On the surface, this looked like an unusual case of heart attack. This 40-year-old patient of mine had a very desirable LDL (low-density lipoprotein or bad cholesterol) of 55 mg/dL. As cardiologists, we tell patients to keep their LDL below 70 mg/dL. He had no other risk factor as such, be it obesity, smoking, diabetes or alcohol addiction. Yet he had a heart attack and needed a procedure to open up his arteries. So, what was the aberration in his blood report that he overlooked while focussing on LDL and feeling happy about it?
While LDL is always discussed as a major threat, there are allied figures in the cholesterol report that we must look into, particularly the interlinked figures of triglyceride and HDL (high-density lipoprotein or good cholesterol). His triglyceride was 325 mg/dL and HDL was 28 mg/dL. The ideal triglyceride to HDL ratio, which is calculated by dividing your triglyceride level by your HDL cholesterol level should be 1 or less. This indicates lower cardiovascular risk and better insulin sensitivity. A ratio above 4 is considered high, with some sources pointing to specific optimal ranges like under 1.85 for men and 0.88 for women. In my patient’s case this ratio was above 11!
Why is the triglyceride-HDL ratio a red flag?
A high ratio means that triglycerides have the upper hand. And in higher levels, they manage to change the nature of LDL. A high triglyceride/HDL ratio suggests that you have more small, dense and sticky LDL, which easily penetrate walls of key heart arteries, get oxidised and form plaque, unlike larger, fluffier LDL particles. Now these constrict the arteries and are unstable in nature, getting dislodged easily, causing a tear in the artery wall and blocking supply of oxygenated blood, leading to a heart attack. This can happen even when your LDL readings seem normal.
A high ratio signals more inflammation and risk, predicting future cardiovascular events better than individual lipid levels alone.
It is a sign of insulin resistance
This ratio flags insulin resistance, something that my patient was unaware of. It was clear that he was approaching prediabetes. Insulin resistance disrupts normal fat metabolism, converts excess free fatty acids to triglycerides and packages them into Very Low-Density Lipoprotein (VLDL) particles, which again end up forming plaques.
Insulin resistance also increases the activity of hepatic lipase, an enzyme that breaks down HDL particles, making them smaller, less functional, and accelerating their quick removal from blood circulation. Which means that HDL cannot clear LDL from your arteries anymore.
How should we look at our total fat profile in a cholesterol report?
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This is simple. Just subtract HDL from total cholesterol and you will get non-HDL cholesterol, which includes all the artery-clogging cholesterol (LDL, VLDL) in your blood. This helps you assess your heart risk better than just looking at LDL. Lower numbers are healthier. We advise this number to be 100 mg/dL for diabetics and 130 mg/dL for non-diabetics.
How to reduce triglycerides
Remember, existing plaques won’t disappear. What you can slow down is formation of LDL cholesterol, which cannot be done in the short term and needs a lifetime of medication to maintain healthy levels. Luckily triglycerides respond quickly to lifestyle changes easily unlike LDL.
To lower triglycerides, cut down on sugar and refined carbohydrates as excess sugar is converted into triglycerides. Limit alcohol consumption, as alcohol significantly raises triglyceride levels. Maintain a healthy weight and engage in regular physical activity, which helps burn excess triglycerides for energy.
Statins, the most common cholesterol-lowering drugs, reduce LDL cholesterol and have a mild effect on triglycerides. If triglycerides are very high, doctors prescribe fibrates, Omega-3 fatty acid supplements, or niacin, which specifically lower triglyceride levels.
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(Dr Shetty is lead cardiologist and medical director, Sparsh Hospital, Bengaluru)
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