Endothelial dysfunction—think of it as poor blood-vessel tone—can contribute to poor peripheral circulation, hypertension (high blood pressure), and coronary heart disease. As you might expect, poor dietary habits (including refined carbohydrate and trans fat consumption) and nutritional deficiencies can cause endothelial dysfunction.

L-Arginine

The principal regulator of endothelial function is nitric oxide (not to be confused with nitrous oxide). The body’s production of nitric oxide depends on the presence of its precursor, the amino acid L-arginine. Indeed, L-arginine may very well be the single most important nutrient for vascular health.

Several studies have demonstrated the vascular benefits of L-arginine. In one study, researchers found that the amino acid improved endothelial function in patients with heart disease.² Other research has shown that L-arginine can reduce blood pressure, apparently by boosting levels of nitric oxide and relaxing blood vessels. Indeed, the same vascular problems underlying endothelial dysfunction can impact a man’s ability to maintain an erection. Supplemental L-arginine has been shown to improve the ability of blood vessels in the penis to dilate, resulting in firmer erections,³ and the benefits may be enhanced by combining it with the antioxidant Pycnogenol® . ⁴

Pycnogenol®

Other studies have found that Pycnogenol® supplements alone can improve blood vessel tone. So can flavonoids in general and anthocyanidins (a subgroup of flavonoids) specifically. And at least one study reported that supplemental anthocyanidins (which would include blueberries and bilberries) can lower the “bad” low-density lipoprotein (LDL) cholesterol and increase the “good” high-density lipoprotein (HDL) form of cholesterol. Flavonoids work in tandem with vitamin C to maintain the integrity of blood vessel walls. ^{5 6 7}

Indian Gooseberry (amla)

Another option is Indian gooseberry (Phullanthus emblica). A recent study noted that supplements containing an extract of the herb improved blood vessel tone in people with type-2 diabetes. The 80 subjects in the study took either 250 mg or 500 mg of the extract or placebos twice daily for 12 weeks. At both dosages, levels of nitric oxide increased while a marker of free radical stress decreased.⁸

Omega-3s

The omega-3s, found in both fish oils and algae-source supplements, have broad cardiovascular benefits. They are potent natural anti-inflammatories. They also serve as mild blood thinners and improve endothelial function.^{9 10}

Venous insufficiency is caused by impaired valve function in the veins of legs, which in turn leads to blood pooling instead of moving up and returning to the heart. Problems with deep veins can lead to deep-vein thrombosis (see next section), whereas problems with superficial veins can cause varicose veins. Conventional treatments use compression with special socks or surgery to treat varicose veins. But some nutritional treatments are definitely worth trying. In addition to vitamin E, a combination of vitamin C and flavonoids can be helpful.

Horse Chestnut

This herb (Aesculus hippocastanum) can be especially beneficial in treating venous insufficiency and varicose veins. In 2012, researchers conducted a careful review of published studies and concluded that horse chestnut was an “efficacious and safe short-term treatment” for chronic venous insufficiency. Several other studies have also reported benefits from taking horse chestnut for venous insufficiency and varicose veins, including less water retention in the lower legs, as well as reduced pain and itching.¹¹ An herbal study using an extract of Chinese buckeye seed, which contains the same active ingredient found in horse chestnut, found that it also led to improvements in venous insufficiency.¹²

Thrombophlebitis, also known as peripheral vascular disease, refers to a clot in a vein combined with inflammation, whereas deep-vein thrombosis describes a clot without inflammation. The latter is potentially serious. According to Alan R. Gaby, M.D., author of Nutritional Medicine (2011), some research suggests that food allergies and chemical sensitivities can precipitate thrombophlebitis. At the same time, several supplements might prove helpful.

Nattokinase

This enzyme is derived from natto, a traditional Japanese fermented soy food. It has impressive clot-busting benefits. In a study conducted in Taiwan, researchers asked 45 subjects to take 800 mg of nattokinase after dinner each day for two months. By the end of the study, three key measures of blood clotting—fibrinogen, factor VII, and factor VIII—had decreased from between 7 to 19 percent. ¹³

Vitamin E

Canadian doctors pioneered the use of vitamin E for cardiovascular disease in the 1940s, and since then the vitamin has gone in and out of fashion. Nonetheless, compelling evidence justifies its use in preventing or resolving thrombophlebitis. In a Harvard Medical School study of almost 40,000 women, those who took 600 IU of vitamin E every other day for 10 years had a substantially lower risk of life-threatening blood clots. Overall, women taking vitamin E had a 21 percent lower risk of deep-vein thromboses or pulmonary embolisms. Those who had such clots before joining the study had a 44 percent lower risk of future clots, and those with a genetic tendency toward clots had half the risk if they took vitamin E supplements.¹⁴

The kidneys play an important role in blood pressure, and high blood pressure increases the risk of coronary heart disease and kidney disease. But considerable research also suggests that elevated blood levels of insulin—a sign of prediabetes or type-2 diabetes— boost the risk of high blood pressure.¹⁵ Part of the solution, therefore, is a diet that includes a moderate amount of protein, healthy fats, and a lot of vegetables and restricts refined sugars and other types of processed carbohydrates.

Vitamin D

People with low blood levels of vitamin D have a higher risk of heart disease and, specifically, hypertension. People with inadequate vitamin D were twice as likely to have hypertension, compared with people who had the highest levels of the vitamin, according to a study in the journal Circulation. ¹⁶ Two other recent studies found that low vitamin D levels were associated with a greater risk of high blood pressure, and one of those studies also linked inadequate vitamin D to endothelial dysfunction and kidney disease.^{17 18}

Magnesium

A large number of studies have found that magnesium supplements can also reduce blood pressure. In an analysis of seven studies, researchers confirmed that magnesium supplements reduced both systolic and diastolic blood pressure.¹⁹ Other researchers investigated magnesium levels in people with and without pre-hypertension, which reflects a slight but consistent increase in blood pressure. People with prehypertension had low levels of magnesium, but no other apparent differences with healthy subjects.²⁰

Strokes, the result of cerebrovascular disease, are a leading cause of disability and death. Each year, an estimated 795,000 Americans suffer a new or recurrent stroke, according to the American Heart Association.²¹ Ninety percent of strokes are ischemic—that is, caused by a blood clot in the brain. The remaining 10 percent of strokes are hemorrhagic, caused by a rupture in a blood vessel.

Prediabetes is a major risk factor for stroke.^{22 23} In a Japanese study, doctors found that two-thirds of 427 stroke patients had glucose intolerance.²⁴ Again, adopting a moderately high-protein diet with a lot of vegetables is the best way to control blood sugar.

B Vitamins

Elevated levels of homocysteine damage blood vessels, and the relationship between homocysteine and stroke risk is well established. Luckily, homocysteine levels can be quickly reduced with supplemental B vitamins, particularly folic acid and vitamins B6 and B12. Several studies have found that high intake of folic acid and other B vitamins can reduce the risk of ischemic stroke by about one-fifth. ^{25 26 27 28} Researchers just analyzed 14 human studies, including almost 55,000 people, and reported in the journal Neurology that B-vitamin supplements reduced the risk of stroke by 7 percent.²⁹

DHA

Docosahexaenoic acid, one of the two principal omega-3s, can reduce post-stroke brain damage, according to an animal study conducted at Loma Linda University in California. The DHA supplements reduced brain damage by up to 66 percent and also sped recovery.³⁰ The finding shouldn’t be all that surprising because DHA is needed for normal brain development and function throughout life. But why wait for a stroke to occur? It makes better sense to take DHA preventively.

Flavonoids

Considerable research indicates that antioxidant flavonoids can reduce the risk of stroke, but two specific types of flavonoids might be of particular value. First, the flavonoids found in green and black tea appear to protect against stroke. ^{31 32 33 34} Second, the herb Ginkgo biloba serves as a blood thinner, but it is also rich in flavonoids that strengthen blood-vessel walls.³⁵

Raynaud’s disease is characterized by spasms in tiny blood vessels in the fingers or toes, resulting in pain, numbness, and a transient very white skin color. The spasms are most commonly caused by exposure to cold and stress.

Various Supplements

Some research suggests that fish oils (4 grams of EPA and 2.5 grams of DHA daily) and magnesium (200-400 mg daily) can lessen the symptoms of Raynaud’s. Inositol hexanicotinate (4 grams daily) might also be of benefit. Natural thyroid treatment might also be helpful—taking selenium (200 mcg daily) and iodine (1,000 mcg daily) can boost thyroid activity.

The heart may be the all-important center of our cardiovascular system, but it works in tandem with our thousands of miles of arteries, veins, and other blood vessels. For this reason it’s important to keep the entire cardiovascular system in mind—and to take the steps needed to keep it healthy.

References available upon request