You can go to fitday.com and enter in all the food you eat for a week or two. Then you can get a report that tells you a daily average of the nutrients you take in, and what you are short on. For example, I discovered that I did real well except for slight shortages in vitimins A, D, E, and K; also the minerals magnesium and zinc. I figured I'm really getting enough vitamin D (the sunshine vitamin) because I'm outdoors so much. Then I found out which foods supplied the other missing nutrients and started eating more of them.
Problem solved without supplements.