Apolipoprotein B (ApoB) is the primary protein in lipoproteins that transport fats, like cholesterol, through the blood. It is the main structural protein in low-density lipoprotein (LDL) particles, often called “bad” cholesterol. These ApoB-containing particles can become trapped in artery walls, contributing to plaque formation (atherosclerosis), which narrows arteries and increases the risk of heart attacks and strokes.
Each potentially harmful lipoprotein particle contains one ApoB molecule, so an ApoB blood test directly counts these particles. This makes ApoB a more accurate indicator of cardiovascular risk than standard LDL cholesterol (LDL-C) tests. An ApoB test can identify risk even when LDL-C levels are normal but particle numbers are high, offering a clearer picture of cardiovascular health.
Lifestyle and Dietary Approaches
Managing ApoB levels starts with dietary changes, focusing on fat intake. Reducing saturated and trans fats, commonly found in red meat, full-fat dairy, and commercially baked goods, is recommended. Replacing these with unsaturated fats from sources like avocados, nuts, and olive oil can help lower the concentration of ApoB particles by improving how the liver processes these lipoproteins.
Increasing the consumption of soluble fiber is another effective strategy. This type of fiber forms a gel in the digestive tract that binds to cholesterol and its precursors, preventing their absorption and facilitating their excretion. This action lowers both LDL and ApoB levels. Foods rich in soluble fiber include:
- Oats
- Barley
- Apples
- Citrus fruits
- Beans
Plant-based compounds known as sterols and stanols can also contribute to lower ApoB. These substances are naturally present in fruits, vegetables, and whole grains, and are often added to fortified foods like certain margarines and yogurts. Plant sterols and stanols have a structure similar to cholesterol and work by blocking its absorption in the small intestine, which helps reduce the number of ApoB-containing particles in the body.
Regular physical activity complements these dietary changes. Aerobic exercise, such as brisk walking or swimming, for at least 150 minutes per week can improve the lipid profile. Exercise stimulates enzymes that help move LDL from the blood to the liver for conversion into bile and excretion. This process lowers ApoB and supports overall cardiovascular health by improving heart function and maintaining a healthy weight.
Commonly Prescribed Medications
When lifestyle modifications are not sufficient to reach target ApoB levels, medications are often prescribed. Statins are the most frequently used class of drugs, working primarily in the liver to block an enzyme called HMG-CoA reductase, which is necessary for cholesterol production. By inhibiting this enzyme, statins reduce the liver’s cholesterol output.
With less cholesterol being made, liver cells respond by increasing the number of LDL receptors on their surfaces. These receptors are responsible for pulling LDL particles—and their associated ApoB—out of the bloodstream. This enhanced clearance of circulating particles leads to a direct reduction in plasma ApoB concentrations, making statins a first-line treatment.
Ezetimibe functions differently, working in the small intestine to inhibit the absorption of cholesterol from both diet and bile. By blocking a specific transporter protein, it reduces the amount of cholesterol delivered to the liver. This prompts the liver to pull more cholesterol from the circulation, effectively lowering ApoB levels. Ezetimibe is often prescribed with a statin or as an alternative for individuals who cannot tolerate them.
For patients who experience muscle-related side effects from statins, bempedoic acid offers another option. It also works in the liver to reduce cholesterol synthesis but acts on an enzyme earlier in the pathway called ATP-citrate lyase. Bempedoic acid is a prodrug that becomes activated only within the liver, which is thought to reduce the likelihood of muscle-related side effects.
Advanced and Emerging Therapies
For individuals with genetic conditions like familial hypercholesterolemia or those who cannot reach ApoB goals with standard medications, advanced therapies are available. PCSK9 inhibitors are a class of injectable medications that target a protein called proprotein convertase subtilisin/kexin type 9. This protein normally degrades the LDL receptors on liver cells that clear LDL particles from the blood.
By blocking the action of PCSK9, these inhibitors prevent the degradation of LDL receptors. This results in a higher number of active receptors on the liver, increasing its ability to remove LDL and its associated ApoB from circulation. These drugs are administered via self-injection every two to four weeks and can lead to substantial reductions in ApoB levels.
A newer approach involves small interfering RNA (siRNA) therapy, with inclisiran as a primary example. This treatment uses RNA interference to lower ApoB levels by targeting and degrading the messenger RNA (mRNA) that carries instructions for making the PCSK9 protein inside liver cells. By “silencing” the gene, inclisiran prevents the protein from being made.
This leads to a sustained increase in LDL receptor availability and a potent, long-lasting reduction in ApoB. A primary advantage of this therapy is its infrequent dosing schedule. It requires administration by a healthcare professional just twice a year after an initial starting phase, offering a convenient option for long-term management.
Developing a Personalized Treatment Plan
The management of elevated Apolipoprotein B requires a tailored strategy developed in partnership with a healthcare provider. The initial step is a thorough assessment of the person’s overall cardiovascular risk. This considers their ApoB level, other lipid measurements, family history, and the presence of conditions like hypertension or diabetes.
Based on this evaluation, a personalized treatment plan is developed that integrates lifestyle recommendations with an appropriate selection of medications. For someone with mildly elevated ApoB and low overall risk, intensive lifestyle changes may be the primary focus. In contrast, an individual with very high ApoB or established cardiovascular disease will likely require a combination of diet, exercise, and medication.
Ongoing monitoring is an important part of any treatment plan. Regular blood tests are used to track ApoB levels and assess the effectiveness of the chosen interventions. These results allow the healthcare provider to make informed adjustments, such as modifying medication dosages or adding a new therapy. This ensures the individual reaches and maintains their target ApoB goal.