both and的both是什么词性,as important as 是什么词性,在这个句中

both and的both是什么词性,as important as 是什么词性,在这个句中
In my point of view,mental health is as important as physical health to us,and to make people healthier both(adv.两者都) physically and mentally,there is no other way than adopting a positive attitude toward life.