Is LDL Really always the "Bad Guy?"

When it comes to cardiovascular matters, modern medicine affirms that Low-Density Lipoprotein (LDL) cholesterol (as opposed to HDL - the High-Density Lipoprotein - or the "good" cholesterol) causes clogged arteries that can subsequently lead to coronary heart disease (CHD.) As such, dietary and therapeutic measures aimed at reducing LDL cholesterol in the blood are at present already regarded as essential courses of action in our attempt to prevent CHD. While this precept is already widely accepted by health authorities and medical practitioners as a truism, numerous pockets of evidence are now raising questions as to LDL's reputation as purely the bad cholesterol.

 

Understanding Cholesterol

Cholesterol is one member of a large family of chemical compounds known as "lipids" or, more commonly, fats. Nevertheless, cholesterol is by no means synonymous with "simple" fat. Despite its association with the oily substance, cholesterol is a separate, specialized type of lipid and, contrary to its popular image as a potent enemy of health and longevity, it is actually crucial to the performance of a number of vital functions in the body. The plain reality is, every cell membrane requires it. Although one can obtain cholesterol from foods, the body is capable of making all the cholesterol it requires primarily in the liver and the intestines - derived from fragments of fats, proteins and carbohydrates.

Distributed throughout the body via the bloodstream, cholesterol doesn't blend well with the blood but rather has the tendency to coagulate into globs. So, in order for our bodies to get around cholesterol's problematic tendency, the body packages cholesterol and other fats into very tiny protein-covered particles called "lipoproteins" (lipid plus protein) that blend easily with our blood.

 

Two's Company?

To re-visit an important, associated anatomical reality, the two main types of lipoproteins important to understanding heart disease are low-density lipoproteins (LDL) and high-density lipoproteins (HDL). Though their acronyms are probably too similar (separated only by letters H (high) and L (low), the two are as different as night and day, their major differences stemming from their respective densities, which in actuality are a representation of the "ratio of protein to lipids." LDL, which has the particles with "more fat and less protein," has a lower density than its "high-protein, low-fat" counterpart, HDL. There are countless other lipoproteins but in order to get a basic understanding of how cholesterol affects the body and how food determines cholesterol levels, LDL and HDL are the ones to start with.

HDL, or "good cholesterol"as it is generally labeled nowadays, acts as a vacuum cleaner, sucking up much of the excess fat from cells and tissues and taking it back to the liver where it is used to produce bile or recycled for reuse by the body. This reaction is thought to explain to explain why high levels of HDL are associated with low risk for heart disease. HDL also contains antioxidants molecules that may prevent LDL from being changed into another type of lipoprotein that is even more likely to cause heart disease.

 

But Hold on a Sec...

Commonly regarded as harmful, LDL particles carry 60 to 70 percent of the body cholesterol to the myriad of different internal body parts that continuously require cholesterol for the three important functions it provides:

Helping to make the protective outer coating of the organ cells,

Making up the bile acids that work to digest food in the intestines,

And allowing the body to make Vitamin D and hormones like estrogen in women and testosterone in men. These combine to make up LDL's upside.

The downside,unfortunately, is too much LDL in the bloodstream results in deposits of cholesterol on arterial linings. These deposits are known as plaque and can cause arterial blockages that reduce blood flow to the heart. This is the reason why people regard LDL as bad but, as noted in the preceding paragraph, LDL being regarded as the bad guy is not absolutely the truth.

 

Real Culprit

As published in the Journal of American Physicians and Surgeons in 2005, a number of researchers began to recognize that an increased LDL level per se was not the sole risk factor for heart disease. Half of all who suffers from CHD have LDL levels within normal limits. In addition, cardiovascular events occured even in individuals whose LDL cholesterol level was less than the generally accepted amounts. A strong association researchers found was that harmful LDL that has been exposed to oxidation contributes to the development of CHD. This finding suggests that a person's antioxidant level is a very important determinant in developing advanced plaques independently from overall LDL levels. Also observed in the study was that oxidized LDL was commonly high among the elderly participants than in the younger ones, regardless of their normal lipid profile.

 

Resulting Distinction Required

From the preceding, it appears that it is more important to distinguish between "native" and "oxidized" LDL cholesterol than just keeping its overall levels in check. Native LDL is the type that the body produces daily as a normal metabolic function while oxidized LDL cholesterol is the type that has been bombarded by free radicals.

According to answers.com, a free radical is an atom or group of atoms that has at least one unpaired electron and is therefore unstable and highly reactive. In animal tissues, free radicals can damage cells and are believed to accelerate the progression of the cancer, cardiovascular disease, and age-related diseases.

In other, simple words, native LDL is a vitally important substance and is not in any way harmful, but the oxidized LDL is believed to promote various pathogenic conditions due to the tissue damage it causes. In a study by the National Institutes of Health, USA, this oxidation process predicted myocardial infarction (heart muscle damage or death) in well-functioning elderly people, even after adjusting for age, gender and race. Although definitive studies have yet to be concluded, suspected, factors that bring about high rates of LDL oxidation are diets in trans-fats, smoking, poorly controlled diabetic tendencies or conditions, or a specific condition called metabolic syndrome, whereby the body is unable to fully utilize food for energy or cellular functions. Interestingly, once diagnosed with CHD, patients treated with a "statin" (a class of drugs that lowers cholesterol), appears to have decreased levels of oxidized LDL even beyond its cholesterol-lowering effect. Nevertheless, the role of diet modification to fight LDL oxidation should not be excluded when choosing to take statin.

In a research dubbed the Lyon Diet Heart Study in France, an experimental group was advised to increase consumption of root vegetables, green vegetables, fish, fruit and omega-3 fatty acids. This group experienced greatly improved cardiovascular and survival outcomes. One little-publicized finding from the trial was that the LDL cholesterol levels of the treatment and control groups were virtually identical throughout the study. Those in the treatment group, however, did demonstrate  significantly higher blood levels of HDL and antioxidants.

 

What the Future Holds

A diagnostic test called the Oxidized LDL Triple Marker Test used for identifying patients with CHD linked to oxidized LDL was presented at American Heart Association's Scientific Sessions in November of 2011 in Orlando, Florida, USA. With a simple blood sample drawn, the test provides actionable information that helps clinicians make better decisions on how aggressively to treat a patients whose lipid profile results are prone to LDL oxidation. It may also help identify patient at risk who may not be clearly indicated by the traditional cholesterol level tests.

At present, Sheil Medical Laboratory in Brooklyn, NY, is the only clinical laboratory worldwide to offer the Oxidized LDL Triple Marker Test. Nevertheless, it would not be surprisingly if the test becomes available in diagnostic clinics and hospitals worldwide in the not-too-distant future. This will significantly change the way doctors determine the commonly tested lipid profiles of patients susceptible to, or in danger of, developing heart disease. Meanwhile, the aforementioned dietary food suggestions followed in the French study may greatly help to reduce oxidative processes, and increases HDL and antioxidants in the body.

 

Change of Perspective

Cholesterol is so important to our internal anatomies that the human body cannot exist without it. Th fact that the body has the innate capability to make and regulate it (during times that the diet doesn't provide enough of it) is remarkable.

In a modern world where a cholesterol-free diet is the popular advocacy, this discussion may be considered unusual, but recent clinical findings are apparently now supporting it or, at least, proposing it with substantial viability. In any case, the role of humans in balancing what nature provides for healthful use is one of the remaining delicate processes that need proper study, control and application of supported conclusions. Thus, it can be be coming to a full understanding of cholesterol's role in health which can hopefully change our view towards the maintenance of a healthy heart.