Aging is not an illness, but it does make the body more vulnerable to disease. There are many theories on aging and its auses. Some of the more prominent ones are as follows:DNA/genetic theory. The DNA in our bodies contains agenetic blueprint, which we inherit from our parentsand ancestors. This is a unique code, which determines a number of factors affecting aging. Things that happenduring our lifetime that damage the DNA, such as exposure to pollutants, toxins, radiation, our diet, and manysureother environmental and lifestyle factors, can ffect theability of our body to repair damage. This genetic damage can cause the production of abnormal proteins and sugar-protein complexes, which leads to defective celrepair, loss of cell elasticity, and other symptoms of the aging process.Neuroendocrine theory. The pituitary gland and hypothalamus (a structure in the brain) regulate the release of key hormones to influence cell metabolism, protein synthesis, immune function, and the biochemical functioning of all bodily cells. The theory is that the hypothalamusto regulate all these functions.over time loses its abilit The secretion of hormones gradually decreases overtime, and this deterioration in the regulatory and hormone production process leads to aging. For instance,the decline in the polypeptide hormone insulin-like growth factor 1, or 1GF-1, is linked to a decline in cel activity. IGF-1 is a liver-produced product of humangrowth factor (HGH) that is secreted by the pituitaryBland. Research has shown that IGF-1 increases insulin ensitivity, increases lean body mass, reduces tat, and s bone, muscle, and nerves. One of IGF-1 S greae dts 1s the ability to repair peripheral nerve u has been damaged.