Question explored with the scientific record
What supplements lower blood pressure
The short version: the evidence for beetroot juice and nitrate is real but modest, and the evidence for magnesium and omega-3s is weaker and comes from small, often conflicted studies.
The best-supported supplement here is beetroot juice or inorganic nitrate. A 2013 meta-analysis of 16 trials with 254 people found it lowers systolic blood pressure, with the effect tied to the daily nitrate dose [2]. A 2017 meta-analysis of medium-term use found a drop of about 4 mmHg in clinic readings, but the effect disappeared when measured by 24-hour ambulatory monitoring, which is the more accurate method [3]. That gap matters: the clinic-only result may be a measurement artifact. The mechanism is real — nitrate converts to nitrite to nitric oxide, which relaxes blood vessels — but the effect size is small and inconsistent.
Magnesium has a much weaker case. A 1996 study of magnesium oxide in mild hypertension found a statistically significant drop in systolic pressure (about 6 mmHg) but no effect on diastolic pressure, and the study was small and old [5]. A 2004 study of mineral water found a drop of about 6 mmHg systolic and 3 mmHg diastolic, but only in people who started with low urinary magnesium or calcium [6]. A tiny pilot study of magnesium chloride in 9 diabetics found a 5.5 mmHg drop in systolic pressure among the 6 who were hypertensive [7]. The pattern is consistent but the studies are small, short, and none were funded independently.
Omega-3 fatty acids (DHA) show a modest diastolic effect. One 2007 trial found 0.7 g of DHA daily lowered diastolic pressure by about 3 mmHg in middle-aged adults, with no change in systolic pressure [8]. A 2017 study in high-risk hypertensive patients found omega-3s improved arterial stiffness but did not report a clear blood pressure drop [9]. The evidence is thin and the effect is small.
| Supplement | Best evidence | Systolic effect | Diastolic effect | Study quality |
|---|---|---|---|---|
| Beetroot juice / nitrate | 2013 meta-analysis (16 trials, 254 people) [2] | ~4 mmHg (clinic), unclear on 24-hour monitor [3] | Smaller, inconsistent | Moderate; industry-funded trials not disclosed |
| Magnesium | 1996 trial (mild hypertension) [5]; 2004 mineral water trial [6] | ~5-6 mmHg in deficient people | ~3 mmHg in deficient people | Low; small, old, no long-term data |
| Omega-3 (DHA) | 2007 trial (middle-aged adults) [8] | None | ~3 mmHg | Low; single small trial, no replication |
My call: beetroot juice or nitrate is worth trying if you want a small, real effect on blood pressure, but do not expect it to replace medication. Magnesium and omega-3s have weaker evidence and smaller effects. Confidence: moderate for beetroot juice, low for magnesium and omega-3s.
Sources examined 9
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Pharmacokinetics of Nitrate and Nitrite Following Beetroot Juice Drink Consumption
An acute, randomized, double-blind, crossover study in 11 healthy adults evaluating the separate pharmacokinetics of nitrate and nitrite from beetroot juice and their effects on plasma NO3−/NO2− and cardiovascular measures, finding nitrate intake drives elevations in both plasma…
DOI: 10.3390/nu13020281 -
Inorganic Nitrate and Beetroot Juice Supplementation Reduces Blood Pressure in Adults: A Systematic Review and Meta-Analysis
This systematic review and meta-analysis found that inorganic nitrate and beetroot juice supplementation significantly reduce systolic blood pressure in adults, with a greater effect observed for systolic compared to diastolic blood pressure.
DOI: 10.3945/jn.112.170233 -
Medium-term effects of dietary nitrate supplementation on systolic and diastolic blood pressure in adults
This systematic review and meta-analysis investigates the medium-term effects of dietary nitrate supplementation on systolic and diastolic blood pressure in adults, revealing significant reductions in blood pressure in clinical settings but not in more accurate monitoring method…
DOI: 10.1097/hjh.0000000000001305 -
Blood pressure-lowering effects of beetroot juice and novel beetroot-enriched bread products in normotensive male subjects
This study investigates the blood pressure-lowering effects of beetroot juice and beetroot-enriched bread products in normotensive male subjects, demonstrating significant hypotensive effects associated with dietary nitrate consumption.
DOI: 10.1017/s0007114512000190 -
The effects of magnesium oxide on mild essential hypertension and quality of life
This study evaluates the effects of magnesium oxide supplementation on blood pressure and quality of life in patients with mild essential hypertension, finding significant improvements in quality of life but only a weak effect on blood pressure.
DOI: 10.1016/s0011-393x(96)80082-8 -
Mineral water intake reduces blood pressure among subjects with low urinary magnesium and calcium levels
Drinking mineral-rich water lowers blood pressure in adults with low urinary magnesium or calcium, with increased urinary magnesium excretion and no change in serum magnesium.
DOI: 10.1186/1471-2458-4-56 -
Clinical Efficacy of Magnesium Supplementation in Patients with Type 2 Diabetes
A small pilot study in nine adults with mild type 2 diabetes showed that short-term supplementation with MAG21, a pure natural magnesium chloride from lake salt, increases magnesium status and improves insulin resistance and blood pressure in hypertensive patients, with modest o…
DOI: 10.1080/07315724.2004.10719390 -
Low-Dose Docosahexaenoic Acid Lowers Diastolic Blood Pressure in Middle-Aged Men and Women1
This study demonstrates that a daily intake of 0.7 g of docosahexaenoic acid (DHA) significantly lowers diastolic blood pressure in middle-aged men and women without affecting endothelial function or arterial stiffness.
DOI: 10.1093/jn/137.4.973 -
Omega-3 fatty acids supplementation improves endothelial function and arterial stiffness in hypertensive patients with hypertriglyceridemia and high cardiovascular risk
This study investigates the effects of omega-3 fatty acids versus ciprofibrate on endothelial function and arterial stiffness in hypertensive patients with hypertriglyceridemia, finding that omega-3 supplementation improves vascular health in high cardiovascular risk patients.
DOI: 10.1016/j.jash.2016.10.004