Immunity is the ability of body to fight against the disease.

Particularly, immunity is the ability of an organism to resist a particular infection or toxin by the action of specific antibodies or sensitized white blood cells. WBCs are generated by the bone marrow, soft fatty tissue inside bone cavities. Not only WBCs but T cells , B cells are also immunity cells i.e. all these cells make immunity system that fight against viruses, bacteria or any other foreign material which also keeps memory of a encountered pathogen.

To have low immunity while having healthy food means that either something is missing in the diet or the wrong cooking practise.  The absence of particular vitamin or specifically vitamin c might lead to lower the immune system as vitamin c helps generating WBC. Sources of vitamin c are citrus food. Fruits or Bright coloured vegetables are also source of carotenoids such as beta carotenoid helps triggering immune system. If one feels, can consume vitamin tables as supplement with no side effects. Importantly freshly cooked food is another stipulation of keeping powerful immune system as stale food is microbial food in which immune system has to fight with it unnecessary microbes . Cooking practices is also important. As time of boiling of fruits and vegetables. Excessive boiling degrades all the necessary ingredients in it. Even food kept for long duration in refrigerator makes the food less nutrient. Basics such as washing after chopping should be avoided. And should practice healthy cooking methods.

To have low immunity while having healthy diet is a bit of concern if person falls ill frequently. Might have some autoimmune disease by birth or might need to have excessive immunity booster, which needs expert supervision like immunologist, specifically consulting a doctor for a disease free healthy life.