Study raises questions about vitamin levels in commercial Brazilian supplements

By Stephen Daniells

- Last updated on GMT

© Getty Images / artisteer
© Getty Images / artisteer
Improved quality control may be needed for commercial vitamin supplements in Brazil, according to a study that found that only 21% of products were within 20% of the label claim for vitamins A, C, and E.

Scientists from the University of São Paulo and the Adolfo Lutz Institute analyzed 57 different brands of single vitamin supplements and multi-vitamin supplements, and found that the vitamin content in the supplements ranged from zero (or “non-detectable”) to 81% higher than that reported on the label.

“The results of this study demonstrate the wide variation that exists between the amounts of vitamins A, C, and E reported on supplement product labels and those determined analytically. The highest non-compliance percentage was detected for vitamin A, and the highest compliance percentage was detected for vitamin C,” ​they wrote in the Journal of Food Composition and Analysis​.

“Besides vitamins A, C, and E, analyses of other vitamins in multivitamin supplements are necessary to confirm their actual values with those indicated on the label, considering the demand of these products in the market. Furthermore, additional studies are required to evaluate whether the low values of vitamins obtained in this study are because of their degradation or lesser amount of vitamins added during production, indicating lack of quality control in the industries.

“Given the high rates of non-compliance detected, the needs for greater quality control and surveillance actions are urgent. Such measures will help to ensure the consumer’s right to purchase safe multivitamin supplement products that are provided with reliable information concerning their contents,” ​added the researchers.

Study details

The São Paulo-based scientists obtained 57 commercial vitamin and multi-vitamin supplements from the Health Surveillance Agency of the State of São Paulo or they purchased them directly from drugstores and supplement stores. The supplements were in various forms, including tablets, sugar coated tablets, hard and soft gelatin capsules, suspensions, and solutions. Eighty-two percent of the samples were manufactured in Brazil.

High-performance liquid chromatography with diode-array detection (HPLC-DAD) was used to analyze the vitamin A, E, and beta-carotene contents, while automatic potentiometric titration was used for vitamin C.

“The typically recommended daily portions of vitamins A, E, and C, corresponding to 100% of the DRI, are 600 [micrograms], 10 mg, and 45 mg, respectively,” ​explained the researchers. “This upper limit (100% of the DRI) is established in Brazil, whereas the American and European standards establish maximum levels of vitamins and minerals in supplements, based on security levels, in terms of the tolerable upper limit of intake (UL) and the no observed adverse effect level (NOAEL).”

The results showed that only 12 commercial supplements met their label claims for the vitamin content. Nine of these 12 were manufactured by multinational pharmaceutical companies.

Vitamin A levels lower than the levels claimed on the labels in 71% of the samples analyzed, said the scientists, while vitamin E levels were lover in 50% of the samples tested.

On the other hand, vitamin C contents of the supplements matched label claims in 67% of the samples tested.


"The results of this study are of concern because it was observed that some supplements have levels of vitamins ranging from “not detected” (Sample 54 for vitamin A and sample 57 for vitamin C) to 81% higher than the level reported on the label (Sample 2 for vitamin E) ,” ​wrote the researchers.

“Given that Brazilian regulations allow a 20% difference between the nutrient content reported on the label and the actual content, it was found that 66% of the samples analyzed were non-compliant because they had lower levels of one or more vitamins than those reported and 30% were non-compliant because they had higher levels of one or more vitamins than were reported, considering the total of 57 samples.”

“Dietary intake of vitamin supplements can help to reduce the prevalence of micronutrient deficiencies, but the levels of supplements reported on product labels must be consistent with the actual levels in the products,”​ they added.

“Ensuring the accuracy of the information on multivitamin supplement product labels will help to maintain the health of the population because it will allow individuals to consume amounts of micronutrients that are consistent with intake recommendations.”

Source: Journal of Food Composition and Analysis
Volume 72, Pages 141-149, doi: 10.1016/j.jfca.2018.07.001
“Do the labels of vitamin A, C, and E supplements reflect actual vitamin content in commercial supplements?”
Authors: L. Tiemi Abe-Matsumoto

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