Concept of Immunity (Vyadhikshamatva) in Ayurveda
When etiological factors come into contact with the body they try to produce disease. At the same time the body tries to resist the disease. This power of the body, which prevents the development of diseases or resists a developed disease, is called Immunity (Vyadhikshamatva) in Ayurveda. ( Ch. Su. 26 /81 Chakrapani )
It is commonly observed that certain persons do not develop a disease even after coming into contact with the relevant etiological factors, while others become victims of the disease. The reason is that when the resistive power of the body is sufficiently strong it destroys the causes. A beautiful simile is used in Manusmriti to illustrate this fact: when a seed is sown in non-fertile soil it is destroyed.
Immunity depends upon the maintenance of the equilibrium of doshas and the healthiness of tissues and channels. Similarly the strength of the body is related to immunity and it also depends upon the healthiness of tissues. The factors, which are related to the healthiness of tissues, are:
Birth in a country where people are naturally strong
Birth at a time when people naturally gain strength
Favorable disposition of time (pleasant and moderate climate)
Excellence of the qualities of the sperm and the ovum
Excellence of the ingested food
Excellence of the physique
Excellence of mind
Favorable disposition of the race and species
Cheerful disposition during sexual indulgence
This strength is attainable from three sources-constitutional, temporal, and acquired. Constitutional strength is that gained from the time of the formation of the fetus onwards. Hence it is dependent on the healthiness of sperm and ovum and also on the excellence of time and place. The temporal strength is the one, which is gained from the favorable condition of time, such as youth, and favorable season.
The acquired strength is one, which is achieved by the proper combination of diet, exercise, and other regimens. ( Ch. Su. 6 / 13), Ch. Su. 11/ 36)
Avyadhisaha sharirani - Individuals incapable of resisting diseases
Those who have improper physiology of the musculature
Those with defective blood
Those who have defective bone tissues
Emaciated and weak persons
Those nourished with unwholesome food
Those who have feeble minds
We know that excessively obese or excessively emaciated persons are very weak. Similarly, the strength of the body depends largely upon the healthiness of tissues, especially healthiness of the muscle, blood, and bony tissues. Hence persons in whom these three tissues have improper physiological functions are naturally very weak. Persons who consume unwholesome food are also very weak, as their tissues are not properly nourished. And lastly, strength of the body also depends upon the mental health. Hence persons having feeble minds are also weak. Therefore it may be inferred that the common factor of all these eight types of individuals who cannot resist diseases is their weak constitution. ( Ch. Su. 28 /7)
Vyadhikshama sharirani - Individuals having good resistance against diseases
On the other hand, individuals whose physical constitutions are of a type opposite to the eight types mentioned above are capable of resisting diseases. If a person's physical and mental strength is of a high degree then naturally his immunity is also good and such persons can resist diseases very well.
Individuals whose bodies are neither too corpulent nor too emaciated, who possess healthy and good musculature, blood, and bone tissues, who are well nourished with wholesome and sufficient food and who have strong minds are capable of resisting diseases.
Persons having proportionate bodies and musculature, compactness of the body, and healthy sense organs are not overcome by the onslaught of diseases. They can withstand hunger, thirst, and the heat of the sun, cold weather, and physical exertion. They can also digest and assimilate food properly. ( Su. Su. 21 / 18,19)
Amongst the factors responsible for immunity, the greatest importance has been assigned to the healthy condition of the three tissues-blood, muscle, and bone. In our opinion the reasons for this are:
Here is a typical relation of between these three tissues and tridosha-i.e. between blood and Pitta, muscle and Kapha, bone and Vata. The healthy condition of these three tissues will naturally maintain equilibrium of the three doshas, which is also required for resisting disease.
The white cells of the blood are the force, which fights against any infection and prevents any foreign substance from entering the body. The plasma of the blood contains gamma globulins, which are antibodies. Muscular tissue also produces these gamma globulins.
Red bone marrow in the bones is the organ of the reticulo-endothelial system responsible for the manufacture of the red and white cells of the blood.
Ashtau Nindita [Eight undesirables]
There are eight types of undesirable constitutions: too tall, too short, too hairy, hairless, too white, too black, too corpulent and too emaciated. ( Ch. Su. 21 / 3)
These constitutions are considered undesirable because they do not possess sufficient resistive power against diseases. The qualitative and quantitative proportions of the tissues are not proper in them. The measurement by finger (anguli parimana) of the body and the compactness of the tissues is also abnormal.
In our opinion these eight types of undesirable constitutions are mainly related to some sort of hormonal dysfunction of the body. The dysfunction of thyroid, gonads, adrenal cortex, and pituitary is related to obesity. Hyperactivity of the thyroid causes wasting of muscles and develops wasting.
The excessively tall constitution is associated with disturbances in the anterior pituitary, which produces gigantism. In this condition a person becomes abnormally healthy. He also becomes impotent and cannot resist diseases. Dwarf constitution is also associated with disturbances in the pituitary. In conditions such as Frolich's syndrome and Cushing's syndrome such dwarf constitutions are produced. Excessively hairy and hairless are associated with dysfunction of the pituitary, adrenal cortex, and gonads. The advanced modern medicines are also unable to cure these eight conditions even today.
Yoga and Ayurveda
The role of the mind in immunity has been stressed in both Yoga and Ayurveda. In rejuvenation treatment for increasing immunity this has been made very clear by many Ayurvedic texts. Similarly, Yoga texts have given methods to increase the strength of mind for this purpose. One should adopt all the procedures for increasing the Sattvic quality of mind-sattvic diet and sattvic behavior. Ayurveda has explained the ethical regimen for the same purpose. Increased sattva is related to good pain tolerance, a health-conscious attitude, and increased immunity.