Reducing protein intake could promote healthier ageing in most people, according to a review of studies
Numerous sources, including the new dietary guidelines from the United States, recommend increasing protein intake. Now, a review of more than 350 studies —primarily in laboratory animals— carried out by two researchers suggests, on the contrary, that consuming less protein could have greater health benefits. According to the authors, “it is clear that protein provides benefits for muscle growth and the response to exercise in active people, but, given that most people are relatively sedentary, it is likely that many consume more protein than they actually need, which is likely to have negative health consequences”. The study is published in Cell Press Blue, a journal of the Cell group.
José M. Ordovás - proteínas longevidad
José M. Ordovás
Senior scientist and scientific advisor at the Jean Mayer USDA Human Nutrition Research Center on Aging and professor at the Gerald J and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University.
It is a comprehensive, interesting and timely review, but it is not a new clinical trial, nor does it prove that reducing protein intake prolongs human life. The most compelling evidence on longevity still comes from animal models, whilst studies in humans are few and, generally speaking, of short duration.
The study serves as a counterbalance to the increasingly widespread notion that more protein is always better. However, it does not justify recommending less protein for everyone: requirements vary according to age, physical activity, nutritional status and clinical condition.
We should not replace the slogan ‘more protein is better’ with another equally simplistic one: ‘less protein prolongs life’. The sensible message is to consume an adequate amount – not necessarily the maximum – paying attention to the quality and source of food and tailoring intake to each individual.
Esther López - dieta proteínas
Esther López-García
Professor of Preventive Medicine and Public Health at the Autonomous University of Madrid, President of the Nutrition and Obesity Study Observatory (NAOS), and member of the Nutrition Group of the Spanish Society of Epidemiology
This article summarizes basic research (in experimental animals) on the impact of protein restriction on the development of disease and longevity markers. It is well-written, and the way the review is organized around the possible biological mechanisms that link protein restriction to the effects examined is particularly effective. This work parallels what is known about the effect of calorie restriction on longevity.
It is a bold article because it questions the current recommendation to the general population to increase protein intake to improve health. This recommendation has long been given to pregnant women and older adults, but the 2025 US Dietary Guidelines include it for the general population. In Spain, the 2023 dietary guidelines do not make this recommendation, but the reality is that there is a widespread trend in our country to promote high-protein diets for everyone.
The authors are correct in suggesting that more research is needed to understand whether high-protein diets truly have beneficial effects for the general population. However, their work needs to be supplemented with evidence from observational science and clinical trials in humans, because not everything observed in animal models can be directly translated to humans.
Knopf et al.
- Research article
- Peer reviewed
