This is a clinical intervention study of PKU carriers (cases) and non-carriers (controls). Upon completing the informed consent process, participants will complete baseline measures of chronic mental health prior to the intervention (PHQ-9, GAD-7, BIS-11). Participants will attend the Human Nutraceutical Research Unit (HNRU) at the University of Guelph, fasted, and first undergo baseline measures of cognition and acute mental health (mood) and provide samples or saliva, urine and dried blood spots to evaluate phenylalanine (Phe), tyrosine (Tyr) and their metabolites (PAH pathway functioning) as well as for genetic testing of the PAH gene. Participants will also complete a brief questionnaire which will include age, sex, ethnicity, income, weight and height (measured using a stadiometer and calibrated weigh scale), and confirmation that participants arrived to the lab fasted (i.e. have only had water to drink and no other foods/ beverages prior to analyses). Blood pressure and heart rate will also be measured at baseline. Following baseline tests, participants will consume a pure L-Phe supplement dosed at 100 mg/kg mixed with 125 mL of water and 125mL of orange juice. Blood pressure and heart rate will be repeated at 1-hour post-L-Phe consumption. Two-hours postprandial, participants will repeat the cognitive tests and acute mental health (mood) assessment, blood pressure and heart rate measurement and provide follow-up saliva, urine and dried blood spot samples. Participants will also be asked to report any side effects they experienced with the L-Phe consumption.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
56
100 mg/kg
University of Guelph
Guelph, Ontario, Canada
Stop Signal Reaction Time
Response Inhibition
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Working Memory
N-Back Test Outcome
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Individual Coefficient of Variance (Variability in Reaction Time)
Stop Signal Task Outcome
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Phenylalanine Levels
Blood, saliva and urine sample analyses
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Tyrosine Levels
Blood, saliva and urine sample analyses
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Phenylalanine Metabolites
e.g. phenylethylamine, tyramine, phenylpyruvate, others
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Tyrosine Metabolites
e.g. L-DOPA, dopamine, norepinephrine, epinephrine, p-hydroxyphenylpyruvate, homogentisic acid, fumarate, others
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Mood
Profile of Mood State (POMS) Outcome
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Blood Pressure
Systolic and Diastolic
Time frame: Change from baseline to 1-hour and 2-hours post L-Phe supplementation
Heart rate
BPM
Time frame: Change from baseline to 1-hour and 2-hours post L-Phe supplementation
Side Effects Following L-Phe Consumption
To be monitored throughout the visit to the research unit
Time frame: 0-3 hours post L-Phe consumption
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