Dietary Restriction and Supplementation with Omega-3 Fatty Acids Improves Polyunsaturated Fatty Acid Ratio

by | Apr 29, 2025 | 2025, Fish Oil Supplements, Obesity, Omega - 3, Polyunsaturated, Recent Articles

Written by Chrystal Moulton, Science Writer. In the omega-3 group, TNF-alpha (p=0.001), IL-6 (p=0.01), IL-10 (p=0.035), Resolvin D1 (p=0.048), and MCP-1 (p=0.04) improved significantly.

omega 3Culture, genetics, and social factors contribute to obesity, which is associated with other chronic conditions such as type 2 diabetes, dyslipidemia, and hypertension1. Among various disorders associated with obesity, researchers have also cited an imbalance in polyunsaturated fatty acid intake which can create a state of constant low-grade inflammation worsening the metabolic status of individuals with obesity2-4. In the current study, researchers investigated the effect of dietary omega-3 fatty acids on changes in inflammatory biomarkers and anthropometric measures in obese adults5.

Subjects between 25-50 years old with a BMI >30kg/m2 and/or abdominal obesity were eligible for this trial. The study was 8 weeks and designed as a randomized, double-blind, placebo- controlled trial. Eligible participants were randomly assigned to a 200kcal/day diet restriction with omega-3 from fish oil or alpha-linoleic acid (ALA) from flax and chia seed [chosen as the placebo since it has no effect on inflammatory markers6]. Both were provided supplements in capsule form. The fish oil supplement contained 1080mg of EPA and 720mg DHA while the placebo was a 1600mg capsule of vegetable sourced ALA. Volunteers were provided a recipe book with 20 days of carefully curated meals and snacks. Each meal was curated to maintain a 5:1 ratio of omega-6/omega-3. At baseline, eligible participants were interviewed by a nutritionist who collected sociodemographic data and clinical records from each participant. Also, a 3-day dietary record was collected from each volunteer at baseline and week 8. Specialized software was used to calculate the polyunsaturated fatty acid content of each meal. Fasting blood samples were collected and anthropometric measures were conducted at baseline, week 4, and week 8. Blood samples were used to assess inflammatory biomarkers such as hs-CRP, TNF-alpha, and plasma Resolvin D1 along with HDL-C, LDL-C, total cholesterol, triglycerides, serum glucose, and insulin levels. Insulin resistance was calculated. Researchers assessed whether a restrictive diet with marine sourced omega-3 supplementation would elicit physical and physiological changes in the intervention group.

Forty eligible adults who were randomly assigned to the omega-3 (n=21) and placebo group (n=19) completed this trial. No statistical differences were observed between each group at baseline. Also, no significant difference in adherence to study protocol was observed between groups. Adherence was 70 ±18.2% in the placebo group and 77 ±25.2% in the omega-3 group. Both groups had a significant increase in omega-3 intake [placebo group: 1.0g at baseline versus 2.9g at week 8, p=0.012, omega-3 group: 1.2g at baseline versus 1.8g at week 8, p=0.023] and improvement in n-6/n-3 ratio [placebo group: 9.9 at baseline versus 3.4 at week 8, p=0.019, omega-3 group: 9 at baseline versus 2.8 at week 8, p=0.003]. The omega-3 group also had a significant decrease in omega-6 (p=0.012), saturated fat (p=0.047), and percent fat (p=0.028) intake by week 8. In anthropometric measurements, both groups showed significant improvement in weight, BMI, and waist circumference in both male and female participants (p<0.05). However, percent body fat improved for male participants only in the intervention group (p=0.015). Significant improvements were observed in triglyceride and vLDL-C in both groups (p<0.05). However, among male participants in the intervention group, researchers observed a significant reduction in HDL-C (p=0.012). Between groups however, not significant differences were observed in lipid profile, serum glucose, and anthropometric measurements. The prevalence of abdominal obesity was significantly reduced in the intervention group (95% at baseline v. 60% at week 8, p=0.016). TNF-alpha was significantly reduced in the placebo group (p=0.002). In the omega-3 group, TNF-alpha (p=0.001), IL-6 (p=0.01), IL-10 (p=0.035), Resolvin D1 (p=0.048), and MCP-1 [monocyte chemoattractant protein 1](p=0.04) improved significantly. Furthermore, researchers observed a significant reduction in IL-6 (p=0.015) and a significant increase in Resolvin D1 (p=0.041) and IL-10 (p=0.001) in the intervention group versus placebo.

Overall, both placebo (vegetable sourced ALA) and marine sourced omega-3 supplementation accompanied by a 200kcal restrictive diet exhibited significant improvements in omega-3 intake and n-6/n-3 status. Both groups also had significant improvement in anthropometric measures. However, only omega-3 supplementation significantly improved inflammatory biomarkers. Additional studies will be needed to verify these findings.

Source: Torres-Vanegas, Joel, Roberto Rodríguez-Echevarría, Wendy Campos-Pérez, Sarai Citlalic Rodríguez-Reyes, Samantha Desireé Reyes-Pérez, Mariana Pérez-Robles, and Erika Martínez-López. “Effect of a Diet Supplemented with Marine Omega-3 Fatty Acids on Inflammatory Markers in Subjects with Obesity: A Randomized Active Placebo-Controlled Trial.” In Healthcare, vol. 13, no. 2, p. 103. MDPI, 2025.

© 2025 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 April 29, 2025.

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.

References:

  1. Dávila-Torres J, González-Izquierdo JJ, Barrera-Cruz A. [Obesity in Mexico]. Rev Med Inst Mex Seguro Soc. Mar-Apr 2015;53(2):240-9. Panorama de la obesidad en México.
  2. DiNicolantonio JJ, O’Keefe J. The Importance of Maintaining a Low Omega-6/Omega-3 Ratio for Reducing the Risk of Autoimmune Diseases, Asthma, and Allergies. Mo Med. Sep-Oct 2021;118(5):453-459.
  3. Zhang Y, Sun Y, Yu Q, et al. Higher ratio of plasma omega-6/omega-3 fatty acids is associated with greater risk of all-cause, cancer, and cardiovascular mortality: A population-based cohort study in UK Biobank. Elife. Apr 5 2024;12doi:10.7554/eLife.90132
  4. Simopoulos AP, DiNicolantonio JJ. The importance of a balanced ω-6 to ω-3 ratio in the prevention and management of obesity. Open heart. 2016;3(2):e000385. doi:10.1136/openhrt-2015-000385
  5. Torres-Vanegas J, Rodríguez-Echevarría R, Campos-Pérez W, et al. Effect of a Diet Supplemented with Marine Omega-3 Fatty Acids on Inflammatory Markers in Subjects with Obesity: A Randomized Active Placebo-Controlled Trial. Healthcare (Basel). Jan 8 2025;13(2)doi:10.3390/healthcare13020103
  6. Su H, Liu R, Chang M, Huang J, Jin Q, Wang X. Effect of dietary alpha-linolenic acid on blood inflammatory markers: a systematic review and meta-analysis of randomized controlled trials. Eur J Nutr. Apr 2018;57(3):877-891. doi:10.1007/s00394-017-1386-2