The World Health Organization estimates as many as 10 million people each year develop dementia, a neurodegenerative brain disease which affects cognition. Japanese research shows that number could be reduced with a simple dietary change. Consuming ample amounts of essential amino acids has been shown helpful in laboratory experiments in preventing dementia.
Dementia affects mainly older people and finding ways to prevent it have proven to be elusive but scientists are determined to find breakthroughs. Researchers from the National Institutes for Quantum Science and Technology published their findings on the subject in the journal Science Advances.
Scientists fed mice susceptible to Alzheimer’s disease a low protein diet and found it accelerated brain degeneration. They then fed mice an amino acid supplement and found it slowed down the brain degeneration and the development of dementia. This work built on previous research that showed the effectiveness of essential amino acids in improving cognitive function.
"In older individuals, low protein diets are linked to poor maintenance of brain function," Dr. Makoto Higuchi said. "Amino acids are the building blocks of proteins. So, we wanted to understand whether supplementation with essential amino acids can protect the brains of older people from dementia, and if yes, what mechanisms would contribute to this protective effect."
Researchers studied how a low-protein diet affected the brain which generally displayed neurodegeneration and abnormal protein aggregates called “Tau.” The mice on a low-protein diet also showed poor neuronal connectivity in addition to accelerated brain degeneration. Those effects were reversed after supplementation with amino acids, showing researchers the ability of amino acids to inhibit brain damage.
Mice on a low-protein diet had high levels of progressive brain degeneration but those given an amino acid supplement had neuronal death and brain degeneration suppressed, even though Tau aggregates remained.
"Tau plaques in the brain are characteristic of Alzheimer's and most treatments target them," said Dr. Akihiko Kitamura. "However, we have shown that it is possible to overcome this Tau deposition and prevent brain atrophy via supplementation with Amino LP7."
Scientists observed how the amino acid supplement reduced brain inflammation was also able to prevent kynurenine, which has the ability to induce inflammation, from entering the brain. That means inflammatory immune cells would not have the ability to attack neurons.
"These results suggest that essential amino acids can help maintain balance in the brain and prevent brain deterioration," say fellow researchers Dr. Hideaki Sato and Dr. Yuhei Takado. "Our study is the first to report that specific amino acids can hinder the development of dementia. Although our study was performed in mice, it brings hope that amino acid intake could also modify the development of dementias in humans, including Alzheimer's disease."