Missing links
What is most clearly established today is the final step. “When there is less translation and less protein production, that leads to an increase in lifespan,” says Obata. This extension of lifespan, he believes, is due to improved proteostasis, the cell’s ability to keep its proteins in good condition.
The connection between Lsp2 and ribosomes is less understood. “We need to find out why this Lsp2 preferentially reaches the ribosome,” says Obata. “That part is still a mystery.” The team also couldn’t directly demonstrate that fewer ribosomes lead to longer lifespans by restoring ribosome levels. “Ribosomal proteins are a mixture of about 100 different proteins,” Obata told Ars. “If you want to manipulate ribosome levels, you have to either increase or decrease these 100 proteins at once, which is currently not technically possible.”
But even if all the details are sorted out, it is unlikely that young children will be put on longevity diets in the foreseeable future, especially because mammals, including humans, do not have a direct equivalent of Lsp2.
Translation problems
Obata believes that the best functional counterparts of Lsp2 in humans are albumin and globulins, which together make up about 90 percent of the protein in our blood. Like Lsp2, albumin is produced in large quantities, metabolized quickly, and is sensitive to how much protein we eat.
Testing whether these proteins, like Lsp2, carry nutrient memory would be a step-by-step process. “We need to do this first in mice, because we can manipulate proteins there directly, and then perhaps in primates,” says Obata. “In humans, we would need to conduct studies to investigate whether there is a relationship between albumin levels and lifespan.” If albumin is confirmed as a carrier of human dietary memory, the team still needs to figure out many more details.
Human albumin is not particularly rich in tyrosine or phenylalanine. So if a similar mechanism exists in humans, it could rely on other amino acids. “We have to find out which amino acids are crucial, which molecular carrier corresponds to Lsp2 and whether there really is a connection between human lifespan and diet,” says Obata.
Nature, 2026. DOI: 10.1038/s41586-026-11031-3
