A huge US cohort (> 130.000 participants from the Nurses Health Study and and Health Professionals Follow-up Study, followed for more than 30 years) examined the effects of different sources of dietary protein. It was concluded that a high intake of protein from animal sources was associated with a higher mortality rate, while a high intake of protein from plant sources was associated with a lower risk of premature death.
The study results suggest that replacing animal protein with a similar amount of protein from plant sources is associated with lower mortality. A weak association between animal protein intake and an increased risk of death from cardiovascular disease was observed, while plant protein intake was associated with a reduced risk of death from all causes.
The researchers calculated that switching just 3% of energy from animal protein for a corresponding amount of energy from plant protein would reduce the risk of death from all causes. This effect appears more pronounced when it is processed red meat (34% decrease). Replacing 3% dairy protein with plant-derived protein resulted in 8% reduced risk for premature mortality.
Public health recommendations should focus on improvement of protein sources: plant protein in favour of animal protein. The choice of plant over animal protein may lower the risk of death and likely has a number of additional health benefits.