Ask The Experts

Total cholesterol level can be misleading

The pomfret is higher in cholesterol than beef.
The pomfret is higher in cholesterol than beef. ST FILE PHOTO

Q I am a 67-year-old woman. I had some laboratory tests done recently. The results were normal or optimal, except for the lipid panel.

The readings are:

•Total cholesterol: 6.6 mmol/L

•Triglycerides 1.04 mmol/L

•High-density lipoprotein (HDL): 2.22 mmol/L

•Low-density lipoprotein (LDL) 3.9 mmol/L

•Cholesterol to HDL ratio is 2.97 mmol/L

The doctor wanted to start me on cholesterol-lowering medication. I asked for time to improve on the results and was given three months.

I have been on a healthy diet nearly the whole of my adult life. Is it necessary to start on medication at this stage?

A Based on your latest result, it seems that your total cholesterol is high due to two factors.

You have a high HDL level of 2.2 millimoles per litre (mmol/L) as well as a high LDL level of 3.9 mmol/L. On balance, the ratio is all right as it is only 2.97 mmol/L.

This is derived by dividing the figure for total cholesterol with that for HDL cholesterol.

An optimal ratio is between 1 and 3.5 mmol/L. A higher ratio means a higher risk of heart disease.

If you focus only on total cholesterol, it would give you the wrong impression that your cholesterol is unacceptable.

It is also important to look at the individual HDL and LDL numbers, as well as the ratio.

HDL is "good" cholesterol, which you want to be as high as possible. The minimum level should be 1.03 mmol/L.

LDL is "bad" cholesterol, which you want to be as low as possible, below 3.36 mmol/L for healthy patients, and below 2.58 mmol/L in higher-risk patients like those with diabetes.

The lower the ratio, the better.

In high-risk patients, such as those with prior coronary artery disease and diabetes, the LDL level should preferably be closer to 1.82 mmol/L.

To achieve such a low level, the patient will almost always need to be on medication, such as statins.

In your case, I would not advise medication.

However, if you have diabetes, your LDL should be less than 2.58 mmol/L. But I assume you are not diabetic as you said that your other results are normal.

Two-thirds of the cholesterol in our body is determined genetically. Lifestyle modifications, such as diet and exercise, will affect only the remaining one-third.

As your good HDL is high and your ratio is all right, I will suggest a healthy diet and exercise for you, with no medication.

Reduce your intake of meat and egg yolks, and increase your cardiovascular exercise. This will further increase your good HDL and reduce your bad LDL.

However, you should also know that cholesterol comes from animal products, even fish and chicken. In fact, the cholesterol in pomfret is higher than that in beef. On the other hand, coconuts, durians and french fries do not contain cholesterol.

As you are 67, I will recommend cardiovascular exercises, such as brisk walking. The standard recommendation is to exercise four times a week for a minimum of 30 minutes each time.

Aim to reach 80 per cent of your maximum predicted heart rate. This is calculated by subtracting your age from 220.

Cardiovascular exercises like zumba, line dancing and swimming are beneficial too.

You may also wish to repeat your cholesterol test in six to 12 months' time. If you have been exercising more and eating less meat, your HDL will go up and your LDL will drop.

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Health screening physician at Mount Alvernia Hospital

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A version of this article appeared in the print edition of The Straits Times on January 05, 2016, with the headline Total cholesterol level can be misleading. Subscribe