Get Your Personalized Supplement StackSupplement Stack Quiz

Flaxseed Pdr

Also known as: Linum usitatissimum, Flaxseed, Linseed

Overview

Flaxseed, derived from the plant *Linum usitatissimum*, is a rich source of dietary fiber, alpha-linolenic acid (ALA), and lignans. It is commonly used as a dietary supplement for its potential health benefits, including supporting cardiovascular and digestive health, and promoting hormonal balance. Flaxseed is characterized by its high ALA, lignan, and dietary fiber content. Research on flaxseed is considered to be at a moderate to high level of maturity, supported by numerous clinical trials and meta-analyses. The available evidence is generally of high quality, with several systematic reviews and meta-analyses from reputable databases. Flaxseed is available in various forms, including whole seeds, ground flaxseed, flaxseed oil, and lignan extracts. Ground flaxseed is often recommended due to its fiber content and ease of digestion.

Benefits

Flaxseed supplementation has demonstrated several evidence-based benefits. A meta-analysis of 33 RCTs showed significant reductions in both systolic and diastolic blood pressure. Another meta-analysis of 62 RCTs indicated improvements in serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol levels, suggesting a potential delay in the progression of heart disease. Additionally, flaxseed supplementation significantly decreased fasting blood glucose and high-sensitivity C-reactive protein (hs-CRP) levels in patients with coronary artery disease. While a meta-analysis found no significant overall effect on sex hormones, subgroup analyses suggested potential benefits in specific populations, such as increased SHBG in subjects with PCOS and increased TT in men with prostate cancer. Greater effects on blood pressure reduction were observed in trials with subjects having hypertension and a BMI of 25-30 kg/m². Benefits on blood pressure were more pronounced in trials with an intervention duration of >20 weeks.

How it works

Flaxseed's beneficial effects are primarily attributed to its high content of ALA, lignans, and dietary fiber. ALA, an omega-3 fatty acid, influences lipid metabolism and reduces inflammation. Lignans, acting as phytoestrogens, may affect hormone balance. Dietary fiber contributes to improved digestive health and promotes satiety. Flaxseed components interact with the cardiovascular, endocrine, and digestive systems. The lignans in flaxseed may bind to estrogen receptors, and ALA influences the production of eicosanoids, which are involved in inflammation and cardiovascular health. The bioavailability of ALA from flaxseed is generally good, but the absorption of lignans can vary based on gut microbiota composition.

Side effects

Flaxseed supplementation is generally considered safe, but some side effects have been reported. Common side effects include gastrointestinal symptoms such as bloating, gas, and diarrhea, primarily due to the high fiber content. Uncommon side effects may include allergic reactions, although these are rare. No significant rare side effects have been consistently reported in the literature. Due to its omega-3 content, flaxseed may interact with blood thinners, although this interaction is not well-studied. Caution is advised in individuals with severe gastrointestinal conditions. Pregnant or breastfeeding women should consult healthcare providers before using flaxseed supplements due to the lack of comprehensive studies in these populations. It is important to start with a low dose and gradually increase intake to minimize gastrointestinal discomfort.

Dosage

The minimum effective dose for cardiovascular benefits appears to be around 30 g/day of flaxseed, providing approximately 2-3 g of ALA. Optimal dosages range from 30-60 g/day of ground flaxseed or 1-8 g/day of ALA from flaxseed oil. There is no established maximum safe dose, but high doses (>60 g/day) may increase the risk of gastrointestinal side effects. No specific timing is recommended, but it is advisable to consume flaxseed with meals to minimize gastrointestinal side effects. Ground flaxseed, flaxseed oil, and lignan extracts are commonly used forms. Ground flaxseed is often recommended for its fiber content and ease of digestion. The presence of water and adequate chewing can enhance the absorption of flaxseed components.

FAQs

Is flaxseed safe?

Flaxseed is generally safe, but individuals with severe gastrointestinal conditions or those taking blood thinners should consult healthcare providers before use.

When is the best time to take flaxseed?

It is best to consume flaxseed with meals to minimize potential gastrointestinal side effects.

What results can I expect from taking flaxseed?

Improvements in blood pressure, lipid profiles, and glycemic control can be expected over several weeks to months with consistent flaxseed consumption.

Does flaxseed have estrogenic effects?

Flaxseed does not have significant estrogenic effects on sex hormones in most adults, contrary to some earlier suggestions.

Research Sources

https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1222584/full – This systematic review and meta-analysis of 33 RCTs (n=2427) found that flaxseed supplementation significantly reduced both systolic and diastolic blood pressure. The effects were more pronounced in trials with hypertensive subjects and interventions lasting longer than 20 weeks, suggesting a clinically relevant benefit for blood pressure management.
https://pubs.rsc.org/en/content/articlelanding/2023/fo/d2fo02566c/unauth – This meta-analysis of 62 RCTs (n=3772) showed that flaxseed supplementation improved serum total cholesterol, triglycerides, and LDL-C levels. The findings suggest that flaxseed may play a role in delaying the progression of heart disease by positively influencing lipid profiles.
https://pubmed.ncbi.nlm.nih.gov/31899314/ – This systematic review and meta-analysis investigated the effects of flaxseed on sex hormones. While no significant overall effect was found, subgroup analyses suggested potential benefits in specific populations, such as increased SHBG in subjects with PCOS and increased TT in men with prostate cancer.
https://www.archivesofmedicalscience.com/A-systematic-review-and-meta-analysis-of-clinical-trials-investigating-the-effects,74141,0,2.html – This study focused on the impact of flaxseed supplementation on glycemic and inflammatory indices in patients with coronary artery disease. The meta-analysis of 6 trials revealed significant decreases in fasting blood glucose and hs-CRP levels, indicating potential benefits for managing glycemic control and inflammation in this population.
https://onlinelibrary.wiley.com/doi/full/10.1002/clc.24211 – This research investigated the effects of flaxseed on various health outcomes. The findings contribute to the understanding of flaxseed's potential role in supporting overall health and well-being, although specific details of the study's findings are not provided in the given context.