Low Dietary Tryptophan Intake Associated with Increased Risk of Insomnia

by | Sep 24, 2024 | 2024, Amino Acids, Recent Articles, Sleep, Tryptophan

Written by Chrystal Moulton, Science Writer. Students within the lowest quartile of tryptophan intake had a higher risk of insomnia (OR= 1.57, p<0.05) and short sleep duration (OR= 1.19, p<0.05).

Issues with sleep is an increasing problem among university young adults1. Some studies have shown that 75% of university students have occasional sleep problems2,3. Other research has clearly documented that university students generally sacrifice sleep to maintain academics and social life4,5. However lack of sleep is associated with anxiety, emotional instability, impaired memory and driving, risk taking behavior, and reduction in academic performance just to name a few4-6. Although various factors play a role in sleep, diet may also influence sleep7. Tryptophan, which is essential for sleep, is mostly found in animal products, legumes, whole grains, as well as in nuts and seeds. Tryptophan is also a precursor of serotonin and melatonin both of which are necessary to regulate sleep wake cycles and sleep quality8. In the current trial, researchers evaluated the relationship between tryptophan intake and sleep quality in first year university students within the UNIHCOS project9.

The UNIHCOS project is a multi-center prospective study involving 11 universities in Spain10. The objective of the UNIHCOS project is to understand lifestyle habits of first year university students how long with the lifestyle changes made during their university life. Researchers in this trial did a cross-sectional study within the framework of the UNIHCOS project. Eligible students had to be first year students enrolling in an undergraduate program for the first time in one of the participating universities during 2011 to 2022. Any students who were previously enrolled in any undergraduate courses along with any students pursuing higher degrees were excluded from this cross-sectional study. Questionnaires related to sociodemographic information, dietary intake, and sleep were collected through online questionnaires. Tryptophan intake was calculated based on the food frequency questionnaire which assesses dietary intake. Researchers then used logistical regression or odds ratios to determine sleep related factors based on the data collected.

The number of university students included in this study was 11,485. The median age was 20.11 ±4.62 years old. Median sleep duration for all students was 7.49 ±1.24 h/ day. Researchers found that female students reported longer sleep duration than their male counterparts; however, female students presented poor scores for sleep quality variables. This includes waking up early (P<0.001), waking up while sleeping (P<0.001), difficulty sleeping (P<0.001), and sleep efficiency (P<0.001). Researchers also noted that female students reported insomnia at a much higher rate than male students (40.9% versus 28.1%, P<0.001). Based on the Athens Insomnia Scale, female students had much more poor scores across 6 out of 9 subsections of the insomnia assessment compared to male students. Dietary assessment of tryptophan showed a significant difference between male and female students. However, this was expected since tryptophan requirement is dependent on body weight and female students tend to be smaller than male students. Logistical regression analysis of the whole sample (11,485) showed that students within the lowest quartile of tryptophan intake had a higher risk of insomnia (OR= 1.57, p<0.05) and short sleep duration (OR= 1.19, p<0.05).

Data from this cross-sectional study suggests that female students experience poor sleep quality at a higher rate than male students. The research also determined that students in the lowest quartile of tryptophan consumption had a higher risk of sleep problems including insomnia and short sleep duration. Additional studies will need to be conducted to verify these findings.

Source: Morales-Suárez-Varela, María, Carmen Amezcua-Prieto, Isabel Peraita-Costa, Ramona Mateos-Campos, Carlos Ayán, Rocío Ortiz-Moncada, and Tania Fernández-Villa. “Sleep Patterns and Tryptophan Consumption among Students at Spanish Universities: The Unihcos Project.” Nutrients 16, no. 14 (2024): 2376.

© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/
4.0/).

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Posted September 24, 2024.

Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.

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