Diet Planning in Disease

A diet for a patient  suffering from a specific disease is'  called a therapeutic diet. Therapeutic diets are adaptations of the normal or  regular diet. 

At this point you  may  wonder-why  does the diet have to change in certain disease conditions? What types of changes are  frequently made? And finally, do we need to make dietary modifications only in the case of persons suffering from a disease or also for those who are likely to suffer from a disease (i.e. individuals who are at risk)?

You just need  wait a little while for the answers to these crucial questions. To arrange the information Systematically, we will discuss the issue with respect to: 

• How disease affects nutritiond requirements 
• Influence of disease on food intake and dietary patterns 
• Types of dietary modifications 

How Disease Affects  Nutritional  Requirements 

Several diseases bring  about changes in the body's need for nutrients. Why? The reason is usually a change in metabolic or physiological processes as well as accompanying changes in  the structure and/or function of specific organs and tissues. 

A few examples will  help to clarify these aspects. 

Example A: Gopi is suffering from nephritis. (Nephritis is an inflammatory condition of the kidneys i.e.  the kidney cells or nephrons). Her kidney  function is affected and she is unable to excrete electrolytes such as sodium and chloride resulting in their accumulation in the body. 

Example B: Kartik completed his 45th birthday last week. He has been suffering from diabetes for five years now.  Due to lack of insulin (or lack of functional insulin) his body is unable to utilize  carbohydrates efficiently. 

Example C: Raju is suffering from typhoid. He is extremely weak and  has lost a lot of weight. High fever continues to trouble him.

Can you predict which nutrient requirements will be influenced in  each case? 

In  nephritis the inability of the kidneys to function effectively result in accumulation of water, electrolytes, urea and other waste products in blood and other tissues. So in Gopi's case, intake of  sodium and protein has to be resuicted. This is because breakdown of protein results in production of urea which must be excreted. Carbohydrates are emphasized. Kartik's diet, on the other hand, should not include carbohydrates such as sugar but complex carbohydrates (such as fibre and starch) need to be emphasized. Fat usually is restricted and  should be of the unsaturated type. 

Raju  has  high fever. Fever pushes  up the metabolic rate. If the metabolic rate increases, energy needs will also increase. In other words, Raju would need a diet which supplies more energy. He is also losing weight because of loss of tissue. How is this to be replaced? Obviously by giving more protein. 

We have used these examples to indicate just  some of the changes in nutrient needs caused by these diseases. These are not  the  only dietary modifications required in diseases such as diabetes, typhoid and nephritis. Several others such as modification in texture and inclusion/exclusion of specific foods are required. 

In  general we can say that diseases that cause the  loss  of a particular nutrient would increase the need for that nutrient. On the other hand, if a disease results in accumulation of a particular nutrient. the intake of that nutrient is usually restricted or it may be given in  a different form. 

One point that we must emphasize here is the fact that  sometimes the disease process does not alter nuuient needs and yet we may need to make dietary modifications. We will take a closer look at this aspect in the subsequent discussion. 

Remember, however, that requirements depend on 

• nutritional status (i.e. condition of health as influenced by intake of nutrients) 
• modification in activity 
• increased or decreased metabolic  demands made by the illness and 
• efficiency of digestive, absorptive and excretory mechanisms 

Influence of Disease on Fwd Intake and Dietary Pattern 

The disease process very often influences both  the quality and quantity of the diet. Further changes in meal frequency and other aspects of the dietary pattern may be required. 

Disease may cause the patient to: 

• lose appetite and therefore eat less 
• feel more hungry  and therefore eat more .
• have problems with digestion or absorption of food or specific nutrients leading to changes in the types of foods which can be tolerated as also frequency of feeding. 

Let us elaborate a little more on how illness modifies food acceptance. Some diseases result in marked anorexia or lack of appetite.'Conditions associated with jaundice are notable examples. On the other hand, hormonal imbalances can make a person eat excessively resulting in overweight and obesity. Also specific foods may be poorly tolerated and lead to distention or flatulence (gas production). Others may irritate the gastrointestiond tract. A good example is the irritating effect of  high fibre foods in conditions where the gastrointestinal tract is inflamed. 

Now let us study the major therapeutic modifications of  the  normal diet. What are the types of quantitative and qualitative changes generally made? Read on to find out. 

Types of Dietary Modifications 

Our previous discussion has highlighted the fact that  dietary  modifications need to be made in the case of several diseases. We must remember that therapeutic diets are always modified versions of normal diets.

What are the types of dietary modifications that become necessary? Take a quick look at this checklist. 

• Change in consistency (e.g. fluid and soft diets) 
• Increase or decrease in energy content or contribution (e.g. low and high caloric diets) 
• Inclusion of more or less amounts of one or more nutrients or other substances (e.g. low purine diet in gout or high vitamin A diet in deficiency of Vitamin A) 
• Increase or decrease in fibre content 
• Elimination of spices and condiments (e.g. bland diets) 
• Inclusion or exclusion (i.e. giving or not  giving) of specific foods e.g. diets in allergic conditions 
• Change in intervals of feeding i.e. meal frequency 

You will find examples of all these types of modifications in the later units of  this block.  At present we  will spend some time explaining the first modification in this checklist-change in consistency. 

As you see, normal diets can be modified to fluid or soft diets. Fluid diets are of two types-full  fluid and clear fluid. Fluid diets are used in febrile states, postoperative or whenever the patient is unable to tolerate solid foods. 

A clear fluid diet is prescribed when intake of nutrients must be restricted and when an acute illness or surgery results in a marked intolerance for  food as may be evident by nausea, vomiting, anorexia, distention and diarrhoea. Obviously a clear fluid diet aims at replacement of fluids and supplies very little of n.  mien&. This is the reason why it cannot be continued for long. 

A full fluid diet, on the other hand, is prescribed whenever a patient is acutely ill or is unable to chew or swallow solid food. A full fluid diet includes all foods liquid at room temperature and at body temperature. Such a diet can be continued for relatively long periods though iron supplementation becomes necessary. 

Let us now talk about the soft and mechanical dental soft diets. The term "soft" refers to the fact that foods included in this type oi diet are soft in consistency, easy to chew and made of simple, easily digestible food. It also contains no harsh fibre or strong flavour. A soft diet may be used in acute infections, some gastrointestinal disturbances and following surgery. It is usually recommended when a patient has to give up a full fluid diet but is yet  not able to tolerate a normal diet. In this sense it is a dietary step between  the full fluid and normal diet. Unlike the fluid diets, properly planned soft diets are nutritionally adequate. 

Mechanical or dental soft diets are normal diets modified to help those who have dental problems e.g. dearly persons. No food is restricted unlike in the case of the customary soft diet we have just  described. Removing the skin and seeds, cutting, or chopping into fine pieces are processes usually employed. 

A word about methods of feeding would be helpful here. Feeding through the oral route (i.e. food by mouth) is the  method of choice. It is used for persons who can eat, digest and absorb sufficient food to meet their nutrient needs. However, patients suffering from severe illness cannot consume foods even in the form of fluids orally. For  such patients special feeding methods have been  devised.  Under our conditions, such special feeding methods can only be administered in hospitals or clinics. These feeding methods are:

• Intravenous feeding 
• Tube feeding (nasogastric feeding) 
• Gastrostomy (tube feeding directly into the stomach) 
• Jejunostomy (tube feeding directly into the jejunum) 

You would have noticed that  gastronomy and jejunostomy are also forms of tube feeding when a tube is inserted into the stomach and jejunum respectively by an operation. Highlight 1 gives an idea about the conditions where intravenous and tube feeding become necessary and the objective of these special feeding methods. You can  read it if  you are interested. In routine work you may not find the need  to use these feeding methods.