Enhance Endothelial Function and Reduce Arterial StiffnessMarch 2014
By Michaela Harrod
Despite years of research and billions of dollars spent on lipid-lowering medications, cardiovascular disease remains the number one killer in the United States.
“Statin” drugs have undergone intense scrutiny, with evidence of over-prescribing, the potential for side effects, and somewhat exaggerated claims about effectiveness.1-3 Statin drugs reduce the risk of heart attack in high-risk patients, such as preventing a second heart attack in those individuals having already experienced a first heart attack.The benefit of reducing the risk of a heart attack in otherwise low-risk patients, however, is not clear.
Furthermore, a recent, controversial guideline change on statin drug prescribing for optimal lipid management has been met with deep skepticism by many experts in cardiology.1,2
Many aging individuals who seek to support healthy blood lipid management look for natural products with evidence of support.
Studies show that extracts from an Ayurvedic herbal plant called Amla (Emblica officinalis) can provide support for some of the important aspects of vascular and cardiac health.4
In addition, black tea extracts may offer more benefit for vascular health.5 These natural ingredients, used for centuries in Asian medicine, are available without the need for prescription.6
If you are concerned about vascular and cardiac health, and seek natural strategies to support cardiovascular health as you age, you’ll want to learn more about Amla and black tea extracts.
Endothelial Dysfunction And Stiff Arteries Are Killing You
By now most of us understand that elevated levels of cholesterol and other fats put us at risk of heart attacks, strokes, and other serious cardiovascular outcomes. We also know that having elevated blood glucose, metabolic syndrome, or outright diabetes adds to that risk.7,8 But few people outside of the halls of academia really understand how these factors work together to put your health—and your life—at risk.
In a nutshell, here’s how it works:
Your blood vessels are lined with an ultra-thin layer of sensitive cells called endothelial cells (or simply, “the endothelium”). The endothelium normally regulates blood flow and pressure, assuring that vital tissues always get just the right amount of oxygen- and nutrient-rich blood.
You want to have a healthy endothelium.
But the modern lifestyle works against endothelial health. One culprit is oxidative stress, which arises from a number of exposure sources.9-18
Oxidative stress damages the endothelium and impairs its ability to regulate blood flow, in part by reducing endothelial production of nitric oxide, a signaling molecule that tells the artery when to dilate to improve flow.11 Oxidative stress acts on elevated cholesterol levels to produce dangerous oxidized LDL, a key component of artery-clogging plaque.19
Add to that elevated blood sugar, which produces dangerous advanced glycation end products (AGEs) that chemically cross-link proteins in vessels, and physical and emotional stress, which impairs endothelial function still further, and you have the “perfect storm” of factors that damage endothelial function and ultimately lead to stiffening of the arteries.20-23
A result of thickened, stiff arteries is rising blood pressure, an overworked heart, and restricted blood flow. This ultimately leads to the catastrophes we see as heart attacks, heart failure, and strokes.24-27
So the bottom line is you want to do everything possible to protect your endothelial function and prevent arterial stiffening, long before you develop warning signs of cardiovascular disease.
To do that, it’s wise to attack all of the factors that add up to stiffened arteries and poor endothelial function. The ideal cardiovascular protective pill, therefore, would simultaneously reduce oxidative damage, control lipid and blood sugar levels, improve platelet function, and lower blood pressure.
In clinical studies, that pill would markedly improve endothelial function and reduce arterial stiffening, in healthy people and those at high risk for cardiovascular disease, such as diabetics, smokers, and those with the metabolic syndrome. And that pill would do all of this, without imposing its own risks to your health.
That’s what Amla extract has now been shown to do.28 Black tea extract provides an interesting complement, improving the same risk factors by similar as well as different mechanisms.29,30
How Amla Functions
The fruit of the Amla has long been used in traditional Indian medical systems.31 More recently, interest has grown in the fruit’s impact on blood glucose, lipid profiles, and, increasingly, other risk factors for cardiovascular disease. Let’s see how it stacks up as a supplement for reducing some of the risk factors that produce endothelial dysfunction and ultimately arterial stiffening.
Amla is a potent antioxidant. 32 Amla reduces overall oxidant stress by three separate pathways: It inhibits production of the oxidizing free radicals that damage endothelial cells, it scavenges and neutralizes those reactive oxygen species that have already been produced, and it enhances production and activity of natural cellular antioxidant enzyme systems.33-37 The result is a significant decrease in oxidant damage, as measured by biochemical markers of oxidation.38,39 Amla has very little pro-oxidant activity, ensuring a low rate of undesirable effects.40
Amla lowers cholesterol. Animal studies show that, while a high-fat or high-fructose diet will produce signs of the metabolic syndrome and unhealthy lipid profiles, treatment with Amla extract has been shown to help reduce total cholesterol and triglycerides.38,39,41,42 Importantly, this effect was especially noticeable in a rat model of menopause; at menopause, women’s risk for heart disease rapidly rises to become similar to men’s.42
It was recently discovered that Amla lowers serum lipids through an important pathway.43 Amla activates the “metabolic sensor” molecule called PPAR-alpha; the PPARs lower both blood lipids and glucose by increasing their consumption in cells.39 PPAR-activating drugs are increasingly being recommended for use in combination with statins, especially for diabetics. Amla may provide this benefit with less potential for the side effects seen with the two drugs.39,44,45
Amla fights diabetes. Diabetes is a disaster for endothelial function and arterial stiffness, and substantially raises the odds for a heart attack or stroke. When rats are made diabetic in the laboratory, Amla administration prevents rises in blood sugar and insulin resistance; it also prevents diabetes-associated increases in food intake.42,46
A unique anti-diabetic property of Amla is that it inhibits an enzyme called aldose reductase.47,48 This enzyme produces a toxic chemical called sorbitol, which damages proteins in the eye to cause cataracts, and which more recently has been implicated in production of arterial stiffening and cardiovascular disease.47-51
Amla lowers blood pressure. Elevated blood pressure is both a cause and a consequence of arterial stiffening; it can be produced in the laboratory by inducing the metabolic syndrome in rats through high-fructose diets, eventually resulting in damage to the heart and kidneys, exactly as in humans.41 But if the animals are supplemented with Amla extracts, blood pressure and elevated heart rates return to near-normal levels, heart and kidney swelling are reduced, and elevated sodium and depressed potassium levels are normalized.52,53 And in animals with full-blown diabetes, Amla prevents blood pressure-induced heart muscle dysfunction as well.46 Anyone using Amla to help with hypertension should have regular blood pressure checks, ideally using an at-home blood pressure monitor to ensure that blood pressure readings stay at the optimal range, which we at Life Extension have long argued are around 115/75 mm Hg.
Amla protects endothelial function. Poor endothelial function, as we’ve seen, underlies the arterial thickening and stiffening that ultimately leads to cardiovascular disease. Laboratory studies using cultured endothelial cells and experimental models show that treatment with Amla extract enhances production of nitric oxide, the signaling molecule that the endothelium uses to “tell” arterial walls to relax and maintain normal blood flow.52,54,55
Amla is cardioprotective. The sum of all of Amla’s beneficial effects in the laboratory can be seen in studies that demonstrate how it protects heart muscle from damage. A laboratory model of the overworked, underfed, diseased heart can be produced by treating the animals with the drug isoproterenol, a powerful heart stimulant that eventually impairs cardiac muscle function by excessive oxidative stress. Animals treated with isoproterenol develop decreased heart rate, poor contractility (“squeeze”), and increased pressure inside the heart, which leads to heart failure.56 But treatment with Amla extract restored normal heart function and pumping pressures, preserves antioxidant levels, reduces enzyme markers of heart muscle damage, and prevents microscopically-visible injury to heart muscle.56 And in diabetic rats, Amla also reduced ominous increases in heart size and muscle damage.46
Human Clinical Trials Using Amla
Laboratory studies show that Amla may rectify many problems associated with the endothelial dysfunction that conspire to cause cardiovascular disease. Now there’s exciting new evidence from a series of clinical studies that shows just how powerful these effects are in humans.
The first of these clinical trials examined the effects of Amla fruit extract supplementation on acute physical stress in healthy volunteers.57 Both acute and chronic stress are known risk factors for coronary artery disease, acting through oxidative mechanisms to damage the endothelium and stiffen arteries.57,58 Subjects received either a placebo or 500 mg Amla fruit extract twice daily for 14 days.57 Before and after supplementation, subjects underwent a “cold pressor” test that required placing the hand in ice water for a set period, which is a proven means of acutely impairing endothelial function and raising bloodpressure.57,59
All patients showed the same increases in blood pressure (10-12%) and arterial stiffness (12-20%)before treatment was started, but after 14 days, while placebo patients had those same increases, supplemented patients had decreases in both blood pressure (3-5% less than baseline) and arterial stiffness (8%), a marked and significant difference compared with placebo.57
In a similarly-designed study, researchers looked at the impact of Amla supplementation on mitigating the effects of mental stress on arterial stiffness. Mental stress is known to produce increased risk for acute cardiovascular disease, including even heart attacks.60,61 Here, healthy subjects took placebo or 500 mg Amla fruit extract twice daily for 14 days, and were subjected to a series of stressful mental math exercises before and after the supplementation period.62 Subjects taking Amla had a decrease in their aortic blood pressure compared with baseline values, while no such change was seen in placebo patients. No significant change in arterial stiffening occurred in either group.62
Because smoking is known to threaten endothelial function,13-18,63 another study was done to compare markers of endothelial dysfunction in smokers who received either placebo or 250 mg Amla extract twice daily for 60 days.64 Participants indicated their status on a group of subjective parameters of smoking-related health (e.g., of mouth hygiene, productive cough, painful breathing with exertion, sleep, and palpitations), while objective parameters of endothelial function and risk (including blood counts, lipid profiles, cardiac risk factors, toxicity to genes/chromosomes, platelet aggregation, C-reactive protein, antioxidant status, and lung function) were measured at baseline and the end of the study. With the exception of lung function (which remained constant and showed no signs of further deterioration), the supplemented group had significant improvement on all subjective and all objective measurements, demonstrating the broad-spectrum efficacy of Amla at reducing endothelial risk in one of the most challenging groups, namely smokers.
People with the metabolic syndrome are also at increased risk for cardiovascular disease as a result of endothelial dysfunction and increased arterial stiffness.27,65 Scientists studied placebo vs. Amla fruit extract (250 and 500 mg twice daily for 12 weeks) in metabolic syndrome patients with known endothelial dysfunction.66 They used the same proven technique for measuring arterial stiffness as in the previous studies. The placebo group had a small increase (1.3%) in stiffness after 12 weeks, while both Amla doses produced significant decreases (-6.6 and -7.5% for the 250 and 500 mg doses, respectively). Both Amla groups, but not the placebo group, also had significant increases in beneficial nitric oxide, which helps arteries dilate to allow increased blood flow. And both Amla doses produced significant increases in endogenous antioxidants such as glutathione, and reduced markers of oxidative damage and inflammation such as C-reactive protein. Finally, both dose levels of Amla caused drops in triglycerides, total cholesterol and LDL, with no change in the placebo group.
People with diabetes (types I or II) are at massively increased risk of endothelial dysfunction and stiffening of their arteries.23,65 Researchers have now studied the impact of Amla extract (500 mg twice daily for 12 weeks) vs. placebo in a group of diabetics, using the same measures of arterial stiffness as in the other studies.28 Supplemented subjects had a 7.6% drop in stiffness, compared with a 1.3% increase in placebo recipients.28 Amla also produced drops in total cholesterol, LDL and triglycerides, with beneficial increases in HDL and native antioxidant enzymes. An additional benefit of Amla was a drop in hemoglobin A1c , a measure of chronic glucose exposure and a contributor to cardiovascular risk. Again, virtually every measured outcome was improved in this very high-risk population.28
Together, these studies seem to validate the idea that Amla, particularly at doses of 500 mg twice daily, provides meaningful cardiovascular protective benefits.
Black Tea: The Ideal Complement To Amla
The world’s second most popular beverage after water is tea, which contains more than 4,000 chemical constituents, many of which have proven health benefits, especially the catechins and theaflavins found in black (and green) tea.67,68 Higher catechin consumption is associated with a 51% reduction in the risk of dying from cardiovascular disease, a 40% reduction in stroke risk, and a 90% reduction in lipid disturbances. 69-72
Clinical trials of black tea or its components have shown substantial benefits on the risk factors for arterial stiffening and cardiovascular disease:
- Endothelial function is improved by consumption of black tea for both short- and long-term intervals in healthy volunteers as well as in patients with known coronary artery disease or elevated lipid profiles.29,73,74 Black tea consumption also increased the function of the essential coronary arteries by increasing blood flow in a group of healthy volunteers.75 These effects are similar to those of green tea, also known for its endothelial function-improving properties.76
- Cholesterol levels (LDL and total cholesterol) were lowered by black tea consumption in adults with mildly elevated levels, with reductions in total cholesterol of 6.5% and LDL of 11.1%.77 Black tea extract showed similar effects in other studies.30,78
- Inflammatory changes and metabolic toxins that promote endothelial dysfunction can be reduced by black tea consumption, as shown in studies of C-reactive protein (a marker of inflammation) and uric acid, an ammonia-like toxin produced in the liver. Levels of both were significantly reduced by consumption of black tea for 12 weeks.79,80
- Oxidative stress , another major contributor to endothelial dysfunction, is also reduced by black tea extract consumption in patients with type II diabetes and in healthy volunteers.78,80
- Large variations in blood pressure are an independent risk factor for cardiovascular disease, and recent evidence suggests that these variations are reflections of increased arterial stiffness.81,82 Regular black tea consumption can reduce the rate of blood pressure variation and so lower the risk.83