Cholesterol deconstructed

Let’s take a look at the different aspects of cholesterol.

Movement of cholesterol

Cholesterol, like oil, is insoluble in blood. Therefore it needs to be carried from one place to another in the body. The carriers are called lipoproteins (fat (lipid) + protein). There are essentially two types of carriers: Low Density Lipoprotein (LDL) and High Density Lipoprotein (HDL), Dr Ray says.

1) LDL v/s HDL

LDL is termed bad as it helps form plaque in the blood vessels. Plaque comprises hard deposits that make the vessels thicker and less flexible. This condition is called atherosclerosis.

Dr Philip Chua, of the Cebu Cardiovascular Centre, added that arterial blockage deprives tissues and organs of oxygen and accelerates ageing.

On the other hand, HDL is considered good cholesterol because it carries the bad cholesterol to the liver where it is broken down to be excreted from the body. Therefore, a fair amount of good cholesterol may be good for the heart. Or, the higher the High Density Lipoprotein (HDL) the better the heart and body will be, Dr Chua says.

What’s the truth about HDL/LDL ratio?

Typically, there is a ratio which balances good and bad cholesterol and if one can manage to arrive at this ratio, there is no problem with heart health.

According to Dr Ray, “We are born with a bad cholesterol level of about 0.4 mmol/l (millimoles per litre, a unit of measurement), so when we talk about levels of 2, 3, 4, these are manifold higher than we need.

LDL cholesterol and numbers

People with heart disease or who have had a stroke: <1.8mmol/l

Those with diabetes and family history of hypercholesterolaemia: <2.5mmol/l

Everyone else: <3.0 mmol/l

(Dr Ray)

High: 160-189mg/dl

Very high: Exceeding 189mg/dl

LDL levels are optimal if they are less than 100mg/dl, near optimal from 100-129mg/dl

(Dr Yahya Kiwan, Consultant Interventional Cardiologist at Canadian Specialist Hospital, Dubai)

“One has to consider the patient’s general health condition. If diabetic or with history of heart disease, LDl should be less than 70mg/dl.

Normal upper limit for LDL: 130mg/dl.”

(Dr Omar Hallak)

The higher and longer LDL remains outside these markers for respective categories, the more the risk.

Important: People with diabetes and other medical conditions such as hypertension may develop problems even with low levels of LDL as these diseases act as additives.

Hereditary and lifestyle both play a role in raising LDL cholesterol, doctors say.

Dr Ray explained: “Genetic imprint can make an individual develop a 20-fold higher level of LDL from birth. Smoking, obesity and diabetes increase the levels.”

2) HDL, the good cholesterol and numbers

Desirable: More than 60 mg/dl

Low: If less than 40mg/dl

(Dr Kiwan)

Ideal HDL level

Above 50mg/dl

Ideal TC/HDL (Total cholesterol/High Density Lipoprotein) ratio is less than 4; higher ratio means higher risk for heart disease.

(Dr Omar Khallak).

3) Total cholesterol

One of the most vexing issues for an individual is determining the healthy levels of total cholesterol. Is it 250mg/dl? 220 or 200? Over the last decade, the healthy total cholesterol numbers have undergone revisions.

Current advisory that is internationally accepted: 200mg/dl.

Dr Rao explained the reasons for the shifting goalposts. “Many decades ago, people led a more active life, ate wholesome food, had lower levels of stress. So a TC (total cholesterol) level of 250 was acceptable. However, in the current scenario, where smoking, alcoholism, poor eating habits, proliferation of trans fats in our food and a higher stress level are everyday givens, the medical fraternity has changed the goalpost to 200 as people are now at a higher risk of developing hypertension and heart disease even at lower thresholds of cholesterol.”

Dr Rao added that although people belonging to certain regions in the world such as Asia and the Indian subcontinent have a higher genetic predisposition for high cholesterol, the widespread rise in hyperlipidemia can no longer be only linked to heredity. “Lifestyle has become an exacerbating factor and high cholesterol is found in people who have hitherto had no family history of the condition,” he added.

Dr Omar Hallak says there’s no ethnic difference on “normal” level of total cholesterol. “It is generally recommended that the level is kept below 200mg/dl across the board.”

Dr Kiwan said, “Total cholesterol is related to race; it varies by race, ethnicity and sex, the reason why around the world, there are different bars for total cholesterol. Research has revealed that some factors, like social, economic, or genetic, could provide an explanation for variations in total cholesterol levels.

“The ideal total cholesterol is less than 180 mg/dl. In addition to total cholesterol levels, it is important to analyse the overall risk assessment as well. It is important to know your numbers, but it is equally important for you to work with your doctor to treat your risk.”

4) Trigylcerides

Another troublesome group of lipids or fats that cause health problems are triglycerides. According to Dr Mohammad Hassanein, Consultant Endocrinologist at Dubai Hospital: “Triglycerides are another type of fat in the blood and can also contribute to atherosclerosis [hardening of the arterial walls due to build-up of plaque] but to a lesser extent [as compared to cholesterol and LDL].

Dr Ray added: “Triglycerides are [also] a source of energy as cells use these or glucose to create energy for cells to work. Triglycerides go high [in the blood], especially after a fatty meal. They alone don’t increase the risk of heart disease but the cholesterol particles they sit inside are the real culprits. Triglycerides are higher in people with obesity and diabetes and should be considered a marker of risk, not a target for treatment.”

Normal: Less than 150mg/dl

High: Between 200-499mg/dl

Very high: Exceeding 500mg/dl

(Dr Kiwan)

Treatment

There are traditional treatments as well as breakthroughs that have had a dramatic impact on lowering bad cholesterol. Specialists make a particular mention of statins, a class of drugs that have been around for a long time.

Dr Ray said: “Statins are the first line of treatment as they are known to reduce cholesterol by 50 per cent with side-effects on the liver that are as low as less than one per 100,000 per year.”

The right type of statins should be used at the right doses at the right time, he said.

Other drugs for people who cannot tolerate statins are ezetimibe, which reduce cholesterol by 20 per cent.

A revolutionary new class of drugs, according to Hassanein, Shehab and Ray, are PCSK9 inhibitors. “These are monoclonal antibodies, a type of biologic drug. They inactivate a protein in the liver called pro-protein convertase subtilisin kexin 9 (PCSK9). The best way to think about this is like the video game Pac-Man. The new therapy eats the PCSK9 proteins, it removes them. That means that the body’s LDL receptors are not destroyed. If you have many LDL receptors, your cholesterol levels in the blood can come down by 50-60 per cent. On top of additional drugs, these can give you a massive reduction in cholesterol levels but it is a very different way of working because it is an injection. It is called a monoclonal antibody, it is not a tablet,” said Dr Ray.

Striking the right balance

To have safe levels of total cholesterol, based on HDL/LDA ratio and triglycerides, an overall approach to good health is the best option.

A healthy lifestyle, proper diet and regular checkups will lead to good numbers in total cholesterol and LDL-HDL balance and contribute to overall heart health in controlling LDL/HDL and triglycerides.

• Eat a diet rich in fresh fruits, nuts, whole grain, vegetables, fish, and lean meats

• Reduce portion size

• Opt for healthy fats such as olive oil instead of margarine as a cooking medium

• Cut down on fatty foods.

Get active. Take the stairs, walk to your car. Exercise.

Eat high-fibre foods that can act as a natural scrub, cleaning out plaque and preventing build-up in your arteries

• Talk to your doctor about your cardiovascular risk and take your medicines on a regular basis

• Go for genetic screening if you have a family history of heart disease or high cholesterol

• Give up tobacco and smoking

• Abstain from alcohol