Can an avocado a day lower cardiometabolic disease risk?

In this 26-week, multi-center, randomized controlled trial, researchers studied 1,008 participants aged 25 and older with abdominal obesity and typically low avocado intake.

Participants were divided into two groups. One group was provided with a daily supply of one avocado (approximately 168 grams) and received guidance on how to include it in their daily diet. The other (control) group, was asked to maintain their usual dietary habits, limiting their avocado consumption to two or fewer per month, and received no dietary counseling.

Diet quality was evaluated through unannounced 24-hour recalls at various intervals during the study, and scored with the Healthy Eating Index-2015 (HEI-2015) to measure adherence to dietary guidelines.

As per the USDA’s classification, this clinical trial considered avocado servings — one-half cup chopped or approximately 75 grams — as part of the total vegetable component in the HEI-2015 scores.

The participants’ cardiometabolic disease risk factors, including visceral fat volume, liver fat fraction, C-reactive protein, metabolic syndrome criteria, body weight, body mass index (BMI), insulin, VLDL cholesterol, and the total cholesterol to HDL cholesterol ratio, were also monitored to understand the effects of daily avocado consumption on these factors.

During the study, researchers found that individuals who consumed avocados daily showed a “potentially clinically relevant” increase of 4.74 points in their HEI-2015 scores compared to the control group that consumed their regular diet.

This improvement was mainly attributed to an increase in total vegetable intake and a more favorable ratio of unsaturated to saturated fats, both of which were directly related to daily avocado consumption.

In comparison to the control group, individuals who consumed avocados daily did not show any significant difference in their intake of saturated or polyunsaturated fats.

However, their consumption of monounsaturated fatty acids (MUFAs) increased by 13 grams per day, which was almost equivalent to the MUFA content of the avocados provided to them (17 grams).

Despite an overall increased adherence to the dietary guidelines with daily avocado consumption, these dietary improvements did not lead to significant changes in cardiometabolic disease risk factors over the 26-week period, the study authors found.

Studies have consistently shown that enhancing the quality of the diet over time leads to a lower risk of cardiometabolic diseases and mortality.

The authors of the present study proposed two explanations for why their findings did not align with the scientific consensus on diet quality and disease risk.

First, the intervention period of 26 weeks may have been too short to change these risk factors significantly.

Second, the study participants’ initial diet scores were poor and slightly below average. So, despite a notable improvement in diet quality, the follow-up diet scores still received an “F,” the lowest grade.

Therefore, it is unlikely that the overall diet quality was high enough to have a significant impact on cardiometabolic risk factors.

According to Alyssa Simpson, registered dietitian and owner of Nutrition Resolution, not involved in the study, further limitations arose from the study’s non-blinded design, potential biases associated with self-reported dietary intake, and restricted generalizability.

Considering the methodology and avocados’ nutritional composition, it’s not surprising that avocado consumption was found to enhance diet quality scores, especially in terms of total vegetable and fatty acid components.

“Avocados are rich in monounsaturated fats, fiber, essential nutrients, and phytochemicals that are beneficial for health,” shared Claire Rifkin, a registered dietitian not involved in the study.

Perhaps more interestingly, participants following the avocado-enriched diet exhibited reductions in their consumption of sodium, refined grains, and added sugars compared with those who continued their regular eating patterns.

These changes suggest avocados may have partially replaced foods containing sodium, added sugars, and refined grains in the diet.

Simpson explained that this substitution effect “promotes an overall improvement in diet quality by increasing nutrient-dense foods rich in healthy fats and fiber while decreasing the intake of less nutritious, processed foods.”

In the present study, however, avocado consumption had no effect on the participants’ saturated fat intake. Additionally, avocados replaced small amounts of total protein, seafood, and plant protein components in the diet, the impacts of which were not explored.

Long-term avocado consumption could potentially improve lipid profiles and help regulate blood glucose levels, reducing cardiovascular disease risk and aiding in diabetes prevention and management, Rifkin said.

These effects can be attributed to the high monounsaturated fat and dietary fiber content in avocados.

In general, most adults can benefit from including avocados in their daily diet in moderation.

However, Simpson expressed: “[Promoting] avocados as a singular solution for improving dietary habits may overlook the importance of nutritional diversity, accessibility, and affordability, while also neglecting environmental considerations and cultural dietary preferences.”

Instead, aim to include a variety of nutrient-rich foods to foster a more sustainable and inclusive approach, she said.

For individuals seeking nutritional alternatives to avocados, Simpson and Rifkin recommended incorporating various sources of healthy fats and fiber into their diet. Similar options include nuts and seeds such as:

Some people may need to limit avocado intake

While avocados are nutrient-dense, their high fat content also makes them calorie-dense.

Consuming avocados daily may contribute significantly to caloric intake, so portion size is something to be mindful of for individuals with health-related weight management goals.

Additionally, individuals following a low-FODMAP diet, which is often recommended for managing symptoms of irritable bowel syndrome (IBS), may need to limit avocado consumption to smaller servings.

For those with gastrointestinal conditions requiring limited fiber during symptom-flare-ups, like diverticulitis or ulcerative colitis, avocado intake may also need to be managed according to dietary recommendations from a healthcare professional.

Long-term improvements in diet quality can greatly reduce the risk of chronic conditions such as obesity, heart disease, and type 2 diabetes, potentially leading to a longer and disease-free lifespan.

This research highlights the role that specific foods, such as avocados, can play in diet improvement strategies.

According to Kiran Campbell, a registered dietitian not involved in the study, “[a]dding in one specific healthy food is a good start to a healthy diet.”

However, strategies for promoting adherence to dietary guidelines, improving diet quality, and promoting longevity may need to extend beyond specific food-based interventions.

“Relying solely on one or even a few foods would likely not give you enough varied nutrition to reduce the risk of chronic disease or extend longevity. A comprehensive pattern of eating that includes a wide range of nutrient-dense foods is essential for reducing the risk of chronic disease and living a long health[y] life.”

— Claire Rifkin, registered dietitian

Campbell agreed, suggesting that “[s]peaking with health professionals like registered dietitians can help to individualize a healthy meal plan that works long-term and includes a larger variety of healthy foods to help meet the dietary guidelines.”

Beyond an individual focus on diet quality, Rifkin stressed the importance of addressing systemic factors, including:

• corporate marketing of unhealthy foods
• lack of government incentives for healthier options
• food inequities and insecurities

Such a transition is crucial for achieving significant and widespread improvements in diet quality and disease risk — increasing longevity across populations.