Kinetics of creatine ingested as a food ingredient

Area of Science:

• Sports Nutrition
• Nutritional Biochemistry
• Pharmacokinetics

Background:

• Creatine supplementation is popular for enhancing athletic performance.
• Understanding creatine absorption and retention is crucial for optimizing its efficacy.
• Food matrix effects on creatine bioavailability are not fully elucidated.

Purpose of the Study:

• To compare creatine plasma kinetics, erythrocyte retention, and excretion when ingested in an aqueous solution (AS) versus a protein (PP) or beta-glucan (BG)-rich food bar.
• To investigate the impact of food matrix composition on creatine absorption and retention.
• To assess the safety and tolerability of creatine in different food bar formulations.

Main Methods:

• Seventeen healthy young men participated in a crossover study.
• Subjects ingested 2g of creatine as AS, PP-bar, or BG-bar.
• Plasma creatine kinetics, urinary excretion, erythrocyte creatine content, and fecal creatine were measured.

Main Results:

• Creatine absorption was significantly slowed by BG (8-fold) and PP (4-fold) compared to AS.
• Urinary creatine loss was reduced with BG (8% vs. 15% for AS).
• Erythrocyte creatine increase was similar across all forms; no creatine was detected in feces.

Conclusions:

• Ingesting creatine with beta-glucan slows absorption and reduces urinary excretion, enhancing creatine retention.
• Food matrix, particularly beta-glucan, influences creatine absorption kinetics.
• Creatine supplementation in food bars is well-absorbed and tolerated.