Dietary Impact on Sleep, Rhythms and Related Physiology

Official title

Inverkan av Kost pa Dygnsrytmer Och Amnesomsattning

Overview

Sleep and metabolism are closely interconnected, and emerging evidence suggests that dietary composition may influence both sleep quality and key physiological functions such as glucose regulation, cardiovascular activity, and hormonal signaling. This study aims to investigate how a Western-style unhealthy diet versus a healthier, fiber-rich diet affects objective and subjective sleep measures, 24-hour physiological parameters, and a range of biomarkers related to cardiometabolic, neurodegenerative, and gut microbial function.

Detailed description

Metabolism is tightly regulated by sleep and interacts bidirectionally with diet. While it is well established that insufficient or disrupted sleep can impair glucose regulation, cardiovascular function, and promote unhealthy eating behaviors that promote cardiometabolic disease, less is known about how different dietary patterns impact subjective and objective sleep parameters, as well as related physiological systems.

The study will systematically investigate how consumption of an unhealthier "Western" diet, compared to a healthier diet, affects both objective and subjective sleep parameters, as well as 24-hour heart rate and blood pressure profiles, glucose variability, and hormonal and molecular biomarkers.

The study will be conducted as a 2-condition, randomized crossover study, with assessments in the field for about a week, followed by a multi-day stay for measurements under standardized laboratory conditions. Participants will be monitored using polysomnography, and wearable devices, including for continuous glucose and heart rate parameters, with multi-compartment sampling to assess diet-mediated responses across cardiometabolic, neurodegenerative, and microbial pathways. In field and in the lab, biological samples will be collected repeatedly across the day to establish diurnal rhythms.

Cognitive performance, mood, and subjective appetite will also be evaluated. By identifying diet-driven changes in sleep and related physiological functions, this study aims to provide mechanistic insights into how nutrition impacts sleep, cardiometabolic health parameters and molecular pathways.

Interventions

• Other Low-fat dietary intervention
  Low-fat diet for approximately 1 week, preceding in-lab study period (approximately 2 days) under standardized conditions (total dietary exposure up to 9-10 days).
• Other High-fat dietary intervention
  High-fat diet for approximately 1 week, preceding in-lab study period (approximately 2 days) under standardized conditions (total dietary exposure up to 9-10 days).

Primary outcome measures

• Sleep Architecture and Neurophysiological Features [Time frame: Up to 9 nights on each diet]
• Change in 24-Hour Heart Rate Variability (HRV) [Time frame: Up to 9 days on each diet]

Secondary outcome measures (12)

• 24-Hour Heart Rate (HR) [Time frame: Up to 9 days on each diet]
• Heart Rate Response to Standardized Stair Stepping [Time frame: Baseline and day 7-9 of each diet period]
• Morning-to-Evening and 24-h blood pressure (BP) [Time frame: Up to 9 days on each diet]
• 24 Hour Continuous Glucose Levels [Time frame: Up to 9 days on each diet]
• Levels of Blood-based Biomarkers [Time frame: Up to 9 days on each diet]
• Levels of CNS biomarkers [Time frame: Up to 9 days on each diet]
• Urinary Metabolite Levels [Time frame: Up to 9 days on each diet]
• Change in Metabolic Fuel Utilization [Time frame: Up to 9 days on each diet]
• Levels of Fecal Metabolites [Time frame: Up to 9 days on each diet]
• Levels of Fecal Microbiota [Time frame: Up to 9 days on each diet]
• Levels of Salival Biomarkers [Time frame: Up to 9 days on each diet]
• Levels of Salival Microbiota [Time frame: Up to 9 days on each diet]

Eligibility criteria

Inclusion criteria

• Age 18-32 yr
• Healthy (self-reported) and not on chronic medication
• BMI 18-27 kg/m2 (and waist circumference <102 cm), and weight stable (less than 5% body weight change in the past 6 months)
• Non-smoker and non-nicotine user
• Regular sleep-wake pattern, with sleep duration of 7-9.25 hrs per night
• Regular exercise habits the last 2 months
• Regular daily meal pattern with 3 main meals

Exclusion criteria

• Major or chronic illness, e.g. diabetes, renal disease or inflammatory bowel disease
• Current or history of endocrine or metabolic disorders
• Psychiatric or neurological disorders (e.g. bipolar disorder, epilepsy)
• Frequent gastrointestinal symptoms
• Chronic medication
• Any sleep disorder (including recent or chronic symptoms of insomnia)
• Shift work in the preceding three months or for a long duration
• Extreme chronotype or physical activity patterns
• Time travel over two time zones in the preceding month
• Too much weight gain or weight loss in the preceding 6 months (±5% body weight in past 6 months)
• Any issues with or allergies against the provided food items
• Recent major dietary changes or adoption of specific dietary regimens
• Women who are pregnant, breastfeeding, or planning to become pregnant during the study period.
• Use of illicit drugs or substances of abuse

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Crossover

Masking

Open label

Primary purpose

Basic science

Study locations

Sweden · 1 center

• Uppsala biomedical center — Uppsala

Identifiers

NCT: NCT07138313 · CircHFJC2017pt2

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗