Fats and Cholesterol

October 24, 2013 by  
Filed under A Healthy Diet

Let’s explore the relationship between fats and cholesterol. After all, we all know that fat causes an increased level of cholesterol in our arteries which is bad for our health. Is it this simple? No, it certainly is not. Many of us were brought up in the belief that high blood cholesterol levels were caused by the consumption of foods like egg yolks, cheese, liver and crustaceans. Scientific studies have subsequently shown that there is a very weak relationship between the amount of cholesterol contained in food items and your blood cholesterol level.

The truth is that the biggest influence on blood cholesterol is not the amount of fat you eat but the mix of fats in your diet. I have written a separate blog post about the good and the bad fats. The bad fats are saturated fats and trans fats (hydrogenated fats) while the good fats are the unsaturated fats (monounsaturated and polyunsaturated fats).

What is cholesterol?
In scientific terms, cholesterol is a waxy steroid of fat (an organic compound). It is one member of a family of chemical compounds known as lipids. The more common name for lipids is fats. Five major classes of lipoproteins have been identified. Two (LDL and HDL) are commonly measured by blood tests and are linked to risks for coronary heart disease.

  • Sterols (cholesterol and some hormones)
  • Fat soluble vitamins (A, E, K)
  • Glycerol esters (dietary and body fats)
  • Sphingolipids (components of cell membranes)
  • Fatty acids (saturated and unsaturated)

Cholesterol is not synonymous with fat but, as can be seen in the above list, it is a special type of lipid. It is essential for life because your body membranes need it. It is also the substance that your body uses to make vitamin D, steroid hormones such as estrogen, testosterone and, most significantly, bile acids for digestion.

Low density lipoprotein (LDL) is composed largely of lipid (triglyceride and cholesterol) with only a small amount of protein. LDL-cholesterol is generally deposited in tissues, including the artery wall. High levels of LDL-cholesterol are associated with increased health risks. An LDL level less than 130 mg/100 ml of blood is desirable.

High density lipoprotein (HDL) contains less cholesterol and more protein. Higher HDL-cholesterol levels are associated with reduced risk for coronary heart disease. Some of the HDL cholesterol is converted to bile acids in the liver. Both cholesterol and bile acids are then secreted (separated from your body fluids) into the intestine.

How does cholesterol appear in your body?
Cholesterol, as well as fat, does not dissolve in water or blood. In order to transport these substances throughout the body, they are packaged into particles called lipoproteins. The different types of lipoproteins also explain the difference between good and bad cholesterol.

  • Low-density lipoproteins (LDL) carry cholesterol from the liver to the rest of the body. Cells latch onto these particles and extract fat and cholesterol from them. When there is too much LDL cholesterol in the blood, these particles can form deposits on the walls of the coronary arteries and other arteries throughout the body. Such deposits, called plaque, can narrow arteries and limit blood flow. When plaque breaks apart, it can cause a heart attack or stroke. Because of this, LDL cholesterol is often referred to as bad, or harmful, cholesterol.
  • High-density lipoproteins (HDL) scavenge cholesterol from the bloodstream, from LDL, and from artery walls and ferry it back to the liver for disposal. Think of HDL as the garbage trucks of the bloodstream. HDL cholesterol is often referred to as good, or protective, cholesterol.
  • Triglycerides make up most of the fat that you eat and that travels through the bloodstream. As the body’s main vehicle for transporting fats to cells, triglycerides are important for good health. But as is the case for so many things, an excess of triglycerides can be unhealthy.

Where does cholesterol come from?
Although you can and do obtain cholesterol from foods, your body is capable of making all the cholesterol you need. The pool of cholesterol in blood comes from two sources:

  • Cholesterol contained in the foods you eat. Major dietary sources of cholesterol include cheese, egg yolks, beef, pork, poultry, fish, and shrimp.
  • Cholesterol manufactured inside your body.

As already mentioned above, the primary influence on blood cholesterol level is the mix of fats that you eat, not the dietary fats themselves. The important issue is the amount of cholesterol in your bloodstream.

To fully comprehend what I just wrote in the previous paragraph, you need to understand that cholesterol is made in the liver and intestine from fragments of fats, proteins and carbohydrates. The typical western diet provides approximately one third of the cholesterol the body needs on a daily basis (300-500 mg). The balance is manufactured in your liver (700-900 mg).

How does the body use cholesterol?
Cholesterol is withdrawn from blood for use in cell membranes; in tissues such as heart, liver or muscle; and for making hormones and bile acids.

How is it transported?
Cholesterol, being a lipid, does not mix with water. In order to travel through the blood, a watery system, cholesterol is coated with protein. The resulting macro-molecule is a lipoprotein. Lipoproteins are carriers for transporting cholesterol throughout the body.

Where does it go?
Unlike fats, proteins, and carbohydrates, cholesterol cannot be used for energy. Small amounts of cholesterol can be used up making hormones and vitamin D. However, the major substance made from cholesterol is bile acids. Formed in the liver, bile acids are secreted into the intestine where they help digest fat. Some of the bile acids are excreted with waste from the digestive tract. Most of the bile acids are recycled and reused. The body excretes approximately 1,000-1,400 mg cholesterol each day. One way cholesterol-lowering drugs act is to bind bile acids so they cannot be recycled. This continually drains cholesterol from the body to make new bile acids. Some types of dietary fiber may also act this way.

In general, the lower your LDL and the higher your HDL, the better your chances of preventing heart disease and other chronic conditions.

For more information about fats, refer to my blog post Good Fats vs. Bad Fats.

You may be also interested in watching the following video, presented by Dr. Ron Rosedale (courtesy articles.mercola.com/videos.aspx).

Enter Google AdSense Code Here

Speak Your Mind

Tell us what you're thinking...
and oh, if you want a pic to show with your comment, go get a gravatar!