4. Discussion
SECONDARY
To the best of the author’s knowledge, this is the first project to assess the effect of consuming the same oz-eq portions of protein foods, namely pork, eggs, black beans, and almonds, as defined by the DGA, in the context of a mixed meal on EAA substrate bioavailability for protein anabolism in young and older adults. Consistent with our hypotheses, consuming a meal with two oz-eq of unprocessed lean pork or whole eggs resulted in greater postprandial EAA bioavailability compared to a meal with two oz-eq of black beans or raw sliced almonds in (1) young adults; (2) older adults; and (3) young and older adults combined. No differences were observed between young and older adults. In addition, lean pork resulted in greater EAA bioavailability than eggs in young adults and older adults, separately and combined. These findings show that, on the same oz-eq basis, consuming these animal- vs. plant-based protein foods more effectively provides bioavailable EAA for protein anabolism.These findings are consistent with research by Park et al. [Taken together, the findings from our project and others [Consistent with our secondary hypothesis, we did not observe differential EAA iAUCpos responses between young and older adults overall or among protein foods. There is consistent evidence that basal (fasting) protein synthesis does not differ between young and older adults [Our observation that postprandial EAA iAUCpos were greater for females than for males for pork may be due to the females consuming more protein relative to body mass and plasma volume. However, limited evidence suggests the anabolic response to the same protein/AA ingestion or infusion is not different between young [Regarding project strengths and limitations, this is the first project to assess the effects of consuming the same oz-eq portions of protein foods as defined by the DGA on postprandial EAA responses in the context of mixed whole food meals in both young and older adults. We chose to test a two oz-eq portion of each Protein Food to theoretically obtain measurable postprandial EAA responses. We are mindful that this specific portion likely does not reflect the amounts of these protein foods consumed on a meal-to-meal or weekly basis by young and older adults. Importantly, with consideration of protein quantity, EAA content and bioavailability, and disparate metabolizable energy contents, these results highlight the shortcomings of using oz-eq to achieve the DGA recommendations for protein foods. Our combined sample size of 55 (30 females, 25 males) participants exceeded our a priori estimated need based on effect size, and we used conservative Bonferroni-adjusted 