By Chukwuma Muanya (The Guardian Newspaper)
Researchers have identified and validated more local spices and food items that could be effectively used to control and manage hypertension. Top on the list are garlic, beetroot, Zobo and banana.
Several studies have identified hypertension-related diseases and complications as the major cause of sudden deaths in Nigeria. However, researchers have shown that lifestyle modifications including the regular intake of local spices and foodstuffs may reduce the risk of developing the condition and help in managing it in persons already affected.
Top on the list of the local remedies are: garlic, Zobo, beetroot, banana, and carrot.
Hypertension, or chronically elevated blood pressure (BP) (systolic/diastolic BP [SBP/DBP] greater than and equal to 140/90 mmHg at the brachial artery), is a multifactorial condition implicated in the development and progression of cardiovascular disease. Hypertension is among the most important modifiable risk factors for cardiovascular disease.
Hypertension and its complications such as strokes, heart attack and kidney failure are on the prowl!
Garlic (Allium sativum)
Researchers have found that garlic, particularly in the form of the standardizable and highly tolerable aged garlic extract, has the potential to lower BP in hypertensive individuals similarly to standard BP medication, via biologically plausible mechanisms of action.
The recent study published in the journal Integrated Blood Pressure Control is titled “Potential of garlic (Allium sativum) in lowering high blood pressure: mechanisms of action and clinical relevance.”
The authors led by Karin Ried and Peter Fakler wrote: “Garlic supplements have shown promise in the treatment of uncontrolled hypertension, lowering blood pressure (BP) by about 10 mmHg systolic and 8 mmHg diastolic, similar to standard BP medication. Aged garlic extract, which contains S-allylcysteine as the bioactive sulfur compound, in particular is standardizable and highly tolerable, with little or no known harmful interaction when taken with other BP-reducing or blood-thinning medication.
“Here we describe biologically plausible mechanisms of garlic’s BP-lowering effect. Garlic-derived polysulfides stimulate the production of the vascular gasotransmitter hydrogen sulphide (H2S) and enhance the regulation of endothelial nitric oxide (NO), which induce smooth muscle cell relaxation, vasodilation, and BP reduction. Several dietary and genetic factors influence the efficiency of the H2S and NO signaling pathways and may contribute to the development of hypertension. Sulphur deficiency might play a part in the etiology of hypertension, and could be alleviated with supplementation of organosulfur compounds derived from garlic.”
Banana (Musa sapientum)
Researchers have found that banana contains phytochemicals, thus its intake reduces blood pressure significantly among hypertensive individuals.
The study published in the journal Medical Science is titled “Effect of banana on blood pressure of hypertensive individuals: a cross sectional study from Pokhara, Nepal.”
Medicinal use of banana is well known. Musa paradisiaca (plantain)and Musa sapientum is used in diarrhoea (unripe), dysentery, intestinal lesions in ulcerative colitis, diabetes (unripe), in sprue, uremia, nephritis, gout, hypertension, cardiac disease.
Apart from effect in blood pressure, banana inhibits atherosclerosis and gallstones in vivo. Musa paradisiaca inhibits cholesterol crystallization, showing this effect. Banana contains large amounts of potassium. Approximately, 300mg/100g fresh weight. Experimental evidences suggest that potassium is an important regulator of blood pressure. Altered vascular sensitivity to vasoactive hormones and alterations in divalent cation metabolism playing a key role mediating blood pressure. After extensive review of literature relatively fewer documents found enlighten the blood pressure lowering effect of banana on human subjects.
Zobo/Roselle (Hibiscus sabdariffa)
Scientists have confirmed the efficacy of Zobo in the treatment of hypertension and high cholesterol/fat levels.
The study published in the journal Fitoterapia is titled “Hibiscus sabdariffa in the treatment of hypertension and hyperlipidemia: a comprehensive review of animal and human studies.”
The researchers noted: “The effectiveness of Hibiscus sabdariffa (HS) in the treatment of risk factors associated with cardiovascular disease is assessed in this review by taking a comprehensive approach to interpreting the randomized clinical trial (RCT) results in the context of the available ethnomedical, phytochemical, pharmacological, and safety and toxicity information. HS decoctions and infusions of calyxes, and on occasion leaves, are used in at least 10 countries worldwide in the treatment of hypertension and hyperlipidemia with no reported adverse events or side effects. HS extracts have a low degree of toxicity with a LD50 ranging from 2,000 to over 5,000 mg/kg/day.
“There is no evidence of hepatic or renal toxicity as the result of HS extract consumption, except for possible adverse hepatic effects at high doses. There is evidence that HS acts as a diuretic, however in most cases the extract did not significantly influence electrolyte levels. Animal studies have consistently shown that consumption of HS extract reduces blood pressure in a dose dependent manner. In RCTs, the daily consumption of a tea or extract produced from HS calyxes significantly lowered systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults with pre to moderate essential hypertension and type 2 diabetes.
“In addition, HS tea was as effective at lowering blood pressure as the commonly used blood pressure medication Captropril, but less effective than Lisinopril. Total cholesterol, low-density lipoprotein cholesterol (LDL-C), and triglycerides were lowered in the majority of normolipidemic, hypolipidemic, and diabetic animal models, whereas high-density lipoprotein cholesterol (HDL-C) was generally not affected by the consumption of HS extract. Over half of the RCTs showed that daily consumption of HS tea or extracts had favorable influence on lipid profiles including reduced total cholesterol, LDL-C, triglycerides, as well as increased HDL-C. Anthocyanins found in abundance in HS calyxes are generally considered the phytochemicals responsible for the antihypertensive and hypocholesterolemic effects, however evidence has also been provided for the role of polyphenols and hibiscus acid.
“A number of potential mechanisms have been proposed to explain the hypotensive and anticholesterol effects, but the most common explanation is the antioxidant effects of the anthocyanins inhibition of LDL-C oxidation, which impedes atherosclerosis, an important cardiovascular risk factor.
“This comprehensive body of evidence suggests that extracts of HS are promising as a treatment of hypertension and hyperlipidemia, however more high quality animal and human studies informed by actual therapeutic practices are needed to provide recommendations for use that have the potential for widespread public health benefit.”
Recent research showed that beetroot might reduce blood pressure in some people.
A meta-analysis of 16 trials was published in The Journal of Nutrition in 2013.
The researchers found that: “Inorganic nitrate and beetroot juice supplementation was associated with a significant reduction in systolic blood pressure.”
However, the latest study to investigate beetroot and its impact on blood pressure was carried out at Queen Mary University of London (QMUL) in the United Kingdom and published in the journal Hypertension.
British Heart Foundation, senior research advisor, Dr. Shannon Amoils, said: “This interesting study builds on previous research by this team and finds that a daily glass of beetroot juice can lower blood pressure in people with hypertension – even those whose high blood pressure was not controlled by drug treatment.”
The study concluded: “These findings suggest a role for dietary nitrate as an affordable, readily-available, adjunctive treatment in the management of patients with hypertension.”
To put the importance of these findings in context, the authors note that large-scale observational studies show that for every 2 mm Hg increase in blood pressure, the risk of death from heart disease goes up 7 percent and the risk of stroke increases by 10 percent.
Also,, a recent review of natural herbs used in the treatment of hypertension has provided an introduction of the naturally occurring medicinal plants that have so far been scientifically studied and reported to have hypotensive or antihypertensive effects.
The study published in Pharmacognosy Review is titled “Role of natural herbs in the treatment of hypertension.”
According to the study, naturally occurring medicinal plants, herbs having hypotensive/antihypertensive potential include among others: garlic (Allium sativum), buchu (Agathosma betulina), soursop/graviola (Annona muricata), celery (Apium graveolens), breadfruit (Artocarpus altilis), green oat (Avena sativa), tea (Camellia sinensis), stinging weed/coffee weed (Cassia occidentalis), carrot (Daucus carota).
Other herbs for treating hypertension according to the Pharmacognosy Review study are: soybean (Glycine max), zobo/roselle (Hibiscus sabdariffa), stonebreaker (Lepidium latifolium), tomato (Lycopersicon esculentum), Moringa oleiferia, scent leaf/basil (Ocimum basilicum), Phyllanthus amarus (ngwu in Ibo), ginger (Zingiber officinale), sesame (Sesamum indicum).
Phyllanthus amarus belongs to the plant family Euphorbiaceae. To the Efik it is called oyomokeso amanke edem; geeron-tsuntsaayee (birds millet) in Hausa; Ibo (Asaba) buchi oro, Ibo (Umuahia) ngwu; iyeke in Urhobo; and ehin olobe or eyin olobe in Yoruba.
In another published study featured in the Journal of Medicine, it was revealed that common spices can protect from heart disease and the deterioration brought about by aging. In the said study, researchers discovered a connection between the phenol content of certain herbs and spices and their capacity to prevent glycation and formation of AGE compounds that are responsible for premature ageing and heart disease.
Also, according to the study, “An Ethnobotanical Survey of Herbal Markets and Medicinal Plants in Lagos State of Nigeria” published in Ethnobotanical Leaflets by researchers from the Department of Botany and Microbiology, University of Lagos, herbal cures for hypertension include: leaves of Persea americana (avocado) are made into shreds, dried and taken as infusion; leaves of Senecio biafrae (worowo in Yoruba or Sierra Leone bologna) added to fermented seeds of Parkia biglobosa (dawadawa in Hausa, African locust beans in English, Igba/Iyere in Yoruba, and Nere in Bambara) are used to prepare soup which is eaten; leaves of Talinum triangulare (water leaf) or Basella alba (Indian spinach in English, Amunututu in Yoruba) may also be used; and kola nut’s mistletoe mixed with honey is also effective.
Another study titled “Phytochemical Analysis of Medicinal Plants Used for the Management of Hypertension by Esan people of Edo State, Nigeria” and published in Ethnobotanical Leaflets by researchers from Ambrose Alli University, Ekpoma, Edo State, identified 14 endemic plant species distributed in 12 taxonomic families commonly used to manage hypertension.
They include: guava (Psidium guajava), West African black pepper/Ashanti pepper (Piper guineense, Uziza in Igbo and Ata iyere in Yoruba), mistletoe (Loranthus spectobulus), water leaf (Talinum triangulare), Nigerian senna/negro coffee (Senna occidentalis), serpent wood or swizzler stick (Rauwolfia vomitoria), garlic (Allium sativum), onions (Allium cepa), pawpaw (Carica papaya), asthma herb (Euphorbia hirta), scent leaf/basil (Ocimum gratissimum), avocado (Persea americana), cow-foot (Peperomia pellucida), and bitter leaf (Vernonia amygdalina).
Method of preparation
The bulbs of garlic are blended with honey for the purpose of hypertension. The unripe rind of pawpaw is peeled and soaked in water and after three days, a cup is taken daily. The leaves are also used for treating hypertension.
Leaves of avocado pear are cut into pieces, dried and made into tea, for the management of hypertension. The cotyledons of avocado pear seed are cut into pieces, dried and grinded into powder. A dessert spoonful in 200ml hot water taken after meals gives relieve for the ailment.
Guava leaves are soaked in salt water, washed and squeezed and product made up with fresh water to give a greenish liquid that is taken, one glass two times daily for one week to increase blood level and offer protection against heart attack.
Also, the fresh leaves of bitter are chewed and swallowed or ground, or stirred in water, and the liquid taken, to manage hypertension.
Annona muricata is a member of the family of custard apple trees called Annonaceae and a species of the genus Annona, known mostly for its edible fruits Annona. The tree grows natively in the Caribbean and Central America. The leaf extract of the plant has been reported to lower an elevated BP by decreasing the peripheral vascular resistance.
The plant is native to the Malay Peninsula and western Pacific islands. A study has shown that the leaf extract of the plant decreased the tension of phenylephrine-stimulated isolated guinea pig aorta rings by 15 to 35 per cent.
It has been used in traditional medicine to treat hypertension. Activity-directed fractionation of aerial parts of D. carota resulted in the isolation of two coumarin glycosides coded as DC-2 and DC-3. Intravenous administration of these compounds caused a dose-dependent (1–10 mg/kg) fall in arterial BP in NMT anesthetized rats. In the in vitro studies, both compounds caused a dose-dependent (10–200 mg/ml) inhibitory effect on spontaneously beating guinea pig atria as well as on the K+ -induced contractions of rabbit aorta at similar concentrations.
These results indicate that DC-2 and DC-3 may be acting through blockade of calcium channels, and this effect may be responsible for the BP-lowering effect of the compounds observed in the in vivo studies. Two new guaiane-type sesquiterpene terpenoids containing an interesting epoxy unit, daucuside and daucusol, have been isolated from fruits of D. carota.
Tomato extract contains carotenoids, such as lycopene, beta carotene, and vitamin E, which are known as effective antioxidants, to inactivate free radicals and to slow the progress of atherosclerosis. A study showed that extract of tomato (Lyc-O-Mato) modestly reduces BP in patients with mild, untreated hypertension.
A significant correlation has been observed between systolic BP and lycopene levels.