Flax Seed Milled
Also known as: Flaxseed, linseed, milled flaxseed, Linum usitatissimum
Overview
Flaxseed, derived from the flax plant, is a versatile dietary supplement and functional food ingredient, particularly when consumed in its milled (ground) form. Milled flaxseed is preferred over whole seeds due to enhanced digestibility and bioavailability of its key nutrients. It is a rich source of alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid, dietary fiber, and lignans, which are phytoestrogens. Primarily, flaxseed is utilized for its potential to improve cardiovascular health, aid in glycemic control, optimize lipid profiles, and potentially influence hormonal balance. Research into flaxseed's health benefits is ongoing, with a moderate level of maturity, supported by numerous randomized controlled trials and meta-analyses, though some heterogeneity in study designs exists.
Benefits
Milled flaxseed offers several evidence-based health benefits. A meta-analysis demonstrated significant reductions in total cholesterol and LDL cholesterol, particularly in individuals with hyperlipidemia, with effects observed within 2 to 52 weeks of supplementation. For glycemic control, a systematic review and meta-analysis of RCTs in prediabetes and type 2 diabetes patients showed significant reductions in fasting blood glucose, HbA1c, insulin concentrations, and HOMA-IR. While some studies suggest potential anti-inflammatory effects, a meta-analysis did not find significant changes in plasma C-reactive protein (CRP), indicating limited direct anti-inflammatory action. Limited evidence from a recent meta-analysis also suggests flaxseed may modulate sex hormone levels in conditions like PCOS and in postmenopausal women, though more research is needed due to data sparsity and heterogeneity.
How it works
The beneficial effects of flaxseed are attributed to its unique nutritional composition. Alpha-linolenic acid (ALA), an omega-3 fatty acid, is partially converted in the body to EPA and DHA, contributing to its lipid-lowering and potential anti-inflammatory properties. Lignans, a type of phytoestrogen, interact with hormone receptors and exhibit antioxidant effects, potentially modulating hormonal balance. The high dietary fiber content in flaxseed plays a crucial role in improving glycemic control by slowing down glucose absorption in the digestive tract and enhancing insulin sensitivity. Milled flaxseed significantly improves the bioavailability of ALA and lignans compared to whole seeds, as the grinding process breaks down the tough outer shell, allowing for better digestion and nutrient absorption.
Side effects
Flaxseed is generally considered safe for consumption, with no serious adverse effects reported in clinical trials. The most common side effects are mild gastrointestinal symptoms such as bloating, gas, or flatulence, primarily due to its high fiber content. These symptoms can often be mitigated by gradually increasing intake and ensuring adequate hydration. Caution is advised for individuals with pre-existing bowel obstructions or those sensitive to high fiber diets, as flaxseed could exacerbate these conditions. While evidence is limited, there's a theoretical potential for interaction with anticoagulant medications due to the omega-3 fatty acid content, which could affect blood clotting. Individuals on such medications should consult a healthcare professional before supplementing with flaxseed.
Dosage
For optimal benefits, most randomized controlled trials have utilized dosages of 20-40 grams of milled flaxseed per day to achieve significant improvements in lipid profiles and glycemic control. It is recommended to consume milled flaxseed with meals to enhance tolerance and absorption. The ground (milled) form is strongly preferred over whole seeds due to its superior bioavailability of key nutrients. When incorporating flaxseed into the diet, it is crucial to ensure adequate hydration to prevent or alleviate potential fiber-related gastrointestinal discomforts such as constipation or bloating. There are no established upper limits for flaxseed, but adherence to recommended dosages is advised to avoid excessive fiber intake.
FAQs
Is milled flaxseed better than whole?
Yes, milled flaxseed is superior to whole flaxseed because grinding improves the digestibility and absorption of its beneficial nutrients like ALA and lignans.
How soon can I expect to see benefits from flaxseed?
Improvements in lipid profiles and glycemic control are typically observed within 4 to 12 weeks of consistent daily supplementation with milled flaxseed.
Is flaxseed safe for long-term use?
Current research indicates that milled flaxseed is safe for long-term use at recommended dosages, though ongoing monitoring by a healthcare professional is advisable.
Research Sources
- https://www.archivesofmedicalscience.com/A-systematic-review-and-meta-analysis-of-clinical-trials-investigating-the-effects,74141,0,2.html – This meta-analysis investigated the effects of flaxseed supplementation on C-reactive protein (CRP), a marker of inflammation. The study found no significant effect on plasma CRP levels, suggesting limited anti-inflammatory action of flaxseed in the trials analyzed. Limitations included small sample sizes and heterogeneity across studies.
- https://pubmed.ncbi.nlm.nih.gov/35843472/ – This systematic review and meta-analysis of randomized controlled trials examined the impact of flaxseed on glycemic control in patients with prediabetes and type 2 diabetes. It concluded that flaxseed supplementation significantly reduced fasting blood glucose, HbA1c, insulin concentrations, and HOMA-IR, highlighting its potential in managing blood sugar.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3361740/ – This meta-analysis of 28 randomized controlled trials assessed the effects of flaxseed on cholesterol levels. It reported significant reductions in both total cholesterol and LDL cholesterol, particularly in hyperlipidemic individuals, supporting flaxseed's role in cardiovascular health. The study noted variability in study quality but used Jadad scoring for assessment.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1222584/full – This systematic review and meta-analysis explored the effects of flaxseed on sex hormone levels across various populations, including those with PCOS and postmenopausal women. While suggesting a potential modulatory effect on hormones, the study highlighted the limited and heterogeneous nature of the available data, indicating a need for further research.
