About
the Author
Dr DF Smallbone is Senior Medical
Adviser and Senior Medical Lecturer in Medical Sciences to the College
of Natural Nutrition
In summary:
Mouth
to ileum
mainly involved with digestion
Jejunum
to transverse colon
mainly involved in absorption
Transverse
colon & descending colon
mainly involved in balancing
Rectum
mainly involved in storage
Anus
responsible for ejection
Absorption
is aided by:
Adequate
water intake before and after meals (not during).
Proper
balanced food intake of foods of known origin and content.
Where
deficiencies may be anticipated, adequate supplementation of appropriate materials in a food state (truly chelated) form.
No
megadosing with minerals.
Adequate
fibre intake.
Ensuring
no intake of non-food chemicals,
additives or contaminants.
A proper
balanced fatty acid intake.
Adequate
ancillary digestive processes. Chew well, eat slowly and savour
food (enjoy the smell beforehand this is all part of good
digestive practices).
Maintain
regular healthy bowel activity which requires regular general
exercise/activity be maintained.
Rest
after food for 20-30 minutes to allow energy to be directed to digestion, not rushing around.
No
drinking with meals as this increases the air intake which reduces
digestion and final elimination.
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Although the gastro-intestinal tract is not the
only way that materials have of entering our body, it is the most
usual and direct route for our nutritional requirements to be satisfied.
There are many criteria that have to be satisfied in order for
proper absorption to occur, regularly.
Adequate amounts of nutrients
Unless adequate amounts of the body requirements are
provided, then even if the absorbability is 100%, insufficient will be available
for the body needs. Failure to provide this may result from a variety of causes,
such as:
a) Inadequate food intake.
b) Nutritionally deficient food.
c) Poor food balance resulting in inadequate diet (fad diets, modern
junk food, etc.)
Adequate
enzyme activity
Unless the food is broken down into nutritionally available
units, the absorption will be inadequate. For this to be accomplished, adequate
enzyme activity is necessary throughout the whole of the gastro-intestinal tract from
mouth to descending colon. Any deficiency in correct enzyme production, either
specific enzymes or quality, will result in incomplete digestion and, hence,
absorption.
Proper
functioning bowel flora
We rely upon the symbiosis (of mutual benefit) between
the bacteria and other organisms that normally inhabit our colon and ourselves.
Many materials produced by these bacteria, we have come to expect to be present.
Without their presence in adequate amounts we are in dire peril of not surviving.
Such nutrients as Vitamin K, Vitamin B12, Vitamin D, Biotin and Folic acid are
among those included. These organisms, that are so crucial to our needs, are
as susceptible to antibiotics as are any pathogenic bacteria, and are often far
more fragile. Antibiotics are a common enough material in our diet and as treatments,
in this day and age, that it makes one wonder how many of us have a fully functioning
bowel flora!
Adequate
amounts of water are present
We are creatures of water. So many of our internal patrol
and control mechanisms cease to function with an inadequate water supply. The
intestinal tract is no exception. It is imperative that adequate amounts of water
are available throughout our gastro-intestinal tract. Without a gut surplus,
many biochemical activities cannot be pursued and poor digestion ensues along
with poor absorption.
Minimal
amounts of inorganic minerals are present at any time
Most inorganic mineral salts interfere with each other's
absorption. As there is a very small segment of the ileum for absorption of these
forms of minerals, there is much competition at the available sites. Absorption
of inorganic, or unbound, minerals is through very specific cells that have the
appropriate ligand (bonding material) in the cell to carry that mineral. Several
minerals share the same cell for absorption. For instance, calcium, magnesium,
iron, zinc and molybdenum all share one gastro-intestinal transport cell. Too
much excess of any of these elements will block the absorption of the other minerals
in that group and produce a potential malabsorption state with consequent deficiency.
Therefore, megadosing of these minerals with supplements, or high intake from
any other source, is contra-indicated.
The minerals
are in a true state of chelation, as they occur in nature
True chelation means the mineral is bound, in some form,
in a food matrix or other base material such as protein, lipid, polysaccharide
or combination. This bonding, for true chelation to occur, is happening at the
molecular level. Many so-called "chelates" are not. They are merely
mixes of which a small percentage will bond by proximity, but insufficient to
enhance the absorption rate. True chelated minerals are absorbed through the
channel of their bonded substrate (the protein, lipid or polysaccharide) and,
because of this, have a much greater absorption port and, hence, have improved
absorbability.
Proper,
patent blood supply to the intestinal tract
The blood supply to the gastro-intestinal tract must
be whole and intact to allow proper assimilation of the absorbed materials into
the body. Any damage to, or paucity of, blood supply, from whatever cause, will
limit the effectiveness of absorption.
No "filming" of
intestinal lining is present
There must be a clear route through from the intestinal
lumen to the lining of the gastro-intestinal tract wall for absorption to occur
unhindered. Accretions and thickened mucous accumulates on the gut wall, such
as occur in many disease states and dehydration, will adversely affect absorption.
Proper
presentation of food
Food must be presented in such a way that the enzymes
and other breakdown activities of the gastro-intestinal tract can come to bear
upon it and work. Therefore, food presentation is all-important, from taste and
smell, which stimulates and informs in advance that food is on the way, to not
damaging the food beyond recognition, as can occur in some processing methods
and overcooking
Absence
of large amounts of substances that interfere with absorption
There are many substances in food, naturally sometimes,
that can interfere with the absorption processes. Such a material is phytic acid
or hexaphosphate inositol. This material interferes with zinc and calcium absorption.
This material is present in unrefined flours but not in refined flours. Therefore
it is important to know which foods contain these materials in any quantity that
will affect absorption. Leavening and cooking destroys the phytic acid to some
degree.
Adequate
digestion of food
This is very much linked to enzyme activity although
other factors also play a part. Mastication (chewing) must be adequate for proper
exposure of the food stuffs to enzymes. A reasonable stomach acidity also is
essential for proper digestion, especially of liquids. Proper intestinal agitation
is also necessary.
No
intestinal hurry hence value of fibre
Intestinal hurry can be due to several things. Inflammation
of the gut wall is the commonest invasive disruption. This may also arise from
chemical irritation from incomplete digestion products or residues in food such
as herbicides, pesticides, etc. It may also be some aspect of the food itself
such as alkaloids in some plants, natural plant poisons and toxic breakdown products
of meat and fish. Fibre plays a crucial role in combating the irritation of gut
contents and binds very potentially dangerous materials, preventing contact with
the gut wall.
Intact
villal structure of intestinal wall
Any process that destroys or minimises the villus structure
of the gastro-intestinal cell wall will adversely affect absorption. This may
occur as the result of chronic, persistent irritation or acute degenerative events.
Again, fibre and water are protective. Such diseases as Crohn's Disease and diverticular
disease are common end-results.
Absorption
sites within the intestinal tract
Different materials within our food have different sites
for maximal absorption. There is a whole range of normally acceptable areas for
them to pass through. There is also a range of transport mechanisms that the
body can use. Some of them are active, requiring energy expenditure to perform,
and others are passive, occurring provided there is sufficient material present
in the lumen of the tract to drive the absorption. In general, the following
list is standard for most people.
a Inorganic minerals salts are absorbed in the first 6 inches or so
of the jejunum/ileum
b Fats are absorbed over the mid ileal section, mainly (see below lacteals)
c Carbohydrates are mainly absorbed through the first 1/3rd. of the
ileum, although much sugar balancing occurs in the colon
d Proteins, amino acids and peptides are absorbed through most of
the length of the ileum, but especially the last 2/3rds
e Vitamin
B12, many antibiotics and other drugs and other vitamins are absorbed
through the very low end of the ileum and the ascending part of the
colon
f Nutrients
produced by friendly bacteria in the gut are mostly absorbed from
the ascending colon, as this is where the bacteria live.
Colon
Balancing
In the ascending and transverse colon much of the water,
electrolyte and sugar balancing occurs between the inside and outside world,
except for, perhaps the kidneys.
It is also in this area that the symbiotic (living mutually
together) bacteria live. It is reasonable, therefore, that their products should
be absorbed from this area. These include: Vitamin K Vitamin B12 Biotin Vitamin
D Folic acid and many of the B vitamins in small quantities.
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