Bilberry

FAMILY: Ericaceae.

HABITAT: Abundant in undergrowth with siliceous and therefore acidic soil in mid-mountains, throughout the northern hemisphere.

PART USED: the leaves and berries harvested in summer.

RECOMMENDED PHARMACEUTICAL PREPARATION: nebulised dry extract titrated in total anthocyanosides expressed as anthocyanidins min. 23.8 % and max. 26.2 % (Italian Pharmacopoeia X). The daily dosage used in studies published in the literature is 2-3 mg/kg/day, divided into two or three administrations preferably away from meals. As these studies were conducted with different extracts with different titres, the above posological value represents an indicative average value.

CHEMICAL COMPOSITION: is a drug rich in anthocyanins, of which at least seven have been identified and are cyanidin, delphinidin, pelargonidin, malvidin, peonidin, hirsutidin and petunidin. We then find flavonoids, simple and complex sugars, organic acids, phenolic acids. There are also plenty of tannins.

THERAPEUTIC PROPERTIES:
Anti-radical and cardio-vascular-protective action. In vitro and animal studies: Blueberry polyphenols effectively inhibit free radicals, being able to trap all known radical species in membranous lipid peroxidation models. They also protect cell membranes from lipid peroxidation both by trapping the radicals formed and by forming chelates that make cellular structures unavailable to oxidation reactions.
Blueberry dry extract is able to significantly reduce copper-induced LDL oxidation in vitro, as evidenced by its marked reduction in the formation of lipoperoxides and other oxidation products. This action becomes maximal after about 60 minutes and remains at significant levels for about 6 hours, and is very important since the importance of LDL oxidation in the genesis of vascular atherosclerosis is well established. Bilberry extract also hinders free radical damage in the central nervous system and improves the body's antioxidant defences.
At the level of the heart and vessels, bilberry extract protects the wall of blood vessels and the heart from damage caused by free radicals. It also promotes vasodilation and thus the passage of blood through capillary vessels, thereby improving the oxygen supply. It also hinders the formation of atherosclerotic plaques in blood vessels and promotes their strength and elasticity.

Anti-radical and cardio-vascular-protective action. Clinical Trials A clinical study evaluated the effect of dried bilberry extract on plasma lipoprotein levels and LDL oxidation. Twenty-one apparently healthy subjects were enrolled, who had to drink 7 ml/kg weight per day of bilberry juice for 2 weeks.  The administration of bilberry juice led, after 2 weeks, to a significant decrease in oxidised LDL and a significant increase in total plasma antioxidant capacity. No significant changes in cholesterol and triglycerides were noted. The study confirms that blueberry juice reduces oxidised LDL and improves total antioxidant defences in humans.
A clinical study evaluated whether the consumption of blueberries in the diet could reduce post-meal oxidation caused by a diet rich in carbohydrates and fat. Fourteen healthy volunteers were enrolled, maintaining a diet of the above type supplemented with either 75 or 35 g/day of fresh blueberries or a placebo for 3 weeks, measuring LDL oxidation and blood levels of urates and glucose 1, 2 and 3 hours after the meal. It was seen that in the group treated with 75 g blueberries there was also a significant reduction in LDL oxidation 3 hours after the meal. There were no significant changes in urate and glucose levels. The study indicates that a daily dietary content of blueberries of 75 g has a significant postprandial antioxidant action in humans (38).

Action on the eye. In vitro and animal studies: It has long been known that bilberry extracts are able to sharpen night vision. In fact, they facilitate the regeneration of rhodopsin, which is the retinal pigment essential for low light vision. Their usefulness at ocular level is not limited to this, however; in fact, they have been shown to combat vessel fragility and hyperpermeability, thus displaying an anti-oedemigenous and capillaroprotective action, now well demonstrated at both retinal and peripheral microcirculation levels.

Action on the eye. Clinical trials.
Controlled clinical studies show that bilberry anthocyanosides reduce retinal microcirculation damage statistically significantly compared to placebo in patients with hypertensive and/or diabetic retinopathy. Research in adult diabetic subjects has shown that oral administration of 600 mg per day of bilberry dry extract causes a significant reduction in connective tissue synthesis. Since one of the main causes of diabetic retinopathy is increased connective tissue production, anthocyanosides may be helpful in preventing diabetic retinopathy.
A study collected the results of clinical studies on the ocular protective effect of bilberry. Thirty studies of acceptable quality were selected. These studies indicated a superiority of bilberry extract in promoting night vision and improving blood circulation in the capillaries of the retina.

Main indications: Capillary fragility, particularly in the retinal microcirculation, veno-lymphatic insufficiency, lower urinary tract infections particularly bladder infections, diarrhoea.

Predominant action: capillaroprotective and antioxidant.

Other actions: antiplatelet, cardioprotective.

SIDE EFFECTS: none worth mentioning.

CONTRAINDICATIONS: none relevant.

DRUG INTERACTIONS: not known to date.

TOXICOLOGY: In animal studies, the oral LD50 has not been reached to date.