Higher serum phenylalanine concentration is associated with more rapid telomere shortening in men

Telomere length is a marker of cellular aging and is inversely associated with age. A shorter telomere length has been associated with increased mortality, morbidity and cardiovascular risk factors. However, previously most studies have been of cross-sectional design and very few longitudinal studies are available.

The Eriksson Group in collaboration with researchers from Pisa, Italy studied the longitudinal relationship between telomere length, change in telomere length and circulating amino acids. Previously telomere length has not been focused upon longitudinally in an aging population.

In previous studies higher concentrations of aromatic amino acids have been shown to correlate with cardiovascular risk factors. Therefore, the aim of this study was to see whether there was a relationship between telomere length and circulating amino acids.

Over 800 men and women from the Helsinki Birth Cohort Study born between 1934 and 1944, were studied at three different time points between 2001 and 2013. Leukocyte telomere length was measured with quantitative real-time polymerase chain reaction, while amino acids were measured with high-throughput NMR spectroscopy.

Women had a significantly longer telomere length compared with men, despite similar age. Of the amino acids studied an inverse association was observed between phenylalanine concentration measured five years previously and telomere length. However, this finding was significant in men only. In a similar way the change in telomere length over 10 years was inversely associated with phenylalanine concentration, in men, but not in women.

The authors conclude that serum phenylalanine concentration is associated with telomere length and potentially also with the aging process. Phenylalanine is an essential amino acid, and cannot be synthesized in the human body. It is a precursor for tyrosine, dopamine, norepinephrine and adrenaline, and present in most foods that contain protein such as beef, pork, milk, eggs ad cheese. The artificial sweetener aspartame is also high in phenylalanine. However, little is known whether protein intake has a major impact of plasma concentrations of phenylalanine.
The study suggests that aromatic amino acids and especially phenylalanine could be involved in the aging process and that the role of phenylalanine should be examined in more detail in future studies.
Original study:

Eriksson JG, Guzzardi MA, Iozzo P, Kajantie E, Kautiainen H, Salonen MK. Higher serum phenylalanine concentration is associated with more rapid telomere shortening in men. Am J Clin Nutr 105(1): 144-150, 2017 (doi: 10.3945/ajcn.116.130468) Epub ahead Nov 23, 2016