What is oxidized LDL and how is it different from regular LDL?

Oxidized LDL (ox-LDL) refers to LDL particles that have undergone lipid peroxidation, reacting with reactive oxygen species to form modified particles that are taken up by arterial wall macrophages (scavenger receptors are not regulated by cellular cholesterol feedback, so macrophages engorge with lipid and become "foam cells"), driving the initial stages of atherosclerotic plaque formation in a way that native unoxidized LDL does not directly (Witztum & Steinberg, J Clin Invest, 1991).

Oxidized LDL is why particle count (ApoB) matters more than cholesterol content, and why antioxidant capacity matters for cardiovascular risk. The interventions that reduce LDL oxidation: omega-3 fatty acids, polyphenol-rich foods (olive oil, berries, cocoa), smoking cessation (smoking dramatically increases LDL oxidation), and blood glucose control (glycated LDL oxidizes more readily). Ox-LDL testing is available but not standard clinical practice, ApoB combined with standard cardiovascular risk factors gives sufficient clinical information for most treatment decisions.

Honesty Scale: Solid (1) for ox-LDL as the atherogenic mechanism. Promising (2) for specific dietary antioxidant interventions reducing ox-LDL in vivo.

What to do: Reduce LDL oxidation through modifiable factors: quit smoking, control post-meal glucose, eat antioxidant-rich foods. These are additive benefits to ApoB reduction from statin or lifestyle interventions.

For the full picture, read The ApoB/Lp(a)/Lipids Deep Dive