Scientists Crack 30-Year Mystery of Hidden Brain-Protecting Nutrient

Scientists have cracked a 30-year-old biochemical puzzle by identifying the cellular gateway through which a little-known micronutrient enters human cells — a discovery that could reshape understanding of how diet influences brain health, memory, stress resilience, and cancer defense at the genetic level.

The nutrient is queuosine — pronounced "cue-o-scene" — a vitamin-like micronutrient first identified in the 1970s that the human body cannot produce on its own. It must be obtained from specific foods and is also synthesized by gut bacteria. Scientists have known for decades that queuosine plays important roles in brain function, immune response, and protection against cancer, but the mechanism by which it crossed from the digestive system into the body's billions of cells was entirely unknown. That gap left researchers unable to understand how dietary intake translated into biological effects.

The new study, published April 7 in the Proceedings of the National Academy of Sciences, identifies the gene SLC35F2 as the transporter responsible for moving queuosine from the bloodstream into cells throughout the body, including neurons in the brain. The discovery was led by Valérie de Crécy-Lagard, a microbiology professor at the University of Florida, working in collaboration with Vincent P. Kelly of the School of Biochemistry and Immunology at Trinity College Dublin, along with researchers from San Diego State University and Ohio State University. The work was funded by the National Institutes of Health, Research Ireland, and Health and Social Care in Northern Ireland.

What makes the finding particularly striking is that SLC35F2 was previously studied exclusively for a very different role: enabling certain viral drugs and cancer treatments to enter cells. Scientists had never suspected it served a normal physiological function before this discovery. "This transporter was hiding in plain sight," de Crécy-Lagard said. "We knew it helped drugs enter cells. We had no idea it was doing the same thing for a nutrient our brains depend on."

Queuosine functions inside cells by modifying transfer RNA — the molecules that carry amino acids to ribosomes for protein assembly. By altering tRNA, queuosine fine-tunes how the body reads genetic instructions, subtly changing which proteins are made in what quantities. De Crécy-Lagard described this process as queuosine "fine-tuning how your body reads your genes." Kelly said the discovery explains how the nutrient is "salvaged from the gut and distributed to billions of human cells."

The practical implications are potentially significant. If queuosine levels in the body are measurable and correlate with health outcomes — as the researchers believe — the discovery could eventually lead to dietary recommendations, supplements, or even pharmaceutical interventions targeting queuosine transport for conditions ranging from cognitive decline to stress-related disorders to cancer prevention. First, researchers need to characterize what levels of queuosine reach the brain under different dietary conditions and how deficiency affects neurological function in humans.