterol, which in turn determined the likelihood of atherosclerosis (build-up of plaque in the arteries leading to heart attacks) in humans). Therefore, in his subsequent studies, he only measured the total serum cholesterol in the blood samples to assess the risk of heart disease in his subjects.Based on his observations, he initially theorized that total fat and cholesterol in the diet causes an increase in LDL (Low Density Lipoprotein) level in the body, which in turn eventually leads to heart diseases.

While it is a fact that a higher level of LDL is a risk factor for heart disease, this is not the complete picture of how humans develop plaque in their arteries. We’ll come to how that happens a little later. But it is pertinent to note how cholesterol’s role has continued to be misunderstood. No doubt, it has been observed that patients having severe arteriosclerosis often have a total cholesterol level of 1,000 mg/dl. Since higher cholesterol seems to be associated with higher risk of heart disease, it has helped perpetuate the belief that cholesterol alone is the main cause of heart disease and elevating it by any amount will increase the risk of heart attack.

The reality is that Keys’ study oversimplified the role of cholesterol in the development of heart diseases due to an incomplete analysis of the data. This lack of rigor in Dr. Keys’ investigation is partly attributed to the lack of tools & technology available to him to conduct a thorough research and partly to the pressure from the governing authorities to conclude the investigation & suggest solutions at the earliest.

Dr. Keys continued research on the issue

Dr. Keys’ in his subsequent studies discovered that mono-unsaturated fats didn't have an impact on total cholesterol, and so it is neutral. Moreover, his studies also confirmed that poly-unsaturated fats in diet actually reduced total serum cholesterol. This neutrality of mono unsaturated fats comes from its ability to reduce LDL & increase HDL levels. Whereas, the poly-unsaturated fats’ ability to positively impact the cholesterol levels comes from its ability to reduce LDL levels, while having no impact on HDL levels.

On the basis of these new research findings, Dr. Keys theorized that not all fats are responsible for an increase in LDL cholesterol in our body and only saturated fats increase LDL, leading to arteriosclerosis. Thus, based on Keys research findings, the American Heart Association (AHA) recommended in the dietary guidelines to increase the intake of "heart healthy" carbohydrates and unsaturated fats in the diet, and reduce saturated fats in a typical American diet.

According to AHA, this would ensure prevention from heart disease. However, as we now know, this recommendation was based on an incomplete analysis of data & improper understanding of the dietary fats and heart disease hypothesis. Hence, any recommendations stemming from such incomplete understanding of facts were doomed to be misleading! But as this influential research came with such strong credentials and backing, its misrepresentation of the true relation between cholesterol and heart disease sustained for a long time.

In fact, till the early 1980s, no studies were conducted to assess the impact of triglycerides (TGs) converted from excess glucose from carbohydrates in diet, as a risk factor of heart, disease. Till then, it was all about fats and cholesterol in the diet, and its association with heart disease!

These misleading recommendations to eat more "heart-healthy” carbohydrates & reduce the intake of dietary saturated fats became the dogma of good nutrition just by virtue of repetition by nutritional authorities, media & dietitians.

The Evolved Science:

Further research carried by scientists focused on Cholesterol and Triglycerides and improved our understanding of heart diseases. It also fixed anomalies in Dr. Keys' research. The findings of new science have helped us understand the metabolism in the body on the consumption of carbohydrates and fats. It also effectively explains how plaques are formed in our arteries and has helped us break the myths related to our daily diet.

But, before I get into the science of carbohydrates, dietary fats & dietary cholesterol’s influence on our serum cholesterol profile, for the interest of all layman readers, I will firstly get into the basic description of various fats & lipoproteins found in the body, followed by a basic understanding of how they interact with our arteries.

I believe this will provide a better understanding of the topic & will indeed bring a lot of clarity into the science of nutrition and debunk the myths like,
1) The groundless fears of the role of dietary saturated fats in causing heart disease &
2) The misleading comforts of indulgence in the "heart healthy" carbohydrates rich food as a means of protecting the heart from diseases.
Both of which, we will learn are the tales of the wonderland where Cinderella lives!

The physiology of serum lipoproteins & fats:

There are four categories of fats found in the bloodstream: Very-low-density lipoprotein (VLDL), Low-density lipoprotein (LDL), High-density lipoprotein (HDL) and Chylomicrons (CM).
1) The function of VLDL and LDL is to transport cholesterol & triglycerides from the liver into the various tissues in the body.
2) The function of HDL is to carry cholesterol away from the cells of the body and into the liver, to be disposed off in bile produced as waste.
3) CM shuttles dietary fat from the intestine to the tissues for storage.
Due to the conclusions made from Keys’ studies, LDL particles were seen causing heart disease and were perceived as "BAD" cholesterol. HDL, on the other hand, was seen performing the function of taking cholesterol away from the cells to the liver to be secreted as waste and was perceived as "GOOD" cholesterol.

Relation between Lipoprotein particles and Cholesterol

To understand the roles of carbohydrates, dietary fats and cholesterol on our serum cholesterol levels, it is crucial to be aware of the fact that “lipoprotein particles” and “cholesterol” within the lipoprotein particles are two different entities! Initially researchers thought that they are one and the same thing, and they are still used interchangeably in day-to-day layman parlance.

Furthermore, the compounds present in these lipoprotein particles are “triglycerides (TGs)” and “cholesterol”. The cholesterol carried in the lipoproteins is always heavier than the triglycerides. Therefore, the lipoprotein particles richer with TGs will be of very low density nature and hence are termed as VLDL. Similarly, the lipoprotein particles richer with cholesterol are of higher density and are termed as LDL.

Moreover, VLDL & LDL particles are homogeneous balloon-like structures that shuttle the cholesterol and triglycerides throughout the body into the cells, where they are required.
LDL & VLDL are made up of three things:
1) A single LDL/VLDL particle 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) The outermost layer of LDL/VLDL is fat, known as phospholipids.

Inside this balloon-like structure, lipoproteins have more TGs and cholesterol inflating it. The cholesterol inside these lipoprotein particles is not harmful and does not cause heart disease. In fact it is a building block of the body and a very important nutrient for functioning of the body. Except the brain cells, each & every other cell membrane contains cholesterol.

The current research on this subject has confirmed that 80% of the circulating system cholesterol is produced by the liver & only the remaining 20% comes from diet. Yet, in the initial years of research, these lipoprotein particles (LDL/VLDL/HDL/CM) that carry cholesterol were deemed by the researchers as a cause of arteriosclerosis. While the fact remains that these LDL particles have the potential to be oxidized leading to formation of plaques in the arteries, but there is more to it than meets the eye!

Dr. Krauss’ Research

Dr. Ronald Krauss’ discovery of “heterogeneity of LDL” gave more clarity on the nature of cholesterol & its impact on health. Dr. Krauss distinguished LDL particles into two distinct patterns with the use of modern methods and technology.

He termed them as “pattern A” and “pattern B”. “Pattern A” LDL profile was dominated by large & fluffy LDL, implying a low risk of heart disease. “Pattern B” LDL profile was the dangerous one predominantly exhibiting small & dense LDL. He observed that pattern B LDL profile is inevitably accompanied by high TGs and high number of VLDL particles. He also reported that heart-disease patients are three times more likely to exhibit pattern B than pattern A.

Krauss’ in-depth insights into the heterogeneity of LDL particles finally brought in a new era of research on true dietary causes of heart diseases. Dr. Krauss’ techniques now allow medical professionals and researchers to differentiate between different grades of LDL particles & identify which LDL oxidizes easily to form plaques in arteries. Moreover, this technique involved quantifying the concentration of “Apo B” protein in the blood sample.

Krauss identified that the concentration of “Apo B” in the blood sample is a better indicator of heart disease risk than measuring the total cholesterol, and/or the total LDL cholesterol in the blood. For the same level of total cholesterol in two individuals, one with higher “Apo B” number has a higher risk of developing plaques and lesions in the arteries, thereby leading to a blockage and death from heart attack.

This recent discovery led researchers to the fact that the total serum cholesterol is NOT a risk factor for heart disease and LDL cholesterol is a "MARGINAL RISK FACTOR". In fact, they have found that the level of HDL in the blood is the best predictor of heart health. A higher HDL implies that the heart is in good health, and lower HDL level is a BAD NEWS!

How plaques are formed:

One significant reason for an increase in the quantity of the triglycerides (TGs) in our system, is due to a very high intake of carbohydrates in the diet throughout the day. The excess refined carbohydrates in the system get converted to simple molecules called glucose. Moreover, proteins are also converted into glucose by a process called as “gluconeogenesis” and then they enter into the blood stream.

When the hypothalamus in the brain senses such high levels of glucose, the body increases its incretin & insulin levels to deal with the excessive glucose level by converting it into TGs, thereby increasing the amount of triglycerides in the system. This is a prime cause of formation of plaques in the arteries that leads to heart blockage through the increase in the number of small and dense LDL particles in the system carrying the excess amount of TGs.

Carbohydrates rich diet reduces good cholesterol and increases bad cholesterol:

It will be easier to understand the impact of TGs on the total cholesterol, if we picture what happens in the liver when a large amount of glucose enters the bloodstream from a meal recently consumed.

After we eat a meal rich in carbohydrates & proteins, the bloodstream is flooded with glucose. To deal with this, the liver takes at least some if not all of the glucose and transforms it into TGs for temporary storage in our fat cells. These TGs are nothing more than oil droplets circulating in our system. This increase in TGs leads to a reduction in total cholesterol, reduction in HDL particles as well as reduction in the cholesterol carried in the LDL particles.

Considering that reduction in HDL Levels is in fact the only reliable predictor of heart disease that matters, leading to the important conclusion that low fats and high carbohydrates diet are bad for heart health!

The second reason why low fat and high carbohydrates diets are bad for heart health is because all the LDL in the body began its life as VLDL. When we eat a lot of food items containing carbohydrates & proteins, they are converted to TGs. To carry these TGs, the body increases the production of VLDL particles in the liver. This increase in VLDL particles eventually leads to an increase in LDL particles in the blood. The VLDL particles are like ships floating in the blood stream. Eventually, they get filled with more cholesterol and TGs, ending their journey as LDL. These TGs with rich LDL particles are the arteriogenic ones because they are small and dense!

Why small & dense LDL particles are termed as “arteriogenic”?

1) Small & dense LDL particles find their way easily into the damaged areas of arteries to form incipient plaques that lead to formation of atheroma (fatty deposits) in artery walls.

2) Small & dense LDL particles circulate in the system for longer and so are more susceptible to oxidation by free radicals and advanced Glycation End Products (AGEs), leading to formation of clots in the arteries.

It is also important to note that all the circulating LDL particles in the system are NOT of one size and density. As revealed in the study conducted by Dr. Krauss, LDL particles circulating in our system are of heterogeneous nature with respect to their size and density. There are seven gradations to LDL particles that are identified by him. There is a “small and dense” LDL particle rich in TG, and a “large and fluffy” LDL particle rich in cholesterol. Larger and fluffier cholesterol-rich LDL particle has shorter life in our system and therefore, it is;

1) Less susceptible to oxidation.
2) Less likely to stick to the damaged areas of arteries because they are larger and fluffier.

Dr. Keys in his study assumed all LDL particles to be of a homogeneous nature & oversimplified the science of dietary fats & cholesterol’s role in development of heart disease. On the other hand, Krauss differentiated LDL articles into two patterns & identified which LDL can form plaques in arteries.

Carbohydrate-rich diets mean more trouble:

1) Large & fluffy LDL is a result of consuming less sugar & processed carbohydrates through the day.
2) Small & dense LDL particles are the result of food that increases blood sugar (carbohydrate & protein rich foods).

An INCREASE in TGs due to carbohydrate-rich diets lead to four things:
1) Reduction in HDL Level (Good Cholesterol).
2) Forcing the liver to release more VLDL (therefore more VLDL particles in the blood).
3) This VLDL will eventually blossom into more small and dense LDL. Therefore, an abnormally high number of circulating SMALL & DENSE LDL particles!
4) Higher TGs in the system will load into large & fluffy LDL particles, turning them into small & dense LDL particles.

With a reduction in calorie consumption from refined carbohydrates and sugars, the body has to JUST deal with the cholesterol, proteins and fats coming from food. The liver does not have to deal with high levels of TGs (in the absence of excessive carbohydrates in the diet) and therefore, no abnormal elevation of VLDL particles in the body (unlike when high calories from carbohydrates are consumed).

Impact of dietary fats on our cholesterol profile

• Mono Unsaturated fats: Raises HDL and lowers LDL. (Both beneficial things)
• Poly Unsaturated fats: Lowers LDL, but has no impact on HDL. (A good thing and a neutral thing)
• Saturated Fats: Increases LDL, but also increases HDL. (A neutral and a good thing)

In short, this increase in LDL particles by saturated fats in the diet is beneficial for the body because they are the precursor to LARGER & FLUFFIER LDL particles.

The Conclusion

Cholesterol number is different from that of lipoproteins number in the body. Cholesterol found in the body is predominantly produced by the liver. However, the number of LDLs carrying cholesterol & TGs increase unnaturally in the body, due to the high quantum of triglycerides (TGs) converted from high glucose levels.

Due to this repetitive & very stressful state for the body, over the time, the high level of incretin & insulin induced by the high intake of dietary carbohydrates increases fat deposition, leading to an increase of the body weight. When the increased body weight is maintained for a long period of time through bad eating habits & poor lifestyle, it programmes the hypothalamus in the brain to set the body weight to this higher level by holding the subcutaneous fat.

This is one of the potent contributing factors to why recently gained body weight is easily shredded with minimum efforts, whereas the weight gained over the years is much more difficult to shred. The fat levels accumulated for years are considered by the hypothalamus as "natural" & therefore, it takes huge level of patience, hard-work & heavy lifestyle "intervention" to shred the excess weight.

Thus, to stay away from this phenomenon of programming the brain to set a higher body weight via excessive accumulation of body fat & to eliminate the possibility of an excess production of VLDL particles, it's vitally important that one reduces or eliminates the consumption of foods containing refined ingredients such as high fructose corn syrup (HFCS), table sugar (sucrose) & refined flour from the staple diet.

On the contrary, one should choose to consume whole foods in their natural form without stripping off the vitamins, minerals, phytonutrients and dietary fiber through processing. In case of vegetable oils, the artificially processed vegetable oils are high in inflammatory omega 6 fatty acids and hence should not be consumed.

In conclusion, the elimination of all fats from our diet and excessive focus on just cholesterol is not the solution or prevention for heart disease. It is imperative that we eliminate all processed carbohydrates such as refined sugar or flour from our meals, in order to truly have a “heart healthy” diet.