Comparison of the effects of flaxseed oil and sunflower seed oil consumption on serum glucose, lipid profile, blood pressure, and lipid peroxidation in patients with metabolic syndrome

J Clin Lipidol. 2018 Jan-Feb;12(1):70-77. doi: 10.1016/j.jacl.2017.11.004. Epub 2017 Nov 20.


Background: Metabolic syndrome (MetSyn) increases the risk of type II diabetes and morbidity and mortality due to cardiovascular diseases. Flaxseed oil (FO), as a functional food, is one of the major vegetal sources of essential omega-3 fatty acids.

Objective: This study aimed to compare the effects of consumption of FO and sunflower seed oil (SO) on lipid peroxidation and other symptoms of MetSyn.

Methods: This randomized controlled interventional trial was conducted on 60 volunteers aged 30 to 60 years who were diagnosed with MetSyn in Shiraz, Iran. The participants who fulfilled the inclusion criteria were randomly assigned to SO (n = 30, receiving 25 mL/d SO) and FO (n = 30, receiving 25 ml/d FO) groups using block randomization. The diets were identical for all the participants. Blood pressure (BP), serum lipid, fasting blood sugar, and malondialdehyde were measured at baseline and at the end of week 7.

Result: The results showed no significant difference between the 2 groups regarding blood lipid levels and fasting blood sugar at the end of the study. However, significant reductions in total cholesterol, low-density lipoprotein cholesterol (5.6% in FO and 10.8% in SO), and triglyceride levels were seen within each group after treatment with FO and SO (P < .05). Nonetheless, between-group changes were significant (<0.05) for systolic BP (mean [±standard deviation {SD}] changes were -14.0 ± 22.41 in the FO group [P = .004] and 0.92 ± 8.70 in the SO group [P = .594]) and diastolic BP (mean [±SD] changes were -4.26 ± 7.44 in the FO group [P = .007] and 1.30 ± 6.91 in the SO group [P = .344]), but marginally significant (P = .053) for malondialdehyde level (mean [±SD] changes were -1.29 ± 1.48 in the FO group [P < .001] and -0.52 ± 1.34 in the SO group [P = .52]). A significant decrease in weight was also found in both groups. However, waist circumference decreased significantly only in the FO group at the end of the study (P < .05).

Conclusion: Our results indicated that dietary FO could be effective in amelioration of some symptoms of MetSyn and decrease BP and lipid peroxidation.

Keywords: Blood pressure; Flaxseed oil; Lipid peroxidation; Metabolic syndrome; Sunflower seed oil.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / analysis*
  • Blood Pressure*
  • Cholesterol, HDL / blood
  • Cholesterol, LDL / blood
  • Diet
  • Female
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Linseed Oil / analysis
  • Linseed Oil / therapeutic use*
  • Lipid Peroxidation*
  • Male
  • Malondialdehyde / blood
  • Metabolic Syndrome / diet therapy*
  • Middle Aged
  • Sunflower Oil / analysis
  • Sunflower Oil / therapeutic use*
  • Triglycerides / blood
  • Waist Circumference


  • Blood Glucose
  • Cholesterol, HDL
  • Cholesterol, LDL
  • Sunflower Oil
  • Triglycerides
  • Malondialdehyde
  • Linseed Oil

Associated data

  • IRCT/IRCT2015012020737N1