To find out, ConsumerLab, White Plains, NY, recently purchased and tested popular vitamin A supplements sold in the U.S., including beta-carotene supplements and cod liver oils, for their amounts and forms of vitamin A. All products that contained plant-based ingredients (such as carrot powder) or were made with fish liver oil were tested for contamination with lead, cadmium and arsenic, and products made with fish liver oil were also tested for freshness. ConsumerLab also carefully reviewed the latest clinical research regarding the effects and side effects of vitamin A supplementation.
ConsumerLab's tests revealed that two supplements contained less vitamin A than claimed on the label. In addition, the amounts of vitamin A in the retinol form in some products exceeded tolerable intake levels for adults, adolescents or children, indicating that their use carries an increased the risk of adverse effects.
Among the products that passed its tests, ConsumerLab identified its Top Picks for best quality and value, including beta-carotene and cod liver oil products.
Vitamin A supplement labels are in the process of being updated to show vitamin A in the more scientifically accurate form of micrograms of retinol activity equivalents (mcg RAE) instead of international units (IU). During this transition, labels may list dosages in either format—but rarely list both. ConsumerLab’s review shows amounts in both forms for ease of comparison.
The review also summarizes the clinical evidence for and against vitamin A supplementation and provides information about recommended daily intakes for vitamin A based on age and gender, the dangers of getting too much vitamin A, and potential side effects and drug interactions with vitamin A supplements. The differences among forms of vitamin A, including "preformed" retinol forms (such as retinyl palmitate and retinyl acetate) and "provitamin A" (beta-carotene) are explained, as is what to look for on labels when choosing a product.
The findings are available online now in ConsumerLab's Vitamin A Supplements Review, which includes test results and comparisons for eleven products. Nine of the products were selected for testing by ConsumerLab and two underwent the same testing through CL's voluntary Quality Certification Program . Products covered in the report are: Bluebonnet Vitamin A, Bronson Vitamin A, Carlson Kid's Norwegian Cod Liver Oil, NOW Vitamin A, Nutrilite Multi Carotene, Pure Encapsulations Vitamin A, Puritan's Pride Beta-Carotene, Solaray Vitamin Dry A, Spring Valley (Walmart) Vitamin A, The Vitamin Shoppe Cod Liver Oil, and Vitacost Cold Water Arctic Cod Liver Oil.