Lanrong Sun,1,2,* Jiaying Lao,2,* Haihui Guo,1,* Jinzhong Xu,1 Yu-Hsin Chen,2 Xingguang Luo,3 Shencong He,2 Weiming Hu,4 Fan Wang,5 Li Chen,2 Yanlong Liu,2 Qizeng Wang,6 Wenhui Lin6 

1Department of Clinical Pharmacy, Affiliated Wenling Hospital, Wenzhou Medical University, Wenling, 317500, People’s Republic of China; 2School of Mental Health, Wenzhou Medical University, Wenzhou, 325035, People’s Republic of China; 3Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06510, USA; 4Department of Psychiatry, The Third Hospital of Quzhou, Quzhou, People’s Republic of China; 5Department of Psychiatric Research Center, Beijing Hui-Long-Guan Hospital, Peking University, Beijing, 100096, People’s Republic of China; 6Department of Cardiovascular Medicine, Affiliated Wenling Hospital, Wenzhou Medical University, Wenling, 317500, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Yanlong Liu, School of Mental Health, Wenzhou Medical University, Wenzhou, 325035, People’s Republic of China, Email benjaminlyl@wmu.edu.cn Wenhui Lin, Department of Cardiovascular Medicine, Affiliated Wenling Hospital, Wenzhou Medical University, Wenling, 317500, People’s Republic of China, Email Lwh123688@163.com

Background and Objective: Insomnia has various adverse effects on middle-aged and older adults. Improving insomnia by adjusting diet has attracted attention. This study investigated the relationship between soy product intake and insomnia in middle-aged and older adults and explored the role of inflammatory factors.
Methods: The study included 877 middle-aged and older adults aged ≥ 45 years which from general patients who made an appointment or were admitted to the cardiology department at Wenling Hospital in Taizhou City. The proportion of female participants is 35.01%. Soy product intake was assessed using the Food Frequency Questionnaire (FFQ), sleep was quantified using the Insomnia Severity Index (ISI). The median (IQR) of soy product intake is ≤ 1 time per week (≤ 1 time per week, 2– 6 times per week) and the mean/SD value of insomnia score is 5.43/5.13.
Results: In Chinese middle-aged and older adults, soy product intake was negatively correlated with insomnia (|r|s ≥ 0.117, ps < 0.001), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α) and triglyceride (TG) levels (adjusted β: − 0.139, 95% CI: − 0.265 to − 0.012; β: − 0.049, 95% CI: − 0.091 to − 0.006; β: − 0.043, 95% CI: − 0.085 to − 0, respectively). There was no significant correlation between soy product intake and White Blood Cell (WBC), Absolute Neutrophil Count (GRAM), Platelet Count (PLT), Interleukin-1β (IL-1β), Interleukin-2 (IL-2), Interleukin-6 (IL-6), Hemoglobin (Hb), Red Blood Cell (RBC), Low-Density Lipoprotein Cholesterol (LDL-C), High-Density Lipoprotein Cholesterol (HDL-C) and Total Cholesterol (TC) levels.
Conclusion: Lower levels of soy product intake are associated with higher rates of insomnia in the middle-aged and older adults. Additionally, soy product intake is negatively correlated with peripheral blood CRP, TNF-α and TG levels. This study provides a new clinical perspective for middle-aged and older adults to enhance sleep through a balanced diet, wherein the inflammation and lipid may play a potentially crucial role.

Keywords: soy product intake, insomnia, insomnia severity index, serum tumor necrosis factor-alpha, serum C-reactive protein