An avocado a day may be the key to improved diet quality

Eating one avocado per day may improve overall diet quality, according to a team led by researchers in Penn State University’s Department of Nutritional Sciences. Poor diet quality is a risk factor for many diseases, including heart disease, and many American adults have poor diet quality and do not meet key dietary recommendations provided by the Dietary Guidelines for Americans.

This study was led by Kristina Petersen, Associate Professor of Nutritional Sciences, and Penny Kris-Etherton, retired Evan Pugh University Professor of Nutritional Sciences, and recently published in the journal ‘Current Developments in Nutrition’.  The researchers examined how a food-based intervention — one avocado per day — impacts overall diet quality.

“Avocados are a nutrient-dense food, containing a lot of fiber and other important nutrients. We wanted to see if regular intake of this food would lead to an increase in diet quality,” said Petersen. “Previous observational research suggests that avocado consumers have higher diet quality than non-consumers. So, we developed this study to determine if there is a causational link between avocado consumption and overall diet quality.” 

Petersen stated that, because only 2% of American adults are regular avocado consumers, the researchers wanted to determine if including avocados in an individual’s daily diet could significantly increase their diet quality.

Researchers conducted phone interviews with participants before the study began and at a few points throughout to determine what their dietary intake was like in the previous 24 hours and evaluated their diets using the Healthy Eating Index to determine how well they adhered to the Dietary Guidelines for Americans. Adherence to the guidelines was used as a measure of overall diet quality.

The study consisted of 1,008 participants who were split into two groups. One group continued their usual diet and limited their avocado intake during the 26-week study, while the other group incorporated one avocado per day into their diet.

“We found that the participants who had an avocado per day significantly increased their adherence to dietary guidelines,” said Petersen. “This suggests that strategies, like eating one avocado per day, can help people to follow dietary guidelines and improve the quality of their diets.”

Although researchers said that they were not surprised to see that eating avocados daily improved diet quality, they had not predicted how participants were able to achieve it.

“We determined that participants were using avocados as a substitute for some foods higher in refined grains and sodium,” said Petersen. “In our study, we classified avocados as a vegetable and did see an increase in vegetable consumption attributed to the avocado intake, but also participants used the avocados to replace some unhealthier options.”

According to Petersen, having poor diet quality substantially increases the risk for conditions like heart disease, type 2 diabetes, kidney disease and many other preventable diseases.

“By improving people’s adherence to dietary guidelines, we can help to reduce their risk of developing these chronic conditions and prolong healthy life expectancy,” said Petersen.

Petersen has also conducted similar studies investigating the impact of food-based interventions, including the relationship between pistachios and diet quality, but said that more research is needed to determine what other food-based strategies can be used to improve people’s adherence to dietary guidelines. 

“In studies like this one, we are able to determine food-based ways to improve diet quality, but behavioral strategies are also needed to help people adhere to dietary guidelines and reduce their risk of chronic disease,” said Petersen.

Other contributors to the study include Sydney Smith and David M. Reboussin, Wake Forest University School of Medicine; Alice H. Lichtenstein and Nirupa R. Matthan, Tufts University; Zhaoping Li, David Geffen School of Medicine at the University of California, Los Angeles; and Joan Sabate, Sujatha Rajaram and Gina Segovia-Siapco, Loma Linda University. 

The Avocado Nutrition Center supported this study. The funder did not influence the data analysis, data interpretation or writing of the published study.