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defatted Flax

Also known as: Flaxseed, Linseed, Defatted Flax, Flaxseed meal, Linum usitatissimum

Overview

Defatted flax is the residual material of flaxseed (Linum usitatissimum) after the oil has been extracted, primarily composed of dietary fiber, plant protein, and lignans, most notably secoisolariciresinol diglucoside (SDG). It is a low-fat, high-fiber supplement derived from industrial oil extraction processes. Its primary uses include supporting cardiovascular health, aiding in lipid lowering, and contributing to blood pressure regulation. Research indicates its potential for metabolic and inflammatory modulation. While extensive research exists for flaxseed and its components, studies specifically isolating defatted flax are fewer, though its effects are often inferred from general flaxseed powder research. It is available as a meal or powder.

Benefits

Defatted flax offers several evidence-based benefits, primarily in cardiovascular health and metabolic regulation. Meta-analyses indicate that flaxseed powder, which is similar to defatted flax in its fiber and lignan content, significantly reduces systolic blood pressure (SBP) by approximately 2–5 mmHg and diastolic blood pressure (DBP) by 1–4 mmHg. These effects are more pronounced with powder forms compared to oil or lignan extracts, suggesting the importance of fiber and lignans. Flaxseed interventions, including defatted forms, have also shown modest reductions in total cholesterol and LDL cholesterol (around 0.08–0.10 mmol/L decrease), with some variability based on sex and intervention type. Furthermore, flaxseed supplementation has been found to significantly reduce leptin levels, which may be beneficial for metabolic regulation. These benefits are particularly observed in individuals with hypertension, hyperlipidemia, and overweight adults, with less clear effects in healthy populations. Benefits typically manifest after weeks to months of consistent supplementation.

How it works

Defatted flax exerts its effects through several key mechanisms. The fiber content, particularly soluble fiber, contributes to blood pressure reduction by improving endothelial function and binds to bile acids in the gut, leading to reduced cholesterol reabsorption and subsequent lowering of lipid levels. Lignans, such as secoisolariciresinol diglucoside (SDG), are metabolized by gut microbiota into enterolignans, which possess antioxidant properties that may contribute to blood pressure regulation and modulate cholesterol metabolism. The reduction in leptin levels observed with flaxseed supplementation may be linked to the anti-inflammatory and metabolic regulatory effects of both lignans and fiber. These components interact with various biological pathways, including those involved in endothelial nitric oxide synthesis, cholesterol synthesis, and inflammatory cytokine signaling.

Side effects

Defatted flax is generally considered safe, with no serious adverse effects reported in clinical trials lasting up to 12 months. The most common side effects are mild gastrointestinal symptoms, such as bloating and flatulence, which are attributed to its high fiber content. These symptoms can often be mitigated by starting with a lower dose and gradually increasing it, along with ensuring adequate hydration. Caution is advised regarding potential interactions with anticoagulant medications due to flaxseed's mild antiplatelet effects. While no well-established contraindications exist, individuals with pre-existing bowel obstructions or severe sensitivity to high-fiber diets should exercise caution. Data on its use in pregnant women and children are limited, though it is generally considered safe for adult consumption.

Dosage

Effective doses of defatted flax, based on studies using ground flaxseed powder (which has similar fiber and lignan content), range from 13 g to 60 g per day. For optimal effects on blood pressure and lipid profiles, a daily intake of approximately 30–40 g of defatted flax powder is recommended. While a maximum safe dose has not been firmly established, doses up to 60 g per day have been used in studies without serious adverse effects. It is advisable to consume defatted flax daily, preferably with meals, to improve tolerance and absorption. Ground or defatted flaxseed powder is preferred over whole seeds to ensure better bioavailability of lignans and to maximize the effects of its fiber content. Adequate hydration is crucial when supplementing with defatted flax to help prevent or mitigate fiber-related gastrointestinal discomfort.

FAQs

Is defatted flax as effective as whole flaxseed?

Yes, defatted flax retains the fiber and lignans responsible for blood pressure and lipid benefits, making it effective for these outcomes, despite lacking the oil content of whole flaxseed.

Can defatted flax lower inflammation?

While it does not significantly reduce C-reactive protein (CRP), a marker of systemic inflammation, defatted flax can reduce leptin levels, suggesting some beneficial metabolic anti-inflammatory effects.

How soon do benefits appear?

Improvements in blood pressure and lipid profiles typically become noticeable after 4 to 12 weeks of consistent daily supplementation with defatted flax.

Are there safety concerns?

Defatted flax is generally safe. The most common side effects are mild gastrointestinal issues like bloating and flatulence, which can often be managed by adjusting dosage and ensuring adequate hydration.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/26071633/ – This systematic review and meta-analysis of 15 RCTs found that flaxseed powder significantly reduced systolic and diastolic blood pressure, with effects stronger for powder than oil or lignan extracts. The study highlights the efficacy of flaxseed powder in blood pressure management.
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 of 17 RCTs concluded that flaxseed supplementation had no significant effect on plasma C-reactive protein (CRP) levels, indicating a limited direct anti-inflammatory effect on this specific marker. The study included various doses and durations, providing robust evidence.
https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1179089/full – This meta-analysis of 13 RCTs demonstrated that flaxseed supplementation significantly reduced leptin levels, suggesting potential metabolic benefits. However, it found no significant effect on adiponectin, indicating specific hormonal modulation rather than broad adipokine changes.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3361740/ – This meta-analysis of 28 studies reported that flaxseed interventions modestly reduced total and LDL cholesterol, with effects influenced by sex and intervention type. The study used a random-effects model due to heterogeneity, providing insights into cholesterol-lowering potential.