(KIWI) Speeding up a Slow Protein for Muscle Mass With Hay Kiwifruit

Not Applicable

Completed

Interventions: Dietary Supplement: Green Hayward Kiwifruit first, then Gold Kiwifruit
Dietary Supplement: Gold Kiwifruit First, then Green Hayward Kiwifruit

Brief Summary: The specific hypothesis is that the consumption of 2 Hayward green kiwifruit (containing actinidin protease) prior to 100g of ground beef will increase the rate of protein digestion from the beef in the elderly, leading to an increased uptake of the essential amino acids. Furthermore, this increased essential amino acid availability will produce a greater postprandial net anabolic protein response, as well as increased fractional synthetic rates of muscle proteins.

Detailed Description: The specific hypothesis is that the consumption of 2 Hayward green kiwifruit (containing actinidin protease) prior to 100g of ground beef will increase the rate of protein digestion from the beef in the elderly, leading to an increased uptake of the essential amino acids. Furthermore, this increased essential amino acid availability will produce a greater postprandial net anabolic protein response, as well as increased fractional synthetic rates of muscle proteins.

To test this hypothesis, the investigators will use a double-blinded crossover design involving two intervention arms; in both arms 100g of ground beef (cooked weight) will be consumed following either 2 Hayward green kiwifruit (containing actinidin protease) or 2 Hort16A Gold kiwifruit (devoid of actinidin protease) by elderly subjects.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

Inability to chew meats or difficulty swallowing solid foods
History of diabetes
History of malignancy in the 6 months prior to enrolment
History of gastrointestinal reduction or bypass surgery (Lapband, etc)
History of a chronic inflammatory condition or disease (Lupus, HIV'AIDS, etc)
History of chronic kidney disease or currently requiring dialysis.
Allergy to beef or kiwifruit
Subjects who do not or will not eat animal proteins
Subjects who cannot refrain from consuming protein or amino acid supplements during their participation in this study
Subjects who report regular resistance exercise (more than once per week)
Hemoglobin less than 9.5mg/dL at the screening visit
Platelets less than <150,000 at the screening visit
Subjects who are not willing or able to suspend aspirin for several days prior to their muscle biopsies.
Subjects who have been prescribed a blood-thinning medication (Coumadin, lovenox, heparin, Plavix, etc).
Concomitant use of corticosteroids (ingestion, injection or transdermal)
Any other disease or condition that would place the subject at increased risk of harm if they were to participate, at the discretion of the study physician

Arm && Interventions

Group	Intervention	Description
Gold Kiwifruit First, then Green Hayward Kiwifruit	Gold Kiwifruit First, then Green Hayward Kiwifruit	Subjects first ate 2 gold kiwifruit with midday meal for 2 weeks before crossing over to the green Hayward kiwifruit intervention
Green Hayward Kiwifruit first, then Gold Kiwifruit	Green Hayward Kiwifruit first, then Gold Kiwifruit	Subjects first ate 2 green Hayward kiwifruit with midday meal for 2 weeks before crossing over to the gold kiwifruit intervention
Gold Kiwifruit First, then Green Hayward Kiwifruit	Green Hayward Kiwifruit first, then Gold Kiwifruit	Subjects first ate 2 gold kiwifruit with midday meal for 2 weeks before crossing over to the green Hayward kiwifruit intervention
Green Hayward Kiwifruit first, then Gold Kiwifruit	Gold Kiwifruit First, then Green Hayward Kiwifruit	Subjects first ate 2 green Hayward kiwifruit with midday meal for 2 weeks before crossing over to the gold kiwifruit intervention

Primary Outcome Measures

Name	Time	Method
Whole Body Net Balance Measured by Gas Chromatography-Mass Spectrometry (GC-MS)	300 minutes	Blood samples were analyzed to quantify the appearance of the stable isotopes: 2H2-tyrosine, 2H4-tyrosine, and 2H5-phenylalanine in tracer to tracee ratio or mole percent excess. Changes in these markers over time enable the calculation of whole body protein metabolism. Calculations are done as follows: Total plasma rate of appearance = infusion rate/enrichment Fractional rate of appearance of tyrosine from phenylalanine= 2H4-tyrosine/2H5-phenylalanine Phenylalanine hydroxylation = fractional rate of appearance of tyrosine from phenylalanine x rate of appearance of tyrosine Protein Synthesis = \[(rate of appearance of phenylalanine -Phe hydroxylation) x 25\] Protein Breakdown = \[(rate of appearance of phenylalanine - phenylalanine infusion rate) x 25 - phenylalanine intake\] Net Balance = Protein Synthesis - Protein Breakdown

Secondary Outcome Measures

Name	Time	Method
Change in Skeletal Muscle Protein Metabolism Measured by Gas Chromatography-Mass Spectrometry (GC-MS)	9.5 hours	Muscle samples were analyzed to quantify the appearance of the stable isotope 2H5-phenylalanine in trace to tracee ratio or mole percent excess. The change in 2H5-phenylalanine in subsequent muscle biopsy allow for the calculation of muscle protein synthesis. The calculation is done as follows: \[(2H5-phenylalanine enrichment in second biopsy - 2H5-phenylalanine enrichment in second biopsy)/ (2H5-phenylalanine plasma enrichment × time)\] × 60 × 100.