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Flaxseed oil

Also known as: Linum usitatissimum oil, linseed oil, flax oil, Flaxseed oil

Overview

Flaxseed oil, derived from the seeds of Linum usitatissimum, is a dietary supplement renowned for its high content of alpha-linolenic acid (ALA), an essential plant-based omega-3 fatty acid. It serves as a precursor to longer-chain omega-3s like EPA and DHA, making it a valuable source for individuals seeking plant-derived omega-3s. Primarily utilized for its cardiovascular benefits, anti-inflammatory properties, and role in managing metabolic syndrome, flaxseed oil is characterized by approximately 50-60% ALA content. It also exhibits antioxidant properties and may influence hormonal balance. Research, including numerous randomized controlled trials and meta-analyses, supports its efficacy in modulating inflammation, improving lipid profiles, and reducing oxidative stress, though the overall evidence quality is moderate with some study heterogeneity.

Benefits

Flaxseed oil offers several evidence-based benefits, particularly for individuals with metabolic syndrome and hypercholesterolemia. It significantly reduces inflammatory biomarker interleukin-6 (IL-6) and oxidative stress marker malondialdehyde (MDA), with a notable increase in total antioxidant capacity (TAC). These effects are statistically significant but modest, suggesting a supportive role in managing inflammation and oxidative stress. Furthermore, flaxseed oil has been shown to reduce total and LDL cholesterol levels, especially in women and those with elevated baseline cholesterol, demonstrating clinically relevant lipid-lowering effects. While it does not consistently affect C-reactive protein (CRP) levels, its impact on IL-6 and lipid profiles is well-documented. There is also preliminary, though limited and heterogeneous, evidence suggesting potential modulation of sex hormone profiles. Benefits on inflammation and lipids typically manifest within 4–12 weeks of consistent supplementation.

How it works

The primary mechanism of action for flaxseed oil stems from its high alpha-linolenic acid (ALA) content. ALA is an omega-3 fatty acid that, once consumed, can be partially converted in the body to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These omega-3 metabolites exert anti-inflammatory effects by competing with arachidonic acid for key enzymes like cyclooxygenase and lipoxygenase, thereby reducing the production of pro-inflammatory eicosanoids. Flaxseed oil's antioxidant properties are linked to its ability to increase total antioxidant capacity and decrease lipid peroxidation, as evidenced by reduced malondialdehyde levels. While the conversion of ALA to EPA/DHA is limited in humans, it is sufficient to contribute to its observed anti-inflammatory effects. Additionally, there is some indication of its involvement in sex hormone synthesis pathways, though this mechanism requires further elucidation.

Side effects

Flaxseed oil is generally considered safe, with clinical trials reporting no serious adverse effects. Mild gastrointestinal discomfort, such as bloating or diarrhea, is rare but can occur. There are no significant drug interactions widely reported; however, caution is advised when co-administering flaxseed oil with anticoagulant or antiplatelet medications due to the potential for additive effects on blood thinning, which could increase the risk of bleeding. Individuals with pre-existing bleeding disorders or those scheduled for surgery should consult a healthcare professional before using flaxseed oil. No specific contraindications have been established, and the oil is well-tolerated at typical supplemental doses. Long-term safety data beyond several months are limited, but current evidence supports its safety profile for short to medium-term use.

Dosage

Effective dosages of flaxseed oil observed in research studies typically range from approximately 2 to 10 grams per day. For optimal anti-inflammatory and lipid-lowering effects, a daily intake of 3–6 grams is commonly recommended. While there is no officially established maximum safe dose, caution is advised for doses exceeding 10 grams per day due to limited research at higher intakes. Flaxseed oil can be taken flexibly throughout the day, but its absorption may be enhanced when consumed with meals containing dietary fat. No specific cofactors are required for its efficacy, but overall dietary fat intake can support its absorption. It is available in various forms, including liquid oil and softgel capsules, with the liquid form often providing more flexibility in dosing.

FAQs

Is flaxseed oil effective for lowering cholesterol?

Yes, flaxseed oil can significantly reduce total and LDL cholesterol, particularly in women and individuals with elevated baseline cholesterol levels.

Does flaxseed oil reduce inflammation?

It reduces inflammatory markers like IL-6 and oxidative stress markers, but its effect on C-reactive protein (CRP) is not consistently significant.

Can flaxseed oil affect hormones?

Limited research suggests it may modulate sex hormones, but more comprehensive studies are needed to confirm these effects.

Is flaxseed oil safe long-term?

Current evidence supports its safety for typical supplemental doses over several months; however, long-term safety data are still limited.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/33183549/ – This meta-analysis of 12 RCTs found that flaxseed oil supplementation significantly reduced IL-6 and MDA levels and increased total antioxidant capacity in patients with metabolic syndrome. It highlights the anti-inflammatory and antioxidant benefits of flaxseed oil in this population.
https://www.archivesofmedicalscience.com/A-systematic-review-and-meta-analysis-of-clinical-trials-investigating-the-effects,74141,0,2.html – This systematic review and meta-analysis investigated the effects of flaxseed products on CRP levels. It concluded that flaxseed, including flaxseed oil, did not significantly affect CRP levels, suggesting a nuanced impact on different inflammatory markers.
https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1222584/full – This source discusses the potential for flaxseed to modulate sex hormone profiles. While not exclusively focused on flaxseed oil, it provides context for the limited and heterogeneous evidence regarding hormonal effects across various flaxseed forms.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3361740/ – This meta-analysis of RCTs demonstrated that flaxseed significantly reduced total and LDL cholesterol, with more pronounced effects in women and individuals with elevated baseline cholesterol. It supports the lipid-lowering benefits of flaxseed, including its oil form.