As people age, the risk of developing diseases like heart disease, diabetes, and dementia rises. Often, these health complications are considered inevitable downsides of getting older. People always get sick in their sunset years, right?
New research and a related literature review throw a wrench in this conventional wisdom. Taken together, the findings suggest eating a plant-heavy diet can significantly delay the aging process, disease, and death.
The most recent study, published Monday in the JAMA Internal Medicine, analyzed the eating patterns and health outcomes of over 400,000 people over 16 years. The team found higher plant protein intake can cut the risk of disease and death by more than 12 percent.
Beneficial dietary shifts don't have to be massive, the research suggests. Replacing just three percent of energy from animal protein with plant protein was associated with 10 percent decreased overall mortality in both men and women.
These striking findings add to a long list of other studies summarized in a related editorial, published Monday in the Journal of the American College of Nutrition.
In the editorial, researchers suggest plant-based diets can reduce the risk of diseases such as type 2 diabetes, cancer, and heart disease by almost 50 percent. In some studies, it reduced cardiometabolic-related deaths in the United States by half.
Editorial co-author Hana Kahleova, director of clinical research at the Physicians Committee for Responsible Medicine, argues that, on top of reducing disease, plant-based diets present "huge benefits for the global community."
"By eating a healthful diet, we can not only add years to our lives, but life to our years," Kahleova tells Inverse. "By staying healthy as we age, we will improve our quality of life and enjoy life more with the people we love."
Food science — Until now, researchers hadn't pinned down the exact health impacts of consuming plant-protein versus animal protein. To get at that hotly debated question, researchers leveraged data from the NIH-AARP Diet and Health Study, a large prospective cohort of more than 400,000 participants with more than 77,000 deaths.
The study originally kicked off in 1995, recruiting 617,119 participants between age 50 to 71 from six states (California, Florida, Louisiana, New Jersey, North Carolina, and Pennsylvania) and two metropolitan areas (Atlanta and Detroit).
Participants filled out a series of detailed questionnaires documenting their demographics and lifestyle characteristics. The group also completed the National Cancer Institute Diet History Questionnaire (DHQ) which tracked how much people consumed 124 different foods.
Approximately 40 percent of the group's daily dietary protein was from plant sources and 60 percent was animal protein (including 19 percent dairy protein). These diet breakdowns mirror the habits of the United States population, the researchers say.
The team then analyzed who died, as well as their causes of death, over the next 16 years.
The results were striking: Across the board, greater intake of plant protein was significantly associated with lower overall mortality and cardiovascular disease mortality, independent of several other risk factors.
Specifically, swapping out 3 percent of animal protein with plant protein was associated with a 10 percent lower mortality risk in both men and women. Making this swap was also linked to an 11 percent lower risk of dying of cardiovascular disease in men and a 12 percent lower risk in women.
These protective effects were primarily associated with substituting eggs and red meat for plants.
Based on these findings, the authors say modifying the choice of protein sources may promote health and longevity, and that public recommendations should reflect this research.
Diet and disease — On top of this recent study, Kahleova and her co-authors rounded up other studies exploring how plant-based diets influence health and aging. Their editorial was authored and funded by the Physicians Committee for Responsible Medicine, a non-profit research and advocacy organization that tends to favor plant-based eating.
The team found a plant-based diet heavy in fruits, vegetables, grains, and legumes can:
- Reduce the risk of developing metabolic syndrome and type 2 diabetes by about 50 percent.
- Reduce the risk of coronary heart disease events by an estimated 40 percent.
- Reduce the risk of cerebral vascular disease events by 29 percent.
- Reduce the risk of developing Alzheimer's disease by more than 50 percent.
These findings point to clear changes to the way people eat, the researchers say: opt for more plants and less meat.
"Adopting a healthful diet and lifestyle is a powerful tool which may delay the aging process, decrease age-associated co-morbidities and mortality, and increase life expectancy," the researchers write. "This strategy represents the most cost-effective approach, and should be incorporated in everyday practice."
However, transforming one's diet isn't always simple. Access to nutrient-rich foods isn't equally accessible or affordable across communities. (Although some research suggests plant-based diets can come with an annual savings of 750 U.S. dollars.)
In light of the Covid-19 pandemic, which has put health disparities in stark clarity, Kahleova says the time to move toward a healthful, plant-based diet is now.
"More than ever, it’s important that we keep our bodies as healthy as we possibly can," Kahleova says.
The researcher notes that a healthful, plant-based diet can help manage many of the world's leading causes of death — chronic conditions that make Covid-19 more severe.
"It’s one more reason to make sure we’re adding more healthy, plant-based foods to our plates," Kahleova explains.
And there are economic advantages too: By 2050, the population of adults 60 and up is predicted to double from 841 million to 2 billion. The ballooning older set will strain the health system.
"To tackle the challenges of an aging population, we have no choice," Kahleova and her team write. "We must address the major lifestyle risk factors, such as smoking, lack of physical activity, and, most of all, poor diet."
LONGEVITY HACKS is a regular series from Inverse on the science-backed strategies to live better, healthier, and longer without medicine.
HOW THIS AFFECTS LONGEVITY — Growing evidence suggests the plant-based diet can help stave off age-related diseases and extend life.
WHY IT'S A HACK — Swapping out meat for plants is a daily choice people can control to improve long term health. No prescription, surgery, or intensive therapy involved.
SCIENCE IN ACTION — To accrue health benefits, you don't have to cut out animal products completely. Start small: Try swapping a nightly steak for vegetable lasagna or leave chicken off your salad. Daily, consistent changes add up.
HACK SCORE OUT OF 10 — 👨🏻🌾👨🏻🌾👨🏻🌾👨🏻🌾👨🏻🌾👨🏻🌾👨🏻🌾 (7/10 farm-fresh food)
Importance: Although emphasis has recently been placed on the importance of high-protein diets to overall health, a comprehensive analysis of long-term cause-specific mortality in association with the intake of plant protein and animal protein has not been reported.
Objective: To examine the associations between overall mortality and cause-specific mortality and plant protein intake.
Design, Setting, and Participants:This prospective cohort study analyzed data from 416 104 men and women in the US National Institutes of Health–AARP Diet and Health Study from 1995 to 2011. Data were analyzed from October 2018 through April 2020.
Exposures: Validated baseline food frequency questionnaire dietary information, including intake of plant protein and animal protein.
Main Outcomes and Measures: Hazard ratios and 16-year absolute risk differences for overall mortality and cause-specific mortality.
Results: The final analytic cohort included 237 036 men (57%) and 179 068 women. Their overall median (SD) ages were 62.2 (5.4) years for men and 62.0 (5.4) years for women. Based on 6 009 748 person-years of observation, 77 614 deaths (18.7%; 49 297 men and 28 317 women) were analyzed. Adjusting for several important clinical and other risk factors, greater dietary plant protein intake was associated with reduced overall mortality in both sexes (hazard ratio per 1 SD was 0.95 [95% CI, 0.94-0.97] for men and 0.95 [95% CI, 0.93-0.96] for women; adjusted absolute risk difference per 1 SD was −0.36% [95% CI, −0.48% to −0.25%] for men and −0.33% [95% CI, −0.48% to −0.21%] for women; hazard ratio per 10 g/1000 kcal was 0.88 [95% CI, 0.84-0.91] for men and 0.86 [95% CI, 0.82-0.90] for women; adjusted absolute risk difference per 10 g/1000 kcal was −0.95% [95% CI,−1.3% to −0.68%] for men and −0.86% [95% CI, −1.3% to −0.55%] for women; all P < .001). The association between plant protein intake and overall mortality was similar across the subgroups of smoking status, diabetes, fruit consumption, vitamin supplement use, and self-reported health status. Replacement of 3% energy from animal protein with plant protein was inversely associated with overall mortality (risk decreased 10% in both men and women) and cardiovascular disease mortality (11% lower risk in men and 12% lower risk in women). In particular, the lower overall mortality was attributable primarily to substitution of plant protein for egg protein (24% lower risk in men and 21% lower risk in women) and red meat protein (13% lower risk in men and 15% lower risk in women).
Conclusions and Relevance: In this large prospective cohort, higher plant protein intake was associated with small reductions in risk of overall and cardiovascular disease mortality. Our findings provide evidence that dietary modification in choice of protein sources may influence health and longevity.