We do not need expensive or luxury food like bird nest and Lingzi to strengthen our body. What we actually need is to replenish enzyme supply, which is the fundamental requirement. It brings ultimate goodness on the human body such as maintaining body functions, assisting digestion, repairing tissues and etc.
Enzymes are mainly proteins, that catalyze (i.e., increase the rates of) chemical reactions. Although it is an invisible microorganism, but it able to break down protein, vitamin and mineral. No matter it is a tear, a form of saliva or a drop of blood, there is an exist of enzyme. Almost all processes in a biological cell need enzymes to occur at significant rates. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur on that cell.