From adding a refreshing zing to your water to marinating your fish to perfection, lemons serve a wide range of culinary functions. If you use only the juice and discard the peel, though, you may be doing your diet a disservice. Lemon peels contain a spectrum of vitamins, minerals and fiber that can give your menu a nutritional boost, although you would have to consuming large amounts of peel to glean significant nutritional benefits.