Capillary Fragility

Severe vitamin C deficiency (scurvy) is a well-recognized but uncommon cause of increased capillary fragility. Whether vitamin C supplementation can help capillary fragility in people who do not have scurvy is less clear. Patients undergoing dialysis may develop low levels of vitamin C,^1,2 which can lead to capillary fragility, but giving dialysis patients 50 mg of vitamin C per day had no effect on capillary fragility in one study.³ People with kidney failure and those undergoing dialysis should not supplement with more than 100 mg per day, unless supervised by a doctor.

According to preliminary studies, vitamin C may reduce capillary weakness in diabetics, who often have low blood levels of vitamin C compared to non-diabetics.^4,5 In a double-blind trial, elderly people with low vitamin C levels and capillary fragility were helped with supplementation of one gram per day of vitamin C.⁶

Compounds called flavonoids may help strengthen weakened capillaries. In test tube and animal studies, they have been shown to protect collagen, one of the most important components of capillary walls.^7,8 A preliminary study found that proanthocyanidins (flavonoids extracted from grape seeds), 150 mg per day, increased capillary strength in people with hypertension and/or diabetes.⁹ A double-blind trial found a combination of two flavonoids (900 mg per day of diosmin and 100 mg per day hesperidin) for six weeks reduced symptoms of capillary fragility.¹⁰ Use of vitamin C with flavonoids, particularly quercetin, rutin, and hesperidin, is sometimes recommended for capillary fragility.¹¹ Doctors often recommend 400 mg of rutin or quercetin three times per day or 1 gram of citrus flavonoids three times per day.

Compounds called flavonoids may help strengthen weakened capillaries. In test tube and animal studies, they have been shown to protect collagen, one of the most important components of capillary walls.^12,13 A preliminary study found that proanthocyanidins (flavonoids extracted from grape seeds), 150 mg per day, increased capillary strength in people with hypertension and/or diabetes.¹⁴ A double-blind trial found a combination of two flavonoids (900 mg per day of diosmin and 100 mg per day hesperidin) for six weeks reduced symptoms of capillary fragility.¹⁵ Use of vitamin C with flavonoids, particularly quercetin, rutin, and hesperidin, is sometimes recommended for capillary fragility.¹⁶ Doctors often recommend 400 mg of rutin or quercetin three times per day or 1 gram of citrus flavonoids three times per day.