Probiotics for a Good Night Sleep

By: Robert M. Blair, Ph.D., Strategic Research Scientist


Getting a good night sleep is one of the most important things we can do for our health. Numerous studies have reported that inadequate amounts of sleep and poor sleep quality are linked to poor diet, obesity, and chronic health conditions [1, 2].

According to the National Sleep Foundation, most adults should get between 7 – 9 hours of sleep each night [3]. Similarly, the American Academy of Sleep Medicine and the Sleep Research Society make the following recommendation… “Adults should sleep 7 or more hours per night on a regular basis to promote optimal health” and further state that “Sleeping less than 7 hours per night on a regular basis is associated with adverse health outcomes, including weight gain and obesity, diabetes, hypertension, heart disease and stroke, depression, and increased risk of death” [4].

Despite the importance of getting adequate amounts of good quality sleep, many of us are not getting the sleep we need. According to the National Sleep Foundation, 35% of Americans reported their sleep quality as “poor” or only “fair”. Similarly, a 2013 Gallup poll reported that only 59% of Americans get seven or more hours of sleep each night, while 40% get six or less hours of sleep each night.

A recent research study reported that one possible way to support a good night sleep is by supplementing with probiotics [5]. In this study, 4th-year medical students who were being exposed to a stressful situation (national qualification examinations) were randomly assigned to drink 100 ml of milk (placebo) or 100 ml of milk containing the probiotic bacteria Lactobacillus casei. The drinks were consumed daily for 11 weeks starting 8 weeks before the national examinations took place. Measures of anxiety and sleep quality were assessed at the beginning of the study, at various time points prior to the exam, and at two time points after examinations were complete.

The results of this study showed that anxiety increased in both groups of subjects starting 2 weeks before the exams and peaked the day before the exam. Similarly, overall sleep quality decreased as the exams neared. However, when individual components of sleep quality were assessed, it was observed that supplementing with the probiotic helped students feel less sleepy when they woke up and significantly increased sleep length compared to the placebo group. Additionally, probiotic supplementation helped students fall asleep easier and experience a deeper sleep compared to the placebo group.

These results suggest that supplementation with L. casei probiotics may combat the negative effects of stress on sleep and lead to a better night’s sleep. The research on probiotics and sleep quality is still in the very early stages and the mechanism(s) by which probiotics might improve sleep quality are not yet completely understood. Nonetheless, this study adds to the accumulating evidence of the many health benefits of probiotics.



  1. Dashti HS, Scheer FA, Jacques PF, Lamon-Fava S, Ordovás JM. Short sleep duration and dietary intake: epidemiologic evidence, mechanisms, and health implications. Adv Nutr 2015; 6(6):648-59.
  2. Nedeltcheva AV, Scheer FA. Metabolic effects of sleep disruption, links to obesity and diabetes. Curr Opin Endocrinol Diabetes Obes 2014; 21(4):293-8.
  3. National Sleep Foundation. 2014 Sleep Health Index.
  4. Watson NF, Badr MS, Belenky G, Bliwise DL, Buxton OM, Buysse D, Dinges DF, Gangwisch J, Grandner MA, Kushida C, Malhotra RK, Martin JL, Patel SR, Quan SF, Tasali E. Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep 2015; 38(6):843-4.
  5. Takada M, Nishida K, Gondo Y, Kikuchi-Hayakawa H, Ishikawa H, Suda K, Kawai M, Hoshi R, Kuwano Y, Miyazaki K, Rokutan K. Beneficial effects of Lactobacillus casei strain Shirota on academic stress-induced sleep disturbance in healthy adults: a double-blind, randomised, placebo-controlled trial. Beneficial Microbes 2017; 8(2):153-162.