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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

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

Status
Recruiting
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07526909
Enrollment
10
Registered
2026-04-14
Start date
2025-10-01
Completion date
2026-07-15
Last updated
2026-04-16

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Phenylketonuria

Keywords

Phenylketonuria, Phenylalanine, Low-protein diet, Exercise

Brief summary

This study will be the first in the literature to evaluate the relationship between aerobic and resistance exercises, plasma amino acid levels, metabolic control of patients, and the metabolic response to exercise with different types of meals in patients with Phenylketonuria (PKU). In patients with phenylketonuria, the aim is to determine which pre-exercise dietary recommendations are more physiologically appropriate and ideal for achieving good metabolic control. In the literature, there are very few studies examining the effects of exercise on plasma amino acid levels and metabolic parameters in PKU patients.

Detailed description

With this study, it is aimed to determine the effects of amino acid mixtures and carbohydrates on the plasma amino acid (phenylalanine, tyrosine, branched-chain aa, etc.) concentrations of patients with Classical Phenylketonuria (PKU) during different types of exercise and to investigate the hormonal responses to exercise. Adults (≥18 years) with classical phenylketonuria (PKU), who are on a phenylalanine-restricted diet and using amino acid substitutes, followed at the Hacettepe University Faculty of Medicine, Department of Pediatric Metabolism (outpatient clinic), will be assessed using the International Physical Activity Questionnaire (IPAQ) and dietary intake records. Based on these assessments and evaluation by sports medicine specialists, 10 participants deemed physically suitable will be allocated to the intervention group. The study, planned as a single-center, randomised, meal-based trial, will include 10 individuals with Classic Phenylketonuria (PKU) aged 18 and above, who are on a phenylalanine (PA) restricted diet and use an amino acid mixture. All participants will be invited to the hospital on different days with a one-week interval for a total of 6 days. After a standard breakfast, they will perform 30 minutes of exercise before the amino acid mixture, amino acid+carbohydrate mixture, carbohydrate only, and water only, in two different types (3 aerobic + 3 resistance exercises) for a total of 6 exercises over 6 different weeks. On the first day of the study, the patients included will undergo blood FA level control, pre-exercise EKG measurement, and evaluation of exercise conditioning status. The daily protein requirement of the patients will be provided in the remaining meals, taking into account the amount consumed in their individual diets, using amino acid mixtures. In the study, each patient will undergo both aerobic and resistance exercises separately in two different types of exercise (aerobic and resistance). Prior to these exercises, three different test diets (water only, carbohydrate only, carbohydrate+protein test diets) will be administered to monitor the patients' blood amino acid levels and some metabolic control parameters. Therefore, patients will have their blood profiles monitored for 2 hours each time they receive one type of exercise and one test diet once a week for 6 weeks (the washout period is 1 week). Before the exercise, 3 test diets will be administered with 2 types of exercise on 6 different days, and the analyses of plasma amino acid concentration, glucose, insulin, lactate, BUN, and creatinine levels will be evaluated. The content of the given test diets will be prepared. Before exercise, 3 test diets will be administered on 6 different days with 2 types of exercise, and the analyses of plasma amino acid concentration, glucose, insulin, lactate, BUN, and creatinine levels will be evaluated. The content of the provided test diets will be prepared to include only water, only carbohydrates, and a mixture of amino acids + carbohydrates. The prepared test diets will be presented to the patient both before resistance and aerobic exercise, resulting in a total of 6 different measurements. The plasma aa levels of the patients will be examined before breakfast (120 minutes before exercise), at the start of exercise (0 minutes of exercise), and in venous blood at 30-minute intervals over a 2-hour period. Two hours before exercise, blood samples will be taken at 0, 30, 60, 90, and 120 minutes to investigate plasma amino acid, glucose, insulin, and lactate levels. It is aimed to investigate the levels of essential amino acids such as blood FA, Tyrosine (Tyr), and Branched-Chain Amino Acids (BCAA), as well as plasma glucose, insulin, lactate, BUN, and creatinine levels in patients with aerobic exercise. The obtained data will be evaluated using appropriate statistical analysis methods. All participants will be invited to the hospital on different days with a one-week interval, and two hours after a standard breakfast (different test diets 10 minutes before exercise), they will receive 1 g/kg/hour of carbohydrates, 0.4 g/kg/hour of protein equivalent amino acids (aa) + 1 g/kg/hour of carbohydrates, and fasting (only hydration with 200 ml of water) to determine their role in post-exercise blood metabolic parameters. At the same time, these test diets will also be applied before aerobic and resistance exercises to examine the changes according to the type of exercise. In the literature, there are very few studies examining the effects of exercise on plasma amino acid levels and metabolic parameters in PKU patients. Determining which dietary recommendations before exercise are more physiologically appropriate and ideal for achieving good metabolic control in patients with phenylketonuria will be guiding.

Interventions

BEHAVIORALAerobic Exercise

Participants performed 30 minutes of moderate-intensity aerobic exercise on a treadmill at 80% of maximum heart rate with a 3% incline.

BEHAVIORALResistance Exercise

Participants performed a resistance exercise session including 3 sets of 10 repetitions of crunch, push-up, forward lunge, and squat exercises.

OTHERWater

Participants consumed 200 ml of water prior to the exercise session.

DIETARY_SUPPLEMENTCarbohydrates

Participants consumed carbohydrates at a dose of 1 g/kg/hour prior to the exercise session.

DIETARY_SUPPLEMENTProtein

Participants consumed protein equivalent to 0.4 g/kg/hour (amino acids) prior to the exercise session.

Sponsors

Hacettepe University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
NONE

Intervention model description

Two different exercises with three different diets, a total of six models in a crossover study.

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

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.

Design outcomes

Primary

MeasureTime frameDescription
Change in Plasma Phenylalanine LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Venous blood samples will be analyzed to determine changes in plasma phenylalanine concentrations in response to exercise and different pre-exercise meal types.

Secondary

MeasureTime frameDescription
Change in Plasma Tyrosine LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Plasma tyrosine levels will be analyzed to assess amino acid metabolism.
Change in Plasma Leucine LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Plasma leucine levels will be measured to evaluate metabolic response to exercise and nutritional interventions.
Change in Plasma Isoleucine LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Plasma isoleucine levels will be measured to evaluate metabolic response to exercise and nutritional interventions.
Change in Plasma Valine LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Plasma valine levels will be measured to evaluate metabolic response to exercise and nutritional interventions.
Change in Plasma Methionine LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Plasma methionine levels will be analyzed to assess amino acid metabolism.
Change in Plasma Threonine LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Plasma threonine levels will be measured to evaluate metabolic response to exercise and nutritional interventions.
Change in Plasma lysine LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Plasma lysine levels will be measured to evaluate metabolic response to exercise and nutritional interventions.
Change in Plasma Tryptophan LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Plasma tryptophan levels will be analyzed to assess amino acid metabolism.
Change in Serum Glucose LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Serum glucose levels will be measured to assess metabolic response to exercise and nutritional interventions.
Change in Serum Insulin LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Serum insulin levels will be measured to assess hormonal response to exercise and nutritional interventions.
Change in Blood Urea Nitrogen (BUN) LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)BUN levels will be measured to evaluate protein metabolism and renal response.
Change in Serum Creatinine LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Creatinine levels will be measured to evaluate renal function during the intervention.
Change in Serum Lactate LevelsBaseline, pre-exercise, and post-exercise (0, 30, 60, 90, and 120 minutes)Serum lactate levels will be measured as an indicator of exercise intensity and metabolic response.

Countries

Turkey (Türkiye)

Contacts

CONTACTDAMLA KALKAN, MSc, PhD(c)
damla.yildirim@hacettepe.edu.tr+905543528779
PRINCIPAL_INVESTIGATORSERAP SIVRI, Professor, MD

Hacettepe University

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Apr 17, 2026