Marketplace analysis demonstrates quality control standards needed for black raspberry dietary supplements

Area of Science:

• Nutritional Science
• Pharmacognosy
• Food Chemistry

Background:

• Black raspberries are rich in anthocyanins, potent antioxidants with potential health benefits.
• Dietary supplements are a popular source of bioactive compounds, but their quality and composition can vary significantly.
• There is a lack of regulatory standards for anthocyanin content in black raspberry supplements in the US.

Purpose of the Study:

• To determine the anthocyanin concentration in commercially available black raspberry dietary supplements.
• To assess the variability and authenticity of black raspberry products sold as supplements.
• To compare the reliability of supplements versus whole foods as sources of dietary phenolics.

Main Methods:

• Procurement of 19 different black raspberry products (dietary supplements, freeze-dried powders).
• Analysis of anthocyanin composition and concentration using established chemical methods.
• Quantification of anthocyanins per unit weight (mg/100g) and per serving (mg/capsule or mg/teaspoon).

Main Results:

• Seven out of 19 samples (37%) contained no detectable anthocyanins from black raspberry.
• Three samples lacked any detectable anthocyanins, indicating potential mislabeling or adulteration.
• Anthocyanin concentrations varied widely in the remaining 12 products, ranging from 18.1 to 2,904.8 mg/100g.
• Per serving, concentrations ranged from 0.1 to 145.2 mg, with an average of 28 mg.

Conclusions:

• Significant variability and lack of authenticity exist in the black raspberry supplement market.
• Current US regulations for dietary supplements do not ensure consistent anthocyanin content.
• Whole black raspberries or unprocessed food forms are more dependable sources of dietary anthocyanins than supplements.