Assessment of the intake of tryptophan-enriched cereals in the elderly and its influence on the sleep-wake circadian rhythm

Abstract

Sleep-wake circadian rhythm disturbances are a common problem associated to aging. Although this problem can be caused by several factors, low levels of the indol melatonin are related with these alterations. Our aim was to evaluate if the consumption of cereals enriched with tryptophan, the precursor of both serotonin and melatonin, can enhance sleep problems in elderly people. Participants (n=12; aged 55-67 yr) were selected from Elderly people University of The University of Extremadura. During all the assay participants wore a wrist actimeter and they filled every week an STAI anxiety test. Data were collected following this schedule: Control week: participants ingested a control cereal both at breakfast anddinner (22.5 mg tryptophan/ 30g product per dose); Treatment Week: volunteers consumed a tryptophan enriched cereal both at breakfast and dinner (60mg tryptophan/30g product per dose); Post-treatment week: participants ingested their habitual diet. We observed a decrease in sleep latency (p<0.01), wake bouts (p>0.05) and sleep fragmentation (p<0.001); on the other hand, an increase in actual sleep time (p<0.01), sleep efficiency (p<0.01) and immobile time (p<0.01) were detected. With respect to the anxiety test, there was an improvement in the state of anxiety. In conclusion, through a tryptophanenriched diet age related sleep problems can be improved.