Flax oil is a nutritional oil derived from the seeds of the flax plant, Linum usitatissimum, known for its fatty acid content. Standard flax oil is produced by cold-pressing the seeds, but this process leaves the majority of plant compounds called lignans in the fibrous hull. Lignan flax oil is a specialized product intentionally processed to retain high concentrations of these beneficial compounds. This difference is achieved by incorporating the lignan-rich fiber back into the finished oil. The resulting cloudy oil offers both healthy fats and the unique biological activity of the flaxseed’s fibrous components.
The Source and Specialized Extraction
The flax plant, Linum usitatissimum, has been cultivated for millennia, yielding fiber for textiles and seeds for oil. While the oil is concentrated in the seed kernel, the lignans reside primarily in the seed’s tough outer shell, or hull. Standard flaxseed oil extraction separates and filters the oil, leaving the solid, lignan-rich meal behind.
To create lignan flax oil, manufacturers use a specialized cold-pressing technique to preserve oil quality. They then deliberately add the lignan-rich, partially defatted flaxseed meal or powder back into the oil. This re-introduction of solid particulates gives the oil its characteristic cloudy appearance and ensures a much higher content of lignans than clear, filtered flax oil.
Key Nutritional Components
Lignan flax oil is a source of two main active ingredients. The first is Alpha-Linolenic Acid (ALA), the primary fatty acid component. ALA is an essential Omega-3 polyunsaturated fatty acid that the body must obtain through diet. Flax oil is one of the richest plant sources of this fatty acid.
The second component is the high concentration of lignans, specifically Secoisolariciresinol Diglucoside (SDG). SDG is the predominant lignan in flaxseed, concentrated within the suspended meal and hull fragments. SDG is responsible for most of the unique biological activity, but it requires further processing by the body to become active.
Metabolic Action of Lignans in the Body
Once ingested, Secoisolariciresinol Diglucoside (SDG) must undergo a transformation to become biologically active. This metabolic conversion is performed exclusively by the gut microbiota residing in the large intestine. Gut bacteria first hydrolyze the SDG, breaking down its sugar-like structures, converting it into an intermediate compound called secoisolariciresinol.
This intermediate is further metabolized by intestinal microorganisms. The final products of this bacterial transformation are the two primary mammalian lignans: Enterodiol and Enterolactone. These mammalian lignans are classified as phytoestrogens because they are structurally similar to the hormone estrogen. Enterolactone is the metabolite most often measured in the blood to assess lignan intake.
The production of these metabolites is time-dependent. Peak serum concentrations of Enterodiol appear 12 to 24 hours after consumption, and Enterolactone peaks between 24 and 36 hours. The mechanism of action involves these phytoestrogens weakly binding to estrogen receptors, which can modulate hormonal activity.
Safe Storage and Consumption Methods
Lignan flax oil is susceptible to degradation due to its high content of polyunsaturated fatty acids, particularly ALA. Exposure to light, oxygen, or heat causes the oil to oxidize and become rancid. Therefore, the oil must be purchased in opaque containers, such as dark plastic or glass bottles, to protect it from light.
Once opened, the oil must be stored under cold conditions; refrigeration is the minimum requirement to slow oxidation. Some users store the oil in the freezer, as its high ALA content prevents it from freezing solid. Before consumption, the bottle should be shaken well to ensure the lignan particulates, which settle, are evenly distributed.
Lignan flax oil should never be used for cooking or frying, as heat rapidly destroys the beneficial Omega-3 fatty acids and lignans. It is best consumed by mixing it into cold or room-temperature foods, such as smoothies, yogurt, oatmeal, or salad dressings. A typical daily intake for nutritional support is one to two tablespoons.