Natural Extracts Lower Blood PressureOctober 2014
By Brandon Dewitte
The World Health Organization has determined that hypertension is the leading cause of cardiovascular mortality.1
It affects as many as 1.5 billion people worldwide and is a major risk factor for atherosclerosis.
Drug therapy for hypertension is often comprised of one or a combination of medications that may include an angiotensin II receptor blocker, calcium channel blocker, beta blocker, angiotensin converting enzyme (ACE) inhibitor, and/or a diuretic.2,3
Some of these drugs and drug combinations have potential side effects, which is troubling since blood pressure medications may be required for the rest of a person’s life.4,5 That does not mean a person with hypertension should discontinue their prescribed medications. But if natural approaches can reduce blood pressure readings so that drug doses can be reduced or eliminated, then side effect concerns can be mitigated.
In an exciting new discovery, scientists have uncovered two natural extracts that have similar mechanisms to some of the most effective drug therapies for hypertension.
Olive leaf extract has been shown to function as an ACE inhibitor and celery seed extract has potent calcium channel blocking properties.6,7 Clinical studies have demonstrated that both extracts are able to safely lower blood pressure.8,9
These specialized extracts offer a natural approach to blood pressure management.
Current Treatments For Hypertension
Numerous recent, large, randomized clinical trials have indicated that treating hypertension in older adults can reduce the risk of kidney disease, stroke, and cardiovascular events.10 Unfortunately, bringing blood pressure down to healthy levels is easier said than done.
Many clinicians start therapy with a mild diuretic (“water pill”) at low doses, then gradually increase doses until either blood pressure is controlled or the maximum dose is reached.10
However, nearly 75% of patients do not get adequate blood pressure control on a single drug, which means a second medication is often necessary.11 This process may continue until a person finds himself or herself on three, four, or more drugs.2,11,12
A frequently prescribed class of antihypertensives used today are the angiotensin II receptor blockers. These drugs block the angiotensin II receptor and often induce more profound and sustained blood pressure control than older classes of medications. However, there are side effect risks associated with angiotensin II receptor blocker drugs. In some individuals, angiotensin II receptor blockers can cause an increase in potassium and changes in kidney function. Also, do not take angiotensin receptor blockers if you are pregnant or plan on becoming pregnant because this class of medication can cause harm to the fetus.
One of the most commonly used approaches to treating hypertension involves the combination of two drugs: an ACE inhibitor and a calcium channel blocker.2,3 A large 2013 study demonstrated that for most people, this combination was more effective at reducing cardiovascular consequences of hypertension than using either drug with a diuretic.13 This combination also demonstrated the greatest probability of reducing death.14
Here’s how the combination drug therapy works.
Angiotensin converting enzyme, or ACE, is a natural enzyme in the body that activates the hormone angiotensin, which causes blood vessels to constrict, thus increasing blood pressure.15 Inhibiting ACE can return blood pressure to lower levels. ACE inhibitors alone, however, are not always entirely effective, which is why doctors often combine them with a second drug called a calcium channel blocker.16
Calcium channel blockers lower blood pressure by a different mechanism than ACE inhibitors. They prevent the entry of calcium ions into muscle cells in the arterial wall. Since calcium ions are a major signal telling those cells to contract and raise muscle tone in the artery, blocking calcium influx into the cells will prevent contraction and lower blood pressure.17
Use of the combination of an ACE inhibitor and a calcium channel blocker has become one of the mainstays of modern pharmacological blood pressure control, since the two drugs act in parallel, but different ways. Unfortunately, as is usually the case, both drugs bring with them side effects.17,18
Scientists have discovered two natural ingredients that work in ways similar to mainstream drugs, but without the numerous side effects. Olive leaf extract and celery seed extract act as ACE inhibitors and calcium channel blockers, respectively.6,7 Each has been shown in clinical studies to lower blood pressure.
Olive Leaf Extract: A Natural ACE Inhibitor
Extracts from leaves of the olive tree (Olea europaea) contain compounds known as secoiridoid glycosides.6 When ingested, these substances break down into molecules with the ability to inhibit angiotensin converting enzyme (ACE) and its harmful effects on blood vessels.6,19 Studies now show that olive leaf extract is effective at lowering blood pressure, just as would be expected from an ACE inhibitor.20
In preclinical trials, researchers found that when they gave rats an olive leaf extract at the same time as hypertension-inducing chemicals, it prevented them from developing experimentally induced hypertension.21 Similarly, in rats that had already been hypertensive for six weeks, administration of olive leaf extract normalized blood pressure, even when the rats continued receiving the hypertension-inducing chemical.21 Animal studies have also shown that olive leaf extract is effective at reducing the signs of metabolic syndrome, a major cardiovascular risk factor.22
Human studies have been extremely encouraging as well. A cleverly designed human trial using identical twins demonstrated the antihypertensive effects of olive leaf extract, with one twin serving as a control.8 Treated twins received either 500 or 1,000 mg/day of the extract while the other received advice regarding a “favorable lifestyle.”
After eight weeks, compared to their controls, twins taking 500 mg/day saw an average drop in systolic pressure of 6 mm Hg, while the twins taking 1,000 mg/day saw an average drop in systolic pressure of 13 mm Hg. In the group taking the higher dose, blood pressure fell from an average of 137/80 at baseline to 126/76 after eight weeks and LDL cholesterol was also reduced.
Olive leaf extract was recently compared directly with the ACE inhibitor captopril in patients with Stage I hypertension and it was found to be almost equally as effective.20 The extract dose was fixed at 500 mg twice daily for the eight weeks of the study, while captopril dosing started at 12.5 mg twice daily, and increased to 25 mg twice daily if needed for blood pressure control.
At the end of the study, both groups experienced significant reductions in systolic and diastolic blood pressure as compared to baseline. The olive leaf extract group experienced a mean systolic blood pressure reduction of 11.5 mm Hg, while the captopril group reduced systolic blood pressure by 13.7 mm Hg. Diastolic pressures fell 4.8 mm Hg in the olive leaf extract group and 6.4 mm Hg in the captopril group. The differences between groups were not statistically significant.20
In addition, triglyceride levels fell significantly from baseline in the olive leaf supplemented group but not in the drug group. This important study showed that olive leaf extract was similar in effect to the ACE-inhibiting drug, but with the added benefit of triglyceride reduction.
A subsequent human study showed that olive leaf extract could also improve insulin sensitivity by 15% in overweight middle-aged men, an important step in further reducing cardiovascular risk.23 It also led to a 28% improvement in pancreatic responses to blood sugar.
Celery Seed Extract: A Natural Calcium Channel Blocker
Celery is a simple food with a complex chemical makeup. Studies show that celery seed components produce a relaxing, dilating effect that lowers blood pressure. This appears to occur, at least in part, by blocking or antagonizing the flow of calcium into muscle cells lining blood vessels—similar to the action performed by calcium channel blocking drugs.7,24,25 One key blood pressure-lowering compound in celery seeds has the technical name of L-3-n-butylphthalide, abbreviated as 3nB.26,27
3nB has been used in a number of studies for the management of vascular diseases in the brain, such as stroke and vascular dementia.26,28,29 And even now, a synthetic form of 3nB is being developed as a drug in China for the treatment of cerebral ischemic stroke and mild cognitive impairment as well as for the prevention of Alzheimer’s disease—all of which have components of abnormalities in blood flow.26,30-33
Animal and lab studies reveal that 3nB-rich extracts of celery seeds produce blood pressure reductions of up to 38 mm Hg in hypertensive rats (this effect was not seen in those with normal blood pressures).27 Animal studies also demonstrate that celery seed extract has no significant toxic effects even at very high doses.34
A human study demonstrating the effectiveness of a celery seed extract standardized to 85% 3nB recently appeared in the Natural Medicine Journal.9 For the study, 30 middle-aged patients with mild-to-moderate hypertension took 75 mg doses of a celery seed extract twice daily for six weeks. To obtain an equivalent amount of 3nB, one would have to consume approximately 530 stalks (nearly 50 pounds) of celery.
Mean blood pressures at baseline were 139.4/85.4 mm Hg. At three weeks, they fell to 134.8/80.9, and at six weeks they fell to 131.2/76.9. This represents total drops of 8.2 mm Hg systolic and 8.5 diastolic from baseline.
Of great importance, while pharmacological calcium channel blockers and ACE inhibitors are known to reduce blood flow to the brain—which can leave patients feeling tired, depressed, dizzy, or forgetful—celery seed extracts rich in 3nB appear to improve brain blood flow, prevent stroke, and may protect brain cells and enhance their energy consumption.9,30,33,35