Effect of dietary flexaseed oil on the prognosis of actue anterior cruciate ligament rupture: a randomized placebo-controlled trial.

Tang H, Xu Z, Lin J, Sun W, and Xiw Y. Am J Transl Res. 2022;14(10):7252-7259.

Full Text is Freely Available

Take-Home Message

People who supplemented their diet with flaxseed oil experienced slightly better outcomes 2 years after an anterior cruciate ligament (ACL) reconstruction than participants in a control group.


While we often focus on surgery and rehabilitation to optimize outcomes after an ACL injury, we may also want to consider other strategies to improve someone’s prognosis. Flaxseed oil, which contains α-linolenic acid (an omega-3 fatty acid), may suppress inflammation and be beneficial. However, the impact of flaxseed oil supplementation on the recovery after ACL reconstruction remains unclear.

Study Goal

Tang and colleagues completed a randomized placebo-controlled trial to explore the impact of dietary flaxseed oil on outcomes among people receiving an ACL reconstruction.


The authors randomized 142 participants who underwent ACL reconstruction into two equal groups. The experimental group took six flaxseed oil capsules (9 grams total, 4.2 g of α-linolenic acid) per day. The control group took six corn oil capsules (9 grams total, minimal α-linolenic acid) per day. Dietary supplementation continued for two years after the ACL reconstruction. The researchers contacted participants every two weeks by phone to ensure compliance with the study guidelines. After the 2-year intervention period, participants completed a battery of questionnaires to assess patient-reported outcomes: 1) Knee Injury and Osteoarthritis Outcomes Score (KOOS), 2) International Knee Documentation Committee (IKDC) score, 3) the Lysholm Knee Scoring Scale, and 4) Tegner Activity Scale.


After two years, the participants taking flaxseed oil had 1) better IKDC scores, 2) better KOOS sport and quality of life scores, 3) higher rates of returning to their prior level of sport (56 vs. 39%), and 4) fewer adverse events at the knee (e.g., episodes of giving way, pain) than the control group. The groups had no differences in KOOS pain or symptoms, Tegner scores, Lysholm scores, or treatment satisfaction.


Participants who received flaxseed oil supplements had slightly better outcomes than those in the control group. This preliminary study demonstrates that a diet supplemented with flaxseed oil containing high levels of α-linolenic acid may improve outcomes after an ACL reconstruction. It will be interesting to see if other high-quality research verifies these results with flaxseed oil or another source of α-linolenic acid. One detail not reported, which could be important, is the dietary habits beyond the flaxseed oil. For example, some of the participants in the control group may have had a diet high in α-linolenic acid.

Clinical Implications

Despite the need for more research, clinicians can discuss the small benefits and few risks associated with flaxseed oil supplementation. It is also important to remind athletes to purchase supplements that have been tested to ensure they are getting what they expect in each capsule.

Questions for Discussion

Do you recommend this or any other nutritional supplementation for patients who have undergone ACL reconstruction? If so, what have you suggested, and what resources caused you to recommend this supplement?

Written by Kyle Harris
Reviewed by Jeffrey Driban

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