To highlight the importance of protein quality rather than the total protein content of a meal, the investigators will demonstrate that unlike high quality proteins, a single meal containing 30 g of an incomplete protein source does not stimulate skeletal muscle protein synthesis. Secondly, the investigators will directly challenge a prevalent, but untested, assertion that has the potential to negatively impact health. The goal is to demonstrate that complementary plant-proteins (i.e., two or more incomplete protein sources) must be consumed at the same meal to stimulate protein synthesis.
The investigators will test the following hypotheses in middle-aged men and women (45-60) years old using a randomized, cross over design. All study objectives will be met concurrently: 1. Meals containing 30 g of high quality, predominantly beef-protein (PRO-A) will stimulate acute (i.e., single meal response) and 24 h skeletal muscle protein synthesis \[confirmatory hypothesis\] 2. Meals containing 30 g of complementary plant-based proteins (PRO-B: complete essential amino acid profile at each meal) will stimulate acute and 24 h skeletal muscle protein synthesis, but to a lesser extent than beef-protein. 3. A single meal containing 30 g of an incomplete plant-based protein source (PRO-C: lacking one essential amino acid) will fail to acutely stimulate skeletal muscle protein synthesis 4. Meals containing 30 g of plant-based protein that are incomplete at each separate meal, but complementary over a 24 h period, will fail to stimulate 24 h skeletal muscle protein synthesis. 5. Beef-and plant-based meals will have a similar effect on satiety and 24 h blood glucose \[descriptive\] If these hypotheses are correct, the investigators will demonstrate that meals containing a moderate amount of high quality protein, such as beef, are an efficient and effective way to augment a largely plant based diet and stimulate skeletal muscle protein synthesis - a prerequisite for outcomes related to physical function, performance, successful aging and metabolic health.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
23
Unversity of Texas Medical Branch
Galveston, Texas, United States
Acute muscle protein synthesis: PRO-A
Muscle protein synthesis response to PRO-A breakfast meal (%/h)
Time frame: 3 hours after consuming meal
Acute muscle protein synthesis: PRO-B
Muscle protein synthesis response to PRO-B breakfast meal (%/h)
Time frame: 3 hours after consuming meal
Acute muscle protein synthesis: PRO-C
Muscle protein synthesis response to PRO-C breakfast meal (%/h)
Time frame: 3 hours after consuming meal
Acute muscle protein synthesis: CON
Muscle protein synthesis response to CON breakfast meal (%/hour)
Time frame: 3 hours after consuming meal
24-hour muscle protein synthesis: PRO-A
Muscle protein synthesis response to PRO-A diet over 24 hours (%/hour)
Time frame: Approximately 24 hours
24-hour muscle protein synthesis: PRO-B
Muscle protein synthesis response to PRO-B diet over 24 hours (%/hour)
Time frame: Approximately 24 hours
24-hour muscle protein synthesis: PRO-C
Muscle protein synthesis response to PRO-C diet over 24 hours (%/hour)
Time frame: Approximately 24 hours
Blood amino acid response to diet: PRO-A
Blood samples will be drawn to measure amino acid concentrations response to PRO-A breakfast (µmol/L)
Time frame: Approximately 5 hours
Blood amino acid response to diet: PRO-B
Blood samples will be drawn to measure amino acid concentrations response to PRO-B breakfast (µmol/L)
Time frame: Approximately 5 hours
Blood amino acid response to diet: PRO-C
Blood samples will be drawn to measure amino acid concentrations response to PRO-B C breakfast (µmol/L)
Time frame: Approximately 5 hours
Blood amino acid response to diet: CON
Blood samples will be drawn to measure amino acid concentrations response to CON breakfast (µmol/L)
Time frame: Approximately 5 hours
Blood glucose response to diet: PRO-A
Blood samples will be drawn to measure blood glucose response to PRO-A diet (mg/dl)
Time frame: Approximately 24 hours
Blood glucose response to diet: PRO-B
Blood samples will be drawn to measure blood glucose response to PRO-B diet (mg/dl)
Time frame: Approximately 24 hours
Blood glucose response to diet: PRO-C
Blood samples will be drawn to measure blood glucose response to PRO-C diet (mg/dl)
Time frame: Approximately 24 hours
Blood glucose response to diet: CON
Blood samples will be drawn to measure blood glucose response to CON breakfast meal (mg/dl)
Time frame: Approximately 5 hours
Appetite and Hedonic Questionnaire: PRO-A
Questionnaires will be given to assess hunger, fullness, desire to eat, thirst, desire to eat something sweet, desire to eat something salty, desire to eat something savory, sleepiness, physical energy, mental energy, and nausea in response to PRO-A diet. All outcomes are scored individually on a 10 pt visual analog scale using "not at all" being 0 and "extremely" being a 10.
Time frame: Approximately 8 hours
Appetite and Hedonic Questionnaire: PRO-B
Questionnaires will be given to assess hunger, fullness, desire to eat, thirst, desire to eat something sweet, desire to eat something salty, desire to eat something savory, sleepiness, physical energy, mental energy, and nausea in response to PRO-B diet. All outcomes are scored individually on a 10 pt visual analog scale using "not at all" being 0 and "extremely" being a 10.
Time frame: Approximately 8 hours
Appetite and Hedonic Questionnaire: PRO-C
Questionnaires will be given to assess hunger, fullness, desire to eat, thirst, desire to eat something sweet, desire to eat something salty, desire to eat something savory, sleepiness, physical energy, mental energy, and nausea in response to PRO-C diet. All outcomes are scored individually on a 10 pt visual analog scale using "not at all" being 0 and "extremely" being a 10.
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Time frame: Approximately 8 hours
Appetite and Hedonic Questionnaire: CON
Questionnaires will be given to assess hunger, fullness, desire to eat, thirst, desire to eat something sweet, desire to eat something salty, desire to eat something savory, sleepiness, physical energy, mental energy, and nausea in response to CON diet. All outcomes are scored individually on a 10 pt visual analog scale using "not at all" being 0 and "extremely" being a 10.
Time frame: Approximately 5 hours
3 day dietary record: PRO-A
Diet records will be collected and analyzed with ASA24 to assess habitual energy intake the week prior to PRO-A study visit
Time frame: Approximately 36 hours
3 day dietary record: PRO-B
Diet records will be collected and analyzed with ASA24 to assess habitual energy intake the week prior to PRO-B study visit
Time frame: Approximately 36 hours
3 day dietary record: PRO-C
Diet records will be collected and analyzed with ASA24 to assess habitual energy intake the week prior to PRO-C study visit
Time frame: Approximately 36 hours
3 day dietary record: CON
Diet records will be collected and analyzed with ASA24 to assess habitual energy intake the week prior to CON study visit
Time frame: Approximately 36 hours
Palatability Questionnaire:PRO-A
Questionnaires will be given to assess palatability of the PRO-A diet. Outcomes include the participants ranking of the food appearance, aroma intensity, aroma, flavor intensity, flavor, texture and overall appeal of the food. A 10 pt visual analog scale will be used to assess the subject's response with 0 being "extremely dislike", 5 being "neither like nor dislike" and 10 being "extremely like".
Time frame: Approximately 8 hours
Palatability Questionnaire:PRO-B
Questionnaires will be given to assess palatability of the PRO-B diet. Outcomes include the participants ranking of the food appearance, aroma intensity, aroma, flavor intensity, flavor, texture and overall appeal of the food. A 10 pt visual analog scale will be used to assess the subject's response with 0 being "extremely dislike", 5 being "neither like nor dislike" and 10 being "extremely like".
Time frame: Approximately 8 hours
Palatability Questionnaire:PRO-C
Questionnaires will be given to assess palatability of the PRO-C diet. Outcomes include the participants ranking of the food appearance, aroma intensity, aroma, flavor intensity, flavor, texture and overall appeal of the food. A 10 pt visual analog scale will be used to assess the subject's response with 0 being "extremely dislike", 5 being "neither like nor dislike" and 10 being "extremely like".
Time frame: Approximately 8 hours
Palatability Questionnaire:CON
Questionnaires will be given to assess palatability of the CON diet. Outcomes include the participants ranking of the food appearance, aroma intensity, aroma, flavor intensity, flavor, texture and overall appeal of the food. A 10 pt visual analog scale will be used to assess the subject's response with 0 being "extremely dislike", 5 being "neither like nor dislike" and 10 being "extremely like".
Time frame: Approximately 5 hours