The researchers found that daily avocado consumption was linked to a lower concentration of low-density lipoprotein (LDL) particles in the blood. These particles carry cholesterol throughout the body. The size of the reduction was associated with an estimated 4% decrease in heart disease risk.

“If people want to improve the quality of their diet, making one small change might be a more feasible strategy than attempting to change their entire diet,” said Janhavi Damani, postdoctoral scholar at Penn State and first author of the study. “For people with obesity, including avocados in their daily diet might be a good starting place.”

LDL Particle Count Can Reveal Hidden Heart Risk

LDL particles are not the same measurement as LDL cholesterol, often called “bad cholesterol.” Both are associated with cardiovascular disease, but particle concentration can reveal risk that a standard cholesterol test may not show. The researchers noted that this risk is often greater in people with abdominal obesity.

LDL cholesterol cannot travel through the bloodstream on its own. It must be carried by protein particles. A person with more LDL carrying particles may face a greater risk of heart disease, even when their total amount of LDL cholesterol is the same as someone with fewer particles.

“Imagine two people with the same high levels of LDL cholesterol,” Damani said. “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.”

Smaller LDL particles can more easily enter artery walls and contribute to plaque buildup, Damani explained. Plaque narrows blood vessels and makes them less flexible, increasing the strain on the cardiovascular system.

When the heart must work harder because of exercise, heat, stress or another cause, stiffened blood vessels may be less able to accommodate the increased blood flow. Blood pressure can then rise more sharply, potentially contributing to a cardiac event such as a heart attack.

Testing One Avocado a Day

For the new analysis, the team examined data from 786 participants enrolled in the Habitual Diet and Avocado Trial. The six-month study included adults ages 25 and older.

Men qualified for the study if their waist circumference was greater than 40 inches, while women were eligible if their waist circumference exceeded 35 inches.

Half of the participants were asked to continue their usual diets and physical activity. The remaining participants also maintained their normal routines but received one avocado to eat every day.

Earlier results from the Habitual Diet and Avocado Trial showed that adding a daily avocado did not reduce body weight or waist circumference in people with obesity. However, it appeared to lower LDL cholesterol levels.

Daily Avocados Lowered LDL Particle Levels

For the current study, researchers compared blood samples collected at the beginning and end of the six-month trial.

Among participants assigned to eat one avocado per day, LDL particle concentrations fell by 49 nanomoles per liter. According to the researchers, that change corresponds to an estimated 4% reduction in heart disease risk.

“Four percent is a modest reduction compared with the 14-29% lower heart disease risk associated with improving the overall diet,” Damani said. “However, it is a step in the right direction.”

The improvement in LDL particle levels was consistent across participants. Sex, race, ethnicity, age and body mass index did not significantly affect the likelihood of experiencing the benefit.

The findings suggest that adults with obesity from a wide range of backgrounds could potentially benefit from including avocados in their diets. However, the researchers advised people to speak with a registered dietitian nutritionist or physician for personalized guidance before making dietary changes.

A Benefit Seen in Real World Diets

Previous Penn State research also found that avocado consumption could lower LDL cholesterol and LDL particle levels. In that earlier experiment, however, researchers closely controlled everything the participants ate.

“Penn State researchers demonstrated several years ago that avocado consumption could reduce LDL cholesterol and levels of LDL particles,” said Kristina Petersen, associate professor of nutritional sciences and senior author of this study. “But in that study, the researchers controlled participants’ entire diets throughout the experiment. This study demonstrated benefits in the real world, where people’s diets are much less predictable. In the course of people’s normal lives, avocado consumption still contributes to a healthier diet.”

The latest findings indicate that a single, manageable change may improve one measure of cardiovascular health even when the rest of a person’s diet remains largely unchanged. The benefit was modest and did not lead to weight loss, but the researchers said it could still represent progress toward better heart health.

Penny Kris Etherton, retired Evan Pugh University Professor of Nutritional Sciences at Penn State, also contributed to the research.

Other co-authors include Nirupa Matthan of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University; Zhaoping Li of the David Geffen School of Medicine at University of California, Los Angeles; Joan Sabaté of the School of Public Health at Loma Linda University; and David Reboussin of the Wake Forest University School of Medicine.

The Avocado Nutrition Center supported this research.

Researchers at McMaster University have now identified a biological pathway that could help explain why these muscle symptoms develop. The finding may eventually lead to treatments that make statins easier to tolerate without reducing their important cardiovascular benefits.

Published in Science Advances, the study points to a previously unrecognized interaction between the immune system and muscle cell metabolism. The mechanism appears to contribute to muscle damage caused by statins and challenges earlier ideas about the origins of these side effects.

Why Statin Side Effects Matter

“Statins are among the most effective medications we have for reducing cardiovascular disease risk and preventing early death,” said Jonathan Schertzer, professor in McMaster’s Department of Biochemistry and Biomedical Sciences and senior author of the study.

“Unfortunately, muscle side-effects lead some people to reduce their dose or stop taking the medication altogether. We wanted to understand why this happens and whether it might be possible to separate the side-effects from the benefits.”

An estimated seven to 29 percent of statin users experience muscle-related symptoms. Although the connection between statins and muscle problems has been recognized for years, scientists have not fully understood the biological processes responsible.

Statins Can Disrupt Muscle Cell Energy

The research was led by first authors Nazli Robin and Nicole Barra of the Schertzer Lab at McMaster. Their team found that statins can interfere with the way muscle cells generate energy.

That disruption appears to activate an immune response inside the muscle cells, leading to tissue damage. In experiments involving muscle cells and mouse models, the researchers prevented much of the damage by blocking the immune response.

“One of the most exciting findings of the research is that the mechanism causing muscle side-effects appears to be separate from the mechanism that lowers cholesterol,” said Schertzer. “That suggests it may one day be possible to target the side-effects without interfering with the cardiovascular benefits that make statins so valuable.”

A Surprising Connection Between Immunity and Metabolism

The findings also uncovered an unexpected relationship between metabolism and the immune system. Changes in the way muscle cells processed energy caused the cells to activate their own immune response.

This discovery offers new insight into how inflammation may contribute to medication side effects. It also suggests that scientists could potentially protect muscle tissue by targeting the immune pathway while leaving the cholesterol-lowering effects of statins intact.

More research is needed before the findings can be developed into treatments for patients. Still, the newly identified pathway provides several possible targets for medications designed to prevent statin intolerance.

“These findings give us a clearer understanding of why some patients experience muscle symptoms and provide promising directions for making these important medications safer and more effective in the future,” added Schertzer.

An International Research Collaboration

The project involved researchers from the Centre International de Recherche en Infectiologie (CIRI) in Lyon, France; the Centre for Muscle Research at the University of Melbourne, Australia; the Murdoch Children’s Research Institute and The Royal Children’s Hospital in Australia; York University in Canada; and McMaster’s Department of Pathology and Molecular Medicine.

The research was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).

An international research team led by The University of Manchester analyzed magma from the 2021 Tajogaite eruption on La Palma, Spain. The scientists found that “superheating,” which occurs when magma becomes hotter than the temperature at which crystals remain stable, can postpone crystal formation as the magma moves toward the surface.

Superheating Removes Crystal Seeds

The study, published in Nature Communications, found that intense heat can dissolve tiny existing crystals that normally act as “seeds” for the growth of new crystals.

Superheating also reorganizes the magma at a microscopic level, making its internal structure more uniform and less favorable for new crystals to develop. These changes can affect both the speed at which magma rises and the ease with which volcanic gases escape. Together, those factors can strongly influence whether an eruption produces dramatic lava fountains or a slower release of lava.

The results provide new insight into a long-running scientific question about how magma’s temperature history affects crystallization before and during an eruption.

Lead author, Dr. Barbara Bonechi, Research Associate at The University of Manchester, said: “The history of crystal and bubble growth can dramatically control how a magma erupts; in particular, as more crystals grow, they eventually have a dramatic effect on magma viscosity. Until now, we did not fully understand the dynamics of crystal growth for magmas that received an injection of superheat just before ascent. But using our exciting and newly developed X-ray transparent pressure vessel combined with synchrotron X-ray microtomography, we can actually observe these processes ‘in situ’.”

Recreating Volcanic Conditions in the Laboratory

To investigate the process, the researchers recreated conditions found inside a volcano using magma collected from the Tajogaite eruption. That magma may have been superheated before the eruption and while it was rising through the crust.

At Diamond Light Source, the team used synchrotron X-ray microtomography to watch crystals form inside the magma in real time. They also conducted complementary ex-situ experiments in Prague, which made it possible to observe the samples over longer periods.

Together, the experiments allowed the scientists to follow crystallization under carefully controlled conditions of intense heat and pressure.

Crystal Growth Delayed for More Than Eight Hours

The difference between the samples was striking. Magma that had not been superheated began forming crystals after about 20 minutes.

By comparison, strong superheating prevented crystal formation for more than eight hours.

The researchers used these experimentally measured nucleation delays in numerical models of magma ascent. These simulations were designed to show how magma moves and changes as it travels upward through Earth’s crust.

How Heat Can Change an Eruption

The models indicated that a long delay in crystallization can keep magma relatively fluid, allowing it to rise rapidly toward the surface. This fast-moving magma could help generate dramatic lava fountains.

When crystals begin forming earlier, however, the magma becomes thicker and more viscous. It then rises more slowly, giving volcanic gases additional time to escape and making a gentler, effusive eruption more likely.

The researchers say this newly recognized role of superheating could help volcanologists better interpret monitoring data and improve forecasts of eruption behavior.

Co-author Dr. Margherita Polacci, Senior Lecturer in Volcanology at The University of Manchester, said: “Current volcanic hazard models typically focus on magma chemistry, gas content and pressure changes. This work suggests that pre-eruptive thermal history and crystallization kinetics may also play an important role in controlling magma ascent and eruptive behavior, with implications for volcanic hazard assessment.”