6 Vitamins and Minerals You May Not Be Getting Enough Of

Why you might be low: This is also a case of poor diet. Vitamin A is on the list of nutrients missing from many American diets, according to the U.S. Dietary Guidelines, and like vitamin C, the reason is likely that it's found primarily in colorful produce.

Why you need it: Let's start with your eyes. Vitamin A is critical for sight, since it helps make up a protein that allows your retinal receptors to absorb light. Without enough of it, you can experience night blindness, or an inability to see in low or no light. Vitamin A also helps your vital organs function normally by assisting in cell growth.

Where to find it: "If you eat things that are orange or yellow, you can easily get enough," says Thacker, so try adding more sweet potatoes, carrots, mangoes, cantaloupes and peppers to your shopping cart.