The dipeptide used in the study is the only known amino acid to make the trip from a mouse’s stomach to its brain intact, according to the study authors.
Researchers at Kyushu University have found that a protein fragment that makes its way to the brain after being ingested can reduce memory degradation in mice treated to simulate impaired memory funcion.
The memory-effecting molecule is classified as a dipeptide and contains 2 of the protein building blocks known as amino acids. The dipeptide used in the study is the only known amino acid to make the trip from a mouse’s stomach to its brain intact, according to the study authors.
“On top of the possibility of being broken down during digestion, peptides then face the challenge of crossing a highly selectively barrier to get from the blood into the brain,” said lead study author Toshiro Matsui in a press release.
The researchers investigated the effects of the dipeptide, consisting of the amino acids tyrosine and proline, by feeding it to mice for several days before and after injecting them with a chemical that impairs memory function.
Impaired mice that had ingested the dipeptide over the past 2 weeks performed better than those that had not in tests to evaluate short-term memory by comparing a mouse’s tendency to explore different arms of a maze, according to the study authors. However, both groups were overall outperformed by mice without induced memory impairment.
The study authors noted that although there have been other reports suggesting some peptides can reduce the decline of brain functions, this study is the first case in which evidence also exists that the peptide can enter the brain intact.
“We still need studies to see if these benefits carry over to humans, but we hope that this is a step toward functional foods that could help prevent memory degradation or even improve our memories,” Matsui said in a press release.
Memory impairment in mice reduced by soy derivate that can enter the brain intact. Kyushu University. https://www.kyushu-u.ac.jp/en/researches/view/152. Published June 19, 2020. Accessed June 22, 2020.