Three years ago, in May 2001, the World Health Assembly came to the
conclusion that it was safe for the majority of infants to be exclusively
breastfed for the first 6 months of life, and extending the period of exclusive
breastfeeding to that age would also be beneficial. This conclusion was
translated into a recommendation of exclusive breastfeeding for 6 months,
and while complementary feeding of high-quality should be introduced at
that age, breastfeeding should preferentially be continued beyond the second
year of life.
Immune tolerance is an essential mechanism which maintains a state of
unresponsiveness to autoantigens and food while generating protective
immunity against pathogens. This phenomenon was discovered by the fact
that exposure to an antigen before the development of an immune
response specifically abrogates the capacity to respond to that antigen in
later life [1, 2]. Tolerance-inducing strategies have been demonstrated in
animal models of autoimmunity, allergy and transplant graft rejection and
therefore have opened the way for testing such approaches in human
diseases. Immune tolerance can be established by respiratory or oral
exposure to the allergen.
The normal immunological response to food antigens is geared to the
induction of tolerance, that is to say, unresponsiveness in the case of their
further ingestion. Allergic sensitization may be considered as a failure or a
breaking of immunological tolerance. It is becoming clearer and clearer that
the development of oral tolerance is highly dependent on the intestinal microflora;
indeed the intestinal bacteria have the ability to induce the formation of
cytokines of Th1 immunity (particularly of INF) and also IL-10 and IL-12,
which counteract the Th2-dependent allergic sensitization and favor the state
of Th1/Th2 equilibrium that prevails later in life in normal children .
From the weaning period and onwards the intestinal mucosa is exposed
to an increasing number of antigens, e.g. food components and microorganisms.
Of all the antigens that reach the systemic circulation from the
gut lumen, only a minority are potentially harmful to humans and need to
be defended against. The majority of intestinal antigens do not require a
protective immune response, but may even be beneficial for the individual.
Thus, the mucosal immune system must have the capacity to discriminate
between when an appropriate protective immune response to harmful
foreign antigens is required and when a muted or non-response is preferable.
The indigenous microbiota of an infant’s gastrointestinal tract is created
through complicated contact and interaction with the microbiota of the
parents and the infant’s immediate environment. Nature-induced initial
colonization is enhanced by galacto-oligosaccharides in breast milk and the
microbiota of the mother. This process directs the later microbiota succession
and health of the infant throughout the rest of his/her life [1, 2]. Thus,
understanding and positive guidance of the process through dietary means is
an important target when facilitating the mother–infant relationship through
birth, breastfeeding, weaning and the first years of life. This process forms
the platform for healthy gut microbiota throughout the entire life and is
described in figure 1 [3, 4].
Carbohydrates are responsible for 25–50% of daily energy intake. The
carbohydrate composition of the diet changes with age. In breast milk and
standard infant formulas, lactose is the only or predominant carbohydrate;
starches and other sugars follow with the introduction of ‘beikost’. In the
healthy, balanced diet of children and adults starches (and fiber) should
prevail. The small bowel only absorbs monosaccharides, so dietary carbohydrates
have to be hydrolyzed into their constituent monosaccharides
glucose, galactose and fructose.
Over the past half century, the entity known as chronic nonspecific
diarrhea of childhood or toddler’s diarrhea, has followed a path from case
descriptions to disease and finally, within the past 10 years, to a defined
functional disorder. Chronic nonspecific diarrhea of childhood was originally
thought to be part of the ‘celiac syndrome’. As Davidson and Wasserman 
noted in their seminal paper published in the Journal of Pediatrics in
December of 1966, the pioneering pediatric gastroenterologists of the time,
had defined a number of specific disorders within what was then called the
‘celiac syndrome’, including gluten-induced enteropathy, disaccharidase
deficiencies, lympangiectasia and abetalipoproteinemia.
Advances in neonatology over the past 2 decades have resulted in the
survival of very preterm infants. However, the major limiting factor to survival
of such infants is the ability to initiate and maintain adequate nutrition.
Multiple maturational events are necessary for successful enteral nutrition
of the infant: coordination of sucking and swallowing; effective gastric
emptying; forward propagation of small intestinal contents, and finally, colonic
elimination. Since normal gastrointestinal function relies on the integrated
maturation of absorptive, secretory and motor function, a delay in any one of
these processes will result in disturbed gastrointestinal function. Immature
gastrointestinal motility manifested by vomiting, abdominal distention, delay
in stooling and constipation commonly postpone the time of full enteral
feeding in premature infants.
Food allergy occurs in 6–8% of children and 1–2% of adults and is
permanently increasing throughout the world [1, 2]. Most of the adverse
reactions to food are immune-mediated reactions, and food antigens may
cause IgE and non-IgE immune responses. Of the numerous symptoms of food
allergy, at least in the early stages, gastrointestinal disorders, from food
protein-induced enterocolitis to constipation, are of paramount importance
and are often associated with proctitis.
Since the 1970s the importance of dietary fiber for human health has been
acknowledged and investigated. In the 1970s a relation was found for the first
time between constipation, hemorrhoids and fiber-depleted food. The term
dietary fiber is familiar to most people, although many do not fully
understand the nature of dietary fiber and its role in the diet. Dietary fiber is
a normal constituent of healthy food. Both in enteral and oral feeding the
presence of fiber is necessary; not only in the face of problems like
constipation and encopresis but also for a wide range of other disorders in
adults and children such as diabetes mellitus, hypercholesterolemia, high
blood pressure and colon cancer. In this chapter we will review the
nomenclature, physiological properties and fate of fiber in man and its
applications in pediatric gastroenterology .
In this review, the ‘early influences’ considered include genetic, prenatal,
early postnatal and childhood influences on perception and taste preferences.
‘Taste’ is used in its broad sense, including taste, flavor, and texture.
‘Preferences’ include responses to tastes and flavors, as well as to foods and
Despite the widespread epidemic of overweight and obesity, little attention
has been given until recently to the potential of ‘junk foods’ in its causation.
This essay discusses the role of ‘junk food’ in nutrition-related disorders and
some associated factors that affect this problem. It also considers whether
‘junk foods’ are intrinsically unhealthy, whether their pattern of consumption
is contributory, and whether the term ‘junk eating’ is useful.
An epidemic of obesity is occurring in the US and many other developed
countries, and appears to be responsible for an associated increase in the
prevalence of type-2 diabetes, dyslipidemia, and hypertension. Alarmingly,
this trend for increasing adiposity and its comorbidities is not limited to
adults, but is also threatening children at younger and younger ages. Over
the last three decades, the prevalence of overweight among children age
2–19 years has nearly doubled in the US .
Type-1 diabetes is an autoimmune disease which attacks insulin-producing
ß cells in the pancreas. This autoimmune process is characterized by the
appearance of circulating autoantibodies against ß-cell antigens, such as
insulin, glutamate decarboxylase (GAD) and tyrosine phosphatase. The
infants of mothers with type-1 diabetes do not have autoimmune diabetes
despite the transfer of IgG antibodies, including autoantibodies to ß cells, to
the child via the placenta.
Much is known about the short-term effects of complementary feeding
(CF), especially how an optimal diet can prevent poor growth, malnutrition
and nutrient deficiencies. The CF period has always been identified as a period
during which the infant has a high risk of developing stunting, protein-energy
malnutrition and specific nutrient deficiencies such as iron-deficiency anemia
and rickets. Furthermore, during this period, the risk of infectious diseases
increases dramatically and the mortality from infectious diseases during this
age is closely associated with the nutritional status.
There is relatively little systematic evidence on which to base any informed
advice about the introduction of foods other than breast milk or breast milk
substitutes. Arguably once solids have become the major component of a
young child’s diet there is even less evidence about optimum feeding .
Typically diversification of an infant’s diet has been very much influenced by
parental belief and cultural practice.
In the post-war period in the Western world, consumption of food has
changed from a daily activity to fill the stomach to a social event. Daily meals
play an important part in family life. Diners are used to tie friendships,
relations, to create a suitable climate for business deals and to celebrate. But
at the same time concern about food as a factor that will influence health and
disease has been growing rapidly.