My biggest pet peeve is that when we hear the word “vitamin,” we automatically think of pills instead of food — and then use “vitamin” to refer to all dietary supplements. This is incorrect. There are only 13 vitamins, which are essential for health, compared to over 85,000 dietary supplements for sale in America. Also, we assume that scientists know exactly what vitamins do in our bodies and how much of each we need, but they don’t. We assume that all vitamins and dietary supplements are required to be tested for safety and effectiveness before they’re sold. But they’re not.