Is ApoB more important than regular cholesterol (LDL)?

ApoB sits on every 'bad' fat particle in your blood: one molecule per LDL, VLDL, or IDL particle. It therefore counts the total number of at-risk particles. LDL cholesterol does something different: it measures how much fat is inside those particles, not how many particles there are. The two do not track each other nearly as closely as you might expect, and that is where the problem lies.

That ApoB tells us more than LDL is shown by several large human studies. A systematic review of 15 studies involving more than 593,000 participants found that ApoB was a better predictor of cardiovascular disease than LDL cholesterol in all 9 available comparisons. The conclusion: LDL cannot adequately replace ApoB¹. A Danish cohort study of 95,108 people confirms this: the more additional information ApoB adds on top of LDL, the greater the risk of a heart attack, for both men and women, across the entire range of LDL values².

Compared with non-HDL cholesterol, which is already a broader measure than plain LDL, the advantage of ApoB is smaller. In the same review, ApoB scored better in 7 out of 9 comparisons, but in one study non-HDL was superior and in one they were equivalent¹. Anyone who already measures non-HDL is therefore considerably better off than with LDL alone.

ApoB does not capture everything. An analysis of 17,532 people without known cardiovascular disease found that elevated remnant cholesterol, the cholesterol in triglyceride-rich particles, was associated with a 65% higher risk of a cardiovascular event, even after adjustment for both LDL and ApoB³. And a British cohort study of 271,760 participants suggests that the composition of LDL particles also provides additional information beyond ApoB⁴.

Despite consistent evidence, ApoB is still rarely measured in routine care. One important barrier is that clear treatment targets in clinical guidelines are still lacking, whereas targets for LDL have existed for years⁵. Want to lower ApoB through diet? A meta-analysis of 58 randomised studies shows that the fibre in oatmeal at around 3.5 grams per day significantly, though modestly, lowers ApoB (by an average of 0.03 g/l)⁶.