Adding an avocado to your daily diet helps lower bad cholesterol and reduce the risk of heart disease, a study says.

"Including one avocado each day as part of a moderate-fat, cholesterol-lowering diet provides additional LDL (bad cholesterol) lowering affects which benefit CVD (cardiovascular disease) risk," said Penny Kris-Etherton, professor at Pennsylvania State University.

Known to have originated in Mexico and Central America, avocado is cultivated in a very limited scale in Tamil Nadu, Kerala, Maharashtra, Karnataka in the south-central India and in the eastern Himalayan state Sikkim.

Avocados are known to be a nutrient-dense food, high in monounsaturated fatty acids. Previous studies have suggested that avocados are a cholesterol-lowering food, but this is the first study to look at health implications of avocados beyond monounsaturated fatty acids, the researchers added.

For the study, the researchers tested three different diets, all designed to lower cholesterol: a lower-fat diet, consisting of 24 percent fat, and two moderate fat diets, with 34 percent fat.

The moderate fat diets were nearly identical, however, one diet incorporated one Hass avocado every day while the other used a comparable amount of high oleic acid oils - such as olive oil - to match the fatty acid content of one avocado.

The researchers tested the diets with 45 healthy, overweight adults between the ages of 21 and 70. All participants followed each of the three diets for five weeks.

The avocado diet decreased bad cholesterol by 13.5 mg/dL ( milligram per per decilitre), while LDL was decreased by 8.3 mg/dL on the moderate-fat diet and by 7.4 mg/dL on the low-fat diet.

The study was published in the Journal of the American Heart Association.