Missing links
What’s most firmly established today is the final step. “If you have less translation and less protein production, that leads to the lifespan extension,” Obata says. This lifespan extension, he argues, relies on improved proteostasis, the cell’s ability to keep its proteins in good working order.
The link between Lsp2 and ribosomes is less understood. “What we have to find out is why this Lsp2 is preferably going to the ribosome,” Obata says. “This part is still kind of a mystery.” The team also couldn’t directly demonstrate that fewer ribosomes cause the longer lifespan by restoring ribosome levels. “Ribosomal proteins are a mixture of roughly 100 different proteins,” Obata told Ars. “If you want to manipulate ribosomal levels, you have to either up or down these 100 proteins at once, which is not technically possible at this moment.”
But even with all the details figured out, feeding longevity diets to toddlers is unlikely to become a thing in the foreseeable future, mainly because mammals, including humans, have no direct equivalent of Lsp2.
Translation issues
Obata thinks the best functional counterparts of Lsp2 in humans are albumin and globulins, which together make up around 90 percent of the protein in our blood. Like Lsp2, albumin is made in large amounts, turns over quickly, and is sensitive to how much protein we eat.
Testing whether these proteins carry a nutritional memory just like Lsp2 does would be a stepwise process. “We have to do this first in mice, because there we can manipulate proteins directly, and then maybe in primates,” Obata says. “In humans, we would have to perform studies looking at whether there is a correlation between the level of albumin and lifespan.” If albumin gets confirmed as a human nutritional memory carrier, the team will still have plenty of other details to figure out.
Human albumin is not particularly rich in tyrosine or phenylalanine, so if a similar mechanism exists in people, it may rely on different amino acids. “We have to find out which amino acids are key, which molecular carrier would be equivalent to Lsp2, and then whether there really is a connection between lifespan and the diet in people,” Obata says.
Nature, 2026. DOI: 10.1038/s41586-026-11031-3