Lysine and threonine isotope plasma-to-meal ratio

Older age has no effect on lysine and threonine isotope plasma-to-meal ratio in humans.

“whereas it was not significantly different for milk (P = 0.277) and black beans (P = 0.849).”

Human trialMilk and black bean test meals; older versus young adultsplasma20 g 2H-labeled protein5.5–8.0 h after meal consumption

Differences in amino acid digestibility between young and older adults: a randomized crossover study using the dual tracer method

The American journal of clinical nutrition·19 May 2026

Older age is associated with lysine and threonine isotope plasma-to-meal ratio in humans (19% lower in older versus young adults).

“The isotope plasma-to-meal ratio for lysine and threonine was 19% lower in older adults compared with young adults for sorghum (P = 0.041)”

Human trialSorghum test meal; older versus young adultsplasma20 g 2H-labeled sorghum protein5.5–8.0 h after meal consumption

Differences in amino acid digestibility between young and older adults: a randomized crossover study using the dual tracer method

The American journal of clinical nutrition·19 May 2026