Introduction to Human Nutrition

Food and Nutrition-Related Diseases 355

of the approximately 11 million deaths each year of
children aged under 5 years in the developing world
are associated with malnutrition. In addition to the
undernutrition related to poverty, hunger, and food
insecurity, leading to stunted physical and mental
development, specifi c nutrient defi ciencies are causes
of specifi c diseases (as discussed in Chapters 4, 5, 8,
and 9 of this textbook). The major nutrient defi ciency
diseases prevalent in developing countries are briefl y
summarized in Box 15.2, to illustrate the scope of the
problem and to identify the nutrition challenges in
the developing world for the twenty-fi rst century.

Nutrition-related infectious disease in
developing countries

Nutrition is a major determinant of the human body’s
defense against infectious diseases. Optimal nutrition
is necessary for the integrity of the physical barriers
(skin, epithelium) against pathogens. Specifi c nutri-
ents furthermore play important roles in defi ning
acquired immune function (both humoral and cell-
mediated responses) and to infl uence, modulate, or
mediate infl ammatory processes, the virulence of the
infectious agent, and the response of cells and tissues
to hypoxic and toxic damage.
The immune system and the infl uence of malnutri-
tion on its functions are discussed in detail in the
clinical nutrition textbook of the series. Given the
high prevalence of malnutrition (undernutrition) in
developing countries, it is not surprising that infec-
tious diseases are still dominating mortality statistics
in these countries. In children under 5 years of age
these are diarrhea and common childhood illnesses
in which malnutrition could lead to premature

childhood deaths. In some developing countries,

children die of AIDS-related diseases. HIV/AIDS is an

infectious disease that has pandemic proportions in

developing countries. It will be discussed in more

detail here to illustrate the complex role of nutrition

in this tragic situation.

15.4 HIV/AIDS

Introduction

Infection with HIV and the consequent development

of AIDS is a global pandemic already responsible for

more than half of total deaths in some developing

countries. It is estimated that since the early 1980s

when the syndrome was described and the virus iden-

tifi ed, this infectious disease has already killed more

than 25 million people, including at least half a million

children. A third of these deaths occurred in sub-

Saharan Africa, where more than half of the 33.4–46

million people currently infected with HIV live. The

pandemic has a devastating and tragic social, eco-

nomic and demographic impact on previous devel-

opment and health gains in developing countries. It

affects mostly young, sexually active adults in their

reproductive years as well as babies born from infected

mothers. To understand the nutritional challenges of

HIV/AIDS it is necessary to understand how the virus

is transmitted and to follow the clinical course of the

infection. The virus characteristics, its binding to cell

surface receptors, its entry into cells of the immune

system, its replication and transcription, as well as its

genetic variability, and different classes of the virus

have been intensively researched and described,

Box 15.2 Nutrient defi ciency diseases in developing countries: prevalence (scope)

Nutrient Consequence: disease Estimated: 1995–2006

Iron Anemia; poor brain development in infancy Maternal anemia pandemic: more than 80% in some

countries; globally, more than 2000 million people

Protein, energy Kwashiorkor, marasmus marasmic kwashiorkor, wasting Millions of children are at risk

Vitamin A Blindness; increased mortality from infectious diseases

(children under 5 years especially vulnerable)

140–250 million children suffer from subclinical defi ciency

Iodine Goiter, cretinism (infants) with severe brain damage and

mental retardation

In 1999, 700 million people in developing countries;

remarkable progress made with universal salt iodization

Zinc Its role in stunting and life-threatening childhood illnesses

is only now becoming clear

Thought to be common in children and during pregnancy