Malnutrition-Infection+Complex

toc = Malnutrition-Infection Complex =

Definition
The malnutrition-infection complex refers to the synergistic relationship between malnutrition and infectious disease, during which malnutrition inhibits immune response, and infectious disease can exacerbate malnutrition. The relation is synergistic because not only does undernutrition increase the severity and duration of incidences of infection, but frequent infectious illness can exacerbate undernutrition and micronutrient deficiency by causing anorexia and malabsorption of nutrients from the foods a sick person does consume.

The interaction between malnutrition and infectious disease is cyclic and synergistic. Though the relationship is not necessarily as simple as depicted here (figure to the right) and there is no true beginning of the cycle, it is useful to conceptualize the interaction by tracing the causal pathways.

1. __Inadequate dietary intake__: This can mean both macronutrients (fat, protein, carbohydrates) and micronutrients (vitamins and minerals). Though insufficient macronutrient intake has serious implications for health and well-being, micronutrients also play a large role in immune function (for example, vitamin A--see case study below). Note that this also means that people can be overnourished (excess calories) but still have inadequate dietary intakes (insufficient micronutrients).

2. __Impact on immune function__: Insufficient macronutrient intake can result in growth stunting (in children) as well as weight loss. Micronutrients such as vitamin A, zinc and a large number of others are essential to a number of immune responses, and deficiencies can lead to suppressed immunity, which in turn increases risk of aquiring infections. In addition, inadequate dietary intake can also weaken immune response through changes in mucus membranes of the body; mucosal linings are an essential part of our defense against infection and damage increases susceptibility to infection.

3. __Infection__: Once immune function is lowered, infectious disease such as tuberculosis or HIV can result (see case study below). Malnutrition not only affects the incidence (or occurence) of infectious disease; it can also increase the severity of the illness, and the length of time they are experienced.

4. __Impact on Nutritional Status__: While sick, people often experience a loss of appetite, perhaps due to nausea, which results in a sort of voluntary reduction in dietary intake. Through vomiting or diarrhea, people can also experience nutrient loss even if enough macro- and micro-nutrients are taken in (malabsorption). In addition, some infectious diseases can also result in altered metabolism, such as increased caloric needs for people living with HIV.

History
The malnutrition-infection complex has been called the most widespread public health problem in underprivileged populations. The links between nutritional status and infectious disease have been recognized since early in the 20th century, though the understanding of the mechanisms for this relationship continue to emerge. In 1928, as a result of studies with animal models to determine the impact of micronutrient deficiencies, vitamin A was called the ‘anti-infective vitamin’ because it has profound effects on the survival of those animals.

The concept was more fully explored forty years later by Scrimshaw and colleagues in a series of papers in the late fifties and sixties. In 1959, Scrimshaw, Taylor and Gordon produced a review paper that documented the "extensive and cyclical interactions between malnutrition and infection", arguing that malnutrition resulted in increased susceptibility to infection, and that infection caused deterioration of nutritional status, ushering in a cycle of malnutrition–infection that, if untreated, would lead to death. Several years later, the same authors conducted an extensive review of the laboratory, clinical and epidemiological aspects of the nutrition/infection relationship, which they called the ‘nutritionally acquired immunodeficiency syndrome’. Chandra (1997) later wrote about the ‘nutrition–infection complex’, where he described the process of how malnutrition compromises the immune system at the cellular level.

In the 1970s and up to the present, research has increasingly sought to understand the biological mechanisms by which malnutrition leads to inhibited immune response. As technology and methods have evolved, scholars have been able to identify various bodily structures and processes that may each contribute to reduced immune response. For example, mucosal linings play a role in immune function; they act not only act as an essential part of our defense against infection, but are also linked to the absorption of nutrients in the bowel. In one study, it was determined that when we are exposed to infectious disease, the villi in our intestines are damaged and in turn become less permeable; food cannot be properly absorbed which can lead to nutrient and energy deficiencies. These deficiencies can result in trade-offs; when intake is insufficient (or poorly utilized) those nutrients are funneled towards maintenance of the body and away from growth, which can lead to growth stunting.

Today, the nutrition-infection complex has been described as an example of a syndemic. Syndemic, a term coined by Merrill Singer in the 1990s, refers to the occurrence of one or more epidemics (such as high rates of infectious disease) or other societal problems (such as malnutrition, poverty or violence) that work together to create a greater negative impact on health than the epidemics would produce alone

//**HIV and Food Insecurity**//
When individuals experience inadequate access to food, it compromises their immune function, making them more susceptible to infectious diseases such as HIV ; further, it can serve to hasten the progression of HIV disease for those already HIV-positive. In turn, like other infectious diseases, HIV has been shown to have detrimental effects on nutritional status through reduced absorption of nutrients in the intestinal tract and insufficient food intake.

In this article, Kalofonos discusses the paradox of treating people for an infectious disease like HIV while essentially ignoring other issues like malnutrition and food insecurity. As the author notes, though "hunger is the principal complaint of people on antiretroviral (ARV) treatment" (Kalofonos 2010:363), it is a hunger that is magnified by ARV treatment and demonstrates more than an empty belly. The following quotes, according to the author, were typical of conversations among people with HIV:

<span style="background-color: #e6ffe6; border-bottom-color: #dcdcdc; border-bottom-style: solid; border-bottom-width: 1px; border-left-color: #dcdcdc; border-left-style: solid; border-left-width: 1px; border-right-color: #dcdcdc; border-right-style: solid; border-right-width: 1px; border-top-color: #dcdcdc; border-top-style: solid; border-top-width: 1px; display: block; margin-bottom: 10px; margin-left: 30px; margin-right: auto; margin-top: 10px; padding-bottom: 10px; padding-left: 10px; padding-right: 10px; padding-top: 10px; width: 80%;">“Do you know what it is for your organism to be asking for food? It wakes me in the middle of the night, and I have to eat!” “This treatment really causes hunger!” “Don’t you know why? The body needs food in order to recover. The organism demands it!” “What can I do? I have nothing to eat. All I eat is ARVs!” (Kalofonos 2010:363) Kalofonos draws in Vihn-Kim Nguyen's concept of “therapeutic citizenship”--that is, a biopolitical citizenship based on being HIV positive (biological), coupled with political claims to rights such as access to treatment as ways of integrating being HIV positive into a (new) moral order. Kalofonos notes that narratives about hunger indicated a sense of injustice and even torture--driven by the fact that ARVs themselves can increase nutritional requirements (citation) in contexts where sufficient access to food is already uncertain. Further, inadequate attention to hunger serves to undermine efforts to treat HIV/AIDS by inadvertently fostering conflict, competition, and suspicion between those who receive food aid tied to ARV treatment and those that do not. The paradox of treatment is that while treatment for biomedical (ARV) treatment increases, overall living conditions worsen while the basic issues like hunger and poverty are ignored. The author notes that this should serve as a reminder that "the technological magic bullet of ARVs alone is an insufficient intervention in the face of the increasing hunger and inequalities"(Kalofonos 2010:375-376).

The HIV epidemic is exacerbated by issues such as poverty, food insecurity, malnutrition, and gender inequality. Himmelgreen and colleagues, in an article published in the African Journal of AIDS Research, argued that some of the large amounts of money funding prevention and treatment of HIV and AIDS should be reallocated to address more basic problems such as malnutrition, tuberculosis, malaria, and enteric and diarrheal disease caused by lack of access to clean water. The authors note that while this recommendation is not universally agreed upon, the reassessment of policy priorities could serve to renew and refocus attention on underlying health and social problems affecting populations suffering from high rates of HIV infection. Some of the other applied recommendations include the use of multidimensional programming--that is, those that integrate prevention, treatment, and programs supporting sustainable development in the areas of agriculture, livestock, public works, or even handicrafts projects to generate cash (Himmelgreen et al. 2009). In addition to HIV-prevention education, nutrition education and counseling as well as food-production support should be provided. However, in contexts where all are suffering from malnutrition and food insecurity, food-production support should not be limited to those that are HIV-positive, as this risks conflict when groups compete for scarce resources.

For more information about the link between HIV and Malnutrition: @http://www.fantaproject.org/downloads/preservice/Mod2-Link%20Nutrition%20and%20HIV.ppt
 * Food and Nutrition Technical Assistance II (FANTA-2) presentation: HIV and Malnutrition**

Also, Hans Rosling and Gapminder present HIV data in new ways: media type="custom" key="9244060" width="378" height="378"
 * __HIV: New facts and stunning data visuals__**

**//Vitamin A and Immune Function//**
While these videos focus on a more recent "discovery" of the effectiveness of vitamin A supplementation at reducing morbidity (illness) and mortality (death), in fact the idea that vitamin A can help improve health is not new. As early as 1928, vitamin A had been referred to as an "anti-infective" agent because of its ability to improve survival. Richard Semba noted that vitamin A was subjected to clinical investigations (at least 30) for the twenty years prior to World War II to examine precisely that question--whether supplementation (usually given as cod liver oil) could reduce the morbidity and mortality of respiratory disease, measles, puerperal sepsis, and other infections. These early trials had mixed results but also did not utilize research techniques such as randomization, masking, sample size and power calculations, and placebo controls--methods discussed briefly in the videos below.

media type="youtube" key="AADuvZMZ0qM" height="307" width="382"
 * The A Factor: A video introduction of Dr. Alfred Sommer, his work, and discovery. [segment]**

Video contains a segment of "The A Factor" (starts 4:14), medal presentation (at 13:52), and a lecture by Dr. Sommer (at 23:28) media type="youtube" key="o7LKtzJfuys" height="312" width="384"
 * University of Michigan Francis Medal presentation to Dr. Alfred Sommer**

Related Terms/Pages

 * Chronic Hunger
 * Food Insecurity
 * Food Security
 * Infectious Diseases
 * Malnutrition
 * Syndemic

Online Resources
media type="custom" key="9254260" width="216" height="216"
 * PBS: Malnutrition, A Silent Epidemic**

"EC/FAO Programme on Linking Information and Decision Making to Improve Food Security”, based at the Food and Agriculture Organization of the United Nations (FAO) and funded by the European Union’s “Food Security Thematic Programme (FSTP)”. Offers free e-learning sessions on various nutrition and food security topics. []
 * Online Learning:**

Discussion Board/Comments
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