Fact 1: Vitamins don’t cancel out bad health habits.
There are many different disease-causing culprits in our lives, one vitamin cannot protect against them all. Vitamins can’t significantly undo the toll that risk factors like smoking, excess alcohol, air pollution, obesity, and lack of physical activity take on our health. In fact, research suggests that some people may be more likely to put their health on the line when taking vitamins, because they believe the pills will shield them from harm.

Fact 2: Megadoses are useless and possibly even harmful.
Our bodies have individual requirements for each nutrient, and once they’ve been met, we don’t get an additional benefit from taking more, either from food or supplements. Taking too much calcium, for example, can cause kidney stones and may increase your risk for heart attacks. What’s more, some vitamins and minerals rely on the same mechanisms for absorption. So if you flood your body with one compound, you may interfere with the absorption of other nutrients.

Fact 3: What you put on your plate matters most.
Supplements are not a substitute for the nutrients found in whole foods. Spinach, for instance, is a great source of iron, but it also contains literally thousands of other nutrients; an iron supplement contains only one. As long as you’re eating a varied diet, it’s extremely difficult to overdose on the vitamins and minerals you get from foods, but exceeding your RDA is easy when you’re popping supplements.