Fish Oil for Cognitive Function, Sleep Quality, and Bone Density

Effects of n-3 Fatty Acids on Cognitive Function, Sleep Quality, and Bone Mineral Density in Diabetic Patients: an Ancillary Study of the Precision Nutritional Management for Diabetes (PNMD) Trial

The Precision Nutritional Management for Diabetes trial (PNMD; NCT03708887) is a randomized clinical trial in 415 diabetic patients investigating whether taking daily dietary supplements of omega-3 fatty acids (1.5 or 3 grams) improves glucose and lipid homeostasis in Chinese diabetic patients. This ancillary study is being conducted among PNMD participants and will examine whether fish oil supplements affect A) cognitive function, B) sleep quality, and C) bone mineral density. Cognitive function, sleep quality, and bone mineral density will be evaluated at baseline and post-intervention. The Mini-Mental State Exams (MMSE) will be conducted to evaluate the cognitive function of participants. The Pittsburgh Sleep Quality Index (PSQI) will be calculated through questionnaires to evaluate sleep quality. The Dual-emission X-ray Absorptiometry (DXA) will be assessed to measure the bone density.

Study Overview

• Status: Completed
• Conditions: Sleep; Cognitive Decline; Bone Mineral Density
• Intervention / Treatment: Dietary supplement: Refined olive oil; Dietary supplement: Low-dose fish oil capsules; Dietary supplement: High-dose fish oil capsules

• Study Type: Interventional
• Enrollment (Actual): 415
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Zhejiang
    • Jinhua, Zhejiang, China, 321102
      • Lanxi Red Cross Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosed type 2 diabetes according to WHO diagnostic criteria or those on the use of diabetic medications;
• Between 40 and 75 years old (postmenopausal women);
• Have never used n-3 PUFA supplements before or have stopped using them for more than six months.

Exclusion Criteria:

• Type 1 diabetes;
• Coronary heart disease, stroke, cancer, hepatic or kidney disease;
• Pregnancy or lactation;
• Allergy to fish;
• Have participated in other clinical trials in the last three months.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Control group; Subjects will receive equivalent amounts of refined olive oil daily.	Dietary supplement: Refined olive oil; Participants in the control group will receive 4 g refined olive oil daily
Experimental: Low-dose fish oil group; Subjects will receive four fish oil and refined olive oil mixed capsules containing 1.5 g of marine n-3 PUFAs (72% EPA and 28% DHA) per day	Dietary supplement: Low-dose fish oil capsules; Patients in the low-dose group will receive four fish-oil and refined olive oil mixed capsules containing 1.5 g of marine n-3 PUFAs per day.
Experimental: High-dose fish oil group; Subjects will receive four fish oil capsules containing 3 g of marine n-3 PUFAs (72% EPA and 28% DHA) per day	Dietary supplement: High-dose fish oil capsules; Patients in the high-dose group will receive four fish oil capsules containing 3 g of marine n-3 PUFAs (72% EPA and 28% DHA) per day.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bone mineral density	The Dual-emission X-ray Absorptiometry (DXA) will be assessed to measure the bone mineral density at baseline and post-intervention.	Baseline and 1 year
Sleep quality	The Pittsburgh Sleep Quality Index (PSQI) will be calculated through questionnaires to evaluate sleep quality. The Changes in sleep quality will be quantified by the difference in PSQI scores between the baseline and the conclusion of the intervention period.	Baseline and 1 year
Cognitive function	The Mini-Mental State Exams (MMSE) will be conducted to evaluate the cognitive function of participants at both the start and end of the study. Changes in cognitive function will be quantified by the difference in MMSE scores between the baseline and the conclusion of the intervention period.	Baseline and 1 year

Collaborators and Investigators

• Sponsor: Jingjing Jiao

Study record dates

Study Major Dates

• Study Start (Actual): October 10, 2020
• Primary Completion (Actual): January 2, 2022
• Study Completion (Actual): February 28, 2022

Study Registration Dates

• First Submitted: September 24, 2024
• First Submitted That Met QC Criteria: September 24, 2024
• First Posted (Actual): September 26, 2024

Study Record Updates

• Last Update Posted (Actual): August 13, 2025
• Last Update Submitted That Met QC Criteria: August 11, 2025
• Last Verified: September 1, 2024

More Information

Terms related to this study

• Keywords: cognitive function; bone density; Omega-3 fatty acids; Fish oil; sleep quality
• Additional Relevant MeSH Terms: Mental Disorders; Neurocognitive Disorders; Cognition Disorders; Cognitive Dysfunction
• Other Study ID Numbers: RCT_N3_SUPPLE

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No