A recent study has found that consuming typical amounts of protein—whether from animal or plant sources—is not associated with a higher risk of early death. In fact, the data hints that animal protein may even slightly lower the risk of cancer-related mortality.
While the debate around the health effects of animal-based protein has persisted for decades, this new research offers a more nuanced perspective. Although past studies have raised concerns about meat, eggs, or dairy increasing the risk of heart disease or cancer, this new analysis suggests that such concerns may not be warranted when protein intake falls within typical dietary ranges.
Details of the Study and Analysis
The findings come from a new analysis of data from the Third National Health and Nutrition Examination Survey (NHANES III), which followed over 15,000 U.S. adults aged 19 and older. Participants were enrolled between 1988 and 1994 and tracked for a period of 12 years to monitor mortality outcomes from all causes, including cancer and cardiovascular disease.
Because accurately assessing diet is notoriously difficult—people’s eating habits change daily, and self-reported food data is often flawed—the researchers used a sophisticated statistical method known as the multivariate Markov Chain Monte Carlo (MCMC) model. This allowed them to estimate participants’ usual intake of protein and differentiate between animal-based (meat, dairy, eggs) and plant-based (legumes, grains, nuts) sources.
They also incorporated blood levels of insulin-like growth factor 1 (IGF-1), a hormone previously linked to cancer risk in some studies, to examine any biological mechanisms that might connect protein consumption and mortality.
Adjustments were made for several lifestyle and health factors, including age, gender, smoking habits, physical activity, and total caloric intake, to isolate the specific effects of protein.
No Increased Risk of Death from Protein Consumption
After analyzing the data, researchers found no evidence that higher consumption of protein—whether from animal or plant sources—was associated with an increased risk of death from any cause. This held true for overall mortality and deaths specifically related to cancer or cardiovascular disease.
Surprisingly, those who consumed more animal protein showed a slightly lower risk of dying from cancer. And even when IGF-1 levels were factored in, no significant relationship between this hormone and increased mortality was observed.
The consistency of these findings across all age groups—under 65, over 65, and 50 to 65—was also notable. This is particularly relevant because earlier research suggested that middle-aged adults might be more vulnerable to potential risks from higher protein intake.
Differences in methodology may explain why this study’s results differ from prior research. Earlier studies often used less accurate techniques for estimating long-term dietary patterns. In contrast, the current study’s use of advanced modeling and balanced group sizes enhanced the reliability of its findings.
In conclusion, the evidence suggests that average protein intake, regardless of its source, does not reduce life expectancy. By combining dietary data with biological markers and robust statistical tools, the researchers provided one of the most comprehensive evaluations to date on this topic.
How Much Protein Should You Eat?
Avery Zenker, a medical and health writer at MyHealthTeam (not involved in the study), noted that there’s no need to alter current protein guidelines based on these findings.
“This study showed that even consuming more than the minimum daily recommendation of 0.8 grams per kilogram of body weight didn’t shorten lifespan,” Zenker told Healthline. She pointed out that protein consumption within the range of 10–35% of total calories remains well within safe and healthy limits.
Zenker emphasized the importance of tailoring protein intake to individual needs, such as goals related to muscle maintenance, overall health, and satiety.
She added that this study shouldn’t be interpreted to mean all protein sources are equally beneficial. “Previous research has consistently linked high intakes of processed meat with higher risks of chronic diseases like cardiovascular disease and certain cancers,” she said.
Zenker also urged caution in interpreting findings from observational studies. “Correlation doesn’t always equal causation,” she said, highlighting that multiple lifestyle factors can complicate nutritional outcomes.
Still, the study contributes valuable insights to the broader discussion around healthy dietary patterns.
Zenker also noted that protein-rich foods are complex—they come with more than just protein. “They also contain vitamins, minerals, fiber, fats, carbohydrates, and other nutrients that can affect health,” she explained.
Protein Needs Are Personal, Not One-Size-Fits-All
Maura Donovan, a board-certified sports dietitian and Medical Education Specialist for Sports Nutrition at Thorne (also not involved in the study), agreed that protein needs vary greatly from person to person.
“For example, older adults often benefit from increased protein to help preserve muscle mass and physical function,” said Donovan.
Athletes also have elevated protein requirements to support muscle repair and recovery. In addition, people recovering from illness or injury may need more protein to support the immune system and healing processes.
Vegetarians and vegans, she added, should combine a variety of plant protein sources to obtain a complete amino acid profile.
Working with a registered dietitian is one of the best ways to determine individual protein needs. The Academy of Nutrition and Dietetics offers a directory of certified dietitians to help guide personalized nutrition planning.