Bilberry Supplements Review
Initial Posting: 7/26/13
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What It Is:
Bilberry (Vaccinium myrtillus) is often called European blueberry. Like a North American blueberry (Vaccinium corymbosum), its skin is dark blue or purple on the outside; however its flesh is purple rather than light green and it contains a different mixture of biologically active polyphenols known as anthocyanosides (or anthocyanins).
What It Does:
Some evidence suggests that anthocyanosides may benefit the retina, as well as strengthen the walls of blood vessels, reduce inflammation, and stabilize tissues containing collagen (such as tendons, ligaments, and cartilage).1-7
A small, double-blind, placebo-controlled trial of bilberry extract found significant improvements in retinal lesions in people with diabetic retinopathy or hypertensive retinopathy (damage to the retina caused by diabetes or hypertension). Other studies have also indicated benefits, although they were not double-blind.
During World War II, British Royal Air Force pilots reported that eating bilberry jam just prior to a mission improved their night vision. However, clinical studies have not definitively confirmed this short-term benefit and none have shown a long-term benefit. It would seem, at best, that there may be a short term, e.g., 2 hour, improvement in night vision. (Canter, Surv Opthal 2004). In fact, even the report regarding British pilots may have been a rumor intended to hide the fact that the British were using radar technology, which the Germans did not possess (Tasman, Am J Ophthal 2007).
The anthocyanosides in bilberry resemble the oligomeric proanthocyanidin complexes (OPCs) found in grape seed and pine bark; consequently, bilberry has been suggested for all the same uses as those substances, including easy bruising, varicose veins, minor injuries, and surgery support, but there is currently insufficient evidence to support these uses.
Animal studies also suggest that bilberry leaves (rather than the berry) may be help improve blood sugar control in diabetes, and also in lowering blood triglycerides.
For more details about studies with bilberry, see the Encyclopedia article on ConsumerLab.com.
Quality Concerns and What CL Tested For:
Concern Over Bilberry Authenticity
There is growing concern that some bilberry supplements do not contain authentic bilberry and may, instead, be composed of material from other, less expensive plants (such as other berries or black soybean hull) which contain some, but not all, of the anthocyanin compounds in bilberry. If a manufacturer tests its ingredients only for the total amount anthocyanoside compounds and not the specific types and ratios of these compounds, adulterated ingredient can be passed off as authentic bilberry (The Adulteration of Commercial Bilberry Extracts, American Botanical Council 2012). The cost of authentic bilberry extract is about $600 to $900 per kilogram, while adulterated extract costs much less -- as low as $10 per kilogram, creating an economic incentive for manufacturers to substitute poor quality material or put in less ingredient than listed on labels. In fact, it has been reported that 60 tons of "homemade Chinese bilberry" (which is not authentic bilberry) was exported from China in 2008, most of which went to the United States.
Other Quality Concerns
Like other supplements, neither the FDA nor any other federal or state agency routinely tests bilberry supplements for quality prior to sale. In addition to the authenticity of the ingredient, other quality concerns include the following:
ConsumerLab.com, as part of its mission to independently evaluate products that affect health, wellness, and nutrition, purchased commonly available bilberry supplements and tested them be sure they possessed the claimed amounts of authentic bilberry and were free from unacceptable levels of heavy metals. Products in tablet form underwent disintegration testing to make sure they would properly release their contents. All products were tested to check that levels of anthocyanidin compounds were low, as these compounds (which are anthocyanosides without attached sugar molecules) should normally be present only at low levels in fresh bilberry and extracts; higher levels suggest degradation due to incorrect storage and/or extract production. (See Testing Methods and Passing Score for more details).
- Labeled Amount — Does the product really contain the labeled amount of ingredient?
- Purity — Is the product free of lead and other heavy metals which can occur in plant-based supplements?
- Ability to Break Apart for Absorption — Will the product break apart properly so that it can release its ingredients in the body? For a tablet to be most useful, it must fully disintegrate prior to leaving the stomach, delivering its contents for absorption in the gut. Some tablets are not properly made and can pass through your body completely or partially intact, depriving you of its ingredients. This happens, for example, when a tablet is too tightly compressed (too "hard") or is too thickly coated.