High blood pressure or hypertension is a major health problem around the world and causes 7.5 million (12.8%) deaths per year (1).
High blood pressure is a risk factor for diseases such as chronic heart disease, stroke, and coronary heart disease (2).
Hypertension is defined as systolic blood pressure (SBP) of 140 mmHg or higher and diastolic blood pressure (DBP) of 90 mmHg or higher. The SBP between 120–139 mmHg and DBP between 80–89 mmHg is called “prehypertension”
The normal blood pressure range is SBP lower than 120 mmHg and DBP lower 80 mmHg (3).
A major factor for the development of high blood pressure is oxidative stress and free radicals in the body (4).
Food sources with high antioxidant potential present a natural way to lower blood pressure.
This article explains 9 natural supplements for high blood pressure in the laboratory or population-based research.
These natural supplements lower blood pressure because of their high antioxidant potential and role in other blood pressure-lowering mechanisms.
1) Calcium
Although calcium is known to be good for bone health, it performs several other important functions in the body.
The role of calcium in managing blood pressure is known for a long time via animal and human studies (5,6). These studies show a positive effect of calcium in lowering blood pressure.
High blood pressure during pregnancy can be dangerous for both mother and fetus.
In pregnant women, calcium supplementation 1g/day significantly reduced the risk of pre-eclampsia (7).
A critical review of several studies concluded that calcium intake is positively correlated with reduced Systolic BP (upper limit) but did not improve Diastolic BP (lower limit) (8).
A meta-analysis showed that calcium intake was associated with a reduced risk of high blood pressure. Use of calcium supplementation above 1g/day was associated with a reduction in both Systolic BP and Diastolic BP (9). this study recommended the intake of calcium for hypertension prevention.
Recommended calcium intake
The recommended daily allowance of calcium for adult men and women is 1000 mg or 1 g (10).
Food sources of calcium
As per NIH, the best source of calcium is dairy products (11).
Major calcium sources are:
- Milk
- Yogurt
- Cheese
- Nuts and seeds
- Kale, Broccoli, and turnips
3.5 ounce (100g) Mozzarella provides approx. 800mg calcium. 8 ounce (225g) plain yogurt provides 415mg calcium and 1 cup (237ml) milk provided between 276-299mg calcium.
Calcium Supplements
Calcium supplements are effective in people with low dietary calcium intake.
These supplements are readily available sources of calcium in different salts such as carbonate, citrate, citrate-malate, and lactate-gluconate.
Research has shown that the bioavailability of these calcium salts is similar and they are easily absorbed by the digestive system (12).
Several brands and types of calcium supplements are available in the market.
The most common calcium supplements are:
- Calcium carbonate
- Calcium citrate
2) Magnesium
Like calcium, magnesium is another essential mineral in the body. It influences blood pressure via several mechanisms. It promotes the release of nitric oxide (13). Nitric oxide is a vasodilator i.e. reflexes the inner surface of blood vessels to widen them.
Magnesium reduces the risk of vascular injury because of its antioxidant and anti-inflammatory function (14).
In animal studies, a low level of magnesium in blood was associated with a risk of high blood pressure (15).
In humans, magnesium supplementation improves the effect of antihypertensive therapy (16).
Magnesium sulfate can be effective in reducing the symptoms of preeclampsia and eclampsia (17).
Research shows that magnesium supplementation leads to a small but significant lowering of blood pressure (18). The magnesium supplement intake is associated with a lower risk of blood pressure and vice versa (19).
A meta-analysis concluded that magnesium supplementation significantly lowered blood pressure in individuals with insulin resistance, prediabetes condition, and type 2 diabetes (20).
But some observational population research shows no association with magnesium and blood pressure (21).
Although studies are inconsistent, current research shows that magnesium supplementation can improve blood pressure.
Recommended magnesium intake
According to NIH, the recommended daily allowance of magnesium is between 400-420 mg for men and 310 to 320 mg for women (22).
Food sources of Magnesium
Both animals and plants are sources of magnesium but high magnesium amount is obtained from plants (23).
These include:
- Almonds
- Bananas
- Black beans
- Brown rice
- Cashews
- Flaxseed
- Green vegetables (spinach, broccoli)
- Nuts
- Oatmeal
- Seeds (pumpkin, sesame, sunflowers)
- Tofu
- Whole grains
Magnesium supplements
Several types of magnesium supplements are available in the market.
Research indicates that organic magnesium supplements may be more bioavailable than inorganic magnesium formulations (24).
Organic magnesium includes:
- Magnesium aspartate
- Magnesium citrate
- Magnesium lactate
- Magnesium chloride
Inorganic magnesium includes:
- Magnesium oxide
- Magnesium sulfate
3) Vitamin C
Vitamin C is a strong antioxidant with the potential to reduce oxidative stress (25).
vitamin C in combination with other vitamins show immense potential in lowering blood pressure
For example, vitamin C, E, and folic acid supplementation significantly lower systolic blood pressure in young individuals (26).
Vitamin C and E supplementation is associated with decreased oxidative stress and lowering of blood pressure in hypertensive patients (27).
An inverse relationship between vitamin C deficiency and high blood pressure are known for a long time (28,29).
An increase in vitamin C levels is associated with reduced blood pressure and vice versa (30).
Although several studies have shown vitamin C’s role in lowering blood pressure, increasing the consumption of fruits and vegetables did not result in antioxidant activity or vascular improvement as noted by one study (31).
Other studies show that short-term use of vitamin C supplementation is not effective in reducing oxidative stress and blood pressure in type 2 diabetes patients (32).
Perhaps, a long-term vitamin intake is required to see the antioxidant effects.
Other studies have found that vitamin C deficiency causes an increased accumulation of cholesterol in the thoracic aorta which changes blood vessel physiology.
Vitamin C supplementation causes a significant reduction in LDL and improves HDL (33).
Recommended daily intake of vitamin C
As per NIH, the recommended daily allowance of vitamin C is 90 mg for adult men and 75mg for adult women (34).
Food sources of vitamin C
Animal sources may not have enough vitamin C to reach recommended daily intake.
Fruits and vegetables are the best sources of vitamin C. citric fruits are especially high in vitamin C. Mediterranean diet fundamentally consists of fruits and vegetables which are a rich source of other plant-based vitamins too.
Food sources of vitamin C include (35):
- Citrus fruits (orange, grapefruits, kiwi fruit)
- Green and red peppers
- Strawberries
- Tomatoes
- Broccoli
- Brussels sprouts
- Turnip
- Indian gooseberry
- Leafy vegetables.
Vitamin C supplements
Vitamin C is available in different preparations (36).
These include:
- Powders (oral suspension)
- Capsules
- Granules for oral solution
- Tablets
- Oral drops
- Syrups
4) Vitamin E
Vitamin E is a group of 8 fat-soluble variants with strong antioxidant potential. Alpha-tocopherol is the most studied form with high antioxidant activity among vitamin E variants in the body (37).
Vitamin E and C work together to reduce oxidative stress. Research shows that vitamin E and C decrease arterial stiffness in hypertensive patients (38).
Vitamin E promotes nitric oxide release and improves vasodilation (widening of blood vessels) in hypertensive patients (39).
In animals studies, the use of vitamin E reduces blood pressure and oxidative stress (40).
In humans, the use of vitamin E significantly reduces systolic BP (41).
A comprehensive meta-analysis showed that vitamin E intake significantly lowers the systolic BP but may not be effective in lowering diastolic BP (42).
Recommended daily intake of Vitamin E
The recommended daily allowance for vitamin E for both adult men and women is 15mg (43).
Food sources of vitamin E
Major food sources of vitamin E are also fat sources. vitamin E is found in nuts and oils.
Accodrig to NIH, Vitamin E is present in:
- Wheat germ oil
- Sunflower seeds
- Almonds
- Safflower oil
- Hazelnuts
- Peanuts and Peanut butter
- Spinach
- Broccoli
- Tomato
Vitamin E supplements
Both natural and synthetic vitamin E is available for consumption. The synthetic vitamin E, called all-racemic α-tocopherol, has all 8 isomers of tocopherol. All-rac isomers are commonly used in vitamin E supplements and fortified foods in the USA (44).
Some supplement brands sell natural vitamin E as well.
Research shows that naturally occurring vitamin E is superior to synthetic vitamin E (45). Therefore, it’s a good idea to get vitamin E from food sources or get natural vitamin E supplement.
5) Curcumin
Turmeric has been used as a natural food coloring agent for centuries. Curcumin is the main active ingredient of turmeric with a strong anti-oxidant and anti-inflammatory function that has been established by many robust studies (46).
Research shows the benefit of curcumin in improving hypertensive conditions. curcumin has a positive effect on the morphology of blood vessels in hypertensive disease conditions (47). Curcumin metabolite, Tetrahydrocurcumin prevents blood vessel dysfunction by decreasing oxidative stress (48).
Curcumin supplementation is beneficial for endothelial function by increasing nitric oxide availability and increases in antioxidant function (49).
Population studies show that turmeric use in food is correlated with fewer incidences of hypertension (50).
A meta-analysis concluded that long-term curcumin use may improve the lowering of systolic BP (51).
Recommended daily intake of curcumin
Since curcumin is not essential for the function of the body there is no recommended daily intake of curcumin.
Food sources of curcumin
curcumins are naturally acquired from turmeric.
Curcumin supplements
Curcumin is poorly absorbed in the body. However, it binds with fat molecules therefore adding turmeric to food may increase absorption.
For supplements, to increase the absorption of curcumin several formulations have been available in the market (52).
These include:
- Colloidal nano-particle curcumin (theracurmin) (53).
- Piperine-curcumin complex
- Cyclodextrin curcumin complex
- Meriva, a curcumin-phosphatidylcholine phytosome complex which is the most studied curcumin complex for enhanced absorption
6) Quercetin
Quercetin is a potent antioxidant flavonol from the flavonoid group present in more than 20 plants including leafy green vegetables and fruits (54).
Because of its strong antioxidants function, several studies have shown that quercetin is beneficial for high blood pressure.
Research shows that consumption of fruit and vegetable decreases the risk of stroke and coronary heart disease (55).
Quercetin improves nitrate levels which can dilate blood vessels, thus having a blood pressure-lowering function (56).
Animal studies show that quercetin supplementation reduces oxidative stress and reduces blood pressure (57).
In humans, the use of quercetin supplementation reduces systolic and diastolic BP in hypertensive patients (58).
Quercetin use in obese individuals reduced systolic BP which eventually reduces the risk of heart diseases (59).
Recommended daily intake of Quercetin
Currently, no recommended daily intake dosage exists for quercetin.
Food sources of Quercetin
Quercetin is obtained from plants (60).
These include:
- Apples
- Berries
- Brassica vegetables (broccoli, cabbage, cauliflower, collard greens, kale, and turnips)
- Capers
- Grapes
- Onions
- Shallots
- Tea
- Tomatoes
- Red wine
Quercetin supplements
Quercetin exists as free form or as quercetin glucoside. It is among the GRAS (generally recognized as safe) supplements.
Quercetin is available in the market in several forms ranging from 250 to 1500 mg concentration (61).
These include:
- Quercetin aglycone
- Quercetin rutin
To get the best results, please follow the instructions from the manufacturer regarding the dosage.
7) Catechins
Catechins are powerful antioxidants flavanols present in different fruits and vegetables but the main catechins source is green tea. (-)-epigallocatechin gallate (EGCG) is the most studied and important catechine (62).
Green tea catechins reduce blood pressure by several mechanisms (63).
Reduction of oxidative stress on the major way catechins improve smooth muscle cell physiology (64).
In animal studies, EGCG use significantly improved endothelial function and blood pressure (65).
In obese individuals, the use use of green tea extract supplements induced a small but significant blood pressure reduction (66).
Research from several studies shows that long-term consumption of green tea is associated with lowering systolic BP and overall blood pressure (67,68).
Recommended daily intake of catechins
Currently, no recommended intake of green tea exists. Green tea is on FDA’s GRAS list, therefore, is a safe drink.
1-3 cups of green tea are consumed among tea drinkers (69).
Each serving of 240 ml brewed green tea can provide approx. 304 mg total catechins, with 187 mg EGCG.
704mg EGCG per day in beverage form and 338 mg EGCG per day as concentrated solid bolus dose of green tea extract is considered safe (70).
Food source of catechins
Green tea drinks are the best way to include catechins in your diet.
In addition to green tea, a variety of foods sources provide catechins (71).
These include:
- Apples
- Persimmons
- Cacaos
- Grapes
- Berries
Catechins supplements
Several green tea isolated catechin supplements are available in the market with concentrations from 50-700mg. These supplements can be purchased in capsule or powder form.
8) Omega-3
Omega-3 are polyunsaturated fatty acids (PUFA). EPA and DHA are animal-based omega-3 whereas linoleic acid is plant-based omega-3.
Several studies have shown omega-3’s beneficial effects in cardiovascular diseases (72).
Fish consumption is associated with a lower risk of hypertension (73).
Animal research shows that omega-3 PUFAs improve the dilation of blood vessels via different cell signaling pathways (74).
In humans, PUFA intake also improved the dilation of blood vessels (75).
Research shows that omega-3 reduces arterial stiffness in the older population (76).
High doses of 3-4g omega-3 per day are associated with lowering blood pressure in hypertensive patients (77,78,79).
Recommended daily intake of omega-3
American Heart Association recommends a daily intake of 500mg of omega-3 (80).
Most health organizations’ daily recommendations are within 250-500mg per day for adults.
Food sources of Omega-3
Animal food sources of omega-3 are fish and seafood (81).
These include:
- Salmon
- Mackerel
- Tuna
- Herring
- Sardines
Plants-based sources of omega-3 are nuts and seeds including chia seeds, flaxseeds. Plants-based oils include olive oil, flaxseed oil, soybean oil, and canola oil.
Omega-3 supplements
Omega-3 supplements are available in the market as fish oil supplements. The supplement concentration available in the market ranges between 250-2000 mg.
9) CoQ10
CoQ10 mixes with fats and has a strong antioxidant potential. Due to the high antioxidant potential CoQ10 may help with the vascular system (82).
A plethora of evidence points to benefit of CoQ10 in lowering blood pressure (83).
It decreases blood pressure in hypertensive patients with coronary artery disease (84).
Meta-analysis of randomized control trials shows a reduction in blood pressure after CoQ10 supplementation in metabolic syndrome patients (85).
Another meta-analysis concluded that CoQ10 supplementation can lower blood pressure and LDL in patients with hyperlipidemia condition and heart attack risk (86).
Recommended daily intake of CoQ10
There is no recommended daily intake of the CoQ10 but the average dose required to get the therapeutic effect is 200 mg twice daily with meals (87).
Food supplements of CoQ10
Both animal and plant products are sources of CoQ10 (88).
The major sources of CoQ10 include:
- Oily fish e.g. salmon and tuna
- Organ meats e.g. liver
- Whole grains
CoQ10 supplements
Although CoQ10 is obtained from food, supplements are used in certain conditions. CoQ10 is one of the most sold dietary supplements in the market.
Several CoQ10 supplements are available in the market containing 30-600 mg.
A problem with CoQ10 is its absorption in the body. CoQ10 is unable to mix with water, mixes with lipids to a certain level, and has a high molecular weight. These factors cause its low absorption (89).
Taking CoQ10 supplements with meals containing good quality fats can increase absorption.
Many formulations have been developed to enhance the absorption of CoQ10, including water-soluble Coq10 (90).
Following types of CoQ10 are available in the market:
- Ubiquinone
- Ubiquinol
- Water-soluble Q10Vital®
