For three weeks, a construction worker drank four or five energy drinks per day to help keep up with his intense workload. Then his body went haywire. In a bizarre case Florida doctors describe in the British Medical Journal, the 50-year-old man started gulping down energy drinks on the job but suddenly began vomiting after about three weeks. Soon, his skin turned yellow, but it wasn't the caffeine or even the sugar that was the problem. At a hospital, the man showed signs of liver damage, and a biopsy confirmed he had acute hepatitis, believed to have been brought on by high intake of vitamin B3, or niacin, found in his energy drink of choice. (It wasn't named.) Each bottle had about 200% of the daily recommended dose, reports Gizmodo.
In safe quantities, niacin—also found in green vegetables, meat, and eggs—can improve cholesterol levels and liver function and lower cardiovascular risk. But it also wreaks havoc on the body if too much is consumed. Though the man's daily intake of 160 to 200 milligrams was below the toxic level, the accumulation of niacin over three weeks was enough to do damage; the same thing happened years ago to a woman who drank 10 energy drinks daily for two weeks, reports Medical News Today. The male patient recovered and was told to avoid similar niacin-rich products in the future. But "as the energy drink market continues to rapidly expand, consumers should be aware of the potential risks of their various ingredients," doctors say. (Even a single energy drink may be dangerous.)