Eating more vegetable fats can reduce the risk by up to 14%

In this large prospective cohort study, researchers sought to determine whether the type of fat consumed—whether from animal 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 Nutrition and Health Studywhich collected information from US participants between 1995 and 2019.

The NIH-AARP researchers collected various information on demographics, lifestyle and eating habits, including the participants' sources of fat in their diet, through questionnaires.

They used the National Cancer Institute's Diet History Questionnaire (DHQ) to collect dietary data and tracked causes of death using Social Security Administration records.

The researchers in the current study 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 and consumed more animal fat.

To analyze the data, they used advanced statistical methods to estimate risk ratios taking into account various factors. In addition, they conducted a number of additional analyses and subgroup assessments.

During the 24-year observation period, there were 185,111 deaths, of which almost 32% were due to heart disease.

The participants' average daily intake of dietary fat 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 death from all causes and heart disease.

Specifically, those in the group with the highest vegetable fat intake had a 9% lower risk of overall mortality and a 14% lower risk of dying from heart disease than those in the group with the lowest vegetable fat intake.

Vegetable fats from cereals and vegetable oils in particular reduced the risk of all-cause deaths and deaths from heart disease.

On the other hand, consumption of more animal fats was associated with a higher risk of death.

For people in the group with the highest intake of animal fat, the risk of death from all causes was 16% higher and the risk of death from heart disease was 14% higher.

Interestingly, milk and egg fats were found to be the animal fats with the greatest impact on overall mortality, even ahead of the negative impact of meat.

The researchers also calculated the potential benefits of switching from animal fats to vegetable fats.

Replacing just 5% of calories from animal fat with the same amount from vegetable fat resulted in a significant reduction in the estimated risk – between 4% and 24% for all-cause mortality and 5% to 30% for mortality from heart disease.

Although the results appear promising and are consistent with existing research suggesting A plant-based diet contributes better to a long lifeThe results come from an observational study and therefore do not establish a direct cause-and-effect relationship.

Furthermore, the population studied lacked diversity, which may limit the generalizability of the results to the general population.

In addition to these and other limitations, it should be noted that the calculation of dietary fat intake was based on self-reported data collected at baseline and may not take into account dietary changes over the 24-year follow-up.

The study authors also stressed that the observed associations were “consistent but small,” so the results may have limited practical applicability in real life.

Medical news today spoke with Kiran Campbell, RDN, a registered dietitian who specializes in heart health at Kiran Campbell Nutrition and works as a medical dietitian at Dietitian Insights. Campbell was not involved in the study.

As for why plant-based fats may be better for longevity than animal fats, she said that “plant-based fats have a much higher proportion of monounsaturated and polyunsaturated fats than animal fats, which have a higher proportion of saturated fats.”

“The study shows that these vegetable fats can 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 habits associated with their consumption,” said 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. Medical news today.

Holland also pointed out that “red meat and certain animal fats are high in saturated/trans fats and cholesterol, which can increase LDL cholesterol levels and contribute to the formation of hardening of the arteries, which in turn leads to heart disease.”

He stressed the importance of recognising these risks and explained:

“The study's findings are consistent with other research linking high consumption of animal fats, particularly from red meat, eggs and dairy products, to increased health risks. Although some animal fats, such as those from fish, contain beneficial omega-3 fatty acids, the general recommendation is to limit red meat and other animal products high in saturated fats in favor of plant-based fats.”

Several factors could influence the results of this study, including the fact that in real life we ​​consume whole foods in various combinations in our meals rather than just isolated nutrients.

Dietary fat is just one component of the food we eat, along with proteins, carbohydrates, vitamins, minerals, fiber and various other compounds – some of which are beneficial, others potentially harmful.

Although the researchers attempted to account for dietary factors such as protein (plant or animal), carbohydrates, fiber, and the amount of fruit and vegetables consumed by participants, there were still numerous influencing factors that they could not control.

Holland, for example, said: “The presence of pro-oxidants such as Heme iron in red meat can also increase oxidative stress and inflammation, further exacerbating cardiovascular risks.”

Campbell agreed, similarly noting: “Red meat contains components including heme iron [and] other components that can have negative cardiovascular consequences and increased mortality.”

On the other hand, she emphasized that plant-based sources of fat such as grains, oils, nuts and legumes contain beneficial plant chemicals such as “polyphenols and phytosterols, which may help reduce cardiovascular risk factors.”

Ultimately, given the complexity of foods, it is difficult to determine the specific mortality risks associated with different dietary fat sources, as well as the underlying reasons for these potential risks.

Therefore, to achieve optimal health outcomes, it is 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 focusing solely on individual nutrients.

On this point, Campbell concluded:

“Overall, this study complements our current dietary recommendations that encourage eating more plant-based foods than animal products. There are many different guidelines based on specific diets, including the Mediterranean diet, the DASH diet, the Portfolio diet, the OmniHeart diet, and vegan and vegetarian diets, to name a few. However, they all have one thing in common: eating more minimally processed or unprocessed plant-based foods.”