Objective: To study the effect of Lactobacillus helveticus fermented milk on sleep and health perception in elderly healthy subjects.
Subjects: The study included 29 healthy elderly subjects aged 60-81 years.
Methods: Prospective, randomized, double-blind and placebo-controlled, with a crossover design. The study included two intervention periods of 3 weeks each, separated by a 3-week washout period. Subjects took 100 g of fermented milk drink or a placebo drink (artificially acidified milk) daily in the first supplementary period and the other drink in the second supplementary period. For each period, we measured sleep quality by means of actigraphy and a sleep questionnaire, and assessed the quality of life (QOL) by SF-36 health survey.
Results: There was a significant improvement in sleep efficiency (P=0.03) and number of wakening episodes (P=0.007) in actigraph data after intake of fermented milk, whereas no significant changes were observed for the placebo. Fermented milk did not improve the SF-36 scores significantly from the baseline period. In the GH domain (general health perception) of the SF-36, however, there was marginal improvement as compared to the baseline period. Although the difference between fermented milk and placebo was not statistically significant for any of the sleep or QOL parameters, fermented milk produced slightly greater mean values for many parameters.
Conclusion: This short-term (3-week) intervention study indicates that Lactobacillus helveticus fermented milk may have a more favorable effect on improving sleep in healthy elderly people as compared with placebo.