Dhatu, Dhatu means to support. Ayurveda recognizes 7 distinct dhatu or tissues, namely-rasa (fluids such as plasma, lymph, milk secretary fluids), rakta (blood cells, nourished by rasa dhatu), mamsa dhatu (muscles, ligaments, & skin), meda dhatu (fat and adipose tissue), asthi (bone, teeth), majja (marrow) and shukra (reproductive organs, sperm, eggs, including the desires and urges). In several instances, a dhatu will have associated upadhatu or secondary tissues, e.g., bone is asthi dhatu, and teeth are upadhatu. Mala are the metabolic end products of the creation, growth and repair of the tissues. Consequently, each tissue or dhatu will have mala. For example, rakthahatu (blood cells) make cytokines which are important to conduct normal functions such as defense, immunity etc., but when the same is over-produced, it is an indication of underlying imbalance in the dhosha, leading to disease. Communication within and between the players. The cells in the tissues constanly communicate among other parts of the body. This intra- and inter-organ communication is also well recongnized in modern medicine e.g., hormones, messenger molecules; ligands, receptors, and ions. Ayurveda says that the communication occurs via channels or srotas. Each of the 7 major tissues (dhatus) have respective srotas. These srotas are described to be active, sending and receiving signals from other tissues and cells. In modern terminology, srotas would be similar to ion channels, ion-gates, receptors and signal transducers. Interaction with external stimuli. Ayurveda describes food items in mysterious terms such as ushna, sheeta, laghu or guru. When translated into English, as hot, cold, light or heavy, respectively, the same would not convey effective meaning. On the contrary, all foods are classified based on the predominance of the primordial element it contains. Equally important is the environment, including the seasons. If sheeta food is consumed in winter and fall, it would aggravate kapha, whereas the same would help in summer time. On the contrary, ushna which may be agreeable in winter would cause discomfort and formation in summer-boils. Also, the taste of the food or medicine known to have influence on the doshas. There are 6 tastes-madhur or astringents. Their relationships to doshas is shown in the table.

Rasa Vata Pitta Kapha
Madhura(sweet) Pacifies Pacifies Aggravates
Amla (sour) Pacifies Aggravates Aggravates
Lavan (salt) Pacifies Aggravates Aggravates
Katu (pungent) Aggravates Aggravates Pacifies
Tikta (bitter) Aggravates Pacifies Pacifies
Kasaya (astringent) Aggravates Pacifies Pacifies

Thus, a ‘healthy’ person eating madhur or sweet dishes would increase kapha and suppress pitta, resulting in anabolic conditions and weight gain. Eating bitter (tikta) dishes like fenugreek and bitter melon, would increase vata and suppress kapha, causing e.g., weight-loss. It is important to eat a variety of tasty dishes so that an overall balance would result. Therefore there is no single food in Ayurveda. The myths such as ‘bitter is better’ or ‘raw is healthful’ are not endorsed by Ayurveda. Traditional cuisine would even impose specific dishes on specific days of the lunar month, to ensure periodic supply of essential factors in our diet.