The lifespan extending potential of the extract was greater than that seen for a similar dose of an unfermented soybean extract, reported scientists from the University of Maryland (USA) and Kyungpook National University (South Korea).
The benefits were linked to an effect on pmk-1-skn-1 signaling of the MAPK (Mitogen-Activated Protein Kinase) pathway, the researchers indicated. The MAPK pathway is reported to impact longevity by regulating responses to stress. A reduction in oxidative stress was also found.
“Our study showed that tempeh significantly extends lifespan of C. elegans via PMK-1-SKN-1 signaling axis in MAPK pathway to enhance oxidative stress and reduce intracellular ROS levels in C. elegans,” they wrote in Current Research in Food Science. “Therefore, the findings suggest tempeh as a plant-based protein source for anti-oxidation effect to promote healthy aging.”
Modeling lifespan
The nematode worm Caenorhabditis elegans or C. elegans is often used in studies related to aging because the worms are transparent, making cellular activity easier to view, and they have a short lifespan (2 to 3 weeks). But most importantly, they are a simple organism with specific types of metabolic genes that are similar to mammals.
Over 65 % of the nematode’s genes are similar in position, structure and evolutionary origin to human disease-associated genes, according to the researchers.
In this new study, they explored the potential of different doses of soybean and tempeh extracts lifespan to impact lifespan and healthspan of C. elegans.
Tempeh, which is rich in proteins, dietary fiber and various bioactive nutrients, including isoflavones, is commonly produced by fermenting soybeans using Rhizopus species.
Study details
The researchers tested the soybean and tempeh extracts at doses of 50, 100 and 200 micrograms per milliliter of growth media. Worms given the soybean extract experienced increases in lifespan of 30%, 38% and 29%, respectively, while the tempeh extract extended lifespan by 32%, 45% and 39% at 50, 100, and 200 μg/ml, respectively.
Additional tests revealed that the 100 μg/ml tempeh extract dose improved healthspan, as measured by the bending rate (a marker of physiological function) of the nematodes. Levels of intracellular reactive oxygen species (ROS) were also reduced significantly more by the tempeh extract, compared to the control group.
Experiments with pmk-1 and skn-1 null mutant nematodes revealed that both genes are key for tempeh’s lifespan extension effect, the researchers wrote.
Commenting on the potential mechanism(s) of action, they suggested that the key bioactives are conserved from the original soybeans, but noted that they have not elucidated the mechanism of action.
“Also, the effect of Rhizopus has not been determined,” they added. “Thus, additional studies on determining the effect of Rhizopus and identifying the working mechanism of soybean extract are needed to further understand the effect of tempeh extract on lifespan extension.”
Source: Current Research in Food Science. 2025, Volume 11, 101259. doi: 10.1016/j.crfs.2025.101259. “Tempeh, a fermented soybean, extends lifespan via MAPK pathway and improves healthy aging in Caenorhabditis elegans”. Authors: J. Cho, et al.
