Nutrition is about getting sufficient nutrients for the daily living in a healthy manner. It includes the macro nutrient such as the carbohydrate, protein and fat; micro-nutrient such as vitamins and minerals; trace elements such as cobalt, manganese, selenium….
The person who undergoes for specialized training is called the nutritionist. Many of them are certified by the professional body.
As stated above, the normal requirement for a healthy living is considered the standard reference data level whereby an individual does not fall sick. The level is much lower when compared to the level required for anti aging and other specific requirement.
For the diabetes, the carbohydrate level especially for the simple carbohydrate or the sugar must be greatly restricted to prevent sugar and thus insulin surges. Such a repeated surges will exhaust the Beta cell of the Islet of Langerhans of the pancreas. Its exhaustion will further worsen the sugar level control.
For this special category of patient, normally they require restricted amount of salt or sodium chloride intake. excess intake causes water retention which leads to higher blood pressure.
For the purpose of anti aging, most of the antioxidant level need to be increased so that any free radical that is produced in the cell during the metabolism of the sugar, ie the breakdown of glucose into water, carbon dioxide and energy unit ATP inside the mitochondria, will be efficiently removed. Most of the minerals, vitamins, enzyme and co-enzymes function as antioxidant.
It is usually not possible for the body to get so much of the antioxidant from the normal daily diet. Hence, one has to rsort to take supplement in order to saturate the cell with the antioxidant.
For the body builder, he needs lot of protein unit in the form of amino acid which can be readily absorbed and to be taken to the muscle cell, the myocyte to build up more myofibril so as to increase the muscle bulk.
For the cancer patient, the cell is best kept in an alkaline medium. Many postulate to decrease the animal protein intake. Furthermore, increased intake of antioxidant is supposed to help improve the cancer patient or perhaps even reverse the early stages of abnormal cell. this is with the knowledge that most of cancers are caused by the free radical attack and subsequent cell damage caused by it.
For the kidney failure patient, the excretion of various slat minerals such as the sodium and potassium can not takes place and needs to be removed through the dialysis. hence, it is only logical that such patient decrease the intake of nutrition or food/diet rich in such minerals.