Whey protein rich in lactalbumin increases the ratio of plasma tryptophan to the sum of the other large neutral amino acids and improves cognitive performance in stress-vulnerable subjects
Okay…I know the title is a little difficult to swallow, but there are several important concepts here. First a lesson in biochemistry of neurotransmitters… Tryptophan is an amino acid that crosses the blood brain barrier to get converted to serotonin. Serotonin is a neurotransmitter that plays a major role in mood and satiety. The major class of antidepressants (selective serotonin reuptake inhibitors or SSRIs) increases serotonin’s effects on the brain. However, when tryptophan is absorbed along with a bunch of other large neutral amino acids, passage of tryptophan across the blood brain barrier drops via competition. Hence some of the side effects with those wonderful and safe high protein diets–serotonin depletion from decreased brain tryptophan. Well…this article suggests an alternative method for getting enough tryptophan into the brain in patients under high levels of stress.
AJCN — Abstracts: Markus et al. 75 (6): 1051