Posted by lotus on June 12, 2005, at 3:03:32
In reply to What's so great about Whey Protein?, posted by Sarah T. on June 8, 2005, at 1:23:00
> Lately, I've been seeing so much whey protein at the natural foods store. Has anyone noticed any spectacular results from adding whey protein to their diet?
This may be one possible reason.
One recent study examined whether alpha-lactalbumin-a major subfraction found in whey that has an especially high tryptophan content-would increase plasma tryptophan levels as well reduce depression and cortisol concentrations in subjects under acute stress considered to be vulnerable to stress. It's important to note that levels of alpha-lactalbumin and other important subfractions can vary greatly and depend on how the whey is processed. Some whey products on the market contain very little alpha-lactalbumin and other active subfractions (i.e. lactoferrin). The researchers examined 29 "highly stress-vulnerable subjects" and 29 "relatively stress-invulnerable" subjects using a double blind, placebo-controlled study design. The study participants were exposed to experimental stress after eating a diet enriched with either alpha-lactalbumin (found in whey) or sodium-caseinate, another milk based protein. They researchers looked at:
Diet-induced changes in the plasma tryptophan and its ratio to other large neutral amino acids
Prolactin levels
Changes in mood and pulse rate
Cortisol levels (which were assessed before and after the stressor)
Amazingly, the ratio of plasma tryptophan to the other amino acids tested was 48% higher after the alpha-lactalbumin diet than after the casein diet! This was accompanied by a decrease in cortisol levels and higher prolactin concentration. Perhaps most important and relevant to the average person reading this article, they found "reduced depressive feelings" when test subjects were put under stress. They concluded, "Consumption of a dietary protein enriched in tryptophan increased the plasma Trp-LNAA ratio and, in stress-vulnerable subjects, improved coping ability, probably through alterations in brain serotonin." This effect was not seen in the sodium-caseinate group. If other studies can confirm these findings, whey may turn out to be yet another safe and effective supplement in the battle against depression and stress.In the years of working with people taking whey, it was not uncommon for them to report that they just felt better, but I had no useful explanation as to why. This study may very well explain the anecdotal reports.
The protein alpha-lactalbumin increases the plasma ratio of tryptophan to the other large neutral amino acids, and in vulnerable subjects raises brain serotonin activity, reduces cortisol concentration, and improves mood under stress.[1]
poster:lotus
thread:509500
URL: http://www.dr-bob.org/babble/alter/20050510/msgs/511339.html