The health benefits of blueberries that include anthocyanins and other flavonoids are widely recognized. What is incredibly remarkable is that anthocyanins and flavonoids are metabolized immediately once they enter the mouth.

In fact, human studies have shown that less than 0.1% of the ‘parent’ anthocyanin remain after it is eaten.  This has led some people to suggest that anthocyanin concentration in your blood is too low to provide health benefits.

Are you familiar with anthocyanins or proanthocyanins?  If not you can read about them here and here.

However, what is not mentioned is that the ‘parent’ anthocyanin is metabolized into many different anthocyanin derivatives that could have health benefits.

Wild blueberries (Vaccinium angustifolium Aiton) are a rich and diverse source of anthocyanins including cyaniding, delphinidin, malvidin, peonidin, and petunidin.

A recent study published in Journal of Agricultural and Food Chemistry analyzed the urine of healthy volunteers after they consumed blueberries.  

Here are the study details: 

– Patients ranged from 24 to 60 years old (13 women and 4 men)

– Patients consumed 250 mL (about 8 oz)

– No anthocyanin containing foods were consumed 5 days prior to the study.

– Urine was collected over a 24 hour period on days 0, 7, 14, 28, and 36.

– All urine samples were analyzed by HPLC tandem mass spectrometry

Here are the main results:

• A total of at least 55 major anthocyanins and 316 minor anthocyanins were identified in the urine.

The authors suggest the following in their article:

Taken together, the evidence shows that the human body may be chronically exposed to flavonoid-like anthocyanin metabolites at levels about 20 times higher than previously determined for parent anthocyanin. Determining the bioactivity of the array of anthocyanin metabolites and other products described here will be keenly important to advancing our understanding of the role of anthocyanin in berry health benefits.

Take away message:  

More than 370 different anthocyanins were found in human urine!  I often will be asked “what is the active ingredient in blueberries?”.  The research in this article further suggests that there are many ‘active ingredients’ in blueberries.  Often scientists use an approach of isolating out a phytochemical from a plant and treat it like a drug.  When this happens we are missing all kinds of other polyphenols which are also ‘active ingredients’.  By eating the whole fruit the benefits appear to be exponential.

Reference: Flavonoid Metabolites in Human Urine during Blueberry Anthocyanin Intake. Journal of Agricultural and Food Chemistry. 2017; Volume 65 (Issue 8): pages 1582-1591.

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Jeremy Johnson, PharmD, PhD

Dr. Johnson is a tenured associate Professor and licensed Pharmacist at the University of Illinois at Chicago College of Pharmacy.

His research on plant medicine has led to more than 45 publications and abstracts.This research has been presented at international meetings in the USA, France, Turkey, Peru, Israel, Austria, and Italy.

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Categories: Antioxidant, Clinical Trials, Food