- Plant-based eating patterns have been shown to lower the risk of mortality compared to animal-based eating patterns.
- A new study found that eating more plant fats could lower the risk of dying from any cause and the risk of dying from heart disease.
- The findings suggest that this may be due, in part, to the types and sources of dietary fat consumed, with plant fats being more beneficial than animal fats for lowering mortality risk.
- More research is needed to fully understand the mechanisms behind these associations, but experts recommend following a diet rich in minimally processed plant foods for the best health outcomes.
A recent study of over 400,000 adults followed for more than two decades suggests that obtaining more dietary fats from plants rather than animals may benefit longevity.
The findings are published in JAMA Internal Medicine.
Compared to those eating the lowest amounts of plant-based fats, those eating the highest amounts, especially from grains and vegetable oils, had a 9% lower risk of dying from any cause and a 14% lower risk of dying from heart disease.
On the other hand, getting more fats from animal sources, like meat, dairy, and eggs, was associated with higher mortality risks. Those eating the most animal fats had a 16% higher risk of overall mortality and a 14% higher risk of dying from heart disease.
However, the study had several limitations, and the authors noted that the “effect sizes of the observed risk estimates were small.” This means the findings may not have much practical use in real-world settings, so more research is needed to confirm these results.
In this large prospective cohort study, researchers aimed to determine if the type of fat consumed — whether from animal sources or plant sources — affects overall and heart disease-specific mortality rates in the United States.
From February 2021 to May 2024, they examined data from the National Institutes of Health (NIH)-AARP Diet and Health Study, which gathered information from U.S. participants between 1995 and 2019.
The NIH-AARP researchers collected various information through questionnaires covering demographics, lifestyle, and eating habits, including participants’ sources of dietary fat.
They utilized the National Cancer Institute’s Diet History Questionnaire (DHQ) to gather dietary information and tracked causes of death through records from the Social Security Administration.
The current study’s researchers used this data to divide participants into five categories, or “quintiles.” The top 20% consumed the most plant-based dietary fat daily, while the bottom 20% consumed the least, opting for more animal fat.
To analyze the data, they utilized advanced statistical methods to estimate risk ratios while adjusting for various factors, as well as performing a series of additional analyses and subgroup assessments.
Over the 24-year follow-up period, there were 185,111 deaths, with nearly 32% being from heart disease.
Participants’ median daily intake of dietary fats from animal and plant sources was 29 grams and 25 grams, respectively.
The researchers found that eating more plant-based fats was associated with a lower risk of dying from all causes and heart disease.
Specifically, those in the highest plant-based fat intake group had a 9% lower risk for overall mortality and a 14% lower odds of heart disease mortality compared to those in the lowest group.
Plant-based fats from grains and vegetable oils most notably reduced the chances of all-cause death and death from heart disease.
On the other hand, consuming more animal fats was associated with a higher risk of death.
People in the highest intake group for animal fat had a 16% higher risk of all-cause death and a 14% higher risk of death from heart disease.
Interestingly, dairy and egg fats were identified as animal fats that most significantly influenced overall mortality, surpassing the adverse impact of meat.
The researchers also calculated the potential benefit of switching from animal fats to plant-based fats.
Replacing just 5% of calories from animal fats with an equal amount from plant fats led to a significant decrease in estimated risk—between 4% and 24% for overall mortality and 5% to 30% for heart disease mortality.
Although the results seem promising and align with existing research suggesting plant-based diets better support longevity, the findings stem from an observational study, so they do not establish a direct cause-and-effect relationship.
The study population also lacked diversity, which may limit its generalizability to the broader population.
In addition to these and other limitations, it is important to highlight that the calculation of dietary fat intake was based on self-reported data gathered at the start of the study and may not account for any dietary changes that occurred over the 24-year follow-up.
The study authors also emphasized that the observed associations were “consistent but small,” so the results may have limited practical applications in real life.
Medical News Today spoke with Kiran Campbell, RDN, a registered dietitian who specializes in heart health at Kiran Campbell Nutrition and is a medical nutrition advisor at Dietitian Insights. Campbell was not involved in the study.
Regarding the reasons why plant-based fats might be better for longevity than animal fats, she said that “plant fats have much higher amounts of monounsaturated and polyunsaturated fats than animal fats, which are higher in saturated fat.”
“The study highlights that these plant-based fats may reduce overall mortality and [heart disease-specific] mortality, likely due to their beneficial effects on cholesterol profiles, anti-inflammatory properties, and the overall healthier dietary patterns associated with their consumption,” Thomas M. Holland, MD, MS, a physician-scientist and assistant professor at the RUSH Institute for Healthy Aging, RUSH University, College of Health Sciences, who was not involved in the study, told Medical News Today.
Holland also noted that “red meat and certain animal fats are rich in saturated/trans fats and cholesterol, which can elevate LDL cholesterol levels and contribute to the formation of arterial plaques, leading to heart disease.”
He underscored the significance of recognizing these risks, stating:
“The study’s results are consistent with other research linking high consumption of animal fats, particularly from red meat, eggs, and dairy, to increased health risks. While some animal fats, like those from fish, contain beneficial omega-3 fatty acids, the general recommendation would be to limit red meat and other high-saturated-fat animal products in favor of plant-based fats.”
Various factors could influence the results of this study, including the fact that in real life we consume whole foods in various combinations as part of our meals, not just isolated nutrients.
Dietary fats are just one element of the foods we consume, alongside proteins, carbohydrates, vitamins, minerals, fibers, and various other compounds—some of which are beneficial, while others are potentially harmful.
The researchers did attempt to adjust for participants’ dietary factors like protein (from plants or animals), carbohydrates, fiber, total fruits, and total vegetables, but there are still many influencing factors they could not control for.
For example, Holland said, “The presence of pro-oxidants like heme iron in red meat can also increase oxidative stress and inflammation, further exacerbating cardiovascular risks.”
Campbell agreed, similarly noting, “Red meats have constituents within them, including heme iron [and] other components that may result in negative cardiovascular outcomes and lead to increased mortality.”
On the flip side, she highlighted that plant-based fat sources like grains, oils, nuts, and legumes contain beneficial plant chemicals like “polyphenols and phytosterols, which can help reduce cardiovascular risk factors.”
Ultimately, the complexity of food makes it challenging to pinpoint the specific mortality risks associated with different sources of dietary fat, as well as the underlying reasons for these potential risks.
So, to achieve optimal health outcomes, it’s crucial to consider the overall nutritional value and quality of the foods in your diet, as well as the diet as a whole, rather than solely focusing on individual nutrients.
To this point, Campbell concluded:
“Overall, this study adds to our current dietary recommendations that encourage consuming more plant-based foods over animal products. There are many different guidelines based on specific diets, including the Mediterranean diet, DASH diet, Portfolio diet, OmniHeart diet, and vegan and vegetarian diets, to name a few. However, they all share one similarity: eating more minimally processed or unprocessed plant foods.”
