According to Peter Attia, if every person reduced their ApoB to 20-30 mg/dL in their 20s, heart disease would be eliminated.
The statement is hyperbolic, but shows how the approach to lipid management is changing. In 2019, the European Society of Cardiology concluded that ApoB is a more accurate marker of cardiovascular risk than LDL-C. In 2021, the Canadian Cardiovascular Society recommended ApoB over LDL-C as the primary metric for lipid management. ApoB has become the gold standard of cardiovascular risk.
The U.S., however, still lags behind. Less than 1% of the insured population gets their ApoB tested each year.
The rest of this post will explain why ApoB is widely considered the best lipid marker of cardiovascular risk, and why getting more people tested can help save lives.
What is the ApoB blood test?
ApoB stands for Apolipoprotein B.
Lipoproteins are molecules in your blood made of fats (e.g. cholesterol, triglycerides) and proteins. They’re critical for many physiological processes, like hormone production, bile acid synthesis, and cell membrane formation.
However, at excess quantities, some lipoproteins are atherogenic—meaning they can enter your arterial walls, form plaques, and cause heart attacks.
Source: Cleveland Clinic
There are four main atherogenic lipoproteins:
| Lipoprotein | Function | Size |
|---|---|---|
| vLDL: Very Low-Density Lipoprotein | Triglyceride transport | Large |
| IDL: Intermediate-Density Lipoprotein | Intermediate LDL precursor | Medium |
| LDL: Low-Density Lipoprotein | Deliver cholesterol to cells | Small |
| Lipoprotein(a) | Deliver cholesterol to cells | Small |
An apolipoprotein is a protein wrapper around a lipoprotein that helps makes it soluble in plasma, maintains its structure, and helps with binding during tissue uptake. Apolipoprotein B (ApoB) is the only one found on all four atherogenic lipoproteins—exactly one per particle.
The unit of measure for an ApoB blood test is mg/dL, the total mass of ApoB molecules in one deciliter of your blood.
Limitations of standard lipid panels
A standard lipid panel in the U.S. includes:
- Total cholesterol
- HDL
- Triglycerides
- LDL-C
- Cholesterol/HDLC Ratio
- LDL/HDL Ratio
- Non HDL Cholesterol
You’ll notice it doesn’t include ApoB. One reason for this is increased cost vs. other countries, but the end result is that treatment for high cholesterol is mostly based on LDL-C in the U.S.
As mentioned in a previous post about predicting your risk of a heart attack, the LDL-C value on your lipid panel is not measured directly, it’s estimated using the Friedewald equation:
LDL-C = Total Cholesterol - HDL Cholesterol - (Triglyceride / 5)Your LDL-C (LDL-calculated) estimates the mass of cholesterol carried by LDL particles in one deciliter of blood. There are several limitations to this estimate:
- Inaccurate at high and low triglyceride levels (> 400 mg/dL or <100 mg/dL)
- Assumes that the ratio of Triglycerides to vLDL cholesterol is 5:1, which isn’t always true
- Ignores cholesterol carried by other atherogenic particles: vLDL, IDL, and Lipoprotein(a)
ApoB vs LDL-C
It’s now believed that the number of atherogenic particles is a better predictor of cardiovascular risk than the cholesterol inside LDL particles. Even cholesterol-poor LDL particles can be harmful when there are many of them, so LDL-C can be an incomplete measure.
Since each atherogenic lipoprotein has exactly one ApoB molecule, measuring ApoB provides a direct count of atherogenic particles, and is therefore considered a more accurate measure of cardiovascular risk. More particles = more chances to enter artery walls = higher risk of a blockage.
When ApoB and LDL-C disagree
ApoB, LDL-C, and non-HDL cholesterol are often aligned, but discordance has been found in many scenarios. For example:
- 51% of patients with metabolic syndrome had high LDL-C but normal ApoB (2021 study)
- Men, Hispanics, older patients, statin users, and patients with high triglycerides or high BMI showed more discordance (2024 study)
- 20% of women had discordance in this 2017 study
In young adults, the 2016 CARDIA study quantified the value of ApoB over LDL-C when they diverge. It assessed long-term cardiovascular risk by measuring standard lipid panels and ApoB levels in adults aged 18–30, then evaluating coronary artery calcification (CAC)—a marker of plaque buildup—via CT scan 25 years later. It found that young adults with high ApoB and normal LDL-C had 55% higher odds of developing CAC in the future, but those with high LDL-C and normal ApoB did not show a statistically significant increase in CAC risk.
In other words—although LDL-C and ApoB are often aligned, when they are not, ApoB is a superior predictor of heart disease risk.
Source: “Discordance Between Apolipoprotein B and LDL-Cholesterol in Young Adults Predicts Coronary Artery Calcification: The CARDIA Study”, Wilkins et al.
How to lower your ApoB naturally
The good news is that you can reduce your ApoB through nutrition:
- Increase soluble fiber
- Reduce saturated fat
(Surprisingly, dietary cholesterol does not have a strong effect on the number of atherogenic particles for most people.)
The mechanism for how your diet affects your ApoB is related to cholesterol metabolism. Your liver extracts ApoB-containing lipoproteins from your blood and uses them to create bile acid. During digestion, these bile acids are secreted into your gut to help break down fats. 95% of bile acids are then reabsorbed so they can be reused.
Eating soluble fiber disrupts this cycle. In the gut, soluble fiber absorbs water and thickens into a gel. This gel physically traps bile acid, prevents it from being reabsorbed back to your liver, and it gets excreted. Your liver then senses less bile acid, so it breaks down more ApoB-containing lipoproteins from your blood to replenish.
Eating saturated fat has the opposite effect. Saturated fats are broken down and absorbed in the gut before reaching the liver. This causes the liver to increase production of vLDL (and eventually LDL) and also reduce the clearing of atherogenic lipoproteins from the blood.
How to lower your ApoB with medication
The primary medications to reduce ApoB are statins. Statins decrease your liver’s synthesis of cholesterol and increase your liver’s removal of LDL particles from the blood. The most common is Atorvastatin (Lipitor), with over 100 million prescriptions filled in the U.S. each year. Statins are remarkably effective, with severe patients seeing a 20-40% reduction in ApoB in just a few months, inexpensive (~$5/mo), and safe, with the most common side effect (muscle pain) occurring in <1% of patients.
How can you get your ApoB measured?
Empirical Health’s advanced cardiovascular panel includes ApoB testing, along with a complete lipid panel, and Lipoprotein(a), which is an atherogenic lipoprotein primarily determined by genetics.
ApoB test cost
The entire advanced cardiovascular panel includes 55 biomarkers for $175.
Testing can be completed in a single blood draw at one of 2,000 locations nationwide, and most results come back within a couple days. Within the Empirical Health app for iPhone and Android, you can take several steps to improve your biomarkers:
- Review your results with and MD
- Discuss and start any new medications
- Get a customizable nutrition and exercise plan
