Phosphatidylserine (PS) is a naturally occurring phospholipid nutrient that may possess performance-enhancing properties. Essential to the functioning of all mammalian cells, PS is most concentrated in organs with high metabolic activity, such as the brain, heart and liver. Because most Americans do not consume large amounts of organ meat in their diets, PS is often consumed as a dietary supplement.
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PS as a Weight Loss Aid
Most PS supplementation studies have examined its influence on cognitive and physical performance. These studies have been encouraging as most have showed an increase in performance. Although PS was not originally researched as an aid to weight control, results of early studies examining its effects raise an interesting possibility that PS could prevent weight gain, specifically by lowering cortisol levels.
Stress, Cortisol and Weight Control
It is well established that both mental and physical stress activate the hypothalamic-pituitary-adrenal axis. The end result of such activation is a secretion of hormones, specifically cortisol, from the adrenal gland. If stress is reduced, the body's internal feedback will reduce cortisol secretion until levels fall back to normal. But chronic stress usually results in chronically high cortisol levels. Chronically increased levels of cortisol have been demonstrated to result in difficulty regulating blood sugar, among several other deleterious effects. Consequently, weight gain and insulin resistance can occur with long-term high cortisol levels.
PS as a Mental Stress Reducer
PS is often marketed as an aid in stress reduction. Two studies in published in the journal "Nutritional Neuroscience" reported that PS supplementation improved mood and mitigated subjective stress symptoms in young individuals during bouts of acute mental stress. Although the authors did not measure cortisol levels it is logical that cortisol secretion would be lower in conjunction with lower subjective stress. A study published in the journal "Stress" did, in fact, measure cortisol response under a mentally stressful test. They found cortisol secretion in subjects who had consumed PS was significantly blunted when compared to control subjects who had consumed a placebo.
PS as a Physical Stress Reducer
Similar results have been reported in regards to how PS influences the body's response to physical stress. In the journal "Biology of Sport," Fahey and Pearl reported that oral supplementation with 800 mg/dL PS was effective in reducing serum cortisol concentration following intensive resistance training. A study published in the "International Journal of the Society of Sport Nutrition" reported similar results. In two separate reports published in the "Medicine and Science in Sports and Exercise," investigators were unable to reproduce such a cortisol response. However, they discovered that subjects supplemented with PS for 14 days significantly increased how long they could run before exhaustion.
If PS supplementation reduces the cortisol response associated with mental and physical stress, it would follow that it could reduce weight gain over time. The early studies mentioned here have been promising. However, there are no peer-reviewed published studies to date directly linking PS supplementation to weight loss.