(PTFS07-04-23) Effects of Consuming Ounce-Equivalent Portions of Animal- vs. Plant-Based Protein Foods on Essential Amino Acids Bioavailability in Young and Older Adults: A Cross-Over RCT

Objectives: The Dietary Guidelines for Americans (DGA) recommends consuming a variety of “Protein Foods” based on “ounce-equivalent” (oz-eq) portions. No study has assessed the same oz-eq portions of animal- versus plant-based Protein Foods on essential amino acids (EAAs) bioavailability for protein anabolism in young and older adults. Therefore, we assessed the effects of consuming two oz-eq portions of pork, eggs, black beans, and almonds on postprandial EAAs bioavailability in young and older adults.

Methods: We conducted two investigator-blinded, randomized crossover trials; in young (n = 30; mean age ± SD: 26.0 ± 4.9 y) and older adults (n = 25; mean age ± SD: 64.2 ± 6.6 y). Participants completed four testing sessions where they consumed a standardized meal with two oz-eq of either unprocessed lean pork loin, whole eggs, black beans, or sliced almonds. Blood samples were taken at baseline and 30, 60, 120, 180, 240, and 300 min postprandially. Plasma EAAs bioavailability was based on postprandial integrated positive areas under the curve.

Results: The EAAs iAUCpos values (least squares means ± SE) for young adults for pork, eggs, black beans, and almonds were 7346 ± 401, 4689 ± 413, 2023 ± 402, and 1184 ± 401 µg/mL, respectively. The EAAs iAUCpos values for older adults for pork, eggs, black beans, and almonds were 8424 ± 496, 5725 ± 502, 2084 ± 497, and 1368 ± 492 µg/mL, respectively Participant age did not affect EAAs bioavailability among the four Protein Foods tested. The EAAs iAUCpos values for young and older adults combined for pork, eggs, black beans, and almonds were 7900 ± 313, 5252 ± 320, 2015 ± 314, and 1290 ± 313 µg/mL, respectively. Two oz-eq portions of pork (7.36 g EAAs) or eggs (5.38 g EAAs) resulted in greater EAAs bioavailability than black beans (3.02 g EAAs) or almonds (1.85 g EAAs) in young and older adults, separately or combined (P < 0.0001 for all). Pork resulted in greater EAAs bioavailability than eggs in young adults (P < 0.0001), older adults (P = 0.0007), and combined (P < 0.0001). There were no differences in EAAs bioavailability between black beans and almonds.

Conclusions: The same “oz-eq” portions of animal- and plant-based Protein Foods do not provide equivalent EAAs content and postprandial bioavailability for protein anabolism in young and older adults.

Funding Sources: Pork Checkoff and American Egg Board’s Egg Nutrition Center