LDL Cholesterol

Cholesterol is a building block. Your body uses it for cell membranes, hormones and bile, and your liver makes most of it itself. Because fat does not dissolve in blood, cholesterol travels in lipoproteins: spheres of protein and fat that carry it through the bloodstream. LDL, low-density lipoprotein, is the particle that brings cholesterol from the liver to the tissues. Your LDL cholesterol is the amount of cholesterol on its way in those particles. The problem starts when more LDL particles circulate than the tissues take up. The surplus enters the inner lining of the arteries and lodges there. White blood cells clear those particles, become engorged with them and die; from that accumulated material plaque forms, the narrowing we call atherosclerosis. The more LDL and the longer, the more plaque. That is why, of all the cholesterol values, LDL says most about your heart and blood vessels. Your report shows LDL as one number in millimoles per litre (mmol/L), usually calculated from your total cholesterol, HDL and triglycerides. What is missing is a true normal value, and that is no oversight. For most blood values the report says what healthy people usually have, but what is common is not what your arteries want: atherosclerosis builds up at values everyone around you has too. That is why LDL comes with a target instead of a range, and why that target differs per lab. The table further down shows it.

A high LDL cannot be felt. There is no complaint, no signal, only a number. Meanwhile the damage adds up: every year with a higher LDL adds a little plaque, and that does not simply clear again. That is why it pays to know your LDL young. Someone who knows where they stand at thirty can prevent decades of exposure with small adjustments; someone who hears it at sixty has already had those years. That link is causal, not merely statistical, as the Dutch guideline on cardiovascular risk also confirms. There is no floor below which less LDL stops helping: lower is better for your arteries, even when your value already counts as 'normal'. What is 'too high' depends on the rest. Someone who smokes, has high blood pressure or has already had a heart attack has far more to gain at the same LDL than someone without other risk factors. That is why targets exist per risk group, such as below 1.8 mmol/L after cardiovascular disease and below 2.6 mmol/L at increased risk. Those apply to anyone under treatment; for everyone the direction applies.

A high LDL usually comes from a combination of what you eat, how much you weigh and what you were born with. Saturated fat is the biggest lever: fatty meat, butter, full-fat dairy, biscuits and pastry push LDL up. Excess weight and little exercise add to it, and how much your liver produces and clears again is partly inherited. An underactive thyroid can raise LDL too. If your LDL has been markedly high since a young age, especially when cardiovascular disease runs young in the family, familial hypercholesterolaemia may be involved: an inherited condition in which the liver clears LDL poorly. A low LDL is good news. There is no floor below which it becomes a problem. In people who eat largely plant-based and fibre-rich, are lean and exercise a lot, a low LDL is the ordinary outcome; in others it is inheritance, or the effect of cholesterol-lowering medication. LDL listens to what you do. Replace saturated fat with unsaturated fat: olive oil instead of butter, nuts and oily fish instead of fatty meat and processed meat. Eat more fibre from oats, legumes, vegetables and fruit; soluble fibre binds bile acids in your gut, so your liver has to draw on cholesterol to make new ones. Lose weight if you carry too much, especially around the middle, and move every day. For most people without an inherited condition that is the whole solution, and you see the effect back in your blood within weeks to months. If your LDL is markedly high or inherited, or you already have cardiovascular disease, lifestyle is still the foundation and medication usually joins it. Read LDL beside the rest of your blood fats. Non-HDL cholesterol, your total cholesterol minus HDL, also counts the cholesterol in other harmful particles. High triglycerides with a low HDL next to a normal LDL point to a metabolic pattern in which the LDL particles are smaller and more numerous than the number suggests; ApoB counts those particles directly. And look at the trend: one measurement is a snapshot, two measurements show which way it is going.