A nail will get hot fast in a 400 deg oven. If you insert two nails into a potato, you can cut the baking time considerably. This is a "green " thing to do since it saves energy.
Galvanized nails are a good choice. Since a galvanized nail is composed of zinc as well as iron, the benefits of the zinc are there . Zinc is usually included in vitamin-mineral supplements for its activity as a supposed immune system promoter as well as other nutritional effects. One alleged effect is the enhancement of taste and smell.
Let's not forget that the nail is only coated with zinc. The main material is the underlying iron. Now, we all know iron is good for the blood..it provides the central atom in the hemoglobin molecule.
So, use nails in your potatoes and you will get all these rewards :

1. Faster cooking
2. Good for the environment
3. Improved immune system
4. Enhanced taste and smell to enjoy the potato

5. Brighter red in your blood.
Next, we will consider the advantages, if any , of using a brass nail , made of zinc and copper. However, one consideration will have to be the recent price increases for copper and maybe the melting point of the metal.
OH! Don't forget to remove the nail. They aren't good for the teeth