Soy Nutrition Institute
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Jan 29, 2016

Soybean isoflavone intake is associated with better sleep

An estimated 50–70 million adults in the United States have chronic sleep and wakefulness disorders. Sleep difficulties are associated with chronic diseases, mental disorders, health-risk behaviors, limitations of daily functioning, injury, and mortality. The National Sleep Foundation suggests that most adults need 7–9 hours of sleep per night, although individual variations exist.

New research suggests that a healthful diet and soybean isoflavones improve sleep duration and quality.  In regard to the former, a just-published US cross-over study involving 26 normal weight men and women (30–45 years), habitually sleeping 7–9 h/night, found that that low fiber and high saturated fat and sugar intake was associated with lighter, less restorative sleep with more arousals. With respect to the latter, higher daily isoflavone intake was positively associated with optimal sleep duration and quality in a Japanese population in a cross-sectional study involving 1076 Japanese adults aged 20-78 years. For this study, isoflavone intake was assessed using a brief self-administered diet history questionnaire, and sleep was evaluated using a self-reported questionnaire.

The prevalence of regular sleep duration (7-8 h/day) and sufficient sleep quality were 13.3% and 56.2 %, respectively. After adjusting for potential confounding factors, the odds ratios (95% CIs) for optimal sleep duration (7-8 h) when higher isoflavone intakes quartiles 2-4 (Q2-Q4) were compared with low isoflavone intake (Q1) were Q2: 0.94 (0.53-1.56); Q3: 1.28 (0.73-2.24); and Q4: 1.84 (1.06-3.18) (p for trend = 0.013). In the final adjusted model, sufficient sleep quality across categories of isoflavone intake was Q1: 1.00 (reference); Q2: 1.30 (0.91-1.84); Q3: 1.48 (1.03-2.12); and Q4: 1.78 (1.22-2.60); (p for trend = 0.002).  Isoflavone intake for the four quartiles was Q1: 0–10.96 mg/1000 kcal/day; Q2: 10.97–17.99 mg/1000 kcal/day; Q3: 18.00–26.73 mg/1000 kcal/day; and Q4: 26.74–83.06 mg/1000 kcal/day).

Sources: St-Onge MP, Roberts A, Shechter A, Choudhury AR. Fiber and saturated fat are associated with sleep arousals and slow wave sleep. J Clin Sleep Med 2016;12(1)

Cui Y, Niu K, Huang C, Momma H, Guan L, Kobayashi Y, Guo H, Chujo M, Otomo A, and Nagatomi R. Relationship between daily isoflavone intake and sleep in Japanese adults: a cross-sectional study. Nutr J 2015;14:127.