A study published in the “Journal of Nutritional Science and Vitaminology” has suggested a positive association between the frequency of milk and dairy product consumption and subjective sleep quality during training periods in Japanese elite athletes. The research, which was conducted with prospective candidates for the 2016 Rio Olympic Games, concluded that women athletes who consumed milk more frequently exhibited a lower risk of experiencing a decline in sleep quality.
DOI: 10.3177/jnsv.65.177
Study Overview
In this cross-sectional study (Yasuda et al., 2019), scientists assessed the dietary habits and sleep patterns of 682 Japanese elite athletes, of which 679 athletes without milk allergy (379 men and 300 women) were evaluated. The data collection consisted of self-reported questionnaires that inquired about demographics, lifestyle factors, and specifically looked into sleep quality and frequency of milk or dairy product intake.
The participants were divided into three groups based on their consumption of milk and dairy products: low (0-2 days/week), medium (3-5 days/week), and high (6-7 days/week). After adjusting for potential confounding variables like smoking, drinking habits, and sleep duration, the results indicated that women in the middle and high milk consumption groups were significantly less likely to report a decrease in subjective sleep quality compared to their counterparts in the low consumption group.
Key Findings and Implications
The analysis revealed that among female athletes, those with moderate [OR: 0.48 (95% CI: 0.26-0.91)] and high [OR: 0.38 (95% CI: 0.21-0.71)] milk consumption had a notably lower risk of reporting a decline in sleep quality. However, these associations were not observed in male athletes. These findings may suggest a potential nutritional strategy that female athletes could utilize to maintain or improve subjective sleep quality.
Given the importance of sleep for athletic recovery and performance, these insights could influence dietary recommendations for athletes, particularly in regard to dairy intake. Proper sleep is crucial for cognitive function, physical health, and psychological well-being, all of which are key for elite athletes during intense training periods.
Study Limitations and Further Research
It’s important to note that the study is observational and does not establish causation. The self-reported nature of the data also introduces the possibility of recall bias and subjective interpretation of sleep quality. Further, the study did not account for the precise types or quantities of dairy consumed.
Future research could expand on these findings by conducting long-term, controlled trials to determine if there is a causal relationship between milk consumption and sleep quality, as well as exploring biological mechanisms that could account for the gender differences observed.
References
1. Yasuda, Jun et al. (2019). Association of Frequency of Milk or Dairy Product Consumption with Subjective Sleep Quality during Training Periods in Japanese Elite Athletes: A Cross-Sectional Study. Journal of Nutritional Science and Vitaminology, 65(2), 177-183. DOI: 10.3177/jnsv.65.177.
2. Halson, S. L. (2014). Sleep in elite athletes and nutritional interventions to enhance sleep. Sports Medicine, 44, S13-S23. DOI: 10.1007/s40279-014-0147-0.
3. Hirshkowitz, M., Whiton, K., Albert, S. M., Alessi, C., Bruni, O., … & Adams Hillard, P. J. (2015). National Sleep Foundation’s sleep time duration recommendations: methodology and results summary. Sleep Health, 1(1), 40-43. DOI: 10.1016/j.sleh.2014.12.010.
4. Watson, A. M. (2017). Sleep and Athletic Performance. Current Sports Medicine Reports, 16(6), 413-418. DOI: 10.1249/JSR.0000000000000418.
5. Peuhkuri, K., Sihvola, N., & Korpela, R. (2012). Dietary factors and fluctuating levels of melatonin. Food & Nutrition Research, 56, 10.3402/fnr.v56i0.17252. DOI: 10.3402/fnr.v56i0.17252.
Keywords
1. Sleep Quality in Athletes
2. Dairy Intake and Sleep
3. Nutritional Strategies for Athletes
4. Milk Consumption Benefits
5. Elite Sports Performance and Diet
Through this study, there is an implication of potential dietary adjustments that could benefit not only elite athletes but anyone looking to improve their sleep quality. While we should approach these results with careful consideration due to the aforementioned limitations, the association between dairy products and subjective sleep quality is an intriguing area for further exploration.
As the research unfolds, athletes and individuals seeking to optimize their performance and well-being through nutritional means have yet another reason to consider the role of dairy in their diets. More comprehensive studies will be necessary to confirm these findings and provide specific guidelines for milk and dairy product consumption in relation to sleep and overall health.