Not beetroot or berries – this surprising fruit could help lower heart disease risk, new study says

Simple changes to your lifestyle make all the difference when trying to be healthier. Whether it's lifting weights to improve strength or lowering your cholesterol with breakfast swaps, every little helps.

New research has shown that eating one avocado a day is associated with a reduced risk of heart disease in people with obesity.

Researchers from the Penn State Department of Nutritional Sciences linked a daily avocado with a lower low-density lipoprotein (LDL) particle concentration in the blood. These are particles that carry cholesterol throughout the body. High cholesterol can lead to blocked blood vessels. This can cause a stroke or heart attack.

In the study, published in the Journal of Clinical Lipidology, the researchers analysed data originally collected from 786 participants in the Habitual Diet and Avocado Trial, a six-month study of adults 25 years and older. Men were eligible for the study if they had a waist circumference greater than 40 inches, and women were eligible if they had a waist circumference greater than 35 inches.

Half of the participants were instructed to maintain their normal diet and activity. The other half were provided with one daily avocado, but otherwise, they followed their normal diet and activity routine.

In the new study, the researchers compared blood samples taken at the beginning and end of the study. They found that levels of LDL particles in the one-avocado-per-day group decreased by 49 nanomoles per litre, which equates to an approximate 4% reduction in heart disease risk.

While this is only a small decrease in risk, eating an avocado is an easy change many people can make to their diets. "Four per cent is a modest reduction compared with the 14% to 29% lower heart disease risk associated with improving the overall diet,” says Janhavi Damani, postdoctoral scholar at Penn State and first author of the study. “However, it is a step in the right direction."

Why may avocados help lower heart disease risk?

Avocados are a fruit rich in monounsaturated (i.e. 'healthy') fats, fibre, and plant compounds that improve cholesterol levels by lowering the number of LDL particles that build up in the body's arteries.

As well as having avocado on its own or in a salad, swapping out fatty dairy products with avocado can have a significant impact on your heart disease risk. A different study in the Journal of the American Heart Association found that eating just a quarter of an avocado instead of butter, egg, and cheese in the same portion size reduced the risk of heart disease by 22%.

What are LDL particles?

You might have heard of ‘bad cholesterol’. This refers to LDL cholesterol. It's found in our bloodstream, but it can’t travel through the body on its own. It has to be carried by LDL protein particles. High levels of both of these are linked to cardiovascular disease, but the particles don't show up on a typical cholesterol test, so looking at them individually can help doctors understand patients' health risk.

The researchers highlighted that this risk is often greater in people with abdominal obesity.

"Imagine two people with the same high levels of LDL cholesterol," Damani explains. "Person A carries their cholesterol in fewer, larger LDL particles, and Person B carries their cholesterol in more, smaller LDL particles. Person B's heart disease risk would be higher because their overall particle count is higher even though a test of their LDL cholesterol would look identical."

In the study, the researchers found improvements in LDL particle levels in all participants, regardless of age, ethnicity, sex or BMI. But results from the first Habitual Diet and Avocado Trial showed that eating an avocado daily didn’t reduce body weight or waist circumference in people with obesity. Other studies have shown that avocados might be linked to a lower Type 2 diabetes risk, and their high potassium content can also help keep normal blood pressure.