Journal Title (Medline/Pubmed accepted abbreviation): J Int Soc Sports Nutr
Page Numbers:16 (open access)
Background:Phosphatidylserine (PS) is a naturally occurring phospholipid in plant and animal cell membranes that serves many regulatory and signaling functions. A typical Western diet includes ~130 mg/day of PS. Endocrine and cognitive functions may be affected by PS levels, and supplementation may further improve these functions. Clinical evidence has shown short-term high-dose PS supplementation (600 mg/d) attenuates cortisol response to exercise, and long-term, low-dose supplementation (200 mg/d) reduced perceived stress and improved golf performance; PS supplementation from 200 to 800 mg has demonstrated improvements in mood, cognitive function, sports performance, endocrine stress response, and soreness after exercise.
Hypothesis/Purpose: The purpose of this study was to evaluate the effects of PS supplementation on cognitive function, mood, and endocrine stress response following intense resistance exercise.
Subjects: Eighteen physically active (lower body resistance exercise ≥ 1/wk for past 3 mo) men (mean age, 22.5 ± 2.2 yr; height, 1.77 ± 0.06 m; weight, 84.4 ± 13.6 kg) participated in the study.
Experimental design: Randomized, double-blind, cross-over
Treatments and protocol:
Each man was randomized to 2 servings/day of either PS (enriched soybean-derived phospholipids; 200 mg PS) or placebo (rice flour) for 14 days before lower body resistance testing. Each man completed both conditions followed by an identical exercise session without a washout period between conditions. Lower body resistance testing consisted of a warm-up (treadmill, brisk walk for 5 min) followed by 5 sets of 10 repetitions at 70% of 1-repetition maximum (1-RM; determined previously) squats, leg press, and leg extension, with a 90-second rest between sets and a 180-second rest between exercise types. Cognitive function and mood were assessed by a serial subtraction test and a Profile of Mood States questionnaire, respectively, before supplementation and exercise and at 5 and 60 minutes after exercise. Blood samples were collected for cortisol and testosterone levels before supplementation and exercise and at 5, 15, 25, 40, and 60 minutes after exercise.
Supplementation with PS in this study significantly improved cognitive function before intensive resistance training. However, exercise performance was not assessed and, therefore, no relationship between cognitive function and exercise performance can be made. Previous research has suggested that the improvement in cognitive function included a more relaxed state of mind that could improve performance in sports requiring this mind-set. Mood and endocrine changes were not different with PS supplementation, but that could be due to many variables such as dose and duration of supplementation, differences in training status (physical and mental stress), and untrained versus trained individuals. Further study is needed to elucidate the optimal PS dosing regimen and populations who would receive benefit from PS supplementation.