What's the best way to handle coexistence of the “int enum” pattern with java enums as an API evolves?

public class VitaminType {
 public static final int RETINOL = 0;
 public static final int THIAMIN = 1;
 public static final int RIBOFLAVIN = 2;
}

public enum NutrientType {
 AMINO_ACID, SATURATED_FAT, UNSATURATED_FAT, CARBOHYDRATE;
}

class A
   {
       public static final int MY_CONSTANT=1
   }

   class B
   {
           ....
           i+=A.MY_CONSTANT;
   }

i+=1

public enum Vitamin {

    RETINOL(0), THIAMIN(1), RIBOFLAVIN(2);

    private final int intValue;

    Vitamin(int n) {
    	intValue = n;
    }

    public int getVitaminType() {
    	return intValue;
    }

    public static Vitamin asVitamin(int intValue) {
    	for (Vitamin vitamin : Vitamin.values()) {
    		if (intValue == vitamin.getVitaminType()) {
    			return vitamin;
    		}
    	}
    	throw new IllegalArgumentException();
    }

}

/** Use foo.Vitamin instead */
@Deprecated
public class VitaminType {

    public static final int RETINOL = Vitamin.RETINOL.getVitaminType();
    public static final int THIAMIN = Vitamin.THIAMIN.getVitaminType();
    public static final int RIBOFLAVIN = Vitamin.RIBOFLAVIN.getVitaminType();

}