Type 2 diabetes risk linked to increase in amino acid

High levels of the amino acid tyrosine may play a key role in the development of diabetes, according to a recent study published in the journal PLOS Genetics.
Researchers at The University of Texas Health Science Center in San Antonio, Texas, found that tyrosine is elevated in the blood of people who are obese and at high risk of type 2 diabetes or individuals diagnosed with this form of diabetes.
“It was unknown whether this was simply a marker of diabetes risk or could be playing a direct role in the disease. Our work suggests that tyrosine has a direct effect,” said senior author of the study Dr. Alfred Fisher.
Dr. Fisher, of the Barshop Institute for Longevity and Aging Studies at the UT Health Science Center, has been examining the effect of tyrosine on insulin signalling in animals (roundworms) since 2005.
In that time, he found that increasing the levels of tyrosine in roundworms extended their lifespan. Worms with mutations of certain genes lived between 10% and 20% longer, while one combination of genetic mutations led to a near 60% increase in lifespan.
According to Dr. Fisher, the different effects of increased tyrosine in humans and worms are due to the same inhibition of insulin signalling.
“Interfering with this pathway produces longevity in worms, whereas in people it leads to insulin resistance and an elevated risk of developing diabetes,” he explained.
To test his theory, the physician scientist said he plans to conduct small human clinical trials, which will see tyrosine levels raised “in study participants for a short period to observe whether this changes the ability of the body to respond to insulin”.
As well as being one of the first to associate tyrosine with diabetes risk, this latest research also provides new insights into the roles of amino acids and could potentially lead to novel ways of treating or preventing type 2 diabetes.
“The key concept that comes out of our latest paper is, rather than amino acids being only building blocks in our bodies, they are detected and produce changes in physiology, including potentially undesirable ones such as diabetes in humans,” Dr. Fisher added.