Among ten supplements recently selected for testing, ConsumerLab.com discovered that one delivered nearly double its claimed amount of vitamin A – of concern due to potential toxicity -- and three others provided significantly less vitamin A than stated on the labels.
Vitamin A supplementation may slow the progression of macular degeneration, enhance healing after laser eye surgery, and reduce the risk of certain cancers. Deficiency of vitamin A, which is rare in the United States but common in less developed nations, causes night blindness and increased risk of infection.
Toxicity with vitamin A, as commonly sold as retinyl palmitate and referred to as preformed vitamin A, can occur at doses only moderately higher than required to prevent deficiency. Toxic effects of vitamin A include bone and liver abnormalities, as well as birth defects of the brain, eyes and head. Beta-carotene, or pro-vitamin A, does not carry this toxicity.
Tests of one cod liver oil supplement showed it to contain 7,818 IU of vitamin A as retinyl palmitate, nearly double its claimed amount of 4,000 IU per teaspoon. Such a product should be avoided by pregnant women who, according to March of Dimes, should not exceed 5,000 IU per day due to the risk of birth defects. It should also be avoided by children under 13 years old, whose daily intake should not exceed 2,000 IU to 5,666 IU of preformed vitamin A, depending on their age, based on upper tolerable intake levels established by the Institute of Medicine.
Three supplements that were low in ingredient contained only 68.2% to 77.5% of their claimed amounts of vitamin A (as retinyl palmitate and/or beta-carotene). Six vitamin A supplements passed the testing, including tablets and oils, along with six other supplements tested through ConsumerLab.com's Voluntary Certification Program.
The new report is available at www.consumerlab.com/reviews//vitamin_a/. Brands covered in the new report include Country Life, Ethical Nutrients, Garden of Life, Health from the Sea, Metagenics, Nature Made, Nature’s Bounty, Nature’s Way, Puritan’s Pride, Rite Aid, Solgar, Source Naturals, Spectrum Essentials, Swanson, Vitamin Shoppe, and Vitamin World. The report includes results for sixteen products and information about three others similar to those that passed testing. The report also includes extensive information about how to buy and use these supplements and potential side effects.
Reviews of other popular types of supplements are also available at www.consumerlab.com. New Reviews to be released in coming weeks will cover CoQ10, multivitamins, and zinc, as well as supplements for bone health (calcium, vitamin D and vitamin K) and memory enhancement (ginkgo, huperzine, and acetyl-L-carnitine).
ConsumerLab.com is a leading provider of consumer information and independent evaluations of products that affect health and nutrition. The company is privately held and based in Westchester, New York. It has no ownership from, or interest in, companies that manufacture, distribute, or sell consumer products. ConsumerLab.com is affiliated with PharmacyChecker.com, an evaluator of online pharmacies, and MedicareDrugPlans.com, which reviews and rates Medicare Part D plans. Subscription to ConsumerLab.com is available online. For group subscriptions or product testing contact Lisa Sabin, Vice President for Business Development, at [email protected].