Antioxidants have been hailed as health game changers for over a quarter-century. When originally buzzed back in the early 1990s, the compounds, which include beta-carotene, Vitamin E, and glutathione, were predicted to protect against various cancers, heart disease, and neurodegradation. They’d do this by halting the spread of free radicals in the body, molecules with unpaired electrons that greedily rob other molecules of their electrons in order to stabilize. By stealing electrons to pair their own, however, they create more free radicals in the process, producing “oxidative stress.” Antioxidants graciously lend their electrons to free radicals without turning ravenous themselves, thus halting the damaging chain reaction.

Early on, in vitro and observational studies showed promise, exciting scientists. Health “gurus” hyped the findings with books and articles. Supplement sellers had a new fad to fill their coffers. Food makers began slapping antioxidant claims on everything from yogurt and snack bars to chocolate and soda. The antioxidant craze was on.

But then, in the early 2000s, results from randomized, controlled trials on humans began flowing in, and the stream of positive results soon turned into a torrent of negative findings.

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