Normal cholesterol, but an increased risk? The ApoB marker may reveal what standard tests miss

Many people get good results from a standard lipid profile and are left with the impression that their risk of cardiovascular disease is low. However, a growing body of scientific evidence suggests that normal LDL cholesterol levels do not always indicate a low risk of atherosclerosis, heart attack or stroke.

The reason is that traditional tests measure the amount of cholesterol in the blood, but not the number of particles that carry it.

It is here that a relatively little-used but extremely valuable marker appears – apolipoprotein B (ApoB).

What is ApoB?

ApoB is a protein found on all atherogenic lipoproteins – the particles that can penetrate the arterial wall and contribute to the formation of atherosclerotic plaques.

It appears in:

• LDL (low-density lipoproteins);
• VLDL (very low-density lipoproteins);
• IDL (intermediate lipoproteins);
• lipoprotein(a).

Each of these particles contains exactly one ApoB molecule.

Consequently, measuring ApoB provides direct information on the number of potentially dangerous particles in the bloodstream.

Why doesn’t LDL tell the whole story?

For decades, LDL cholesterol has been the main indicator used to assess cardiovascular risk.

The problem is that two different people may have the same LDL cholesterol level, but a radically different number of LDL particles.

For example:

• Person A has fewer, but larger, LDL particles;
• Person B has many more, but smaller, LDL particles.

Although the LDL level may be the same, the second person has more particles that can penetrate the vessel wall and stimulate the formation of plaques.

This phenomenon is known as discordance between LDL and ApoB.

In such cases, a standard lipid profile may give a false sense of security.

What do the latest studies show?

New analyses published in JAMA Network и JAMA Network Open, have been tracking tens of thousands of participants over a period of years.

The main conclusions are:

• Higher levels of ApoB are associated with a higher risk of heart attack and stroke.
• ApoB is a better predictor of future cardiovascular risk than LDL cholesterol.
• Using ApoB to guide treatment may prevent more cardiovascular events.
• The marker is particularly useful for young people, for whom traditional risk calculators often underestimate the actual risk.

The results for the 18–39 age group are particularly impressive.

In these individuals, an increase in ApoB is associated with an approximately 53% higher risk of developing atherosclerotic cardiovascular disease in the future.

This suggests that atherosclerosis may begin decades before the first symptoms appear.

For which people is ApoB most beneficial?

Testing for ApoB can be particularly informative in the following cases:

• a family history of early-onset cardiovascular disease;
• obesity;
• insulin resistance;
• prediabetes and type 2 diabetes;
• non-alcoholic fatty liver disease (NAFLD);
• metabolic syndrome;
• high triglyceride levels;
• polycystic ovary syndrome (PCOS);
• Normal LDL, but a suspected increased risk of cardiovascular disease.

In such cases, ApoB may provide additional information that is not included in the standard lipid profile.

What does this mean for our diet?

Whether or not a person is taking medication, diet remains a key tool for reducing the number of atherogenic particles.

It is important to emphasise that ApoB responds not only to the amount of fat in the diet, but also to the body’s overall metabolic state.

Dietary strategies that may lower ApoB

1. More soluble fibre

Soluble fibre reduces the absorption of cholesterol and helps to eliminate bile acids.

Good sources include:

• oats;
• barley;
• pulses;
• linseed;
• chia;
• fruit;
• vegetables.

2. Replacing saturated fats with unsaturated fats

Useful sources include:

• extra virgin olive oil;
• nuts;
• seeds;
• avocado;
• oily fish.

This strategy often leads to a reduction in both LDL and ApoB.

3. Weight management

Even a moderate weight loss of 5–10% can improve the lipid profile and reduce the number of atherogenic particles.

4. Limiting ultra-processed foods

Diets high in refined carbohydrates, sugar and ultra-processed foods stimulate the production of VLDL particles and may increase ApoB levels.

5. The Mediterranean diet

It is the Mediterranean diet that offers the strongest evidence of improving the lipid profile and reducing cardiovascular risk.

It includes:

• an abundance of vegetables;
• fruit;
• pulses;
• wholemeal foods;
• olive oil;
• fish;
• limited amounts of ultra-processed foods.

What are the optimal values?

Although reference ranges vary between laboratories, an increasing number of experts recommend:

• below 90 mg/dL for most people;
• below 80 mg/dL in cases of increased risk;
• below 65–70 mg/dL in cases of very high cardiovascular risk.

The assessment must always be carried out on a case-by-case basis and in the context of the other risk factors.

LDL cholesterol remains an important indicator, but it does not always give the full picture.

ApoB measures the actual number of atherogenic lipoproteins and can reveal hidden cardiovascular risk even in people with an apparently normal lipid profile.

For people with a family history of the condition, metabolic disorders, obesity or diabetes, this marker can provide a more accurate assessment of risk and help with earlier prevention.

In the era of personalised medicine, it is not enough to know how much cholesterol is circulating in the blood – it is also important to know how many particles are carrying it.