An avocado a day could keep cholesterol-related heart disease risks at bay, according to the findings of a study published online Jan. 9 in the Journal of the American Heart Association.

The study compared three lipid lowering diets, a lower fat, a moderate fat, and an avocado diet. The low-fat diet replaced 6 to 7 percent of energy consumption from saturated fats with carbohydrates (24 percent fats). The moderate fat and avocado diets replaced the same percentage of saturated fats with monounsaturated fats, either sunflower or canola oil for the moderate fat diet and an avocado a day for the avocado diet (34 percent fats each).

Li Wang, PhD, from the department of nutritional sciences at Pennsylvania State University in University Park, and colleagues enrolled 45 obese or overweight patients. Patients were randomly assigned each of the three diets in turn over the course of five weeks each. Wang et al reviewed blood cholesterol levels at baseline and following each diet.

They found under the avocado diet, low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein (non-HDL) cholesterol dropped 13.5 mg/dL and 14.6 mg/dL, respectively. LDL particles also decreased by 80.1 nmol/L, small dense LDL decreased by 4.1 mg/dL and reduced the ratio of LDL to HDL by 6.6 percent.

LDL reductions were much lower for the moderate fat and lower fat diets; 8.3 mg/dL and 7.4 mg/dL, respectively. Non-HDL was reduced for moderate fat and lower fat diets by 8.7 mg/dL and 4.8 mg/dL, respectively.

Total cholesterol was reduced on the avocado diet by 8 percent and the percentages of LDL to HDL and LDL to total cholesterol by 4.9 percent and 6.6 percent, respectively.

“This was a controlled feeding study, but that is not the real-world -– so it is a proof-of-concept investigation. We need to focus on getting people to eat a heart-healthy diet that includes avocados and other nutrient-rich food sources of better fats,” said Penny M. Kris-Etherton, PhD, RD, senior study author and a distinguished professor of nutrition at Pennsylvania State University, in a press release.

Kris-Etherton noted that avocados are still “not a mainstream food,” however, physicians encouraging patients to consider avocados should remind patients that they “can also be eaten with salads, vegetables, sandwiches, lean protein foods (like chicken or fish) or even whole.”

The study used Hass avocados and was funded by the Hass Avocado Board.

“The effects of the AV [avocado] diet on sdLDL [small, dense LDL] may be due to the combined effects of MUFA (monounsaturated fatty acids) and other bioactives, especially phytosterols and fiber,” wrote Wang et al.

Much like prior studies on bread baked with canola oil and muffins baked with sunflower oil,  this new information on avocados adds another component to potential improved cholesterol diets as a whole. “For individuals who do not lose weight, we have shown that a moderate fat diet high in MUFA, especially from one avocado per day has beneficial effects on lipids/lipoproteins and CVD [cardiovascular disease] risk status,” they wrote.