What is Therapeutic Diets and Modifications of diets?
Diet therapy deals with modifications necessary in the diet in the treatment of different diseases. This is necessary as the metabolism of the individual changes in different diseases with respect to one or more nutrients. Some examples are: inefficient utilization of carbohydrates in diabetes mellitus, inability of the kidney to excrete sodium chloride in nephritis, increased production and inefficient elimination of uric acid in gout and increase in energy metabolism and in the catabolism of tissue proteins in fever. The simplest modification of diets is in the treatment of allergy where the food or foods responsible for the allergic reactions are eliminated.
Modifications in diets in other diseases may involve changes in different constituents such as:
· Balanced diets omitting condiments and spices.
· Low fiber or high fiber diets.
· High protein or low protein diets.
· High fat or low far diets.
· High carbohydrate or low carbohydrate diets.
· High calorie or low calorie diets.
· Low sodium diets and
· Low purine diets.
In case, the patient cannot consume food orally, then administration of nutrients through parental route or through nasogastric tube is essential to avoid starvation and loss of proteins and other nutrients from the tissues. The types of changes required in the diets in different diseases are briefly discussed below:
- Modifications in carbohydrate content – High carbohydrate diet may be indicated in Addison’s disease, various diseases of the liver and in pre-operative conditions. Hypoglycemia may be present in Addison’s disease, while in the other two conditions, adequate glycogen storage is of considerable value in the therapy of these conditions. Restricted carbohydrate diet is essential in the treatment of diabetes mellitus.
- Modifications in calorie content – Diets with increased calorie value are for the treatment of patients who are markedly underweight and also for patients with increased calorie requirements as in fever, infections, mal-absorption and hyperthyroidism. Low calorie diets are used for the treatment of obesity, cardio-vascular disease, acute uremia and hepatic coma.
- Modifications in protein content – High protein diets with restriction in other nutrients are prescribed in a variety of diseases such as protein calorie malnutrition, cirrhosis of liver, peptic ulcer, nephrosis and celiac diseases. Low protein or complete withdrawal of proteins may be necessary in hepatic coma, acute uremia, etc.
- Modifications in fat content – Moderately high fat diet are used in the treatment of severe under nutrition. Restricted or low fat diet may be necessary in the treatment of steatorrihoea, mal-absorption syndrome and diseases of the liver.
- Modifications in mineral content – High calcium diet is essential in the treatment of rickets and osteomalacia, while a diet restricted in calcium and phosphate is desirable in renal calculi. Sodium restricted diets are essential in the treatment of cardiac failure and hypertension. Restriction in sodium chloride intake is essential in diseases of the kidneys.
- Modifications in vitamin content – Increase in the content of vitamins can be easily achieved by the addition of synthetic vitamins. This is essential as most of the therapeutic diets may be partially lacking in one or more vitamins.
- Modifications in fiber content – Diets rich in fiber are prescribed for the treatment of constipation, while low fiber diets are essential in the treatment of several gastrointestinal disorders such as peptic ulcer, ulcerative colitis, celiac diseases, diarrhea's and dysentery.
- Modifications in other constituents – Diets low in purine content are prescribed in the treatment of gout, while diets low in oxalic acid and purines are prescribed in renal calculi.
- Modifications in diet consistency – The most important are the liquid diets used in oral feeding and nasogastric feeding. The basis of such diets is milk to which soluble carbohydrates such as sucrose, glucose and dextrimaltose and emulsified fats are added to increase their calorific value.