Interaction Between Infection and Malnutrition

You have just learnt that children with PEM usually have either diarrhoea or respiratory infection. In fact, children suffering from either PEM or a severe form of vitamin A deficiency most often die due to infections. This is due to the fact that infections and malnutrition increase the severity of each other. 

When two diseases exist in the same person concurrently, the interaction between the two diseases may alter the behavior of the diseases. Suppose, there is a child with PEM who is also suffering from diarrhoea. In such a case, the usual  result is an exaggerated clinical condition or disease. It means that because of the existence of these twp conditions i.e. PEM and diarrhoea, the overall clinical status of the child worsens often resulting  in increased complications or increased duration of the diseases and finally death. In other words, the coexistence of infections and malnutrition in the same child is producing an effect that is beyond the summed effect expected from the two diseases acting alone. This is described as synergism. For example, if a child with moderate PEM also has infections like measles or diarrhoea, the moderate nutritional  disorder such as loss of weight often is precipitated to  manifest as kwashiorkor. Similarly, the severity of the infection process can get increased. Both these put  together can lead to-death and complications in the disease. 

The relationship between malnutrition and infection can be described as a vicious cycle.

Vicious Cycle of Infection and Malnutrition

Malnutrition can increase the risk of infections and infections can, in turn, lead to malnutrition. This interrelationship and the synergistic effect of malnutrition and infections often lead to a high rate of child deaths in poorer communities in India. The cumulative effect of malnutrition and infection produces retardation of physical growth leading to stunting or short stature in children. The effects of stunting are long lasting. As a result, the capacity to do physical work of adults may also reduced. We can, for example, see as to what generally happens to a par rural child starting from birth to adulthood in India. The child at birth weighs much lower than a normal child. Subsequently he/she is solely breast fed for longer periods. The delayed supplementary feeding i.e. delayed introduction of additional food usually triggers slowing in growth. In other words, malnutrition  sets in. In view  of the poor environment and lack of hygiene, the children are constantly exposed to infections like diarrhoea and respiratory  infections. There, is reduction in food intake by the child due to loss of appetite due to these infections.  As a result, there is further slowing down of growth. The cycles of dietary deficit aid infections ultimately may lead to kwashiorkor in a child.

Weight curve of an Infant who developed under nutrition

The story is same in all such children. The ill effects of malnutrition and infection on the health of the child get accumulated year by year and the effects are devastating. Ultimately the child with poor nutrition and health during his childhood enters adulthood as a malnourished adult. They are not only much shorter than their normal counterparts but also have weights lower than healthy  individuals. Consequently their capacity to do physical work is significantly reduced. This, as you know, can hamper the development of the country. 

So far we have studied about interaction of infection and malnutrition. Let us now look at the effect of malnutrition on infection. 

Effect of Malnutrition on Infection :

The following discussion documents, how malnutrition favors infection. 

a)Reduction in antibody production :  A normal child who is adequately fed and well nourished is at a lower risk of infection. More importantly,  the child can fight the infections better.  Why? This is due to the ability of the healthy and well nourished child to produce disease-fighting substances called antibodies. You may recall reading about antibodies (as proteins in the human body which help fight infections) . In view of this, normal children recover from infections faster, as a result, the ill effects of the infections are negligible in the child. However, in the case of severe PEM, or vitamin A deficiency there is a reduction in antibody production. In other words, in malnutrition the disease fighting capability of an individual is considerably lowered, thereby, making the child more prone to infections. 

b)Effect on the integrity of skin and mucous membrane:  In normal and well fed individuals, the skin, mucous membranes and other tissues prevent the entry of infectious agents. These tissues act & barriers to infection and prevent the infectious agents from entering the human body. In PEM, such a protective mechanism will be absent. The secretion of mucous may be reduced, mucous membrane becomes readily permeable and a favorable environment for the growth of the infectious agents will be created. Consequently, a malnourished child can catch infections easily. 

You may know that human intestines harbour microorganisms even when an individual is healthy and normal. In healthy normal individuals these  organisms do not produce any disease. But, in PEM, the microorganisms may produce diarrhoea. 

c) PEM and worm infestation :  You would have learnt that during digestion food that is ingested, is pushed down the digestive tract with the help of certain type of movements. Always remember that proper mobility (movement) of the digestive tract is important for normal digestion. In individuals with malnutrition this mobility of the digestive'tract  may slow down, because of which, there is more time available for the worms to multiply. As a result,  worm infections like round worm disease may become severe. In addition, the duration and severity of gastrointestinal infections may be more in malnourished individuals. 

You have so far learnt how malnutrition  can lead to or aggravate infections. We have also discussed that the relationship between malnutrition and infection is in the form of a vicious cycle. Now  in the next section we will.learn how infections can influence the nutritional  status.

Effect of Infection on Nutritional Status 

Nutritional status, you how, is the condition of health of an individual as influenced by  the utilization of nutrients. How does infection influence the utilization of nutrients? What effect does it have on the nutrient intake? These are the aspects discussed in this subsection.  We begin with the effect of infection on food intake. 

a) Reduced food intake :  When a child is suffering from infections like diarrhoea or respiratory  infection, one of the first  changes noted by the mother is loss of appetite. Quite often, the child may not like or tolerate food. As a result of this, the child consumes less food or there is reduced dietary intake. Furthermore, the antibiotics used in the treatment of infection may also reduce the appetite in the child leading to reduced food intakes. 

One of the common practices in our country when a child is suffering from infection or a disease is restriction or withholding of food. For example, in the case of diarrhoea solid foods and milk are restricted and in their place starchy gruels are given. Such a practice is deleterious to the child particularly, when the child is already on border line of malnutrition due to dietary deficiency over a period of time. It would mean that there is further reduction in the intake of nutrients, thereby, leading to poor nutritional status. 

b) Effect on absorption of nutrients :  We studied about the process of digestion . We learnt that during digestion various nutrients are absorbed and they enter the blood stream. Any decrease in the absorption of nutrients can lead to the deficiency of the particular nutrient. It is observed that in the case of infections like diarrhoea, measles and respiratory disease there is reduction in the absorption of nutrients. Only 60-70 percent of the nutrients consumed are available to the body. Even worm diseases like round worm disease usually reduce the absorption of nutrients, thus, leading to ill-health. 

c) Loss of protein :  In some of the infections and fevers, few nutrients, particularly proteins are excreted i.e. lost from the body. This naturally increases the requirement of protein during infections and fevers. 

The overall effect of the infections on the dietary intake of the child is substantial. In a poor rural child, who is already on a deficient diet, the effect of the infections can, therefore, be devastating. It is not, therefore, surprising that in our country, kwashiorkor or marasmus are commonly precipitated  by diarrhoea1 disease, measles and whooping cough in children  whose nutritional status is already poor. 

Let us now study the effect of few specific infections namely diarrhoea and measles on the nutritional status. 

a) Measles and Nutritional Status 

Measles is a viral disease which generally attacks children around one year of age. Measles leaves the child completely weak and emaciated. The child suffers not only from the effects of measles but is exposed to a number of complications which invariably follow an attack of measles. The common complications of measles are (a) diarrhoea and (b) severe respiratory disease. These complications by themselves lead to loss of weight in children. In the case of poorly nourished children the body weight does not return to the original weight the child had before the disease, for a very long time. Measles by itself decreases the disease-fighting ability of a child thus making the child easily susceptible to infections. Furthermore, one of the common practices observed among rural mothers in India is that they withhold diet to the child during measles. To add to this is the fact that absorption of nutrients is also considerably reduced in measles. Measles also can cause blindness by increasing vitamin A deficiency in a child living on inadequate diet. In other words, the risk of nutritional blindness in children with measles is much more than those without measles. So these factors together lead to poor nutritional status. 

b) Diarrhoea and Nutritional Status 

Diarrhoea is a symptom characterized by the sudden onset of frequent stools of watery  consistency, abdominal pain, cramping, weakness and sometimes fever and vomiting. You  know that diarrhoea is very common among children. As in the case of any other illness, diarrhoea  can reduce the appetite of the child considerably. As a result, the child does not eat properly. 

In addition,  the mother may think that the diet of the child with diarrhoea should be restricted with the belief that the number of loose motions may increase if the child is fed. So what are'the consequences? Obviously, there is reduced food intake; which ultimately  leads to poor health of the child. 

Further you are aware that in diarrhoea fluids are lost from the body. Along with the fluids important minerals such as sodium and potassium (usually known as electrolytes) are also lost. You would  recall reading about these losses. This loss of fluids and electrolytes  during diarrhoea leads to dehydration. It is this dehydration which is responsible for high death rate in the children with diarrhoea. In the villages and slum areas in the cities, the children generally suffer from frequent and repeated attacks of diarrhoea.  Repeated attacks of diarrhoea lead to significant weight loss in children. If we examine the nutritional status of severe cases of diarrhoea we notice that the body weight of these children is much lower than the normal children. Similarly, in the case of kwashiorkor and marasmus the incidence of diarrhoea is higher.