Effect of melatonin-rich night-time milk on sleep and activity in elderly institutionalized subjects

Abstract

Melatonin production decreases with advancing age, leading to insomnia and changes in circadian rhythmicity. Administration of melatonin in variable doses resulting in supraphysiological or physiological night-time blood levels of melatonin has been shown to improve sleep quality in the elderly. To study the effect of low doses of melatonin, which do not affect daytime blood melatonin concentrations, night-time milk containing 10-40 ng/l melatonin was used as a drink with meals. The effect of about 0.5 l night-time milk daily on sleep quality and circadian activity was studied in elderly institutionalized subjects in two long-term double-blind, placebo-controlled, crossover studies. Night-time milk was given for 8 weeks and normal day-time milk for 8 weeks with a 1-week washout period in between. In the first study, which was performed during spring with sleep quality evaluated subjectively by specially trained nurses, 70 demented patients showed only a seasonal effect on their sleep quality. In the second study performed around the winter solstice, 81 fairly healthy subjects living in rest-homes were divided into three groups, two for the crossover study as in the first investigation with a third group consuming only normal daytime milk as a control group to evaluate the effect of season. Caregivers graded the sleep quality and activity that was monitored separately for the morning before noon and for the evening after noon. In the second study, the effect of season was recognizable in the scores for sleep quality, which increased in all groups after the winter solstice. However, there were no changes in activity in the control group or in the group that consumed night-time milk during the first period of the crossover study, whereas both morning and evening activity increased significantly in the group that consumed night-time milk during the later period. Even ultra-low doses of melatonin may benefit the elderly by increasing their daytime activity.

Effects of Diet on Sleep Quality

“…A long-term crossover study in 70 elderly patients with dementia examined the effect of daily nighttime milk consumption on sleep quality and circadian activity. The study found no effect of nighttime milk over 8 wk on sleep quality in patients when compared with the consumption of normal milk from cows milked during the day (41). However, in this study, the elderly participants experienced greater morning and evening physical activity after the consumption of nighttime milk, which was seen as beneficial.…”

“…An analysis of milk content in one study revealed that nighttime milk contained higher amounts of Trp (4.66 mg/g) and melatonin (85.5 pg/g) than daytime milk (3.75 mg/g and 8.8 pg/g, respectively) (50). Another study used nighttime milk with a melatonin concentration of 10.2-18.3 pg/mL, with subjects consuming 0.5 L milk/d (41). This amount did not increase the subjects' blood melatonin concentrations.…”

Milk Collected at Night Induces Sedative and Anxiolytic-Like Effects and Augments Pentobarbital-Induced Sleeping Behavior in Mice

“…9 Altogether, the results of the behavioral experiments strongly suggest that Night milk possesses sedative, anxiolytic, and sleep-promoting effects.…”

“…4 Furthermore, a study conducted in elderly patients showed that Night milk improved sleep quality that resulted in a better daytime activity. 9 In view of these reports, the present study evaluated the psychopharmacological effects of Night milk, particularly its probable sedative and sleep-promoting/enhancing properties. For comparison, the effects of Day milk were also assessed.…”

“…5,6 However, melatonin levels decrease with age leading to impairment in the quality of sleep and other sleep disturbances. [7][8][9] Exogenous administration of tryptophan and melatonin aids in inducing drowsiness and sleep and may ameliorate sleep disturbances and disorders. 10 Recent studies have shown that milk collected during night time (Night milk) may have unique advantages over milk harvested during daytime (Day milk).…”