Vitamin D Improves Vascular Function

Scientists discovered that, in a cell study, vitamin D restored a healthy balance between 2 key compounds required to maintain endothelial function.

The beneficial compound is nitric oxide that maintains youthful blood vessel elasticity. The toxic one is peroxynitrite that inflicts blood vessel damage.^1-4

This study showed that the addition of vitamin D to the cell culture resulted in an increase in protective nitric oxide and a decrease in destructive peroxynitrite.⁴

Restoring this balance represents a novel approach to reducing overall risk for cardiovascular disasters.

Low blood levels of vitamin D are also associated with increased arterial stiffness—the loss of youthful suppleness that allows arteries to properly regulate blood flow and pressure.⁵

In addition to causing high blood pressure,⁶ stiff, inflexible arteries contribute to heart attack, stroke, cognitive decline, and more.^7-11

More than 40% of Americans have insufficient blood levels of vitamin D (defined as levels between 20-30 ng/mL).¹²

Supplementing with vitamin D helps reduce arterial stiffening and may improve endothelial function.^5,13,14

Vitamin D and Heart Health

Research shows a dangerous relationship between low vitamin D levels and heart failure, heart attacks, and high blood pressure.¹⁵ Low levels of vitamin D are also associated with cardiovascular risk factors such as obesity, diabetes, and lipid disturbances.¹⁶

When vitamin D was administered to rats with high blood pressure, it helped keep their aortas loose, relaxed, and able to move blood with minimal resistance.¹⁷

This suggests that there's a connection between vitamin D and how blood vessels respond to changes in flow and pressure.

A New Way to Improve Heart Health

Scientists at the Nanomedical Research Laboratory at Ohio University wanted to find out more about the connection between vitamin D and arterial function.⁴ Their findings take a giant step towards understanding the phenomenon of arterial stiffness.

The researchers used nanosensors to measure levels of 2 opposing chemicals inside of endothelial cells: nitric oxide and peroxynitrite. ⁴

Beneficial nitric oxide helps keep blood vessels dilated, while peroxynitrite is highly reactive and destabilizing.^1-4

In an experiment, just before measuring nitric oxide and peroxynitrite levels, researchers treated endothelial cells with the human hormone angiotensin-II, which produced a state of endothelial dysfunction identical to that seen in living people.⁴

Initially, the distressed endothelial cells produced far too much of the destructive peroxynitrite and very little beneficial nitric oxide. This resulted in very low nitric oxide/peroxynitrite ratios (between 0.11 and 0.20), an indicator of endothelial dysfunction.⁴

But when tiny amounts of vitamin D3 were added, something remarkable happened.

In the presence of vitamin D3, the nitric oxide/peroxynitrite ratios immediately rose to between 2.1 and 3.0. That represented a more than 10-fold increase, restoring (and even exceeding) the normal ratio in healthy endothelial cells.

The improved ratio resulted from an increase in protective nitric oxide and a decrease in destructive peroxynitrite.⁴

This study suggests that vitamin D supplementation can restore normal endothelial function, supporting healthy blood flow and returning youthful suppleness to blood vessels.¹⁸

Arterial Stiffness: A Major Cardiovascular Risk Factor

Arterial stiffness is precisely what it sounds like. Numerous factors—such as aging, and exposure to oxidative stress, glycation, and inflammation—cause artery walls to lose their youthful elasticity and begin to behave more like stiff-walled pipes.^19-22

As a result, instead of buffering the rapid rise in pressure following a heartbeat, old, stiff arteries transmit that pulse wave fast and hard to the organs they feed. Delicate organs, tissues, and cells are hammered by large fluctuations in blood pressure and flow with each heartbeat, which is harmful to their normal function.

In addition to contributing to hypertension, heart attacks, and strokes, arterial stiffness plays a role in kidney and liver disorders, type II diabetes, cognitive decline, and neurodegenerative disorders like Alzheimer's and Parkinson's.^7-11

Vitamin D has properties that help reduce oxidative stress, glycation, and inflammation,^23-27 suggesting that it may play a role in preventing the arterial stiffening induced by these age-accelerating events.

Human Studies

Compelling human studies show that vitamin D supplementation reduces arterial stiffness and blood pressure, directly reducing the risk of heart disease and stroke. As discussed next, in human cases where subjects have chronic kidney disease, obesity or type II diabetes, the addition of vitamin D lessened arterial stiffness.

Chronic Kidney Disease

In individuals with chronic kidney disease and vitamin D deficiency, supplementation with vitamin D caused arterial flow-mediated dilation to nearly double. Flow-mediated dilation is a mea­sure of the ease with which arteries relax.

In addition, a marker of endothelial dysfunction (adhesion molecules that raise the risk of a clot forming or sticking) fell significantly.²⁸

Obesity

Studies of obese people who were vitamin D deficient showed similar findings.

In one study of overweight/obese adults with high blood pressure, a monthly oral dose of vitamin D3 (100,000 IU) for 3 months produced significant reductions in the augmentation index, a measure of arterial stiffness.²⁹

A similar study showed significant reductions in pulse wave velocity, another measure of arterial stiffness. The higher the dose of the vitamin, the better the response.¹³

Type II Diabetes

Diabetes is known to produce increased arterial stiffness,³⁰ and it is closely associated with vitamin D insufficiency.³¹ A study of type II diabetics showed that vitamin D supplementation significantly reduced arterial stiffness, as measured by pulse wave velocity.³²

Benefits for Healthy Individuals

Even otherwise healthy people who have deficient or insufficient vitamin D levels benefit from supplementation.

In 2 studies of vitamin D-deficient individuals, vitamin D3 supplementation significantly reduced both systolic and diastolic blood pressure. It also reduced pulse wave velocity and augmentation index.^33,34

A short study that used a modest dose of 2,000 IU daily in healthy individuals produced impressive results. Compared to baseline, in those receiving vitamin D3:³⁵

• Arterial stiffness dropped by 18%,
• Systolic (top number) blood pressure fell by 8.2%, and
• Diastolic (bottom number) pressure fell by 9.1%.

And, in a study of healthy, older adults with vitamin D deficiency, a single intramuscular injection of 100,000 IU triggered a significant reduction in arterial stiffness (measured by augmentation index).³⁶

LIFE EXTENSION® RECOMMENDATIONS

There are no universal guidelines for frequency of vitamin D testing. However, given the high prevalence of vitamin D deficiency and the strong association of low vitamin D levels with several health issues, annual testing and supplementation to achieve adequate blood levels is highly recommended.

Annual blood tests can let people know whether they are taking the correct dosage to ensure optimal blood levels of vitamin D.

If you do not already maintain an optimal blood level of 25-hydroxyvitamin D of 50 to 80 ng/mL, then take between 5,000 to 8,000 IU of vitamin D daily with a meal for better absorption.

Summary

New research into vitamin D3 indicates it is a heart-healthy vitamin.

Deficiency in vitamin D promotes arterial stiffness, which raises the risk of cardiovascular disease. Supplementation with vitamin D can prevent or reduce arterial stiffness.

One major way vitamin D accomplishes this is by restoring a healthy ratio between nitric oxide, which relaxes blood vessels, and peroxynitrite, a destructive free radical.

Since more than 40% of Americans have insufficient vitamin D levels, supplementation represents a major opportunity for improving public health and reducing cardiovascular risk.

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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