High blood pressure affects around 1 in 3 adults, but only around 45% of people with hypertension have their blood pressure well-controlled, despite taking medication. The World Health Organisation estimate that treating high blood pressure to a target of below 140/80mmHg can reduce the risk of stroke by 40% and the risk of a heart attack by 16%.
If you have poorly controlled hypertension, increasing your intake of vitamins, minerals, antioxidants and omega-3s could improve your blood pressure readings. Ideally this means eating more fruit, vegetables, fish and garlic by following a Mediterranean-style DASH (Dietary Approaches to Stopping Hypertension) diet. Just increasing your intake of fruit and vegetables can lower blood pressure by 4/1.5 mmHg, for example.
Supplements to lower a high blood pressure
Taking a supplement to correct vitamin, mineral, antioxidant or omega-3 deficiencies could make the difference between good control and bad control of your blood pressure. It could also reduce the number of medicines you need to take.
Some supplements have immediate actions to lower blood pressure and can produce effects that are at least as good as some classes of prescribed antihypertensive medicines.
Other supplements offer more long-term, protective benefits, such as antioxidants which help to reduce stiffening of the arteries.
The table to the right summarises how well different supplements can lower systolic blood pressure (the upper reading) compared to the main classes of prescribed antihypertensive drugs:
- Calcium channel blockers
- Angiotensin II receptor blockers
- Thiazide diuretics
- ACE inhibitors.
I’ve provided an overview of the evidence for each supplement below, with links to the research.
If you are taking prescribed medicines, check for known interactions before starting to take any supplements.
Monitor your blood pressure at home and ask your doctor for advice on how to change your medication if significant improvements occur.
Only change or stop your medication under medical supervision.
Magnesium for high blood pressure
Magnesium maintains the electrical stability of cells and relaxes smooth muscle cells in artery linings to promote blood vessel dilation and lower blood pressure. Good magnesium levels also protect against calcification of coronary arteries.
Good food sources of magnesium include nuts and seeds, dark green leaves, beans, fish, dried fruit, wholegrains and dark chocolate (cacao). Tap water in hard-water areas are also important sources for some people.
Magnesium deficiency is common and increases the risk of developing hypertension.
In seven studies, involving people on anti-hypertensive medication, adding magnesium supplements to existing treatment improved blood pressure control. In those whose starting systolic blood pressure was high (greater than 155 mmHg) despite medication, magnesium supplements lowered blood pressure by an average of 18.7/10.9 mmHg.
This is an extraordinarily large and highly significant effect, and suggests that magnesium deficiency plays an important role in the development of medication resistant hypertension. If you are not magnesium deficient, and have mild to moderate hypertension, magnesium supplements may only reduce blood pressure by around 3/2 mmHg.
Data from 19 studies involving almost 533,000 people show that people with the highest dietary magnesium intakes were 15% less likely to experience a heart attack or stroke than those with the lowest intakes. When circulating magnesium levels were checked, those with the lowest levels were 33% more likely to have a heart attack or stroke than those with the lowest levels.
This may partly explain why people with good dietary intakes of magnesium were 37% less likely to die from any medical cause, over a 5 year follow-up period, than those with the lowest intakes.
Magnesium is one of the supplements I make sure to take every day.
A typical dose is 200mg to 400mg magnesium per day. Doses above 400mg per day can have a laxative effect (not always a bad thing). If this occurs, using a magnesium oil spray to absorb magnesium through your skin will avoid intestinal side effects.
Co-enzyme Q10 for high blood pressure
Co-enzyme Q10 (CoQ10) is a vitamin-like antioxidant needed for oxygen processing and energy production in cells – especially heart muscle cells that are constantly contracting. CoQ10 also improves the elasticity and reactivity of the blood vessel wall to produce a significant blood pressure lowering effect.
Co-enzyme Q10 is made in the body but production declines with age, and falling levels mirror age-related increases in hypertension.
Data from 12 clinical trials, involving 362 people, show that taking Coenzyme Q10 supplements reduces blood pressure by an average of 16.6/8.2mmHg compared with placebo. In a cross-over trial, in which the same people took coenzyme Q10 or placebo during two separate periods, their blood press was, on average, 11/8 mmHg lower when they were taking the CoQ10 supplements than when they were taking placebo.
Adding CoQ10 to existing anti-hypertensive medicines in 109 people with hypertension allowed half (51%) to stop taking between one and three antihypertensive drugs (under the supervision of their cardiologist) within four to five months of starting CoQ10. In those who had an echocardiogram, left ventricular wall thickness and heart muscle contraction also became more efficient. Only 3% of patients taking co-enzyme Q10 needed to increase their antihypertensive drug regime.
Taking a statin drug lowers levels of co-enzyme Q10 which may contribute to the muscle-related side effects experienced by some people.
The best form of co-enzyme Q10 to take for hypertension is the reduced, ‘active’, body-ready form known as ubiquinol. The usual dose range is 100mg to 200mg ubiquinol per day.
Vitamin C for high blood pressure
Vitamin C is an important antioxidant within the circulation, protecting against hardening of the arteries and the effects of atherosclerosis on blood pressure receptors which can lead to hypertension. Vitamin C also improves blood vessel dilation by restoring nitric oxide activity. People who have low levels of vitamin C also appear to have greater activity of angiotensin converting enzyme (ACE), which raises blood pressure.
Good food sources of vitamin C are fruit and vegetables, especially berries, citrus fruit, bell peppers, guava, mango and dark green leaves.
Blood levels of vitamin C have a strong inverse association with systolic blood pressure (the upper number). A study involving almost 21,000 people in Norfolk, for example, found that those with the highest vitamin C levels (from fruit and vegetables) were 22% less likely to have hypertension than those with the lowest levels.
Another study of 2,419 men showed that, overall, men with the lowest vitamin C levels were 2.4 fold more likely to experience a stroke during the ten-year follow-up period than those with the highest levels; the risks were even higher for men who were hypertensive or overweight.
Research published in the Lancet found that adding 500mg vitamin C supplements to treatments for hypertension medication lowered systolic blood pressure by 13/10 mmHg within 30 days, although only the reduction in systolic blood pressure was significantly different to placebo.
And in elderly people whose blood pressure was not controlled by medication, adding 600mg vitamin C per day to their medication markedly reduced systolic blood pressure by 20 mmHg, suggesting that vitamin C could be a useful treatment for older people with refractory hypertension.
When researchers explored the effects of higher doses of vitamin C in people with hypertension they found similar reductions in blood pressure (an average of 4.5/1.2 mm Hg) with all doses (500mg, 1000mg and 2000 mg vitamin C). But these results were affected by the poor compliance rate – on average participants took less than half their doses (48%).
A typical dose is 500mg – 1000mg vitamin C per day. A non-acidic form, known as ester-C, avoids indigestion at higher doses.
Lycopene for high blood pressure
Papaya is one of the best fruit sources as its lycopene is stored in a liquid, crystal form that is easily absorbed. In contrast, the lycopene within tomatoes is locked away inside cells but is released by cooking, so that when you eat a cooked tomato you absorb five times more lycopene than when eating the same tomato raw.
Research involving over 4,400 adults suggests that high dietary intakes of carotenoids are associated with a lower risk of developing hypertension.
When 31 people with untreated hypertension took a tomato extract (Lyc-O-Mato supplying 15mg lycopene) for 8 weeks, their blood pressure fell by 10/4 mmHg compared with placebo.
In another study involving 54 people with moderate hypertension, who were poorly controlled despite taking one or two antihypertensive drugs, their blood pressure fell by 13/6 mmHg when taking tomato extracts, compared with no changes when taking placebo.
Research supports taking a dose of 15mg lycopene-rich carotenoids per day if you have hypertension.
NB If you are taking any medications, check the patient information leaflets for interactions before eating grapefruit or drinking grapefruit juice as it can boost absorption to increase the risk of side effects.
Garlic for high blood pressure
Garlic is a source of allicin and other, powerful antioxidants that lower blood pressure by dilating arteries and veins. Garlic has also been shown to improve the elasticity of major arteries and can even reverse atherosclerosis by decreasing calcification the build-up of fatty material (plaque) on artery walls.
Garlic is one of the most widely studied nutritional medicines.
The results from 20 clinical trials, involving 970 people, garlic supplements reduced blood pressure by 8.7/6.1 mmHg compared with placebo.
The combined results from 4 large meta-analyses show that garlic extracts can reduce blood pressure by between 7/5 mmHg and 16/9 mm Hg compared to placebo.
In aged and black garlic, the sulphur-containing components have been converted into derivatives which are less ‘smelly’ and have a more powerful, antioxidant and blood pressure lowering action, which may be better for people with hypertension.
A trial involving 79 people with uncontrolled systolic hypertension found that average systolic blood pressure fell by 11.8 mm Hg over 12 weeks in those who took aged garlic extracts, compared with placebo.
A typical dose is 900mg to 2000mg garlic extracts, per day.
Include garlic in your diet as much as possible, adding it towards the end of cooking for maximum antioxidant benefits.
Probiotics for high blood pressure
Probiotics are live, lactic-acid producing bacteria (eg Lactobacilli, Bifidobacteria). Some strains, such as Lactobacillus helveticus CM4, produce peptides that lower blood pressure through an action similar to that of ACE inhibitor antihypertensive drugs. This particular strain of probiotic bacteria also appears to have an effect on mood to lower stress, which will also have beneficial effects on blood pressure.
In a study involving 80 people with high-normal blood pressure or mild hypertension, the effects of taking 6 tablets (12 g) powdered fermented milk containing Lactobacillus helveticus every day for 4 weeks was compared with placebo. In those with mild hypertension, blood pressure reduced by 11.2/6.5 mmHg compared with placebo. In those with high normal blood pressure, average readings fell by 3.2/5 mmHg.
Vitamin E for high blood pressure
Vitamin E is an important antioxidant that protects circulating LDL-cholesterol from oxidation to reduce hardening and furring up of the arteries. It may also exert a blood pressure lowering effect through nitric oxide.
Interestingly, a study involving Italian centenarians found they had exceptionally high blood levels of vitamin E, which may contribute to their longevity.
Good food sources of vitamin E include avocado, nuts, seeds and vegetable oils.
In a study involving 70 people with mild hypertension, taking 200 IU vitamin E supplements per day reduced starting blood pressure from an average of 154.4/95 mmHg down to 117.4/83 mmHg (an extraordinary fall of 37/12 mmHg) compared with a fall of 2.5/5.8 mmHg with placebo.
Other studies have not shown a benefit for vitamin E used alone in lowering blood pressure however. As vitamin E is temporarily converted into a free radical as a result of its antioxidant action, I believe it is best taken together with other antioxidants, such as vitamin C, to convert it back into its antioxidant form.
A trial involving 110 men with hypertension compared the effects of taking 400 IU (268mg) vitamin E plus 1g vitamin C per day, against placebo for 8 weeks. In those taking vitamins E and C, there were significant reductions in blood pressure of 9.1/7.6 mmHg compared with increases in those taking placebo. The researchers suggested that antioxidant treatment with a vitamin C and vitamin E supplement could help lower blood pressure in people with essential hypertension.
Usual doses for vitamin E supplements are 200 IU (134 mg) to 400 IU (268mg) per day.
Beetroot juice supplements for high blood pressure
Beetroot juice lowers blood pressure partly due to its potassium and magnesium content, but mostly due to its high content of nitrates. When consumed, beetroot nitrates are rapidly converted into nitrites by bacteria (Veillonella and Actinomyces species) that live in the mouth. When absorbed into your circulation, these nitrites form nitric oxide (NO) – a cell-signalling molecule which lowers blood pressure by allowing blood vessels to dilate.
In healthy volunteers with normal blood pressure, taking a beetroot juice supplement (250ml) every day for 4 weeks lowered blood pressure by an average of 7.7/5.2 mmHg compared with placebo when assessed by 24-hour ambulatory blood pressure monitoring.
Benefits start within one hour, reach a maximum after 4 hours, and are still evident 24 hours later, making it at least as effective as many prescribed antihypertensive medications.
Include beetroot in your diet as much as possible. Eating 100g cooked or grated raw beetroot provides the same level of nitrates as 250ml beetroot juice.
If you don’t like the taste of beetroot, supplements are available.
NB Concentrated beetroot can turn urine pink – this may be alarming but is harmless.
Cherry juice lowers blood pressure
A pilot trial involving 20 healthy adults with normal blood pressures showed that a single 300ml serving of cherry juice produced significant reductions in blood pressure of 5.5/5.5 mmHg.
In 15 men classed as having ‘early’ hypertension (blood pressure over 130/80 mmHg) drinking 60ml concentrated Montmorency tart cherry juice (diluted with 100ml water to make it palatable) lowered systolic blood pressure (the upper reading) by 7 mmHg more than a similar tasting fruit-flavoured placebo (even though starting blood pressures were higher in those randomised to the cherry group at 137/82 mmHg versus 134/79 mmHg in those randomised to placebo).
No significant differences were seen in diastolic pressures (the lower reading). The blood pressure lowering effects of cherry juice occurred within one hour and persisted for at least 8 hours afterwards.
Consider adding cherry juice to your daily menu. Cherry supplements are also available.
Potassium for high blood pressure
Potassium is the main positively charged ion found inside cells, where it is present in concentrations that are 30 times higher than in the fluid surrounding each cell. This is because potassium is actively pumped into cells in exchange for sodium ions, which are pumped out to make room for it.
Within the kidneys, these sodium-potassium exchange pumps mean that good dietary intakes of potassium help to flush excess sodium into the urine for excretion. As excess sodium in a high salt diet is linked with high blood pressure in at least one in two people, following a diet that is relatively high in potassium and low in sodium is linked with a lower risk of hypertension and stroke.
Good food sources of potassium include fruit (particularly tomatoes and bananas), vegetables, beans and whole grains.
The results of 15 trials, involving 917 people with either normal blood pressure or untreated hypertension, show that, overall, taking potassium supplements lower blood pressure by an average of 4.7 /3.5 mmHg. In those with untreated hypertension, potassium supplements reduced blood pressure by an average of 6.8/4.6 mmHg.
The researchers concluded that people with raised blood pressure may benefit from increased potassium intake along with controlled or decreased sodium intakes.
In one study, for example, over 80% of people taking antihypertensive medication were able to halve their dose by just increasing their dietary intake of potassium.
It’s best to increase your intake of potassium by eating more fruit, vegetables, and unsweetened juice. This is an excellent reason to aim for the recommended 5-a-day servings of fruit and veg.
It is not a good idea to take high dose potassium supplements, as high intakes can affect heart rhythm. The upper safe level for long-term use from supplements is 3700mg, but most supplements supply much lower amounts. It is relatively safe to take the typical supplemental dose of 350mg. I believe potassium is best combined with other beneficial ingredients, such as magnesium or omega-3 fish oils.
Do not take a potassium supplement if you are on an ACE inhibitor, a potassium-sparing diuretic, or if you have kidney problems, except under medical advice. (Check with a pharmacist if you are taking any medications).
Omega-3 fish oil for high blood pressure
Fish oil contains two long-chain omega 3 fatty acids, DHA and EPA, which are derived from the microalgae on which fish feed. These omega 3s have numerous beneficial effects on the circulation, including maintaining a regular heart rhythm, increasing the elasticity of artery walls and reducing blood stickiness to lower blood pressure.
Data from 38 studies, involving over 794,000 people, show that eating two to four servings of fish a week reduces the risk of stroke by 6% compared to those eating less than one serving of fish a week. Eating five or more servings of fish per week reduces the risk of stroke by 12%. Results were broadly similar for fish and omega-3 supplements so, if you don’t like eating fish, omega-3 fish oils are a good alternative.
The results from as many as 70 clinical trials show that, compared with placebo, a daily fish oil supplement reduces blood pressure in all people – whether or not they had hypertension. In those with untreated hypertension, blood pressure fell by an average of 4.51/3.05 mmHg; in those whose blood pressure was within the normal range, average reductions were 1.52/0.62 mmHg.
And you don’t need high doses – fish oil supplements providing 700mg EPA and DHA daily for eight weeks appears to produce similar results to doses of 1.8g EPA and DHA daily, in reducing systolic blood pressure by an average of 5 mmHg.
Krill oil supplements, which provide omega-3s plus powerful antioxidants (eg astaxanthin) are likely to be even more beneficial but little clinical evidence is currently available on which to judge this.
Ideally, aim to eat two portions (150g each) of oily fish such as salmon, mackerel, herring, sardines, pilchards or fresh tuna per week (tinned tuna doesn’t count as its oil is removed during processing). If you prefer not to eat fish that often, then take a daily, high-strength fish oil supplement that provides at least 700mg EPA/DHA.
NB Seek medical advice first if you are taking a blood thinning drug such as warfarin.
Hawthorn for high blood pressure
Hawthorn (Crataegus sp) flowers and berries are a traditional herbal medicine used to lower blood pressure, and to treat heart problems such as angina and congestive heart failure.
Hawthorn appears to work in a similar way to prescribed ACE-inhibitor drugs. Hawthorn extracts may also increase levels of nitric oxide (a powerful blood vessel dilator) in a similar way to beetroot and has a mild diuretic action.
Among 92 adults with untreated mild hypertension, four months of treatment with Crataegus extracts lowered blood pressure from an average of 146/92 mmHg down to 133/84 mmHg (a reduction which was 9/5 mgHg better than that seen with placebo, and statistically significant).
In people with type 2 diabetes, who were on an average of 4.4 medications to control their glucose levels and blood pressure, those who received 1200 mg hawthorn extracts showed a greater reduction in blood pressure (an average of 3.6/2.6 mmHg) compared with those taking placebo.
As a traditional herbal medicine, high doses of hawthorn are best taken under the supervision of a medical herbalist. Lower doses are often combined with other blood pressure lowering ingredients.
Vitamin D for high blood pressure
Food sources of vitamin D include oily fish, fish liver oils, animal liver, fortified margarine, eggs, butter and fortified milk. Mushrooms, beans and green leaves also provide small amounts, while sensible sun exposure allows vitamin D synthesis in the skin when the UV index is greater than 3.
Eight studies, involving 55,800 people, show that those with the lowest blood levels of vitamin D are 30% more likely to have hypertension than those with the highest levels.
This may explain why 19 other studies, involving almost 66,000 people, found that having a low vitamin D level increased the risk of coronary heart disease by 38% and of experiencing a stroke by 64% more than those with the highest blood levels of vitamin D.
However, trials involving vitamin D supplements have produced disappointing results.
In 8 clinical trials, involving people with hypertension, taking vitamin D supplements only reduced blood pressure by 3.6/3.1 mmHg compared with placebo. Some trials used calcium as the placebo, however, which has its own blood pressure lowering action and may have blunted the results.
In the absence of exposure to sunlight, a minimum intake of 20 mcg (800 IU) vitamin D is needed per day to maintain a healthy blood levels of vitamin D during winter months, although some experts argue that intakes of 40 mcg vitamin D per day are needed – irrespective of sun exposure. I usually recommend intakes of 25mcg (1000 IU). The EU suggested tolerable upper intake from supplements plus food is 100mcg (4000 IU) per day.
NB Taking a vitamin D supplement is especially important if you are on a statin drug, as these lower vitamin D levels.
Select a supplement that provides vitamin D3 which is more bioavailable than vitamin D2. As it is a fat soluble vitamin, take it with food that contains some oil (or select an oil-based capsule).
Vitamin D3 is available as tablets, capsules, sprays and skin creams (vitamin D3 can be absorbed through the skin).
Calcium for high blood pressure
Calcium plays a vital role in muscle contraction, nerve conduction, blood clotting and blood vessel dilation. Calcium also promotes sodium excretion to help reduce fluid retention, so that calcium deficiency is linked with an increased risk of high blood pressure and stroke.
Good dietary sources of calcium include milk and dairy products, broccoli, dark green leaves, nuts, seeds and wholegrains.
The results from 40 studies, involving almost 2,500 people, show that taking calcium supplements (at an average daily dose of 1200 mg) reduced blood pressure by a small but significant amount of 1.86/0.99 mmHg overall. In people with a relatively low calcium intake (800mg per day or less) the protective effect was greater, with calcium supplements lowering blood pressure by 2.63/1.30 mmHg. The researchers concluded that good calcium intakes should be recommended for the prevention of hypertension.
A typical supplement dose is 500mg – 1000mg calcium per day. If you are taking a calcium channel blocker antihypertensive drug, however, the blood pressure lowering effect of calcium supplements is lost.
Fruitflow for high blood pressure
The clear jelly surrounding tomato seeds is a source of at least 35 substances that reduce the spikiness of clotting fragments (platelets) so they are less likely to clump together and form unwanted blood clots.
As a result, a tomato extract called Fruitflow has an authorised health claim from the European Food Safety Authority that it ‘Helps maintain normal platelet aggregation, which contributes to healthy blood flow.’
Fruitflow extracts can also lower blood pressure by blocking the effects of angiotensin-converting enzyme in a similar way to prescribed ACE-inhibitor drugs.
When researchers from the University of Oslo gave different amounts of Fruitflow to healthy people who underwent 24 hour ambulatory blood pressure monitoring they found that a single dose of 150mg Fruitflow significantly lowered the average 24-hour systolic blood pressure reading compared to placebo – even though participants did not have hypertension. During waking hours, both systolic and diastolic blood pressure were significantly lower, while during sleep their systolic pressure was significantly lower. This information was posted on the London Stock Exchange but published clinical results are not yet available to assess the full effect – I will update this post when they are released.
Fruitflow works particularly well when combined with omega-3 fish oils.
Supplements to lower a high blood pressure conclusion
High blood pressure is one of the most important heart disease and stroke risk factors your doctor will even screen you for. Controlling blood pressure down to, ideally, less than 130/80 mmHg is vital for long-term circulatory health. While medication is often needed, diet and lifestyle changes can improve your blood pressure control and help to limit the number and dose of medicines you need.
I have a website dedicated to controlling blood pressure at www.MyLowerBloodPressure.com.
If your blood pressure is raised, self-monitoring is key to maintaining good control.
Click here for advice on choosing a blood pressure monitor to use at home.
Image credits: shawn_h/bigstock; pixabay; valentyn_volkov/shutterstock; jiang_hongyan/shutterstock; yastremska/bigstock;