Asparagus extract and sleep quality in hospital shift workers
What it found
Nurses taking a daily asparagus extract product reported better sleep, less fatigue and more engagement at work over two weeks.
The study had no comparison group, so the authors urge caution.
What they found
Studies in people
Better reported sleep
After taking the asparagus extract, the nurses rated their overall sleep quality higher on questionnaires. Their average sleep score dropped from 7.41 to 6.03, where lower means better sleep. Sleep ratings improved most on nights after a night shift.
Less fatigue, more engagement
The nurses said they felt less tired after the two weeks. They also scored higher on questions about energy, dedication and focus at work.
Fewer slow reactions
In a short smartphone reaction test, the nurses had fewer delayed responses after taking the product. Average reaction time was slightly quicker, but the difference was small.
Activity meter sleep data
Wrist-worn activity meters showed a small rise in sleep efficiency, from 79.73% to 82.08%. The authors say this change was too small to be certain it was not due to chance.
No change in work problems
Scores measuring trouble thinking clearly or doing tasks at work stayed about the same. Ratings of low mood or anxiety also did not change much.
What the authors conclude
- They suggest that regularly taking a food product with asparagus extract may improve sleep, reduce tiredness and boost work focus in shift workers.
- They note that this could be an option when standard sleep advice is hard to follow.
- They call for further research with a comparison group to confirm these results.
How it was done
Shift work disrupts natural body rhythms and often leads to poor sleep. Earlier research suggested that asparagus extract might help the body recover from stress and improve sleep, but no one had tested it in shift workers.
Thirty-four nurses working day and night shifts at one Japanese hospital took part. They ate one 3 g packet of an asparagus extract product every day before their main sleep for at least two weeks. Each period included three night shifts, and researchers measured sleep, tiredness and work focus before and after.
What it can’t tell you
- Because there was no comparison group taking a dummy product, we cannot tell if the improvements came from the asparagus extract itself. People sometimes feel better simply because they expect a product to work. The study only followed 33 nurses at one hospital, mostly women, so the results may not apply to everyone.
Who paid
- Authors work at
- University of Occupational and Environmental Health, Japan
The paper
- Title
- Improved Sleep Quality and Work Performance Among Shift Workers Consuming a "Foods with Function Claims" Containing Asparagus Extract
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Sakai S, Nagata M, Nagata T, Mori K (2021). Improved Sleep Quality and Work Performance Among Shift Workers Consuming a "Foods with Function Claims" Containing Asparagus Extract. Journal of UOEH. doi:10.7888/juoeh.43.15Free full textPubMed 33678782DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error