Investigation reveals 'major problems' with bilberry supplements
Bilberries are used in health supplements for a wide range of health concerns including: cardiovascular health, eye health, lower limb varicose syndrome, ulcerative colitis, and pro-inflammatory cytokines.
The health benefits are largely attributed to the fruit's rich content of antioxidants known as anthocyanins.
Unfortunately, no governmental drug registrations for bilberry products are known. Also, no health claims for the food sector of the European Community have been authorised to date.
This quality assessment, from the University of Münster, Germany, investigated bilberry containing food products and supplements, obtained from internet shopping, health food stores, and community pharmacies in Germany.
They found the majority of dried bilberries were of good quality but investigation of 11 dietary supplements revealed a different story and concluded that consumers would be better off purchasing the fruit as a food or juice product.
Unacceptable samples
Investigating capsule content quality, the team found 4 out of the 11 supplement samples (45%) did not conform to specifications, indicating insufficient and unreliable production technology and implying varying amounts of active ingredients per serving which the report concludes to be unacceptable.
High-performance liquid chromatograms were used to determine the quality and quantity of anthocyanins and anthocyanidins in the samples. Values were then compared to the recommendations of the manufacturers for a daily serving.
One sample did not contain any detectable amount of anthocyanins.
In two samples, only one anthocyanin was detected, together with traces of cyanidin. A literature search indicated that black rice should contain compounds in a ratio similar to the ratios observed in the samples. The investigators obtained black rice from a local food store, extracted the material, and analysed the anthocyanin-rich extract. Both peaks of the two samples matched the peaks eluted from the black rice sample. The report concludes: "substitution of waste extracts from black rice production for bilberry products is obvious".
All-in-all, four samples were found to not contain bilberry but low amounts of anthocyanidins were partly detected, so they were assessed as counterfeit.
One product was in part assessed negatively, because the amount of anthocyanin was quite low (<1 mg per capsule or <2 mg per day). The manufacturer only specified that the product contains berry powder and not a concentrated extract, thus accounting for the low anthocyanin content.
One product specified an anthocyanin content of 156 mg/capsule, corresponding to 468 mg/day, but only 0.9 mg/daily dose was found, so was found unacceptable.
Just two products corresponded well to the declaration and specification, and the analysed anthocyanin contents matched exactly the specified anthocyanin amounts (20 and 36 mg specified; 21.0 and 36.3 mg found, respectively).
The team conclude just 5 out of 11 products (45%) could be fully recommended. For all other investigated products, the dosage of bilberry extract was evaluated as too low for the consumer to benefit from any health benefit.
The report concludes that these results suggest consumers would be better off eating bilberry fruits whole, or juices, in order to gain any health benefits.
"For unambiguous quality control of such extract-containing botanicals, analytical protocols, as used for medicinal plant analysis, are particularly reasonable. Recent analytical studies have shown that the rate of poor quality products in this food sector is quite high. This subjective impression has again been confirmed by the present study. In an overall assessment of the qualitative and quantitative results, only 5 of 11 supplements meet the respective declaration and the consumer expectations.
"In contrast, the quality of the fresh and dried unprocessed bilberry fruits and bilberry juices is rather positive. Because these products can be eaten by the consumer as daily fresh foods or as juices at a concentration that is equivalent to the dosing found for bilberry food supplements, these fresh/ dried bilberries or juices should be favored by the consumer as a result of higher quality, lower pricing, and better sustainability."
Source: J Agric Food Chem
DOI: 10.1021/acs.jafc.0c07784
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