Bilberry May Protect Kidneys

Bilberry (Vaccinium myrtillus) also know as the European Blueberry, has been a popular eye health supplement for years. Over the last decade several studies have tied a group of antioxidant compounds called anthocyanins to potential eye benefits. A recent study recently published in the Journal of Agricultural and Food Chemistry has linked the very same compounds to potential kidney benefits.¹

In the study, the researchers tested the protective potential of a standardized bilberry extract against potassium bromate, a renal-toxic food additive. Potassium bromate is used in bread making to strength the dough and improve rising. Typically the potassium bromate is destroyed in the baking process, provided the bread gets sufficiently hot for a long enough time. While the use potassium bromate has been banned throughout the most of the developed world, including the EU and China, the United States still allows its use. Potassium bromate's use must be declared by the term "bromated flour" on the baked good. Fortunately, it is now very rarely used in the United States.

The researchers administered a single dose of 200mg of potassium bromate per kg of body weight directly into each mouse's peritoneal cavity. They then fed three of the four groups of mice different doses of bilberry extract 50, 100, or 200mg per kg of body weight, over a 5 day period. The control group was not given bilberry extract. The researchers then monitored the amount of kidney damage and markers of renal distress. The single dose of the potassium bromate was sufficient to cause serious kidney damage. However, the researcher found that in all the groups receiving the bilberry extract, two markers, the serum blood urea nitrogen and creatinine levels, quickly returned to normal. The researchers also reported a decrease in levels of malondialdehyde in the kidneys, nitric oxide, and xanthine oxidase, all markers of kidney damage. Antioxidant activity was increased in the kidneys as measured by the oxygen radical absorbance capacity (ORAC) levels.

The researchers concluded that their study "showed that bilberry extract reduced the degree of oxidative stress and kidney damage induced by [potassium bromate]. These findings demonstrate that the protective effect of bilberry extract is attributed to its free radical scavenging activity and lipid peroxidation inhibitory effect."

While bilberry is closely related to the North American blueberry, the anthocyanin profile is very different. Learn more about Bilberries and their more thoroughly-researched eye health benefits.

1. Bao, L., X. S. Yao, et al. (2008). "Protective Effects of Bilberry (Vaccinium myrtillus L.) Extract on KBrO3-Induced Kidney Damage in Mice." J Agric Food Chem 56(2): 420-5.