Eat more plant protein instead of animal protein for longer life, study suggests
Swapping animal for plant protein in your diet can lead to a longer life, research has shown.
A large study found that every 3% increase in calories from plant protein reduced the risk of death from all causes by 10%. It was also associated with a 12% lower risk of death from heart disease.
In contrast, raising the animal protein share of calories by 10% led to a 2% higher risk of all-cause death and an 8% greater chance of dying from a heart problem.
Animal protein foods include all types of meat, fish, eggs and dairy products such as milk and cheese. Plant sources of protein include cereals, beans, nuts, legumes, soya and bread.
The greater risk of dying linked to eating animal protein was more pronounced among people who were obese, had a history of smoking, drank heavily, and who did little exercise.
Among the healthiest participants, the association disappeared - possibly because health-conscious people tended to eat more fish and poultry rather than red and processed meat, said the researchers.
Replacing processed red meat with plant protein was linked to a 34% lower risk of death from all causes for every 3% of calorie intake.
Substituting plant protein for eggs led to a 19% reduction in death risk.
Lead scientist Dr Mingyang Song, from Massachusetts General Hospital, US, said: "Overall, our findings support the importance of the sources of dietary protein for long-term health outcomes.
"While previous studies have primarily focused on the overall amount of protein intake - which is important - from a broad dietary perspective, the particular foods that people consume to get protein are equally important.
"Our findings suggest that people should consider eating more plant proteins than animal proteins, and when they do choose among sources of animal protein, fish and chicken are probably better choices."
The researchers analysed data from two large US studies focusing on diet and health, the Nurses' Health Study and the Health Professionals Follow-up Study.
Together, they recruited a total of 131,342 participants with an average age of 49 whose progress was followed for up to 32 years. Each participant filled out food questionnaires detailing his or her diet.
During the follow-up period more than 36,000 deaths were recorded. Almost 9,000 of these were due to cardiovascular disease, 13,000 to cancer and about 14,000 to other causes.
The findings are reported in the journal Jama Internal Medicine.
The scientists concluded: "Substitution of plant protein for animal protein, especially from processed red meat, may confer substantial health benefit. Therefore, public health recommendations should focus on improvement of protein sources."
Victoria Taylor, senior dietitian at the British Heart Foundation, said: "We hear a lot about whether our diets should be high in protein or carbohydrates, but this study highlights the importance of considering the quality of the protein foods we are consuming, not just the quantity.
"While this study reported benefits to people consuming more protein from vegetable sources, it doesn't mean we need to avoid animal proteins entirely. A portion of oily fish a week, for example, is a helpful addition to a healthy diet. However, it is a good reminder that we should make sure that we include a variety of protein sources in our diet and cut down if we are eating a lot of red and processed meat."
Kierra Box, food campaigner, at the environmental group Friends of the Earth, said: "This study shows the clear health benefits of lower meat diets, especially swapping processed red meat for plant proteins. Lower meat diets also have huge benefits for the environment - cutting climate changing emissions and reducing land use.
"This extensive investigation is the latest in a long line of studies demonstrating the benefits of a lower meat diet. The evidence is now clear - we don't need to debate whether a reduction in meat consumption is necessary for our health and for the planet. We need action. Government and food businesses must step up to the plate and make it easier for everyone to choose and eat a more plant-based diet."
Dr Louis Levy, head of nutrition science at Public Health England, said: "The people in this study with a shorter life expectancy were also either smoking, drinking a lot of alcohol or doing very little exercise.
"We all need to have a variety of foods, including more plant based proteins, as shown in the Eatwell Guide and cut back on salt, saturated fat and sugar to reduce the risk of ill health."