Life Extension Magazine®

Blood vessel within the leg developing deep vein thrombosis due to prolonged sitting

Risks of Sitting Too Long

Americans spend more than half their waking time sitting, which can lead to deep vein thrombosis. Clinical studies have shown two plant extracts reduce leg swelling and prevent venous clots.

Scientifically reviewed by: Dr. Gary Gonzalez, MD, in August 2023. Written by: Marsha McCulloch, MS, RD.

According to a study that evaluated sedentary behaviors, Americans spend more than half their waking hours sitting, whether at work, commuting, or at home.1

Any extended period of sitting increases the risk of deep vein thrombosis.2

These dangerous clots commonly develop in the legs,3,4 but can break loose and travel to the lungs. They cause as many as 300,000 deaths in the U.S. annually5

Scientists have identified two ingredients—the enzyme nattokinase and an extract of French maritime pine bark—that help prevent clotting and break down clots that start to form.6-9

A combination of these compounds has been proven in clinical studies to help prevent venous clots even in high-risk individuals.10

Sitting Too Long Can Be Deadly

Long, uninterrupted periods of sitting are a health hazard, even for those who exercise daily.11

When we sit, our calf muscles aren’t contracting to help propel spent blood in the veins back up to the heart.12

Prolonged sitting can reduce blood flow by up to two-thirds in the legs.13 When blood collects in the blood vessels of the legs, a thrombus (clot) is more likely to form.14

A clot that develops in the deep veins of the body is called deep vein thrombosis (DVT).3

If the clot breaks free and lodges in the arteries of the lungs, it can cause a pulmonary embolism, sometimes signaled by shortness of breath or chest pain. This urgent medical condition is fatal in up to 10% of cases.4,15

About half of individuals with deep vein thrombosis don’t have warning symptoms,16 like leg swelling or pain. That doesn’t mean they’re not in danger.17

The Risk Factors

Deep vein thrombosis can be triggered by long hours traveling in cramped conditions, such as those found on airplanes.13 This increased risk is highest within the two weeks after a long flight.18

Deep vein thrombosis may also develop after hours spent sitting at the computer.19

Other risk factors include recent orthopedic surgery, limited mobility, acute infections, taking estrogen or contraceptive pills, diabetes, hypertension, elevated cholesterol and homocysteine, dehydration, smoking, obesity, and pregnancy.20

Though anyone can be affected, the risk of deep vein thrombosis increases after age 40.3

As we get older, our clot-formation systems start to outpace our clot-breakdown systems, making us more prone to clots.21

Researchers have found a potential solution to this problem: a combination of nattokinase and French maritime pine bark extract.

Anti-Clotting Activity of Nattokinase

Nattokinase is an enzyme extracted from fermented soybeans (natto).7

Scientists found that the anti-clotting power of nattokinase is stronger than any other enzyme in 173 different natural foods tested.22

Nattokinase combats unwanted clotting in several different ways, including by:6-8,23,24

  • Decreasing the activation of pro-clotting factors,
  • Breaking apart fibrin, the main protein in clots,
  • Reducing the conversion of fibrinogen (a fibrin precursor) to fibrin, and
  • Inhibiting platelets from clumping to form a clot.

These actions add up to powerful defense against deep vein thrombosis.

Putting Nattokinase to the Test

In a placebo-controlled study, 12 healthy men were given a single dose of 2,000 fibrinolytic units of nattokinase.23

Markers of the anti-clotting and clot-disrupting properties of nattokinase were detected in the subjects’ blood samples within two hours of just one single dose.

Other placebo-controlled human studies have shown that nattokinase can help decrease high blood pressure.25,26 In addition to increasing the risk of heart attacks and strokes, high blood pressure may raise the risk of clots.27,28

What you need to know

Defend Against Deep Vein Thrombosis

  • Prolonged periods of sitting increase the risk of deep vein thrombosis or clots, particularly in the legs.
  • These clots can break free and move to the lungs, where they can be fatal.
  • A combination of the enzyme nattokinase and French maritime pine bark extract provides a safe, natural approach to combating leg swelling and clotting.
  • This plant-based duo works in several different ways to inhibit clot formation, disrupt existing clots, decrease edema, and support circulation.
  • In a controlled trial of people prone to deep vein thrombosis, a blend of nattokinase and French maritime pine bark extract completely prevented thrombotic events on a long flight, while 5.4% of the placebo group developed deep vein clots.

Complete Relief

In a recent study, researchers tested nattokinase in 153 adults who sought medical treatment for deep vein thrombosis or related vascular disorders.6

All subjects took a daily dose of 2,000 fibrinolytic units of nattokinase, either after a month-long course of an anticoagulant drug or after vascular surgery.

Nattokinase reduced symptoms beyond the previous drug or surgical treatment. It led to complete remission of subjects’ remaining vascular symptoms.

The nattokinase produced these benefits without side effects.6 By contrast, medications for thrombosis carry a risk of adverse events like internal bleeding.29,30

How French Maritime Pine Bark Helps

Extracts of French maritime pine bark are rich in plant compounds called procyanidins.31

These components provide antioxidant, anti-inflammatory, and platelet-regulating benefits, which help protect blood vessels.10,31-33

Another way the extract may help support veins is by promoting nitric oxide production.31

This gaseous molecule is found in the endothelium (lining) of blood vessels. It promotes healthy blood flow.34

In a preclinical screening of 13 polyphenol-rich plant extracts, only French maritime pine bark improved nitric oxide availability in both healthy and dysfunctional endothelial cells of veins.35

Stop Swelling

Edema (swelling) in the lower legs is a common problem for individuals with deep vein thrombosis.

Normally, the one-way valves in leg veins prevent blood from flowing backwards and pooling in the lower legs. These valves also help move venous blood back to the heart. In people with deep vein thrombosis, the valves become damaged.36

Doctors commonly recommend compression stockings to help reduce edema, but many people find them uncomfortable.37

In a 12-month study, 156 patients with a history of a single, major thrombotic event were assigned either to take French maritime pine bark extract daily, wear compression socks, or do both.38

The extract was significantly more effective than compression socks, from six months onward, for decreasing leg edema.

Two new incidents of deep vein thrombosis developed in the compression-sock group within three to six months. No new thrombosis happened in the groups taking the pine bark extract.38

Prevent DVT Recurrence

Approximately one-third of people who experience deep vein thrombosis have another episode within 10 years.39

The highest risk of recurrence is within the first year. But a heightened risk remains for the rest of a person’s life.39

Lingering symptoms after recovery from deep vein thrombosis, called post-thrombotic syndrome, also occur in 43% of cases within two years. These symptoms can include chronic leg pain, swelling, discoloration, and new varicose veins.3,40

In an extensive study, scientists tested 815 people every six months for six years after their initial deep vein thrombosis.41

All participants followed a standard lifestyle regimen of compression socks, weight control, and regular exercise.

Some participants also took pine bark extract, aspirin, or prescription drugs to prevent blood clots.

Only 3.6% of those who took the extract developed recurrent deep vein thrombosis and post-thrombotic syndrome, while in the group that followed only the standard management, 14.9% did.

Pine bark extract was significantly more effective than medications. Recurrent deep vein thrombosis and post-thrombotic syndrome occurred in 12.9% of those using aspirin and in 6.7% and 10.7% of those treated with prescription anticoagulants (but only in 3.6% of those taking pine bark extract).

More Powerful Together

Combining nattokinase and French maritime pine bark extract provides defense against deep vein thrombosis.10

In a randomized, controlled study of 204 people taking long international flights, researchers gave half the group a blend of nattokinase and French maritime pine bark extract two hours before their flight, and again six hours later. The other half were given placebos.10

All subjects were at high risk for deep vein thrombosis, based on their past medical history, including previous episodes of the condition. Preflight, the two groups had equal levels of leg edema.

Exercise and hydration suggestions were given to both groups. The exercise plan consisted of mild, mainly isometric exercise including standing and moving legs for 5 to 10 minutes every hour. The hydration suggestion was to drink 3.4 to 5 oz. of water every hour.

While 5.4% of the placebo group developed flight-related deep vein thrombosis, the treatment group had no cases.

In addition, the placebo group had a 12% increase in ankle edema while the treatment group had a 15% decrease.

This study demonstrates the ability of the combination of nattokinase and French maritime pine bark extract to prevent edema and thrombosis.


The deep veins of our legs are prone to develop clots when we sit for long periods of time, such as on airplanes or at work.

Besides causing uncomfortable leg swelling, deep vein thrombosis carries the risk of the clot breaking free, traveling to the lungs, and causing a potentially fatal embolism.

Nattokinase and French maritime pine bark extract work together to promote healthy blood flow and inhibit venous blood clots.

Clinical trials have proven the protective circulatory benefits of these plant compounds in high-risk groups, including people on long flights and those with a history of deep vein thrombosis.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.


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