Research has shown that flaxseed supplementation may help lower blood pressure (hypertension), though results have varied between studies. As we are interested in easy to implement, whole food practices that support health, consuming readily available and cheap flaxseed seems to be an option worth investigating.
So, what does the research say? Does flaxseed support lowering blood pressure? The 2 meta-analyses of randomised clinical trial below provide some useful results.
As ever, please talk to your doctor or medical practitioner most familiar with your medical history before implementing any changes in diet, exercise or lifestyle, especially if you are under treatment. Links to relevant studies and resources at bottom of page.
Study 1
Li et al (2023) conducted a detailed analysis of 33 randomised clinical trials involving 2,427 participants. The findings revealed that adding flaxseed to the diet can significantly reduce both systolic blood pressure (SBP, the top number in a blood pressure reading) and diastolic blood pressure (DBP, the bottom number).
On average, flaxseed supplementation lowered SBP by about 3.2 mmHg and DBP by about 2.6 mmHg. These reductions were most noticeable in people who:
Consumed at least 30 grams of flaxseed daily.
Continued supplementation for more than 20 weeks.
Had a body mass index (BMI) between 25 and 30 (classifying them as overweight).
Were already diagnosed with high blood pressure.
Flaxseed comes in various forms, including ground flaxseed and flaxseed oil, both of which were found to have beneficial effects on blood pressure. The results suggest that flaxseed could be a valuable addition to blood pressure management, complementing regular medications and a healthy lifestyle.
Study 2
Ursoniu et al (2016) conducted an analysis of 15 randomised clinical trials, involving 1,302 participants. It showed that flaxseed supplementation can help lower blood pressure, though the effects vary depending on the duration of use and the type of flaxseed product.
On average, flaxseed reduced systolic blood pressure (SBP, the upper number in a blood pressure reading) by 2.85 mmHg and diastolic blood pressure (DBP, the lower number) by 2.39 mmHg. Longer durations of flaxseed supplementation appeared to be more effective. In studies lasting 12 weeks or more, reductions in SBP and DBP were greater compared to shorter trials. This suggests that consistent, long-term use may be necessary to achieve the full blood pressure-lowering benefits of flaxseed.
The type of flaxseed product also made a difference. Ground flaxseed significantly reduced both SBP and DBP, while flaxseed oil significantly lowered DBP but not SBP. A lignan extract (a concentrated component of flaxseed) showed no consistent effect on either measure of blood pressure.
These findings indicate that flaxseed, particularly in ground or oil form, may be a useful addition to blood pressure management strategies. However, the benefits are most likely to be seen with regular use over an extended period.
How Does Flaxseed Lower Blood Pressure?
Flaxseed lowers blood pressure primarily through its high content of alpha-linolenic acid (ALA), polyohenol lignans, and fibre, which work synergistically to improve vascular health.
ALA, a plant-based omega-3 fatty acid, reduces inflammation and improves endothelial function, helping blood vessels relax and lower resistance.
Lignans, which are polyphenolic compounds, have antioxidant and oestrogen-like properties that may reduce oxidative stress and improve nitric oxide availability, further supporting vasodilation. Learn more about polyphenols and health, here.
The soluble fibre in flaxseed slows digestion and stabilises blood sugar levels, indirectly benefiting blood pressure by reducing strain on the cardiovascular system.
Additionally, flaxseed’s potential to lower LDL cholesterol and improve arterial elasticity also contributes to better blood pressure regulation.
Comparison to Medications
Standard blood pressure-lowering medications, such as those commonly prescribed for hypertension, reduce blood pressure by varying amounts depending on the class of drug, dosage, and individual patient factors. Here are general estimates:
ACE Inhibitors (e.g., lisinopril): Reduce systolic blood pressure (SBP) by 5–10 mmHg and diastolic blood pressure (DBP) by 2–6 mmHg.
Calcium Channel Blockers (e.g., amlodipine): Lower SBP by 8–10 mmHg and DBP by 4–8 mmHg.
Beta Blockers (e.g., metoprolol): Typically reduce SBP by 7–10 mmHg and DBP by 3–5 mmHg.
Thiazide Diuretics (e.g., hydrochlorothiazide): Lower SBP by 6–12 mmHg and DBP by 3–6 mmHg.
Angiotensin II Receptor Blockers (ARBs, e.g., losartan): Reduce SBP by 5–10 mmHg and DBP by 3–6 mmHg.
Final Thoughts
Want to take flaxseed? Firstly, it has to be ground, otherwise the hard seed will pass straight through your gut and colon. As its fat can oxidise quickly, store the ground flaxseed in the cold and dark - fridge or freezer is ideal.
While flaxseed supplementation provides more modest reductions (around 2.8 to 3.2 mmHg in SBP and 2.4 to 2.6 mmHg in DBP), it may complement standard medications and lifestyle changes. This makes it a potentially useful adjunct for people looking to enhance their blood pressure management naturally, especially in conjunction with a low salt, DASH style diet and regular exercise. Read more about these interventions here.
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Related Studies and Resources
Blood Pressure
Li L, Li H, Gao Y, Vafaei S, Zhang X, Yang M. Effect of flaxseed supplementation on blood pressure: a systematic review, and dose-response meta-analysis of randomized clinical trials. Food Funct. 2023 Jan 23;14(2):675-690. doi: 10.1039/d2fo02566c. PMID: 36622248.
Mahmudiono T, Jasim SA, Karim YS, Bokov DO, Abdelbasset WK, Akhmedov KS, Yasin G, Thangavelu L, Mustafa YF, Shoukat S, Najm MAA, Amraei M. The effect of flaxseed oil consumption on blood pressure among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized clinical trials. Phytother Res. 2022 Oct;36(10):3766-3773. doi: 10.1002/ptr.7566. Epub 2022 Jul 20. PMID: 35859037.
Ursoniu S, Sahebkar A, Andrica F, Serban C, Banach M; Lipid and Blood Pressure Meta-analysis Collaboration (LBPMC) Group. Effects of flaxseed supplements on blood pressure: A systematic review and meta-analysis of controlled clinical trial. Clin Nutr. 2016 Jun;35(3):615-25. doi: 10.1016/j.clnu.2015.05.012. Epub 2015 May 29. PMID: 26071633.
Khalesi S, Irwin C, Schubert M. Flaxseed consumption may reduce blood pressure: a systematic review and meta-analysis of controlled trials. J Nutr. 2015 Apr;145(4):758-65. doi: 10.3945/jn.114.205302. Epub 2015 Mar 4. Erratum in: J Nutr. 2015 Nov;145(11):2633. doi: 10.3945/jn.115.222232. PMID: 25740909.
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