The term immunonutrition usually refers to a
special diet for seriously ill patients, designed to support
their recovery and to prevent metabolic and inflammatory
complications. It is thought to work by balancing
immune system functions. The extended meaning of
the term immunonutrition is a diet based on the knowledge of principles of the immune system and its functions,
intended to help both its proper development in
childhood and its maintenance up to elderly. Targets
of immunonutritional programs are age-based or disease-
based groups of people, according to the WHO
Econutrition reflects the nutritional needs of tissues lining the digestive tract and of a gastrointestinal
microflora. Econutrition is going to be replaced by
ecoimmunonutrition, a diet enriched with supplements
supporting the immune system and the gastrointestinal
microecological equilibrium. Ecoimmunonutrition
is the aim of the WHO program "Nutrition for the 21st
Century," designed to enhance the health state of populations
by promoting the improved diet. Basic terms used
are listed in Table 1.
Over the last century, the life span in industrial
countries prolongated due to many improvements, e.g.
introduction of hygiene precautions, more effective
treatment including an optimalization of patient care,
discovery of new drugs such as chemotherapeutics and
antibiotics, vaccination and consequently erradication
of some lethal diseases. Apart from these causes, there
is another more fundamental cause, and that is: better
On the other hand, the resistance to contagious
diseases, especially those caused by air-borne pathogens,
decreased within the last 30 – 50 years . This may be
attributed to the modern life style which includes social
stress and reduced physical activity, intake of industrialy
processed food, chemicals used as preservatives, nutritional
additives, and, last but not least, the over-usage of
Changes in feeding habits during human evolution
and the rigidity of a genome
For about 100,000 generations of hunter-gatherers,
followed by 500 generations living on agriculture,
our ancestors kept the same feeding habits. Moreover,
they were exposed to environmental and climatic conditions
heavily different from the recent ones, that are
artificially transformed and often damaged by industrial
abiotic immision load. Since the advent of a modern industrial
society, no more than 10 generations could be
counted. The last period is even shorter: People take
modern nutrients, processed by the contemporary hightechnology
food industry, for just about 2 generations –
lets say 50 years.
Eaton and Konner say that human genes, controlling
metabolisms of food components, could hardly reflect recent changes in life style, particularly in nutrition
habits . Genes, adapted through millennia under the
selective pressure, cannot change within decades. Therefore,
the gene pool of people nowadays is in fact almost
the same as the one of our forefathers, adjusted to the
conditions they lived in, and to the food they consume.
One of the most dramatic changes started in the
18th century, when refined sugar became part of daily
nutrition. Since then, the average consumption of refined
sugar has steadily increased, up to approximately 45 kg
(55 kg in the USA) per person and a year nowadays .
This elevation represents an amount of energy equivalent
to three marathon races weekly year around.
Besides the elevation of the energy intake, there
are enormous changes in the composition of the diet.
Fat consumption has risen from 20% of energy intake in
1950 up to 50% in recent years. Simultaneously, the consumption
of food of plant origin has dropped to one half.
The diet of our ancestors contained 5-10 times as much
fiber, n-3 fatty acids, antioxidants, vitamins and other
nutritionally valuable substances, whereas there was 3
times as much proteins as in modern food. On the other
hand, the contemporary diet contains 4 times as much
saturated fat and twice as much monosaturated fat as our
ancestors used to consume .
Finally, the general fat intake rose due to the boom
of n-6 fatty acids, including precursors of prostaglandins
and leukotriens, whereas the fraction of n-3 fatty acids
dropped.The changed n-6: n-3 ratio results in diseases
based on atherosclerosis, e.g. myocardial infarction or
stroke [5,6]. Changes in proportion of dietary fatty acids
in relation to mortality on cardiovascular and cerebrovascular
diseases are demonstrated in Table 2.
Although a number of people think that the vegetarian
manner of feeding is healthier than meat-based,
the general problem is much more complicated. Recently,
the long-term influence of the different feeding habits
on morbidity was exemplified on two African tribes,
pastoralists-hunters and farmers (Table 3). Apart from
the composition of the nutrition, the absolute volumes of
its parts are also important. Proteins and fibers are especially
essential components of nutrition.
The gastrointestinal tract is the second largest internal
surface of the human body, covering a total area of 300 - 400
m2. It represents the place where nutrients are absorbed and
utilized by both the body and by GIT microflora, whereas potentially
dangerous components of the food, such as toxins
and pathogens, are eliminated together with dead cells. The
turnover of mucosal cells is roughly 8.1010 of cells in every 3 - 4
days. This material, approximately 0.33 kg daily, is degraded by
microbes and reutilized.
The GIT microflora is a balanced array of bacterial species.
The intestine harbors 10 times the amount of bacteria as
is the body contents of cells (Table 4) [8,9]. The microflora is
metabolically and digestive active, produces a lot of substances
(to name at least one of them, the vitamin K produced by intestinal
bacteria) and forms the microenvironment of the GIT,
inhibiting the propagation of pathogens and supporting the
regeneration of the intestinal epithelium.
Connection to the immune system
Besides the GIT microflora, the microbial contamination
of the food and its antigen load is one of the strongest cues
to the immune system. Antigens that escaped digestion stimulate
a defense response in the intestinal walls. Therefore, the
GIT-associated lymphoid tissue (GALT) developed in a highly
effective immune tissue forming the largest immune organ of
an endothermic vertebrate body. In humans, about 80% of the
total immunoglobulin producing cells of the body are located
in lamina propria of the GIT .
Nutritional antigen stimulation is crucial for the postnatal
development of the immune system, however, childhood
is also a time when inadequate reactions could be easily settled,
e.g. overshoot activity such as allergies. In adults, the immunomodulative
effect of nutrition is aimed more on antitumor
immunity. All things considered, GALT is a strategically
very important tissue throughout all human life.
In the past, paleolithic food was heavily contaminated
and naturally fermented by microbes. Our ancestors ingested
a million times moremicroorganims beneficial for health as
people living today [11,12]. Over the paleolithic transition
from vegetarian to omnivorous feeding habit, the GIT microflora
changed. Furthermore, nowadays it is strongly inhibited
by chemicals present in the food and by antibiotics.
In addition to their suppressive effect on GIT microflora,
these substances also suppress the immune system and
some of them are even toxic. Trying to avoid preservatives
and artificial flavorings when buying goods is not up to the
mark, and the majority of people do not have such a choice.
Therefore,more pressure should be put on the food industry
to decrease the usage of chemical additives. A complementary
task is to enrich food with essential compounds beneficial for
Fortification of nutrition and nutritional supplements
Fortification of nutrition is an addition of essential nutrients
to the food that contains them naturally, but originally
in smaller amounts. For example, the concentration of vitamin
E has been leveled up in cooking oil. To supplement the food,
means to add the micronutrients such as vitamins in pharmaceutical
preparations, usually in situations of augmented needs
that could not be satisfied by a common food. Nutritional additives
and supplements support the immune system and protect
it from impairment caused by chemicals.
For example, fortification of the diet with soluble fibers
promotes a production of mucus in the gastrointestinal tract.
Mucus, covering the luminal walls, supports the regeneration
of enterocytes and represents a barrier to pathogens, inhibiting
their adhesion and penetrance. Moreover, fibers, causing a
volumetric swelling of intestinal content, accelerate its passage
and inhibit the effect of toxins, both by lowering the time of
exposure and by trapping them chemically. Therefore, besides
other beneficial effects, the fibers are one of the most potent
protectors to colorectal cancer. It is important to note, however,
that the subject of fibers and colorectal cancer is still not
fully understood and some doubts remain. Readers seeking
more details should read a comprehensive review . Some
ecoimmunonutrients used in fortification and supplementation
of food, are listed in Table 5.
Furthermore, the combination of ecoimmunonutrients
brings better results than if they are used separately.For example,
soluble fibers taken together with membrane lipids have
excellent gastroprotective effects.
A worldwide rise of bacterial strains resistant to antibiotics
directs the WHO to demand a cutback of drug consumption
and the development of new therapeutic strategies.
Moreover, regarding human life prolongation, patient
care extends intothe elderly population and becomes more and
more expensive. On the other hand, an age connected deterioration
of immune system functions, caused by a physiological
involution of thymus and by a cummulative effect of exposition
to antigens during life, could be partially compensated by
the specially designed diet.
The enhancement of health to the population by ecoimmunonutrition
is cheaper in comparison to pharmaceutical
industry, and fits more to the metabolic demands of human
body. Ecoimmunonutrition respects the feeding habits settled
through ages of human evolution and help us to sustain the
recent change of life conditions, including a different pattern
of contagious pathogens.
Given the proven beneficial effect of nutrition on immunity,
nutrition starts to play an important role in prevention
and therapy not just of metabolic diseases, but also of the contagious
ones, especially in the Third World. In western countries,
the key role of nutrition in therapy of the most widespread
death causing diseases, i.e. metabolically based cardiovascular
and cerebrovascular ones, is already well known.
The study was supported by The Grant Agency of the
Czech Republic (No. 301/02/1232/A) and by Institutional Research
Concept No. AV 0Z5020903.