Flaxseed Oil Supplementation Augments Antioxidant Capacity and Alleviates Oxidative Stress: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Vali Musazadeh, Jaber Jafarzadeh, Majid Keramati, Meysam Zarezadeh, Mahshid Ahmadi, Zohreh Farrokhian, Alireza Ostadrahimi
Abstract
Objective. Studies have reported controversial findings regarding the flaxseed oil effect on antioxidant status biomarkers. The present meta-analysis aimed to determine the impact of flaxseed oil on the serum level of biomarkers of oxidative stress. Methods. A systematic search was conducted up to November 2020 on PubMed, Embase, Web of Science, Scopus, and Cochrane Central Library. Random-effects model was employed to perform meta-analysis. Subgroup analysis was carried out to determine the effect across different ranges of dosages and durations. Results. Eight trials were included with a total sample size of 429 individuals with a mean age range of 25 to 70 years. The results indicated that flaxseed oil supplementation led to a significant decrease in malondialdehyde (MDA) levels (SMD: −0.52 μmol/L; 95% CI: −0.89, −0.15; <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mi>P</a:mi> <a:mo>=</a:mo> <a:mn>0.006</a:mn> </a:math> , I2 = 71.3, <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mi>P</c:mi> <c:mo><</c:mo> <c:mn>0.001</c:mn> </c:math> ) and increase in total antioxidant capacity (TAC) levels (WMD: 82.84 mmol/L; 95% CI: 19.80, 145.87; <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mi>P</e:mi> <e:mo>=</e:mo> <e:mn>0.006</e:mn> </e:math> , I2 = 92.7, <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" id="M4"> <g:mi>P</g:mi> <g:mo><</g:mo> <g:mn>0.001</g:mn> </g:math> ). No significant effect was observed on glutathione (GSH). Conclusion. Our findings revealed that flaxseed oil supplementation might play a beneficial role in the reinforcement of the antioxidant defense system and amelioration of oxidative stress in adults.