Bilberry

extracts standardized to contain 25% anthocyanosides have been suggested as a treatment for people with early-stage diabetic or hypertensive retinopathy. In a small preliminary trial, people with various types of retinopathy, including diabetic retinopathy and macular degeneration, were given 600 mg of bilberry extract per day for one month. While researchers found that the tendency to hemorrhage in the eye was reduced and that blood vessels were strengthened, there were no reports of improved vision. A small double-blind trial found that 160 mg of bilberry extract taken twice per day for one month led to similar improvements in blood-vessel health in the eye and slightly improved vision in people with diabetic and/or hypertensive retinopathy. Larger and longer clinical trials are needed to establish the effectiveness of bilberry for treating retinopathies.

Animal research suggests bilberry extract may improve glycemic control and lower the risk of some diabetic complications, such as diabetic cataracts and retinopathy. Compounds called anthocyanins, found in bilberry and other dark berries, have strong antioxidant and anti-inflammatory effects that appear to mitigate some of the negative impacts of chronically elevated glucose levels. One preliminary trial found that supplementation with a standardized extract of bilberry improved signs of retinal damage in some people with diabetic retinopathy.

Like other berries and darkly pigmented fruits and vegetables, bilberry (Vaccinium myrtillus) is rich in polyphenolic compounds called anthocyanins. Laboratory and animal studies suggest bilberry and anthocyanins can improve glucose metabolism and insulin sensitivity through multiple actions, including reducing inflammation and oxidative stress, inhibiting carbohydrate-digesting enzymes, and improving the gut microbiome. Eating a diet high in anthocyanins has been consistently found to be associated with lower risk of type 2 diabetes, and clinical evidence shows anthocyanins from bilberry or other berries, especially when taken with meals, can improve blood glucose control and insulin sensitivity in people with type 2 diabetes. In one study, a single 470 mg dose of standardized bilberry extract (36% anthocyanins) before eating reduced the post-meal increase in blood glucose in subjects with type 2 diabetes. Bilberry and anthocyanins may also help to prevent and treat some diabetic complications. For example, a growing body of evidence suggests bilberry and anthocyanins can improve microvascular health and retinal function in people with diabetic retinopathy.

Turmeric ’s active compound curcumin has shown potent anti-platelet activity in animal studies. It has also demonstrated this effect in preliminary human studies. In a similar vein, has been shown to prevent platelet aggregation as has peony. However, none of these three herbs has been documented to help atherosclerosis in human trials.

, a close relative of blueberry, is high in flavonoids called anthocyanosides. Anthocyanosides may protect both the lens and retina from oxidative damage. The potent antioxidant activity of anthocyanosides may make bilberry useful for reducing the risk of cataracts. Doctors sometimes recommend 240 to 480 mg per day of bilberry extract, capsules or tablets standardized to contain 25% anthocyanosides.

Astringent herbs traditionally used for diarrhea include blackberry leaves, blackberry root bark, blueberry leaves, and red raspberry leaves. Raspberry leaves are high in tannins and, like blackberry, may relieve acute diarrhea. A close cousin of the blueberry, , has been used traditionally in Germany for adults and children with diarrhea. Only dried berries or juice should be used—fresh berries may worsen diarrhea.

Cranesbill has been used by several of the indigenous tribes of North America to treat diarrhea. The tannins in cranesbill likely account for the anti-diarrheal activity—although there has been little scientific research to clarify cranesbill’s constituents and actions.

Because coumarin, hydroxyethylrutosides, and diosmin are not widely available in the United States, other flavonoids, such as quercetin, rutin, or anthocyanosides (from bilberry), have been substituted by doctors in an attempt to obtain similar benefits. The effect of these other flavonoids against edema has not been well studied. Also, optimal amounts are not known. However, in one study, quercetin in amounts of 30-50 mg per day corrected abnormal capillary permeability (leakiness), an effect that might improve edema. A similar effect has been reported with rutin at 20 mg three times per day. Doctors often recommend 80 to 160 mg of a standardized extract of bilberry, three times per day.

In a preliminary trial, supplementing with anthocyanins (a group of flavonoids found in bilberry and certain other plant foods) improved visual acuity and partially reversed visual field damage in patients with normal-tension glaucoma (a type of glaucoma associated with normal intraocular pressure). The amount used was 60 mg twice a day for an average of two years.

active flavonoid compounds, anthocyanosides, act as antioxidants in the retina of the eye. Therefore, supplementing with bilberry would theoretically be of value for the prevention or treatment of early-stage macular degeneration. Bilberry has also been shown to strengthen capillaries and to reduce bleeding in the retina. A typical amount of bilberry used in studies was 480–600 mg per day of an extract standardized to contain 25% anthocyanosides, taken in capsules or tablets.

, a close relative of the blueberry, is high in flavonoids known as anthocyanosides. Anthocyanosides speed the regeneration of rhodopsin, the purple pigment that is used by the rods in the eye for night vision. Supplementation with bilberry has been shown in early studies to improve dark adaptation in people with poor night vision. However, two newer studies found no effect of bilberry on night vision in healthy people. Bilberry extract standardized to contain 25% anthocyanosides may be taken in capsule or tablet form. Doctors typically recommend 240 to 480 mg per day.