Elevated serotonin (5-hydroxytryptamine) levels have been shown to help people handle stress and serotonin is deficient in the brain during depression. An increase in the consumption of tryptophan is believed to increase the brain serotonin and to increase the ability of the person to handle stress. Alpha-lactalbumin is a whey protein with a large amount of tryptophan.
Absorption of tryptophan into the brain depends on the ratio of tryptophan consumed to other large neutral amino acids (LNAAs). LNAAs are valine, tyrosine, leucine, isoleucine and phenylalanine. LNAAs are more available than tryptophan in most high protein diets.
A previous study has shown that a carbohydrate rich, protein poor diet increases brain serotonin levels.
The authors put stress on human subjects after pretreatment with either alpha-lactalbumin enriched whey or sodium-caseinate as a placebo. Careful notes were taken of the subject’s reaction to the stress and blood tests were done to measure their bodies’ reactions to stress.
The results showed that the subjects had a 48% higher tryptophan/LNAA ratio after the alpha-lactalbumin enriched whey diet. With the higher tryptophan, they had higher prolactin levels, reduced cortisol levels and less feeling of depression after the stress. Increased prolactin levels are an indicator of increased serotonin activity in the brain.
CONCLUSION: Patients were given a high tryptophan whey drink. The authors concluded that subjects with higher tryptophan intake could cope with stress better, “probably through alterations in brain serotonin.” Tryptophan supports the body’s production of serotonin.
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