A new in-depth study has found that eating typical amounts of protein—whether from animal or plant sources—does not increase the risk of early death. In fact, higher consumption of animal protein may slightly reduce the risk of dying from cancer.
These findings challenge long-standing concerns about the potential harms of animal-based proteins and suggest that current protein recommendations remain appropriate for most people. However, experts emphasize that individual protein needs still depend on factors like age, lifestyle, and overall health.
Study Background and Methods
The research, published on July 16 in Applied Physiology, Nutrition, and Metabolism, is based on data from the Third National Health and Nutrition Examination Survey (NHANES III). This survey followed over 15,000 American adults aged 19 and older, tracking their health outcomes over 12 years.
To assess protein intake accurately, researchers used an advanced modeling technique known as the multivariate Markov Chain Monte Carlo (MCMC) method. This approach accounts for daily variations in diet and the common inaccuracies in self-reported food data.
Importantly, the study distinguished between protein from animal sources (such as meat, eggs, and dairy) and plant sources (such as legumes, grains, and nuts). Researchers also included blood tests for insulin-like growth factor 1 (IGF-1), a hormone that has been associated in past research with cancer development and overall mortality risk.
The analysis also controlled for several lifestyle and demographic factors including age, gender, smoking, physical activity, and total calorie intake, allowing for a more accurate evaluation of protein’s effect on longevity.
Key Findings
The study found no association between higher protein intake—regardless of its source—and an increased risk of death. This held true for all causes of mortality, including cancer and cardiovascular disease.
Interestingly, those who consumed more animal protein appeared to have a slightly lower risk of dying from cancer. Including IGF-1 data in the analysis did not significantly change the results, suggesting that the hormone might not be as influential as previously thought.
One of the most notable aspects of the findings is their consistency across age groups. Whether participants were younger than 65, between 50 and 65, or older than 65, protein intake did not correlate with earlier death—contradicting previous studies that suggested higher risk for middle-aged adults on high-protein diets.
Researchers believe that their more refined methodology may explain the differences in findings compared to older studies, many of which used less accurate tools to estimate long-term dietary habits.
Expert Commentary
Avery Zenker, a health writer at MyHealthTeam (who was not involved in the research), said the findings reinforce the idea that people don’t need to fear consuming protein above the standard minimum.
“This study supports the safety of intakes above the recommended 0.8 grams per kilogram of body weight,” Zenker told Healthline. She added that most people fall within the acceptable range of 10–35% of total daily calories from protein.
Zenker advised planning protein intake based on individual needs, including goals such as muscle maintenance, recovery, or fullness. However, she cautioned that not all protein sources are equal. “There’s still strong evidence linking high intakes of processed meats to negative health effects, including cardiovascular disease and cancer,” she said.
She also emphasized the complexity of nutrition science. “Protein-rich foods contain other compounds—fats, vitamins, minerals—that also affect health,” she noted. “And as with any observational study, correlation doesn’t always mean causation.”
Individualized Protein Needs
Maura Donovan, a board-certified sports dietitian and Medical Education Specialist at Thorne (who also was not involved in the study), stressed the importance of personalized nutrition.
“Older adults often need more protein to maintain muscle and mobility,” she said. “Athletes have greater needs due to the demands of training and recovery, and those healing from illness or injury also benefit from higher intake.”
Donovan also pointed out that vegetarians and vegans should combine a variety of plant proteins to ensure they receive all essential amino acids.
She recommends working with a registered dietitian to determine the best protein strategy based on lifestyle, health conditions, and fitness goals. The Academy of Nutrition and Dietetics offers a directory of certified professionals.
Bottom Line
This large-scale study offers reassuring news: eating regular amounts of protein—whether animal or plant-based—is not associated with a higher risk of early death. In fact, some data suggest that animal protein may offer a slight cancer-protective benefit.
While the quality and source of protein still matter, especially when it comes to highly processed foods, the research supports the idea that protein itself isn’t harmful—and may even be beneficial—when consumed as part of a balanced diet.