The Seven Dhatus in Ayurveda
As per Ayurveda physiology, food is Brahman and contains the same consciousness as in us and this consciousness is the essence of any food. Any food digested is converted into three portions – the gross undigested food is converted into waste (feces), the middle part is converted into one of the Dhatus and the subtlest form gets converted into ojha or the immunity.
As per Ayurveda, food once eaten is converted into the first Dhatu, i.e., Rasa. Once the formation of Rasa is complete, the remaining is converted into Rakta (blood). The left over essence of food makes Mamsa (muscles), left over of which makes Medha (adipose tissue), and so on to form Asthi (Bone), Majja (Bone Marrow) and Shukra (sperm/ova).
As per this physiology, the second Dhatu will only form once the first Dhatu is of good quality and so on. And, at any step, if a Dhatu is not formed properly, the subsequent Dhatu will also show defective formation. For example, a defective Dhatu at the stage of Asthi (bone) will have normal plasma (blood), muscle and adipose tissue but may have an impaired immunity/sperm/bone marrow. Similarly, defective Dhatu at the level of bone marrow may have only impaired immunity with no impairment of other Dhatus. On the other hand, impairment of Dhatus at the level of plasma or blood will involve all other Dhatus in sickness. Isolated disorders of Shukra may have no involvement of other Dhatus at all.
This Ayurveda principle can help us in answering many unanswered questions in modern allopathy such as – Why are all the organs involved in typhoid fever? Why no other organ is involved in azoospermia?
Upanishads have described the formation of Dhatus in much more detail. According to them, different types of foods make different types of Dhatus. The fiery foods like oil and ghee are responsible for formation of Karamaindriyan (part of shukra), bone and bone marrow (Dhatu). Earthy foods are responsible for formation of Gnanandriyan, and water in food is responsible for formation of Rasa and Rakta (plasma and blood) and Pran (Shukra).
This means that every different type of food would make different types of Dhatus and balanced food with a combination of fire, water and earth will only be responsible for formation of shukra, immunity or the essence.