Animal protein not linked to higher mortality risk, study finds

Hamilton, ON, Aug. 22, 2025–Eating animal-sourced protein foods is not linked to a higher risk of death and may even offer protective benefits against cancer-related mortality, new research finds.  

The study, published in Applied Physiology, Nutrition, and Metabolism, analyzed data from nearly 16,000 adults aged 19 and older using the National Health and Nutrition Examination Survey (NHAMES III).

Researchers examined how much animal and plant protein people typically consume and whether those patterns were associated with their risk of dying from heart disease, cancer or any cause. 

They found no increased risk of death associated with higher intake of animal protein. In fact, the data showed a modest but significant reduction in cancer-related mortality among those who ate more animal protein. 

“There’s a lot of confusion around protein – how much to eat, what kind and what it means for long-term health. This study adds clarity, which is important for anyone trying to make informed, evidence-based decisions about what they eat,” explains Stuart Phillips, Professor and Chair of the Department of Kinesiology at McMaster University, who supervised the research. 

To ensure reliable results, the team employed advanced statistical methods, including the National Cancer Institute (NCI) method and multivariate Markov Chain Monte Carlo (MCMC) modelling, to estimate long-term dietary intake and minimize measurement error. 

“It was imperative that our analysis used the most rigorous, gold standard methods to assess usual intake and mortality risk. These methods allowed us to account for fluctuations in daily protein intake and provide a more accurate picture of long-term eating habits,” says Phillips. 

The researchers found no associations between total protein, animal protein or plant protein and risk of death from any cause, cardiovascular disease, or cancer. When both plant and animal protein were included in the analysis, the results remained consistent, suggesting that plant protein has a minimal impact on cancer mortality, while animal protein may offer a small protective effect.

Observational studies like this one cannot prove cause and effect; however, they are valuable for identifying patterns and associations in large populations. Combined with decades of clinical trial evidence, the findings support the inclusion of animal proteins as part of a healthy dietary pattern. 

“When both observational data like this and clinical research are considered, it’s clear both animal and plant protein foods promote health and longevity,” says lead researcher Yanni Papanikolaou, MPH, president, Nutritional Strategies.

This research was funded by the National Cattlemen’s Beef Association (NCBA), a contractor to the Beef Checkoff. NCBA was not involved in the study design, data collection and analysis or publication of the findings.  

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