Are beans and legumes good for longevity?

A large meta-analysis of 32 cohort studies involving more than 1.1 million participants found that people who eat more legumes have a statistically significantly lower risk of death. Specifically, each additional 50 grams of legumes per day was associated with approximately 6% lower mortality risk, and the group with the highest consumption had a 6% lower mortality risk than the lowest group (HR 0.94). The researchers rated the certainty of this evidence as low to moderate, so the finding is promising but not definitive (PMID 36811595).

That same meta-analysis also found a lower risk of death from stroke at higher legume intakes (HR 0.91), but this was based on only five studies, so its reliability is limited. No statistically significant associations were found for mortality from cardiovascular disease overall, coronary heart disease, or cancer. This does not mean there is no effect, but the evidence is too thin to draw conclusions (PMID 36811595).

A modelling study across seven countries estimates that a sustainable shift to a diet with more legumes, whole grains and nuts, and less red meat and sugar, could yield around 6 to nearly 10 extra years of life expectancy for 40-year-olds. These are model calculations, not direct measurements, and they speak to an entire dietary pattern rather than legumes alone (PMID 38692410). A review article confirms that high legume intake is one of the most consistent nutritional characteristics associated with longer life expectancy, across a wide variety of dietary patterns (PMID 24503212).

In a Chinese cohort study of more than 13,000 older adults (aged 65+), those who followed a healthy plant-based diet, with legumes as a key component, had a 19% lower risk of dying than those who ate the least healthily. Notably, an unhealthy plant-based diet actually increased the risk by 17%, demonstrating that the quality of plant-based food choices matters (PMID 37118372). A separate study also found an association with substantially less cognitive decline in older adults who followed a diet rich in legumes and other plant-based foods, although these findings are also observational and should be interpreted with caution (PMID 40922203).

There are also two important points to bear in mind. First, for people over the age of 65, a narrative review warns that plant-based diets can carry a risk of insufficient protein intake. Older adults have relatively higher protein requirements, and legumes contain less protein and protein of somewhat lower completeness than animal sources. It is therefore important, when shifting toward greater legume consumption, to pay attention to adequate total protein intake (PMID 35914402). Second, people with chronic kidney disease should consult their doctor or dietitian, but plant-based phosphate from legumes is absorbed less readily than inorganic phosphate from processed foods, which makes legumes relatively more favourable for kidney patients (PMID 20093346).

Finally, a large American cohort study with more than 521,000 participants and 16 years of follow-up supports the finding that replacing animal protein with legumes or nuts is associated with lower mortality, including from cardiovascular disease and cancer (PMID 33561122). Taken together, the evidence consistently points in the same direction: legumes are a beneficial part of a dietary pattern for a long and healthy life, although the research is almost exclusively observational.