HDL, LDL and ApoB: what actually matters with cholesterol?

You got your blood work back. LDL is "slightly elevated," HDL is "fine," and your doctor says there's no cause for concern. But is that really the case? In recent years, science has shown that the standard lipid panel — the one most people receive — doesn't tell the full story. And that story can be decisive.

What are LDL, HDL and ApoB?

First, the basics. When we talk about "cholesterol," we're really talking about lipoproteins — small particles that transport fats through the blood. Cholesterol itself isn't inherently bad — your body needs it for cell membranes, hormones, and vitamin D. The problem arises when certain particles accumulate in artery walls.

LDL (low-density lipoprotein) — often called "bad cholesterol." But LDL-C, measured in a standard blood test, doesn't count the number of LDL particles — it measures the amount of cholesterol inside them. This is a crucial distinction. Two people can have the same LDL-C but very different particle counts — and therefore very different risk profiles.

HDL (high-density lipoprotein) — long called the "good cholesterol" because it transports cholesterol back to the liver. But newer research shows that high HDL isn't necessarily protective — more on this below.

ApoB (apolipoprotein B) — a protein found on every potentially atherogenic (artery-damaging) particle. Every LDL particle, every VLDL particle, every IDL particle, and every Lp(a) particle carries exactly one ApoB molecule. This makes ApoB a direct measure of the total number of atherogenic particles in your blood — not the amount of cholesterol inside them.

Why is ApoB better than LDL-C?

This isn't opinion — it's an emerging consensus backed by extensive evidence.

A systematic review in the Journal of Clinical Lipidology (2025, 15 studies, 593,354 participants) compared the predictive value of different lipid markers using discordance analyses. The result: ApoB outperformed LDL-C in 9 out of 9 studies. In 7 out of 9 studies, ApoB was also superior to non-HDL-C.

The National Lipid Association Expert Clinical Consensus (NLA, 2024) concluded that ApoB is a more accurate marker of atherogenic burden than LDL-C and recommended incorporating ApoB measurement into routine clinical practice.

The European Society of Cardiology (ESC, 2019) stated in its guidelines that ApoB is a more accurate risk marker than LDL-C, particularly in individuals with elevated triglycerides or metabolic syndrome.

The discordance problem: when LDL-C lies

The phenomenon called discordance occurs when LDL-C and ApoB point in different directions. In practice, this means your LDL-C may be "normal" while your ApoB is elevated — meaning you have more atherogenic particles in your blood than LDL-C would suggest.

The CARDIA study (2016) followed young adults (aged 18–30) and measured coronary artery calcification (CAC) — a marker of arterial plaque — 25 years later. Young adults with high ApoB and normal LDL-C had 55% higher odds (OR 1.55) of developing coronary plaque. Those with high LDL-C and normal ApoB did not show a statistically significant increase in risk.

This is a key finding: risk tracks with ApoB, not LDL-C.

HDL: is high really protective?

For decades, the belief held: higher HDL = better. But Mendelian randomization studies (MR) — the gold standard for establishing causality — have challenged this.

Voight et al. (2012, The Lancet) identified a genetic variant that specifically raises HDL without affecting other lipid or non-lipid risk factors. Despite significantly higher HDL in carriers of this variant, there was no difference in heart attack risk. Even when a broader genetic analysis using 14 HDL-associated polymorphisms was applied, no association with myocardial infarction was found.

This doesn't mean HDL is irrelevant — but it does mean that pharmacologically raising HDL is not protective and that high HDL alone is no guarantee of low risk. Multiple clinical trials with HDL-raising drugs (e.g., CETP inhibitors) failed to reduce cardiovascular events.

Lp(a): the genetic card you need to know

Beyond LDL and HDL, there's another lipoprotein most people have never heard of — but should: lipoprotein(a), abbreviated Lp(a). Unlike LDL-C or ApoB, which you can lower through diet, exercise, or medication, Lp(a) is 70–90% genetically determined (Boerwinkle et al., 1992). You inherit it from your parents and lifestyle changes have virtually no effect on it.

Lp(a) is causally — not just correlatively — linked to atherosclerosis, myocardial infarction, ischemic stroke, and calcific aortic valve disease (Mendelian randomization studies: Burgess et al., 2018, JAMA Cardiology). Approximately 20% of the world's population — 1.5 billion people — has elevated Lp(a) above 50 mg/dL (125 nmol/L), representing an independent cardiovascular risk (Tasdighi et al., 2024, Annual Review of Pharmacology and Toxicology).

A JACC study (Björnson et al., 2024) showed that Lp(a) is substantially more atherogenic per particle than LDL — meaning even moderately elevated Lp(a) carries disproportionately high risk. A participant-level meta-analysis in Circulation (Bhatia et al., 2025, 27,658 participants from 6 statin trials) confirmed that Lp(a) and LDL-C are independent risk factors — lowering LDL-C does not eliminate the risk carried by high Lp(a).

What the experts recommend — and what you can do

Dr. Peter Attia, MD (physician, preventive medicine specialist, author of Outlive) takes an aggressive stance: ApoB should be below 60 mg/dL for everyone, ideally as low as possible, as early as possible. He compares his approach to smoking: "When you have a causal factor that causes disease, you eliminate it. You don't wait for risk to reach some threshold."

Dr. Rhonda Patrick, PhD (biomedical scientist, FoundMyFitness) emphasizes that lab reference ranges for ApoB are merely population percentiles — not health targets. 80 mg/dL isn't "normal" — it's simply the 20th percentile of a population where cardiovascular disease is the leading cause of death.

The National Lipid Association (NLA, 2024) proposes stratified ApoB treatment thresholds (i.e. levels at which to consider initiating or intensifying therapy): below 90 mg/dL for intermediate risk, below 70 mg/dL for high risk, and below 60 mg/dL for very high risk. Note: these are thresholds, not strict targets — but the direction is clear: lower is better.

1. Request an ApoB test. At your next blood draw, ask for ApoB. The test is simple, reliable, and doesn't require fasting.

2. Don't rely on LDL-C alone. Especially if you have metabolic syndrome, elevated triglycerides, insulin resistance, or familial hypercholesterolemia — discordance between LDL-C and ApoB is more common in these cases.

3. Nutrition that lowers ApoB. Reducing saturated fat (Mensink, 2016, WHO; Sacks et al., 2017, AHA) (this significantly lowers ApoB in roughly one-third to one-half of people), replacing it with unsaturated fats (olive oil, nuts, fatty fish), fiber, and plant sterols. Reducing processed carbohydrates helps by lowering triglycerides and insulin.

4. Exercise. Regular aerobic exercise improves the lipid profile (Mann et al., 2014, Sports Medicine; Wang & Xu, 2017, PLOS ONE) — not so much by directly lowering LDL, but by improving insulin sensitivity, lowering triglycerides, and shifting LDL particle composition (fewer small dense, more large buoyant).

5. Talk to your doctor about pharmacological options. If lifestyle changes aren't enough, statins, ezetimibe, and PCSK9 inhibitors are effective tools for lowering ApoB (Khan et al., 2020, Eur J Prev Cardiol; Sabatine et al., 2017, NEJM). The decision is individual.

References

• Attia, P. (2023). Outlive: The Science and Art of Longevity. Harmony Books.
• Attia, P. (2024). AMA #43: Understanding apoB, LDL-C, Lp(a), and insulin as risk factors for ASCVD. The Peter Attia Drive, ep. 238.
• Bhatia, H.S. et al. (2025). Independence of lipoprotein(a) and low-density lipoprotein cholesterol-mediated cardiovascular risk: a participant-level meta-analysis. Circulation, 151, 312–321.
• Björnson, E. et al. (2024). Lipoprotein(a) is markedly more atherogenic than LDL: an apolipoprotein B-based genetic analysis. Journal of the American College of Cardiology, 83(3), 385–395.
• Boerwinkle, E. et al. (1992). Apolipoprotein(a) gene accounts for greater than 90% of the variation in plasma lipoprotein(a) concentrations. Journal of Clinical Investigation, 90(1), 52–60.
• Burgess, S. et al. (2018). Association of LPA variants with risk of coronary disease and the implications for lipoprotein(a)-lowering therapies: a Mendelian randomization analysis. JAMA Cardiology, 3(7), 619–627.
• Ference, B.A. et al. (2017). Low-density lipoproteins cause atherosclerotic cardiovascular disease: EAS Consensus Panel. European Heart Journal, 38(32), 2459–2472.
• Future Cardiology (2025). Current opinions on the role of apolipoprotein B in the clinical management of cardiovascular risk. Future Cardiology, 21(12), 987–989.
• Khan, S.U. et al. (2020). Association of lowering apolipoprotein B with cardiovascular outcomes: systematic review and meta-analysis. European Journal of Preventive Cardiology.
• Koschinsky, M.L. et al. (2024). A focused update to the 2019 NLA scientific statement on use of lipoprotein(a) in clinical practice. Journal of Clinical Lipidology, 18(3), e308–e319.
• Mann, S. et al. (2014). Differential effects of aerobic exercise, resistance training and combined exercise modalities on cholesterol and the lipid profile: review, synthesis and recommendations. Sports Medicine, 44(2), 211–221.
• Mensink, R.P. (2016). Effects of saturated fatty acids on serum lipids and lipoproteins: a systematic review and regression analysis. WHO Technical Report.
• Morze, J. et al. (2025). ApoB-containing lipoproteins: count, type, size, and risk of coronary artery disease. European Heart Journal, 46(27), 2691–2701.
• NLA Expert Clinical Consensus (2024). Role of apolipoprotein B in the clinical management of cardiovascular risk in adults. Journal of Clinical Lipidology, 18(5), e619–e648.
• Patrick, R. & Attia, P. (2024). The INSANE longevity benefits of low ApoB. FoundMyFitness.
• Sabatine, M.S. et al. (2017). Evolocumab and clinical outcomes in patients with cardiovascular disease. New England Journal of Medicine, 376(18), 1713–1722.
• Sacks, F.M. et al. (2017). Dietary fats and cardiovascular disease: a presidential advisory from the American Heart Association. Circulation, 136(3), e1–e23.
• Sniderman, A.D. et al. (2025). ApoB, LDL-C, and non-HDL-C as markers of cardiovascular risk: a systematic review of discordance studies. Journal of Clinical Lipidology. (15 studies, 593,354 participants).
• Tasdighi, E. et al. (2024). Lp(a): structure, genetics, associated cardiovascular risk, and emerging therapeutics. Annual Review of Pharmacology and Toxicology, 64, 135–157.
• Voight, B.F. et al. (2012). Plasma HDL cholesterol and risk of myocardial infarction: a Mendelian randomization study. The Lancet, 380(9841), 572–580.
• Walldius, G. & Jungner, I. (2025). High apoB/apoA-1 ratio is a strong risk predictor of MACE: a review basis for updating guidelines. Expert Review of Cardiovascular Therapy.
• Wang, Y. & Xu, D. (2017). Effects of aerobic exercise on lipids and lipoproteins. Lipids in Health and Disease, 16, 132.
• Wilkins, J.T. et al. (2016). Discordance between apolipoprotein B and LDL-cholesterol in young adults predicts coronary artery calcification: the CARDIA Study. Journal of the American College of Cardiology, 67(2), 193–201.