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Garlic Is a Great Blood Thinner

Analysis by Dr. Joseph Mercola

Story at-a-glance -

  • Studies indicate that people who eat as little as a quarter-teaspoon of garlic powder per day appear to have less aortic stiffness, which is good for anyone wanting to avoid cardiovascular problems such as stroke
  • One expert notes that the “antiplatelet aggregation” activity of garlic, as well as onions to a lesser degree, goes by the wayside when it’s cooked, but there are ways to change that outcome
  • Raw garlic appears to be around 13 times more potent as a blood thinner than raw onions or cooked garlic; crushing it and waiting 10 minutes before cooking it activates the enzyme that releases the antiplatelet compounds
  • High concentrations of sulfur and allicin compounds also impart benefits related to heart health, as well as fight harmful bacteria, inflammation, intestinal infections, yeast infections and diseases associated with carcinogens

As you age, your arteries stiffen and continue doing so over time. It happens to virtually everyone to varying degrees, a 2012 study1 observes, and leads to more frequent physiological problems related to poor blood circulation, including an increased risk of renal impairment — renal being the organs involving your kidneys, bladder and urethra, the system that regulates the passage, storage and elimination of urine — as well as stroke.

In 2013, researchers reported2 following a meta-analysis on the effects of garlic on serum lipids that garlic consumption may help optimize cholesterol levels, leading to a reduced risk of coronary events.

In fact, bestselling author Dr. Michael Greger, a Fellow of the American College of Legal Medicine (FACLM) and a general practitioner specializing in clinical nutrition, says that you can eat less than a quarter-teaspoon of garlic powder per day, as studies found that study participants appeared to have less aortic stiffness.

“We think this is because garlic seems to improve the function of the inner lining of our arteries, which helps our arteries relax. But the protective mechanisms of garlic against cardiovascular diseases are multiple, and include a combination of anti-clotting, clot-busting, antioxidant, and blood pressure- and cholesterol-lowering effects.”3

In addition, Greger notes that the blood-thinning properties of garlic are so pronounced that the American Society of Anesthesiology recommends that people avoid eating garlic altogether for the week prior to undergoing elective surgery. However, if you’re a candidate for surgery, you could go ahead and have your garlic, with one large stipulation: It must be cooked first.

According to Greger, the “antiplatelet aggregation” activity in garlic, as well as onions to a much lesser degree, goes by the wayside when it’s cooked. But comparing these allium vegetables, he explains in the featured video, comes with another qualification stemming from the fact that raw garlic appears to be around 13 times more potent as a blood thinner than either raw onions or the cooked form of garlic, which another study4 noted in 1999.

It should be noted that in the above-mentioned 2013 meta-analysis, the authors noted that garlic in its many raw forms could be considered not just a viable alternative to conventional cholesterol-lowering medications, but also may optimize cholesterol levels to a degree “of clinical relevance … associated with a 38 percent reduction in risk of coronary events at 50 years of age,” and just as significantly with a higher safety profile.5

How to Squeeze the Most From Your Garlic

But what if you’re not planning to have surgery, and you’d appreciate benefiting from the ability of garlic to decrease your heart attack and stroke risks? Greger suggests putting raw onion in tossed salads and raw garlic in salsas, pesto and dips, but there’s another way to squeeze all the heart-healthy goodness there is in this pungent family of vegetables, considered by many to be staples in so many pantries.

In demonstrating exactly how raw garlic can slow the development of blood clots to help prevent cardiovascular disease, researchers used both crushed and uncrushed garlic cloves to compare their in-vitro antiaggregatory activity (IVAA), also comparing numerous cooking methods.

Garlic cloves were boiled in water for three minutes or less; others were oven-heated at 200 degrees Fahrenheit, and neither suppressed the IVAA activity. The scientists noted:

“Heating for six min[utes] completely suppressed IVAA in uncrushed, but not in previously crushed, samples. The latter samples had reduced, yet significant, antiplatelet activity. Prolonged incubation (more than 10 min) at these temperatures completely suppressed IVAA. Microwaved garlic had no effect on platelet aggregation.”6

Then the scientists tried something else: They increased the amount of garlic juice applied to both the crushed and uncrushed garlic and found that in the microwave to have a beneficial effect on the crushed, but not the uncrushed garlic in terms of its ability to prevent platelet aggregation.

The study authors noted that the addition of raw garlic juice to uncrushed garlic cooked in the microwave “restored a full complement of antiplatelet activity that was completely lost without the garlic addition”7 — although I still don’t recommend cooking it in the microwave.

In other words, Nutrition Facts8 explains that by crushing or chopping garlic and waiting, say, 10 minutes before cooking it, the enzyme responsible for making the antiplatelet compounds is activated. Here’s how it works when using raw garlic:

“If you cook it for just a few minutes, it does fine; but after cooking for about five minutes, the benefit is abolished. If, however, you pre-crush the garlic and wait, some of the antiplatelet activity is retained a bit longer.

That’s because the enzyme that makes the antiplatelet compounds is activated by crushing but destroyed by heat faster than it creates the compounds. So, by crushing first and letting the enzyme work its magic before cooking, one can delay the loss of function.”9

Garlic Has Valuable Compounds for Disease-Fighting Strength

Another thing that is highly significant in the study is that the clot-busting activity was “always” linked to allicin and pyruvate levels. Science Direct10 explains that the pyruvic acid amount in onions and garlic is a reflection of their pungency.

Besides having high levels of phosphorus, garlic also has compounds with high concentrations of sulfur. In fact, thiosulfinates, including allicin, compose the most prominent active components in garlic. SelfHacked11 lists a number of functions of allicin, cited in clinical studies:

  • It reacts with proteins, which helps block the pathways associated with inflammation, specifically in ulcers caused by H. pylori, the most common bacterial infection in the world,12 and even antibiotic-resistant superbugs.13
  • Allicin in garlic battles bacteria by deterring sulfur-containing enzymes that (bad) bacteria need to survive.14
  • It helps treat intestinal infections caused by parasites by blocking fat synthesis in them, while promoting immune function by stimulating the formation of white blood cells.15
  • Allicin in garlic “inhibits the growth of Candida, the most common type of yeast infection, by destroying fats present in the outer surface of the yeast.”16

In addition to these actions by garlic compounds, there are many more advantages to finding a garlic-containing recipe you love, because your health can be impacted in a number of positive ways. These include:

Colds and flu

Helps lower your blood pressure

Alleviates damage done by liver as well as kidney toxicity

Preventing tooth decay and oral infections

Detoxifies your liver

Offsets allergies

Reduces signs of aging

Reduces insulin resistance

Helps treat rashes such as psoriasis and eczema

Protects your skin from ultraviolet light

Treats hair loss such as alopecia

Improves your memory

Studies Show Compounds in Garlic Help Treat and Prevent Cancer

Many more dramatic benefits from garlic compounds can be had, including from the nutrients it contains, such as potassium, phosphorus, zinc, selenium and vitamins A and C, and smaller amounts of such minerals as calcium, magnesium, iron and manganese, as well as B vitamins.17

But often it’s the more obscure compounds that exert the most potent results. Here are more studies highlighting the power of garlic, specifically as it relates to cancer and HIV:18

  • It boosts your immune system, and significantly, aged garlic extract has been found to stimulate white blood cell growth, which in turn increases the production of glutathione, a powerful antioxidant that lowers inflammatory proteins known as cytokines.19
  • One study found garlic may help treat HIV by killing off infected immune cells. In addition, diallyl disulfide obstructs the replication of the virus.20 Also, “Ajoene, a garlic extract, prevents normal blood cells from fusing with HIV-infected cells and inhibits HIV replication in infected cells.”
  • Garlic may not only treat, but prevent, cancer due to S-allylmercaptocysteine (SAMC), a sulfur compound that lowers the growth of cancer cells and brings on apoptosis. SAMC binds to one protein responsible for cell production (tubulin) and activates others that cause tumor cell death.21
  • Other cancers garlic compounds may help inhibit or prevent include skin cancer,22 lung cancer,23 bladder cancer,24 colon cancer progression,25 prostate cancer progression,26 liver cancer progression,27 brain cancer,28 stomach cancer growth,29 breast cancer growth30 and more.

Garlic: Not a New Concept in Decreasing Platelet Aggregation

Garlic as a source for possible protection against the numerous aspects of heart disease is not a new concept. In 1997, a study31 conducted in Germany and published in Circulation concluded that ingesting garlic powder decreased aortic stiffness brought on by advancing age, also alluding to its ability to provide elastic properties to arteries.

Scientists can measure the stiffness of the aorta, the main artery leading to the heart, with the “gold standard” noninvasive aortic pulse wave velocity test, which can be “calculated as the ratio between the distance separating two locations along the artery and the transit time needed for the pressure or velocity wave to cover this distance,” according to the Journal of Cardiovascular Magnetic Resonance.32

There’s something called an ischemic stroke, which occurs when arteries to your brain are the ones that become either blocked or narrowed, resulting in reduced blood flow, aka ischemia. In fact, it’s the most common type of stroke, caused by a blood clot that blocks or plugs a blood vessel in the brain; the other type is hemorrhagic, when a blood vessel breaks and bleeds into the brain.33

Yet another study outlines the effects of garlic on endothelial function in patients who’ve suffered an ischemic stroke, as evidenced by 125 Chinese patients, with the conclusion that daily garlic intake is “an independent predictor of endothelial function in patients with ischemic stroke and may play a role in the secondary prevention of atherosclerotic events.”34 According to Cedars-Sinai Medical Centers:

“The endothelium is a thin membrane that lines the inside of the heart and blood vessels. Endothelial cells release substances that control vascular relaxation and contraction as well as enzymes that control blood clotting, immune function and platelet (a colorless substance in the blood) adhesion …

Endothelial dysfunction precedes the development of atherosclerosis, a chronic disease characterized by abnormal thickening and hardening of the arterial walls with resulting loss of elasticity … [and] [a]rtherosclerosis may cause a stroke or heart attack.”35

‘What Does Garlic Have to Do With the Mediterranean Diet? A Lot!’

A website called the Miracle of Garlic cites this strong-smelling veggie as one of the “secret ingredients” of the Mediterranean Diet, so-called because it draws heavily on such cooking staples as olive oil (due to the antioxidant strength), red grapes (and resveratrol, known to improve arteries) and wild-caught salmon as well of plentiful amounts of fresh fruits and vegetables. The site reiterates the featured video and cited studies quite well:

“Garlic may very well be one of the most important ingredients within the Mediterranean diet that helps give the diet its fame for reducing the risk of tumors, cancer and cardiovascular disease, lowering blood pressure, thinning the blood to prevent the formation of blood clots, preventing atherosclerosis and other chronic diseases.

With over 300 powerful chemical substances resulting from crushing raw garlic or after cooking it, this miraculous herbal bulb provides tremendous health benefits to us.”36

No matter what type of diet you eat, adding fresh, crushed garlic to your daily meals is a simple way to increase not only their flavor but also their health benefits — exponentially!