Meal type before exercise and blood amino acid response in adults with classical phenylketonuria

Effect of Different Meal Types Given Before Exercise on Plasma Amino Acid Levels and Metabolic Control Parameters in Classical Phenylketonuria Patients Undergoing Aerobic and Resistance Exercises

This study will test whether different meals given before exercise change blood amino acid levels and metabolic responses in adults with classical phenylketonuria.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 10 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Hacettepe University (Academic / other)
• Locations: 1 site (Ankara, Ankara)
• Trial ID: NCT07526909 on ClinicalTrials.gov

What this trial studies

This single-center, randomized, meal-based crossover trial will enroll 10 adults with classical PKU followed at Hacettepe University. Eligible participants on a phenylalanine-restricted diet who use amino acid substitutes will attend six weekly visits and complete 30-minute aerobic or resistance exercise sessions. Each exercise visit will be done under different pre-exercise conditions (amino acid mixture, amino acid plus carbohydrate, carbohydrate only, or water) with blood samples taken to measure phenylalanine, tyrosine, branched-chain amino acids and hormonal/metabolic responses before and after exercise. The goal is to determine which pre-exercise meal approach best preserves metabolic control during and after different types of exercise.

Who should consider this trial

Good fit: Adults (≥18) with classical PKU who follow a phenylalanine-restricted diet, use amino acid substitutes, are not actively engaged in sports, and have a BMI of 20–28 kg/m2 are the intended participants.

Not a fit: People with non-classical or mild PKU, pregnancy, other chronic diseases, current smoking, or use of medications that alter protein/energy metabolism are unlikely to benefit from these specific findings.

Why it matters

Potential benefit: If successful, the results could identify practical pre-exercise meal recommendations that help adults with PKU maintain better blood amino acid control around exercise.

How similar studies have performed: Very few prior studies have examined exercise effects on plasma amino acids in PKU, so this is a relatively novel approach with limited direct prior evidence.

Eligibility criteria

Inclusion Criteria:

* Be over 18 years old,
* Having a classic FKU diagnosis,
* Not being actively engaged in sports,
* Not having any other existing diseases,
* Not having an active infection,
* Have a BMI in the range of 20-28 kg/m2 within the last 3 months,
* Agreeing to consume test meals and provide blood samples for parameters that will evaluate plasma amino acid levels as part of the research
* Being willing to participate in this study

Exclusion Criteria:

* Presence of a chronic disease accompanying FKU disease (endocrine, etc.)
* The individual with FKU has mental retardation or is deemed unfit for work based on psychomotor assessment,
* Recent weight loss, history of hospitalisation, a past infection, or a diagnosed illness
* Use of drugs or alcohol that alter protein and energy metabolism (e.g., corticosteroids, etc.)
* Pregnancy status
* Smoking habits The considerations to be taken into account when planning the day/date of the test are as follows.
* Having engaged in heavy exercise or sports within 24 hours before the application of test diets,
* Being in the menstrual period for female patients.

Where this trial is running

Ankara, Ankara

• Hacettepe University — Ankara, Ankara, Turkey (Türkiye) (Recruiting)

Study contacts

• Principal investigator: SERAP SIVRI, Professor, MD — Hacettepe University
• Study coordinator: DAMLA KALKAN, MSc, PhD(c)

Conditions Phenylketonuria; Phenylalanine; Low-protein diet; Exercise