What is CHOLESTEROL–The Good and the Bad – Part 1

We have all heard of Cholesterol. We are bombarded with advertising warning us of the dangers associated with an elevated blood Cholesterol and  the importance of lowering our Cholesterol. Many foods have labels advertising Low or No cholesterol content.The terms Light or Extra light are used on packaging to persuade us to buy a particular brand when often they have nothing to do with cholesterol levels. No doubt your Doctor has advised you to have your cholesterol checked. But what exactly is it ?

What is Cholesterol ?

Cholesterol is a white fatty substance found in our blood. It is a naturally occuring fat in humans and other animals. The liver produces about 1 gram of cholesterol per day, which is all the body requires. The body needs cholesterol to make  certain hormones , vitamin D , bile acids, cell membranes and nerve sheaths. Bile acids are essential for digestion and absorption of fats from our intestines.

Question:- Well then, if Cholesterol is necessary for many normal bodily functions, why is it a problem?

Answer:- The answer lies in both the type and quantity of cholesterol in the blood.

Researchers at Framingham near Boston in the USA were among the first to show the relationship between elevated levels of cholesterol and heart disease. Other researchers in California in the USA  found that there were different types of cholesterol which had different functions

How does Cholesterol function in our body?

Cholesterol in the body  rarely exists as pure cholesterol, because it is not soluble in water -and therefore blood. Instead cholesterol molecules  attach themselves to certain types of tiny transport proteins called Lipoproteins.

Two main types of lipoproteins are the carriers of cholesterol and will be the ones we discuss:-

(1)  Low Density lipoproteins  ( LDL ) carry about two thirds , while most of the remainder is attached to

(2)  High Density Lipoprotein ( HDL )

1. Low Density Lipoproteins ( LDL ):- LDL  transports cholesterol to the tissues. The problem arises when there is damage to the inner layer of the wall of an artery particularly in the heart or brain. The earliest sign of damage to an artery is the appearance of “fatty streaks”. These are yellow patches  on the inner wall of the artery which are stuffed with cholesterol. These plaques can increase in size and gradually lead to blockage of arteries, a condition called atherosclerosis. If this occurs in the heart blood vessels, a heart attack ( coronary occlusion) occurs or if  in the brain , a stroke. LDL  is often referred to as ” BAD cholesterol”

Normal Artery

Fatty Streak

Established Cholesterol Plaque

Cholesterol Plaque

 

Narrowed Artery

The discovery of the relationship between LDL cholesterol and heart disease was made byDr Joseph Goldstein and his colleague   Dr  Michael Brown at the Texas Health Science Centre in Dallas USA in the 1970’s. They discovered that human cells have LDL receptors which remove  cholesterol from the blood stream.  The lack of these receptors is the cause of familial hypercholesterolaemia, a severe form of high cholesterol which leads to the development of heart disease at any early age.  Their finding led to the development of the Statin Drugs which are commonly used today in the management of high cholesterol.

They received The Nobel Prize in 1985 for their work.

2. High Density Lipoprotein (HDL):- HDL on the other hand is referred to as GOOD cholesterol. It helps to clear the arteries by removing cholesterol from the artery wall and other tissues and carrying it to the liver to be  converted to other substances or removed from the body through the bile.

Investigations have shown that this reverse transport mechanism has a protective effect and therefore reduces the risk of heart disease.

Recent studies have also shown that HDL has other important functions. It has Anti-oxidant and anti-inflammatory properties which help protect the lining of the blood vessels.

If the lining of the blood vessels are damaged, the cells produce a sticky substance .Certain cells from the blood can adhere to the damaged cell wall, so leading to the development of plaque and consequently atherosclerosis. It appears that HDL can inhibit the secretion of the “sticky” substance and so reduce inflammation.

Factors causing an increase in LDL:-

1. Genetic Factors such as Familial Hyperlipidaemia

2. Diet: Ingestion of foods high in Cholesterol, increased intake of foods containing saturated ( animal ) fats and foods containg Trans Fats

3. Alcohol excess, may increase the production of another low density lipoprotein called VLDL. This  leads to a high cholesterol level and the collection of another type of fat called Triglyceride.

4. Impaired Liver function as a result of alcohol  excess , or Illicit drug use leading to hepatits B and C

5. Overweight

6.  Diabetes

7. Hormone imbalance, such as an under-functioning  Thyroid (Hypothyroidism)

8. Pregnancy and Breast Feeding: Hormone changes which occur during pregnancy and breast feeding may lead to abnormally high cholesterol and Triclyceride levels. Therefore the lady’s diet needs to be monitored carefully by her doctor, while bearing in mind the need for adequate supplies of nutrients and energy.

9.  Post menopausal women are at higher risk of developing high cholesterol levels and therefore heart disease.  This is a result of the falling oestrogen levels due to gradually declining function of the ovaries. Oestrogen has some protective effect on the wall of arteries.

10. Chronic kidney disease

11. Certain Medications, such as , the Contraceptive Pill, and thiazide diuretics,  those used to treat fluid retention and high blood pressure

Factors contributing to a fall in HDL:-

1. Genetic Factors –  certain rare diseases

2. Cigarette smoking.

3. Lack of Physical exercise

4. Obesity

5. Male Hormones – Testosterone excess in women with a condition called Polycystic Ovary Disease

Conclusion: So we have discussed  ” What is Cholesterol ” , we have found that there are different types of Cholesterol and  learned a little of the way they function.

We now know that HDL cholesterol is Good and has a protective effect in our body and the level needs to be high.

We see that the villain  is LDL  cholesterol and a low HDL. We  have discussed the many reasons why the level of LDL may be high.

I would recommend that you investigate the product ” Cholesterol Support ” by clicking on the Dr Sears banner below.

In Part 2, I will discuss that other Fat, Triglyceride and what we can do to solve the problems of  the condition called Hyperlipidaemia.

Doctor Bill


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11 Responses to “What is CHOLESTEROL–The Good and the Bad – Part 1”


  • Comment from Amy

    Thanks Dr Bill, for yet another high quality, easy to understand post, without compromising the necessary details. This subject is of high interest in our house. As always, I look forward to continuing my visits.

  • Comment from docbill

    Hello Rita, Get them done at least annually. It’s worth that little “prick” in the arm Regards . Bill

  • Comment from docbill

    Thanks again Jo for your positive comments. Bill

  • Comment from Rita

    Hi Dr Bill,
    An interesting read, I had better go back to my Dr and have my levels checked again its been a while.
    Thanks Dr
    Rita

  • Thanks Dr Bill, for yet another high quality, easy to understand post, without compromising the necessary details. This subject is of high interest in our house. As always, I look forward to continuing my visits.

  • Comment from docbill

    Thanks Colin. As I said to David above . It is interesting but can get complicated . Tried to make it easy to understand the basics. Glad it helped. Doctor Bill

  • Comment from docbill

    Glad you liked my Wife’s camera work Cherie. Had a bit of fun getting them to fit together on the page. Don’t forget to see the next one on triglycerides . Have been without a computer for the past few weeks due to a nasty “crash.” Did you have any problem with the links. Doctor Bill

  • Comment from docbill

    Thanks for the comment David . It is interesting stuff. It gets really complicated when one goes into the detailed physiology and biochemistry. Your Doctor’s desription is a good one . Watch for the article on Triglycerides. Doctor Bill

  • Comment from David Moloney

    Thanks for the info Dr Bill. I still remember a doctor referring to HDL, LDL and Triglycerides as the good, the bad and the ugly. That’s how I remember which is good and which isn’t.

  • Wow Dr Bill

    When I see my GP there is always a big line up of waiting patients so being very concious of this I try not to take up too much of his time.

    Your photos alone have knocked me into action for my next visit. Wow and thank you very much for your wise knowledge.

    This is a blog that I love to regularly visit.

  • Comment from Colin Schedler

    Very interesting read Doctor Bill. I never fully understood the finer details of LDL and HDL when my GP discussed my blood test results.


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