The teaser for the 2018 film “Vitamania,” a documentary about the history of supplements, recounts a disastrous 1913 Antarctic trek. The last two remaining explorers, Douglas Mawson and Xavier Mertz, had to slaughter their Huskies for food. Later, they became progressively ill, with drying and fissuring of the skin and, for Mertz, madness and death. There’s speculation that eating the dogs’ livers, packed with vitamin A, gave the misadventurers a condition called hypervitaminosis A.

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These days hypervitaminosis A mostly happens when someone takes too much vitamin A for too long. But that’s just one of the hazards of taking supplements. For example, according to the National Institutes of Health, “products labeled as kava have been linked to the development of ... acute liver injury, which can be severe and even fatal.”

Supplements aren’t regulated by the Food and Drug Administration; it’s only able to issue alerts and recalls after dangerous products appear on the market — but the agency recently announced that it would explore improving communication about harmful ingredients and reform regulatory guidelines that ensure product safety. The question: How good a job will it do?

For now, look for a seal from U.S. Pharmacopeia, NSF International or ConsumerLab.com certifying that a supplement isn’t contaminated and the contents are verified. Discuss ALL supplements with your doctor so that you don’t have negative interactions with other supplements or meds you’re taking.

Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is chief wellness officer and chairman of Wellness Institute at Cleveland Clinic. To live your healthiest, tune into “The Dr. Oz Show” or visit www.sharecare.com.