Bilberry Extract Supplement Uses, Benefits, Dosages & Side Effects

Bilberry extract is an herbal supplement made from the fruit of the bilberry plant. It contains active compounds known as anthocyanins which have been seen to have anti-inflammatory and antioxidant effects.

This supplement is most commonly used for eye/vision disorders, improving eyesight, cardiovascular conditions, UTIs (urinary tract infections), diabetes mellitus, hemorrhoids, and diarrhea.

Its medicinal usage began in the 12th century, when Hildegard of Bingen (Saint Hildegard) asserted its usefulness in inducing menstruation. Since then, it has been used for numerous conditions – including typhoid fever, kidney stones, gastrointestinal (GI) disorders, and many others. [1][2]

Bilberry has a long history in traditional medicine and has been used for a variety of conditions for hundreds of years. There is some clinical evidence that supports using bilberry extract for certain health conditions.

More large scale, double-blind placebo-controlled clinical trials are still needed to confirm the results of smaller studies and determine the therapeutic efficacy of bilberry extract for its proposed uses.

The most common uses for this supplement, research study results, safety, side effects, and dosage information will be discussed in detail in this article.

Bilberry

Antioxidant Supplement

Eye Health

Blood Flow

Anti-Oxidant

How It Works:

• Rich source of anthocyanins
• "Super-antioxidants" to protect cells
• Supports circulation and vision

Dosage:

Between 80-160 mg, 3x per day

Safety:

Rated Possibly Safe

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Bilberry Extract Uses

Bilberry extract supplements are most commonly sourced from a low-growing shrub called Vaccinium myrtillus. However, the term “bilberry” can refer to any of several Eurasian species in the Vaccinium genus of the Ericaceae botanical family.

Bilberries are sometimes called European blueberries; however, while botanically related to blueberries, they are not interchangeable with them. Other relatives include huckleberry and cranberry. [2]

Bilberry shrubs produce small purple/black berries with red flesh. As a food, bilberries are commonly used in making jams, jellies, pies, and chutneys. [2]

According to WebMD, both the berries and the leaves of Vaccinium myrtillus are used to make natural medicines. [3] However, bilberry fruit extract is more commonly used than leaf extract.

Some people use this supplement for insufficient venous blood flow, varicose veins, chest pain (angina), and “clogged” arteries (atherosclerosis). [3]

Bilberry is also used for osteoporosis, gout, haemorrhoids, and skin infections. It is also sometimes used inside the mouth and throat for soreness associated with inflammation of mucous membranes. [3]

The Natural Medicines Comprehensive Database (NMCD) states that bilberry extract is also used for: [4]

• Improving visual acuity, including night vision
• CFS (chronic fatigue syndrome)
• Degenerative retinal conditions
• Cataracts (clouded eye lens)

The NMCD rates Bilberry extract as Possibly Effective for chronic venous insufficiency and retinopathy (disease of the retina).

The therapeutic efficacy of this supplement is being studied for many other conditions, including dysmenorrhea (painful menstruation), asthenopia (eye strain), glaucoma, prediabetes (impaired glucose tolerance), and IBS (irritable bowel syndrome). [4]

Bilberry is also being studied for possible effects in weight loss, myopia (nearsightedness), metabolic syndrome, and ulcerative colitis. [4]

While some preliminary clinical trials have been done, more research is needed to determine the therapeutic efficacy of bilberry for these conditions. At this time the FDA has not approved bilberry as a drug to prevent or treat any conditions.

In the next section, some of the proposed mechanisms of action for bilberry extract are discussed.

How Does Bilberry Extract Work in the Body?

Scientists at the National Center for Complementary and Integrative Health (NCCIH) believe that the primary therapeutic benefits of bilberry may be largely due to its anthocyanin content. These compounds are odorless flavonoids that contribute to bilberry’s taste and pigmentation.[1]

Anthocyanins are also called anthocyanosides. In in vitro, animal, and human research studies these plant chemicals have been shown to be potent antioxidants. They are commonly referred to as “super-antioxidants”.

All antioxidants help the body to combat inflammation, infection, and aging by reducing the production of and/or removing free radicals. Free radicals are reactive oxygen compounds created naturally in the body. However the build-up of these compounds can cause cellular damage.

According to ConsumerLab, the anthocyanins in bilberry extract might be beneficial for the retinas. The retina is the light sensitive layer on the back of the eyeball that triggers nerve impulses through the optic nerve to the brain to create visual perception.

Anthocyanins may also help to keep blood vessel walls strong, decrease systemic swelling (inflammation), and preserve collagen-containing tissues such as cartilage, tendon and ligament. [2]

The anthocyanins specific to bilberry are structurally similar to OPCs (oligomeric proanthocyanidin complexes) found in pine bark and grape seed. Because of this, bilberry extracts are recommended for similar uses including for varicose veins, support during surgery, and easy bruising. [2]

ConsumerLab says that bilberry leaf extract might be beneficial for those with type 2 diabetes mellitus. Animal studies have shown bilberry leaf to help normalize blood-glucose levels and to reduce the amount of fatty acids called triglycerides in the blood. [2]

NMCD states that some anthocyanins in bilberry fruit and leaf extracts include “cyanidin, delphinidin, peonidin, petunidin, malvidin, and others.” [4]

NMCD states that every 100 grams of bilberry fruit contains between 300 to 700 mg of anthocyanins. The actual content of samples will vary due to several factors including growth region, soil quality, and hydration. [4] Bilberry extracts are typically standardized to 25% anthocyanin content.

According to the NMCD, some of the effects of anthocyanins include: [4]

• Helping to facilitate the formation of interstitial fluid
• Reducing glomerular basement membrane thickness
• Helping to redistribute microvascular blood flow
• Increasing production of glycosaminoglycans
• Decreasing vascular permeability

Some preliminary research suggests that bilberry may also induce antiulcer, gastroprotective, and antiedema effects. [4]

The extract is believed to help liver and kidney function due to its antioxidant effects. It helps to scavenge free radicals from the body and to reduce the peroxidation of lipids (fats). [4]

According to WebMD, bilberry extract also contains compounds called tannins. Often referred to as tannic acids, tannins are water-soluble polyphenols. [3]

The University of Memphis reports that in animal studies tannins are believed to reduce feed intake, modulate growth, increase the efficiency of feed, upregulate energy synthesis, and enhance protein digestibility. [5]

WebMD states that bilberry tannins might help improve diarrhea, mouth/throat irritation, and swelling. It might also help to lower LDL-C (low density lipoprotein cholesterol), modulate blood-sugar levels, and improve circulation in those with diabetes. [3]

Bilberry extract also contains a well-known polyphenol called resveratrol, and a flavonoid called quercetin. Bilberry also contains trace amounts of chromium which has been found to improve blood sugar regulation. [4]

Cooking bilberry fruit may significantly reduce its nutritional value. For instance, heating bilberries at 375 degrees F for 18 minutes reduces resveratrol content by between 17% and 46%. [4]

Bilberry for Eye Health

Bilberry extracts are most commonly taken for supporting eye health as well as various eye conditions. Some eye conditions that this supplement is used for include retinopathy, night vision, asthenopia, glaucoma, intraocular pressure (pressure within the eye), and myopia (nearsightedness).

The following are some of the most common eye conditions that people take this extract for, as well as any available research study information on efficacy.

Retinopathy

As described before, the retina is a layer of light-sensitive cells on the back of the eyeball that transmits impulses from the optic nerve to the brain to help form visual images. Retinopathy is a retinal disease that causes impaired or lost vision.

Retinopathy is typically caused by abnormal blood flow to the retina, which causes damage and vision loss. It is most commonly seen in people with hypertension (high blood pressure) or diabetes. Diabetic retinopathy is thought to affect up to 80% of diabetics who have had diabetes for 20 or more years.

The NMCD has rated bilberry fruit extract as Possibly Effective for retinopathy, especially when it results from diabetes mellitus or hypertension. [4]

One double-blind placebo-controlled study examined the effects of using bilberry extract in people with diabetic or hypertensive retinopathy. Significant improvements to retinal lesions were seen in the treatment group.

In clinical studies that explored bilberry’s effects on retinopathy, preparations containing 25% bioflavonoid complex anthocyanins were used. [4]
While the research on using this supplement for retinopathy is promising, more research is still needed to determine the therapeutic efficacy of bilberry extract for this purpose.

If you have retinopathy and are interested in taking bilberry extract, it is best to discuss it with your optometrist.

Night vision

British pilots in WWII claimed that eating bilberry jam before night flights improved their night vision. People continue to use it for this purpose, however there is not much reliable research available that demonstrates efficacy at this time.

Two studies from the 1960s showed that bilberry temporarily improved night vision, but the effect did not persist with continued use. However, these trials were not double-blind, which may have introduced bias into the results.

One double-blind, placebo-controlled study found that a single dose of extract improved visual response for 2 hours after it was taken. However three other double-blind placebo-controlled crossover studies found no short or long term improvements to night vision when using bilberry.

The NMCD states that much of the research on bilberry for night vision is of poor quality or small sample size. Most of the reliable research that has been completed does not seem to support using bilberry to improve night vision and it is rated as Possibly Ineffective for this purpose. [4]

Asthenopia

Asthenopia is the medical term for eye strain and includes symptoms such as fatigue, blurred vision, headaches, blurred vision, and occasionally double vision.

One preliminary research study found that taking 53 mg bilberry anthocyanins, along with Omega-3 fatty acid-rich fish oil and lutein, for 4 weeks, reduced lower back pain, stiffness, stuffiness, and dry eyes in patients with asthenopia, relative to placebo controls. [4] If these results are due to bilberry alone are confounded with the other supplements used however.

Another randomized, double-blind, placebo-controlled study on eye fatigue gave patients bilberry extract capsules or a placebo alone. It was observed that eye fatigue, eye pain, eye heaviness, and foreign body sensation (feeling of something on the eye) was reduced more in the bilberry group then the placebo group.

The results from these studies are promising, however more research is still needed to prove the therapeutic efficacy of bilberry extract for asthenopia.

It is recommended that you speak with your optometrist to help diagnose asthenopia and a recommended treatment plan before you begin taking bilberry for eye strain symptoms.

Additional Bilberry Extract Uses

While bilberry extract is most commonly used for issues related to vision and the eyes, it also is used for various other conditions. Most commonly it has been used for chronic venous insufficiency, dysmenorrhea, diabetes mellitus, impaired glucose tolerance (prediabetes), irritable bowel syndrome (IBS), ulcerative colitis, and weight loss.

At this time, few clinical trials have been done testing this extract for these purposes. The NCCIH states, “We have very few high-quality clinical trials (studies in people) of bilberry supplements.” [1]

Bilberry extract has been rated by the Natural Medicines Comprehensive Database as Possibly Effective for chronic venous insufficiency.

While there have been some promising research results in preliminary trials, currently there is not enough evidence for the NMCD to rate the efficacy of this supplement in these other health conditions.

More research trials are still needed to determine the therapeutic efficacy of bilberry for these conditions. Bilberry extract has not been approved by the FDA as a drug to prevent or treat any conditions.

Following are some of the available clinical data concerning bilberry’s effects in specific health conditions.

Chronic venous insufficiency

Bilberry extract is rated Possibly Effective for chronic venous insufficiency (CVI). This condition is marked by dysfunctional venous walls, and/or vein valves. [4]

Especially in the legs, this venous wall and/or vein valve dysfunction can causes stasis, which is the pooling of blood in the veins. Blood that pools in veins is unable to recirculate to the heart to be oxygenated.

Preliminary research in humans suggests that taking 173 mg/day doses of a specific bilberry extract, for 30 days, reduces chronic venous insufficiency symptoms relative to a placebo. [4]

Other research suggests that taking 100-480 mg/day doses of bilberry anthocyanins improves burning, pain, edema (abnormal fluid accumulation), and bruising commonly associated with CVI. [4]

If you have CVI and are interested in taking this extract, then speak with your doctor first. Your doctor will be able to determine if there could be any interactions with current medications or supplements that you take, and help determine safety and proper dosage.

Dysmenorrhea

Dysmenorrhea is severe pain associated with menstruation that is typically more intense than the normal pain and discomfort of menstruation. The pain and cramping associated with dysmenorrhea typically is not relieved with over-the-counter pain medication.

Preliminary evidence suggests that a specific bilberry extract product called Tegens may improve some common symptoms of dysmenorrhea. [4]

Tegens 160 mg taken two times daily starting 3 days before menses, and continuing for 8 days, for a minimum of two menstrual cycles, was seen to: [4]

• Reduce lumbosacral (lower back) pain
• Reduce breast pain
• Reduce pelvic pain

Nausea, vomiting, and headache were also reduced in subjects taking Tegens compared to those who recieved a placebo agent.

While these results are promising, it is only one study, and more research is still needed to prove the therapeutic efficacy of bilberry for dysmenorrhea.

Diabetes

In a preliminary clinical trial, a specific bilberry extract significantly decreased plasma glucose levels relative to a placebo. [4]

In this trial, patients with type 2 diabetes took 470 mg/day doses of Mirtoselect before participating in oral glucose tolerance tests. [4]

In another study, patients with type 2 diabetes who were resistant to standard diabetes medications were given bilberry extract in addition to their standard treatment. Compared to patients who received standard treatment and a placebo, the patients given the extract had significant sreductions in fasting blood glucose levels and glucose levels after eating.

More research is still required to determine the efficacy of bilberry extract for diabetes. If you have diabetes and are interested in trying this dietary supplement then you should discuss it with your endocrinologist.

Weight Loss

In one preliminary clinical trial, consumption of 100 grams of whole bilberries each day, for 33-35 days, was seen to decrease waist circumference and bodyweight in overweight and obese women, compared to pre-treatment levels. [4]

More research is still needed to determine what effects bilberry may have on weight loss, or with maintaining healthy weight levels once they are achieved.

As with any supplement taken for weight loss, it is always recommended to be used as part of a lifestyle that includes a healthy diet and exercise to achieve optimal results.

Bilberry Extract Supplements

NCCIH states that bilberry extract supplements are available as tablets, capsules, powders, liquid drops, and whole plant parts (berries and leaves). [1]

Whole berries and leaves of bilberry are used commonly to brew teas and to make infusions and tinctures.

ConsumerLab reports that there because of the high cost of pure bilberry extract there is a growing concern over the authenticity of bilberry extract products on the market. Some products may not contain bilberry at all, or are mixed with less expensive components which contain similar anthocyanins as bilberry.

Therefore ConsumerLab says that is important to look for authentic bilberry products and do your research to make sure they contain the amount of bilberry and anthocyanins they are labelled to contain.

It is also recommended to shop for supplements that are organic, non-GMO, and free of contaminants such as lead and other heavy metals.

It is important to do your research before buying bilberry extract supplements. Ask for proof of GMP certifications from manufacturers and COAs on all batches of product. Read user reviews online to determine other users’ experiences with the company and product. Only do business with established and trusted manufacturers. [4]

Bilberry Extract Dosage

Bilberry extracts are typically standardized to 25% anthocyanin content, although sometimes this can be higher.

According to ConsumerLab, the commonly recommended dosage is between 120 mg and 240 mg of bilberry extract standardized to contain 25% anthocyanins, taken twice daily. [2]

Some other dosages that have been used in research studies include:

• Chronic venous insufficiency:480 mg daily for up to 6 months
• Dysmenorrhea:160 mg twice daily, start 3 days before period for 8 days
• Diabetic retinopathy:160 mg twice daily for a month

Bilberry Extract Side Effects

The Natural Medicines Conprehensive Database has rated bilberry as Likely Safe when used orally and appropriately in amounts found in food. Bilberry has been give Generally Regarded as Safe (GRAS) status by the FDA in the USA.

ConsumerLab states that bilberry is a natural plant food source, and it is known to be quite safe for most healthy people, even in large quantities. [2]

The NMCD has rated bilberry extract as Possibly Safe when used orally and appropriately in medicinal amounts. Various clinical trials have used this fruit extract safely for up to a year.

In one trial, 2295 people were given a bilberry supplement and then monitored for adverse effects. It was determined that about 4% experienced drowsiness, skin rash, or mild digestive distress. [2]

The safety of bilberry in pregnancy or breastfeeding has not been established. Its safety has also not been established in young children – or in those with severe liver and/or kidney disease. [2]

Some evidence suggests that bilberry leaf extracts may affect blood-glucose levels. If you are considering using a leaf extract it is recommended that you speak with your doctor about possible interactions and appropriate dosages. This is especially important if you have diabetes and are taking any blood-sugar lowering medications. [2]

Bilberry Extract Interactions

According to the University of Maryland Medical Center (UMM), there is concern for possible interactions between bilberry extracts and certain medications and herbal supplements. [6]

Be careful if using this extract in combination with anticoagulant medications used to thin the blood, including aspirin. In theory, anthocyanins in bilberry may reduce clotting ability. This could increase the risks for bleeding and bruising. [6]

Bilberry extract seems to lower blood sugar, but more research is needed to be sure. If it does, it could intensify the effects and/or side effects of any medications used to control blood glucose levels.

This applies to all antidiabetic medications, and also to herbal supplements with hypoglycemic potentials. These include garlic, ginger, fenugreek, turmeric, ginseng, angelica, clove, and more.

Although this supplement is known to be very safe for most people, there are still possibilities for adverse effects in those who with sensitivities.

Before beginning to take any herbal supplements it is always recommended to speak with your doctor, especially if you have any pre-existing conditions. Your doctor will be able to determine if bilberry extract is right for your needs, as well as appropriate dosages and any potential interactions.

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