happens to food after we eat it? Do our bodies use all the
nutrients? Or a better question, "Can our bodies use
all the nutrients?" Bioavailability of nutrients is about
how the little bits of food e.g. vitamins, minerals, amino
acids, fatty acids and simple sugars, are made available to
our bodies for use.
The quality of our diet depends
on the nutrient content and the bioavailability of its nutrients.
The bioavailability of nutrients, which can be defined simply
as the efficiency of absorption and utilization or retention
of the nutrients that are present in food, can vary substantially.
Bioavailability of nutrients
is determined by
- nutrient content of
- food processing,
- the physical state of
- interactions among components
of the diet,
- the presence of anti-nutritional
Cultured Foods and Digestion
Cultured foods are processed
by microorganisms. These foods have been in the diets of many
different peoples all around the world for centuries. They
were an accidental discovery of man that led him to be able
to keep food for longer and make new types of foods and beverages.
Slowly they have been replaced in many peoples' diets by more
processed and refined foods.
Cultured foods contribute to
efficient digestion in three ways: by breaking down foods
to make digestion and assimilation easier, by providing enzymes
to aid digestion, and by supplying and nourishing the correct
intestinal bacteria. What all cultured foods have in common
is an abundance of lactic acid bacteria, yeasts, and moulds
that produce enzymes which break down and alter the original
A significant proportion of
the body's energy is involved in the digestion and transformation
of food. In effect, these organisms predigest the foods, breaking
down the complex proteins, carbohydrates and fats to more
easily assimilable amino acids, fatty acids and simple sugars.
This leads to more efficient assimilation and utilization
of these nutrients and a reduced burden on the digestive tract.
The action of the culture organisms makes the minerals in
cultured foods more readily available to the body. The bacteria
also produce B vitamins, providing a significant increase
to the level of these vitamins in many cultured foods.
Perhaps even more important
than these nutritional benefits is the effect of the actual
bacteria and enzymes in cultured foods. These include many
found in our own bodies, or very similar to them. There are
more than 150,000 different types of enzymes in the human
body and all functions of the body require them. The proteins,
fats and carbohydrates in the food we eat must be broken down
into simpler units to enable the body to absorb and utilize
it. This is achieved by the action of specific enzymes.
Tasks Performed by Enzymes
- Storing surplus nutrients
in the liver and muscles.
- Removing waste products
- Neutralising toxins
and downgrading hormones in the liver.
- Building minerals into
nerves, bones and blood.
- Breaking down other
complex food particles into simpler units that can then
be absorbed and utilized by the body.
Each enzyme has a specific purpose,
so the deficiency or absence of even one can have quite serious
effects. Foods such as fresh raw fruit in particular, but
also fresh raw vegetables, grain foods and unpasteurised milk,
contain enzymes. Food that is cooked or processed in any way
generally has had its enzymes destroyed.
When food does contain enzymes,
some of these can be used by our digestive system, and not
just for digestion of the foods containing those enzymes.
That is, enzyme-rich foods boost the body's enzyme supply.
Cultured foods are very rich in enzymes that are produced
by the culture organisms and take part of the processes of
fermentation. This means that eating cultured foods assists
in the digestion of other foods by building up the enzyme
Summary of Digestive Secretions
|Organ or Gland
Fluid eases swallowing; salivary
enzyme breaks down carbohydrate.
Fluid mixes with bolus; hydrochloric
acid uncoils proteins; enzymes break down proteins;
mucus prtoects stomach cells.
Bicarbonate neutralizes acidic gastric
juices; pancreatic enzymes break down carbohydrates,
fats, and proteins.
Bile stored until needed.
Bile emulsifies fat into small particles
that enzymes can attack.
Intestinal enzymes break down carbohydrate
and protein fragments; mucus protects the intestinal
Source: Whitney, E.N. & Rolfes,
S.R. Understanding Nutrition. West Publishing Company.
MN. 1993. pp75.
on Nutrition and Diarrheal Diseases Control, Subcommittee
on Diet, Physical Activity, and Pregnancy Outcome, Committee
on International Nutrition Programs, Food and Nutrition
Board, Institute of Medicine. 1992. Nutrition Issues in
Developing Countries. Washington, D.C.: National Academy
E.N. Rolfes S.R. 1993. Understanding Nutrition. West Publishing
Wendy. 1999. Cultured Foods. Hyland House Publishing Pty.