The Good and Bad of Blood Cholesterols

Contrary to popular belief, some amount of cholesterol, produced by the liver, is vital for effective functioning of the human body.  Every cell in the body consists of cholesterol in its outer layer.  However, high levels of cholesterol can have devastating effects on the body leading to various health complications. In fact, one of the foremost causes of death across the globe is having higher than recommended levels of blood cholesterol.



The word “cholesterol” is derived from the Greek word ‘Chole’ and ‘stereos’ meaning ‘bile’ and ‘solid stuff’ respectively.


Cholesterol is a wax like fatty substance belonging to a class of molecules known as steroids.  A lipid produced by the liver, cholesterol forms part of the outer membrane that surrounds every cell.  75% of the cholesterol that circulates in the blood is produced by the liver.  The other 25% comes from food.  A high intake of such foodstuff can increase the cholesterol level in the blood.


Cholesterol Functions
Cholesterol is essential to carry out various functions in the body. They are listed below…
  • Helps formation and maintenance of cell membranes
  • Used to insulate nerve fibres
  • Involved in the production of sex hormones such as androgens and estrogens
  • Essential for the production of hormones released by the adrenal glands like cortisol, corticosterone, aldosterone, and others
  • Aids in the production of bile, which help, digest food
  • Imperative for the metabolism of fat-soluble vitamins, including vitamins A, D, E, and K
  • Converts sunshine to vitamin D



Although many foods contain cholesterol, it is poorly absorbed by the gut into the body.  Therefore, cholesterol in terms of food intake has little effect on the body and blood cholesterol level.  A certain amount of cholesterol is present in the bloodstream.  However, a person needs some cholesterol to maintain optimal health. Cholesterol is carried in the blood as part of particles called lipoproteins.  Cholesterol moves through the bloodstream in small packages by molecules called lipoproteins.  Lipoproteins are substances made of both lipid on the inside and proteins on the outside.  The carrier molecules that are made up of protein are called apoliproteins.  They are necessary because cholesterol and other fats (lipids) cannot dissolve in blood.  When these apoliproteins are joined with cholesterol, they form a compound called lipoproteins.  The density of these lipoproteins is determined by the amount of protein in the molecule.  Having healthy levels of both types of lipoproteins is important.


Lipoproteins Types

The three types of lipoproteins are:


Low-Density Lipoprotein (LDL)

Low-density lipoprotein also known as “bad cholesterol“, LDL Cholesterol carries cholesterol from the liver to cells.  Often referred to as bad cholesterol due to the proven relationship between high LDL levels and heart disease elevated levels of LDL cholesterol, contribute to plaque build-up arteries in, a process called atherosclerosis.  Cholesterol plaque inside the walls of your blood vessels cause blood vessels to narrow (coronary artery disease) disrupting normal blood flow from the heart to the rest of the body increasing risk of heart attack and stroke.  A diet high in saturated fats and trans fats tends to raise the level of LDL cholesterol.  For most people, an LDL score below 100 is healthy, but people with heart disease may need to aim even lower. It is therefore imperative to have cholesterol levels checked regularly.  The main goal of any cholesterol treatment program is to lower the LDL cholesterol as much as possible.


High-Density Lipoprotein (HDL)

High-density lipoprotein or HDL Cholesterol helps clear the cholesterol from the cells back to the liver, where they are either broken down or flushed out as waste.  Hence, they are referred to as good cholesterol. The higher the levels of HDL cholesterol, the better as they lower risk of heart disease. For patients with heart disease, lower levels of HDL cholesterol indicate a risk for developing coronary artery disease.  Eating healthy fats, such as olive oil, may help boost HDL cholesterol.



The body converts excess calories, sugar, and alcohol into triglycerides, a type of fat that is carried in the blood and stored in fat cells throughout the body.  People who are overweight, inactive, smokers or heavy drinkers tend to have high triglycerides, as do those who eat a very high-carb diet.  A triglycerides score of 150 or higher puts you at risk for metabolic syndrome, which is linked to heart disease and diabetes.


Factors That Affect Blood Cholesterol Levels


Junk FoodsCholesterol-rich foods, like eggs, shrimp, and lobster are no longer completely forbidden.  Research shows that the cholesterol has only a small effect on blood levels for most people.  A few people however are “responders,” whose blood levels increase after eating eggs.  However, for most people, bigger concerns are saturated fat and trans fats.  Daily cholesterol limits are 300 mg for healthy people and 200 mg for those at higher risk.  One egg has 186 mg of cholesterol.



A body mass index (BMI) of over 30 is another factor affecting cholesterol levels.


Two sources that contribute to high cholesterol come either from the body or from food.  Some people inherit genes that trigger an increase in cholesterol production. For others, diet happens to be the main culprit. Saturated fat and cholesterol occur in animal-based foods, including meat, eggs, and dairy products made with full fat milk.  In many cases, high cholesterol stems from a combination of diet and genetics.



diabetesHigh blood sugar contributes to higher LDL cholesterol and lower HDL cholesterol damaging the lining of the arteries.


High Blood Pressure

Increased pressure on the arterial walls cause damage to the arteries and accelerates the accumulation of fat deposits.


AlcoholBad Habits

Cigarette smoking and alcohol consumption damage the walls of the blood vessels, with increased chances of accumulating fatty deposits.

Physical Inactivity

Lack of exercise increases risk of elevated cholesterol levels.  Therefore, Exercise helps boost body’s HDL “good” cholesterol while lowering LDL “bad” cholesterol.



Women have lower total cholesterol levels than men of the same age until menopause.  Due to their biological factors of female sex hormones, estrogen, women are naturally blessed with higher levels of HDL cholesterol, that elevates level of ‘Good’ (HDL) cholesterol.  Estrogen production peaks especially during the childbearing years and drops off at the time of menopause.  After age 55, there is an increased risk in women of developing high cholesterol.



According to researches, there is ample evidence to prove that there are chances of cholesterol clogging the arteries during childhood. These ultimately lead to atherosclerosis and heart disease during adulthood.  Therefore, it is essential to consume a well-balanced healthy diet right from childhood, avoiding junk foods.  Ideally, total cholesterol should be below 170 in children between the ages of 2 to 19.


Total Cholesterol Ratio 

Total blood cholesterol is the most common measurement for blood cholesterol, which is a combination of LDL, HDL, and VLDL (very low-density lipoprotein) in the bloodstream.  Measured in milligrams per decilitre of blood (mg/dL) total blood cholesterol level is an important first step in determining the risk for heart disease. The ratio is obtained by dividing the HDL cholesterol level into the total cholesterol.  For example, if a person has total cholesterol of 200 mg/dL and an HDL cholesterol level of 50 mg/dL, the ratio would be stated as 4:1.  The goal is to keep the ratio below 5:1; the optimum ratio is 3.5:1.VLDL is a precursor of LDL, the bad cholesterol. A total cholesterol score of below 200 is considered healthy in most cases.


Classification of LDL, HDL, and Total Cholesterol (in mg/dL)
LDL Cholesterol 100
Near optimal/above optimal
130-159 Borderline high 160-189 High >190
Very high
HDL Cholesterol <40 Low >60 High
Total Cholesterol <200 Desirable 200-239
Borderline high
>240 High
Triglycerides <150 Normal 150-199
Borderline high
Very high


Dangers of Elevated Cholesterol Levels

High cholesterol is one of the major risk factors for coronary artery disease.



Atherosclerosis is a dangerous condition of cholesterol deposits on the arterial walls of the heart resulting in narrowing of the arteries disrupting normal blood flow.



Chest pain or angina may occur due to insufficient blood supply in the coronary arteries


Heart attack 

Heart attacks occur due to insufficient blood supply and oxygen to an area of the heart, resulting in death of that particular muscle.



Similar to a heart attack, when blood flow to part of the brain is blocked by a blood clot, a stroke occurs.


Alzheimer’s disease

It also appears to boost the risk of Alzheimer’s disease.


Cholesterol Checking

A fasting lipid profile measures several of the lipid parameters in the blood, therefore it is  important to measure a full lipid profile rather than just a total cholesterol level because each of the different lipid parameters are clinically important.  A lipid profile conveys a large amount of information about the potential risk of heart disease, and points to the best treatment strategies


Ways to Improve Cholesterol Levels

Lifestyle changes

The only way to maintain healthy cholesterol levels is to incorporate a few changes in lifestyle.



ExerciseAn aerobic exercise program could increase good cholesterol by 5% in a couple of months lowering bad cholesterol.  Activities for at least 30 minutes on most days of the week such as a brisk walk, running and swimming increase heart rate.



Changes in diet provide a powerful way to combat high cholesterol.

Fibre: Foods loaded with soluble fibre such as whole-grain breads and cereals, oatmeal, fruits, dried fruits, vegetables, and legumes such as kidney beans helps reduce LDL, the bad cholesterol.


Fats: Saturated fats from animal products and tropical oils raise LDL cholesterol.  Tran’s fats found in baked goods, fried foods margarine, and cookies boost bad cholesterol, while lowering HDL. Unsaturated fats found in avocados, olive oil, and peanut oil lower LDL when combined with other healthy diet changes.


Low Carbs: There is growing evidence that low-carb diets improve HDL (good cholesterol) levels considerably as when compared to a low-fat plan.


Weight Loss

Losing weight can help reduce triglycerides, LDL, and total cholesterol boosting HDL cholesterol.


Quit smoking

Good cholesterol is likely to improve by as much as 10%, while quitting smoking.




MedicinesDespite lifestyle changes if cholesterol levels remain perpetually high, medications like Statins that block the production of cholesterol in the liver, cholesterol absorption inhibitors, bile acid resins, and fibrates may be recommended.



Certain dietary supplements such as flaxseed oil, fish oil, and plant sterols, such as beta-sitosterol may improve cholesterol levels. Niacin, b-complex vitamin, raises good cholesterol while reducing bad cholesterol. However, Niacin found in ordinary supplements should not be used to lower cholesterol.