This is a clinical intervention pilot/feasibility 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-Brief). 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). 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 will also be measured at baseline. Following baseline tests, participants will consume a pure L-Phe supplement dosed at 100 mg/kg mixed into 250 mL water with 1 tsp white sugar. Blood pressure 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 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
7
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
Stop Signal Delay
Stop Signal Task Outcome
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Individual Coefficient of Variance (Variability in Reaction Times)
Stop Signal Task Outcome
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Phenylalanine Levels
Time frame: Change from baseline to 2-hours post L-Phe supplementation
Tyrosine Levels
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 States (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
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