Apolipoprotein A (APOA)

What Is Apolipoprotein A (APOA)?

Apolipoproteins are an important component of lipoproteins whose main role is transporting fats. Apolipoprotein A can be measured to determine an individual’s risk for developing cardiovascular disease, especially if they have a family history of heart disease or high blood fat (hyperlipidaemia)^[1].

As the major protein component of HDL, often referred to as “good” cholesterol, APOA is essential for helping the body to manage and transport fats. It supports reverse cholesterol transport, where cholesterol is carried away from the arteries and back to the liver for excretion^[2]. Its important role in removing bad cholesterol from the body means that APOA can protect against cardiovascular disease^[3].

Why Is APOA Important?

APOA is critical for maintaining cholesterol balance and protecting against the development of heart disease. Its role in reverse cholesterol transport ensures that excess cholesterol is removed from the blood, lowering the risk of fatty deposits or plaque building up on the artery walls, which contribute to the development of atherosclerosis, a condition caused by the narrowing and hardening of the arteries because of these fatty deposits.

Research shows that an increased level of APOA is linked to a reduced cardiovascular risk^[4]. A study published in Circulation found that an increased level of APOA was associated with a reduced risk of cardiovascular events among statin-treated patients and in people achieving reduced low-density lipoprotein (LDL) or “bad” cholesterol levels^[4]. This is because HDL cholesterol which contains APOA clears cholesterol from the arteries, stopping blockages from occurring that can cause heart attacks and strokes.

So, low levels of APOA are associated with low levels of good cholesterol and poor removal of excess cholesterol from the body.

APOA can also be measured alongside apolipoprotein B to give you an APOB: APOA ratio. The ratio gives you an insight into how balanced your apolipoproteins are. For example, a higher ratio where APOB levels are higher than APOA levels, indicates you are at an increased risk of heart disease^[5].

APOA also has potent anti-inflammatory and antioxidant properties which also has major benefits for the cardiovascular system. For example, APOA reduces oxidative stress and inflammation in the arteries which

• maintains healthy blood vessels by promoting vasodilation (widening of the blood vessels)
• encourages blood flow and lowering blood pressure
• prevents damage linked to cardiovascular complications and heart disease^[3]

How Is APOA Measured?

APOA levels can be measured using a blood test, measuring the concentration of APOA-I, the most common form of apolipoprotein A, in the blood. However, it is not a routine test and is usually carried out by hospital specialists or specialist test laboratories. It’s usually used if you have a family history of hyperlipidaemia or a family history of coronary heart disease or peripheral vascular disease, helping your doctor to assess your risk of developing heart disease.

Normal APOA levels can depend on several factors such as age, sex, and general health. However, typical reference ranges are as follows:

What Do APOA Results Mean?

Low APOA levels

Several factors can contribute to low APOA levels, including:

• Genetic conditions such as hypoalphalipoproteinemia which disrupts HDL production^[7] or genetic mutations in APOA-1 gene, increasing the risk of heart disease^[8].
• Lifestyle choices like smoking^[9] and obesity^[10] can result in low APOA levels.
• Chronic medical conditions including liver disease, kidney disease, and diabetes can also affect APOA levels.

Individuals with genetic conditions that lead to low APOA levels, usually have high levels of fat in their blood, including LDL cholesterol which can accelerate the development of atherosclerosis, raising the risk of cardiovascular events such as heart attacks and strokes^[5].

High APOA levels

High APOA levels are typically linked to a lower risk of heart disease and may be beneficial. High levels are rarely a cause for concern, but there are certain factors which may increase APOA, such as:

• Familial hyperalphalipoproteinaemia
• Pregnancy
• Weight loss
• Certain medications – carbamazepine, oestrogens, phenytoin, and statins

So, high levels of APOA may not provide additional cardiovascular protection and can be associated with genetic conditions, such as familial hyperalphalipoproteinaemia. Therefore, it may be necessary to interpret your blood test results with other lipid biomarkers to better understand your APOA levels.

How to Improve APOA Levels?

By maintaining healthy APOA levels, you’ll be promoting good heart health and reducing your risk of developing cardiovascular disease, including coronary artery disease.

Here are some of the ways you can help improve your APOA levels.

1. Exercise regularly

Regular exercise can have a beneficial effect on your HDL, LDL cholesterol, and APOA levels. Research shows that moderate-intensity exercise can raise APOA-1 levels by 11.6% and reduce LDL cholesterol levels by 7.2%^[11].

Try to aim for at least 150 minutes of moderate-intensity exercise every week, like brisk walking, swimming, cycling, or even gardening^[12].

2. Eat a heart-healthy diet

Diets that are low in saturated fat can help improve your APOA levels. For example, the Mediterranean diet is famous for its beneficial effects on heart health because of its high monounsaturated fat content and low saturated fat, meat, and dairy content^[13].

Although you may not necessarily need to comply to a full Mediterranean style diet, there are things you can do to improve your cholesterol balance, such as focusing on:

• Healthy fats – incorporate unsaturated fat sources into your diet, like olive oil, avocados, oily fish (mackerel, salmon, sardines, herring), and nuts and seeds.
• Fruits and vegetables – minimally processed natural foods like fruit and vegetables are a rich source of fibre and provide the essential vitamins and minerals your body needs as well as vital antioxidants that support heart health.
• Whole grains – choose foods like oats, quinoa, brown rice, and wholewheat pasta which can help keep you feeling satisfied for longer and manage your cholesterol levels.

3. Quit smoking

Smoking can have a negative effect on your HDL cholesterol levels, leading to reduced APOA. Research shows that smoking lowers APOA-I and APOA-22 levels and increases the APOB: APOA ratio, contributing to a higher cardiovascular risk in smokers^[14]. Therefore, quitting will improve your HDL and APOA levels, lowering your risk of heart disease.

4. Lose weight

People who have a lower body mass index (BMI) generally have higher APOA levels^[15]. So, maintaining a healthy weight can have a positive impact on your lipid profile and cardiovascular risk.

Exercise induced weight loss can significantly increase APOA levels which is largely associated with the metabolic effects of losing weight. However, the research found that APOA levels were significantly increased in people who were attempting to lose weight using diet alone^[16].

Lowering your body weight through a combination of diet and exercise is preferred and can improve HDL cholesterol levels, and support better reverse cholesterol transport. You can improve your weight loss journey by:

• making healthy diet swaps and ensuring your calorie intake is balanced with your energy output
• avoiding crash or fad diets and focusing on long-term healthy lifestyle changes
• combining a mixture of cardiovascular and strength training exercises to encourage muscle building and fat burning

Maintaining a healthy weight has several other benefits for your health, including an improved mood, lower blood pressure, better blood sugar control, and lower levels of inflammation.

5. Get a good night’s sleep

Not getting enough sleep has been linked to many risk factors known to impact heart health, including obesity, diabetes, high blood pressure, and high blood fats. It is also linked to a higher APOB:APOA1 ratio^[17].

By improving your sleep hygiene practices, you’ll be promoting better sleep which could prevent heart disease and improve your apolipoprotein profile. Consider things like:

• creating a routine by going to bed at the same time each night and waking up at the same time each morning, even at weekends and on days off
• avoiding caffeine, alcohol, and nicotine in the evening
• creating a comfortable sleep environment that’s clean, cool, dark, and quiet
• winding down before bed by taking a bath or shower, listening to relaxing music, or avoiding screens at least 30 minutes before going to bed
• avoiding napping for longer than an hour or late in the day which can disrupt your nightly routine

6. Avoid alcohol

Long-term alcohol consumption can lower APOA levels in your blood and can impair the function of HDL cholesterol^[18].

Although there is no completely safe level of alcohol, keeping your consumption within the guidelines of no more than 14 units per week, spread across at least 3 days can lower the risk of harm to your health^[19].

Written by Leanne Edermaniger

Based in the UK, Leanne specialises in writing about health, medicine, nutrition, and fitness.

She has over 5 years of experience in writing about health and lifestyle and has a BSc (hons) Biomedical Science and an MSc Science, Communication and Society.