Journal Title (Medline/Pubmed accepted abbreviation): J Int Soc Sports Nutr
Page numbers: 39
Summary of Background and Research Design
Background: Phosphatidylcholine is a cellular membrane phospholipid that is necessary for both structural integrity as well as physiologic functions. Choline is also essential in the production of the neurotransmitter acetylcholine and has a potential role in neuromuscular signaling, which could produce ergogenic effects during exercise that involves power performance and response to external stimuli. Supplementation with choline as phosphatidylcholine or L-alpha-glycerylphosphorylcholine reportedly improves memory and cognition and boosts the growth hormone response to resistance exercise. Another cellular membrane phospholipid, phosphatidylserine, is typically found in organ membranes with high metabolic activity and is thought to have anti-inflammatory and antioxidant properties. Therefore, it may enhance exercise recovery time. Clinical studies have evaluated a combination of the 2 phospholipids for the improvement of exercise performance, but there have been limited investigations in exercise that involves power and reaction time.
Hypothesis/purpose of study:To evaluate the effects of a low-dose combination of phosphatidylcholine and phosphatidylserine on reaction time, anaerobic power, alertness, energy, fatigue, and focus in healthy college students.
Subjects:19 volunteers (17 men and 2 women) who were recreationally active for 3 months before this study were randomized to supplement (age, 21.1 ± 0.6 yr; height, 180.2 ± 6.1 cm; body mass, 80.6 ± 9.4 kg; percent body fat, 11.3% ± 6.9%) or placebo (age, 21.3 ± 0.8 yr; height, 181.3 ± 10.2 cm; body mass, 83.4 ± 18.5 kg; percent body fat, 14.9% ± 7.7%). The number of subjects in each group was not stated in the article.
Experimental design: Randomized, double-blind study
Treatments and protocol: Volunteers completed 2 testing sessions 4 weeks apart. Each testing session consisted of supplement ingestion; 10-minute rest; 5-minute cycle and movement warm-up; a focus and alertness survey; 4-minute reaction test (Makoto device); exhaustive exercise (3-sec Wingate anaerobic power test, maximum number of push-ups in 1 min, and maximum number of sit-ups in 1 min); a second focus and alertness survey; and a final reaction time test. The supplement (CRAM) contained α?glycerophosphocholine (150 mg), choline bitartrate (125 mg), phosphatidylserine (50 mg), niacin (vitamin B3; 30 mg), pyridoxine HCl (vitamin B6; 30 mg), methylcobalamin (vitamin B12; 0.06 mg), folic acid (4 mg), L-tyrosine (500 mg), anhydrous caffeine (60 mg), acetyl-L-carnitine (500 mg), and naringin (20 mg). Between each testing session the supplement or placebo was consumed once daily for 4 weeks.
Summary of research findings:
- After the first testing session, the supplement group maintained reaction time performance.
- The placebo group had a significant decline in reaction time performance (P = .05).
- However, differences between the treatment groups for the first and second reaction times were not statistically significant.
- After the second testing session, both treatment groups had significant declines in reaction time performance (P values not given).
- There were no significant differences between the treatment groups for the first or second reaction times.
- There were no significant differences between the treatment groups for power, muscular endurance, energy levels, fatigue, focus, or alertness at any time point.
- Subjective ratings of energy levels declined in both treatment groups at each testing session.
- Fatigue significantly increased in the supplementation group at each testing session (P = .001 and P = .000 [sic], respectively).
- Fatigue significantly increased in the placebo only at the second testing session (P = .029)
- Despite these intra-group differences, the group × time interaction was not significant.
- Focus was maintained in the supplementation group at each testing session (P = .037), while focus significantly declined in the placebo group (P = .014).
- There was no significant group × time interaction, however.
- Alertness was maintained in the supplementation group at the first testing session, but declined in the second session (P = .04).
- Alertness declined in the placebo group at each testing session (P = .005 and P = .033, respectively).
- As with the above findings, there was no significant group × time interaction.
Interpretation of findings/Key practice applications:
Acute effects of supplementation following high-intensity exercise include maintenance of reaction time, focus, and alertness. Prolonged effects of supplementation were only observed with maintenance of focus, although there were no statistically significant differences between the treatment groups. In addition, the concentration of choline in the supplement was lower than that in previous studies showing efficacy. This is the first clinical study to evaluate this combination of ingredients, and further studies are warranted to determine the efficacy of this supplement.
A key limitation in these findings is that while there were some intragroup, pre- vs post-supplement comparisons that were statistically significant, the more important comparisons (ie, the group × time interaction) were not significant in any case. In other words, the magnitude of change from pre to post between groups was not significantly different for any variable studied. Another study limitation is that serum choline levels were not measured to ascertain that the exhaustive exercise did deplete choline (or to what extent following 4 weeks of supplementation vs placebo).