Phosphatidylserine boosts brain function

Phosphatidylserine (PS) is a natural component of cell membranes, but it is particularly prevalent in neural tissue. PS has been shown in animal studies to have a critical role in brain development. As a result, much of the research examining PS has revolved around memory and cognition. But given the broad array of functions associated with cell membranes, the effects of PS may extend beyond cognitive function. Here’s a snapshot of the results from recent PS studies. 


Enhances memory in the elderly

Japanese researchers examined the effects of soy-derived PS supplementation in subjects 50 to 69 years of age with memory problems. This was a randomized, double-blind study with 3 groups who received daily supplements of 100 mg of PS, 300 mg of PS, or placebo.

Overall, the results were mixed, but in a subset of individuals who scored low on memory tests, both PS supplement groups showed a significant increase in test scores related to verbal list recall, which manifests as an early indicator of dementia.

In a shorter study (12 weeks), individuals aged 50 to 90 years who had memory complaints were provided a PS supplement (300 mg/day). A range of memory tests were performed before and after supplementation. PS significantly improved memory recognition, memory recall, and immediate recall.


Improves management of ADHD

More than 10% of children between 4 and 17 years of age have been diagnosed with attention deficit hyperactivity disorder (ADHD). Prior pilot studies showed positive effects of PS supplementation in children with ADHD but they did not have a control group.

A recent placebo-controlled, double-blind study was conducted in children 4 to 14 years of age. The children had a diagnosis of ADHD but had not been prescribed any medication. The PS group was supplemented daily with a soy-based chewable that contained 200 mg of PS.

After 8 weeks of supplementation, the PS group showed significant improvement in a range of accepted symptoms of ADHD compared to placebo. These measures included short-term auditory memory, measures of inattention and hyperactivity-impulsivity, as well as improvement in classroom behaviors and social skills (e.g., talking during class, walking around in class, putting away things in their proper place).


Reduces cortisol, helps fat burning

The catabolic hormone cortisol has been suggested to play an active role in stimulating storage of fat and inhibiting the breakdown of fat. Thus, supplements that could reduce cortisol may help to facilitate weight and fat loss. PS has been shown in animal studies to lower cortisol, but would the same result apply to humans?

A recent study had healthy men supplement with 600 mg PS or placebo for 10 days. Hormone responses to moderate-intensity exercise were examined. Compared to placebo, peak cortisol concentrations were decreased by 39% and the total cortisol response decreased by 35% during the 65 minutes of recovery in the PS group.

Another study conducted by my research group examined the effects of a supplement containing PS and a blend of nutrients such as B-vitamins, calcium, magnesium and L-theanine on cortisol levels before, during, and after a workout. It reduced cortisol levels at several time points when compared to a rest day. It also reduced ACTH (a stimulator of cortisol) and free radical production.

In addition to PS, ashwagandha extract is another supplement that has recently been shown to reduce cortisol levels. The results suggest that supplements designed to lower cortisol can reduce the stress response to exercise. Since elevated cortisol levels promote excessive storage of fat, especially in the mid-section, PS supplementation may contribute to a lowering of body fat in this region.


Enhances exercise performance

PS plays an important role in cell membranes, including muscle cells. For this reason, researchers have explored the effect of PS on exercise performance and recovery. Soccer players supplemented with PS (750 mg/day) or placebo for 10 days. Before and after the supplementation period, subjects performed an intense exercise protocol consisting of intermittent, high-intensity activities for a total of 90 minutes culminating in a test to fatigue as a measure of performance.

The key result was that PS increased blood levels of gamma tocopherol (the main form of vitamin E in the body). This, in turn, could potentially increase the body’s antioxidant defenses. There was also a trend for improved performance, but this was not statistically significant. Performance was increased by 4.2% with PS supplementation and decreased by 3.7% in the placebo group.

In a follow-up study, healthy men were provided either PS (750 mg/day) or placebo for a total of 10 days. An intense exercise test that resulted in fatigue in less than 10 minutes was performed at 85% of maximal oxygen capacity before and after the supplementation period. The PS group was able to exercise for 2 minutes longer after supplementation (7:51 minutes vs. 9:51 minutes) whereas the placebo group had no change in performance.


What’s an effective dose?

The most common PS doses in human studies are between 200-800 mg/day, with many studies showing positive effects at the lower end of this range. The preferred form of PS is derived from soybean (virtually all supplements use this form). Many products combine PS with other nutrients purported to enhance cognitive functioning or mood.

Because PS most likely works by incorporating itself into membranes and altering cell function, hypothetically it should work well with other cognitive or stress-relieving nutrients that work through other mechanisms. 


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