Many things can interfere with the absorption of nutrients.  Disease or
illness can permanently or temporarily disable the ferret's ability of
absorb nutrients; a real problem with diseases such as ECE.  If a nutrient
is dependent on a second nutrient, than a shortage of one can prevent the
absorption or metabolism of the other.  Finally, the ingestion of a compound
at the same time (or within a short time) of an antagonist may make it
difficult or impossible for the body to metabolize the nutrient.
 
Usually when a nutrient is eaten, it is directly absorbed into the body with
no problem.  You eat red meat, and the iron, in a form easily absorbed by
the body, goes directly into the bloodstream for immediate use.  However,
sometimes if the mineral is being consummed in the presence of other
compounds, it changes the body's ability to absorb the nutrient.  This might
be because an electron is added or removed, changing the size and reactivity
of the molecule or element.  This is what happens when you eat iron-rich
foods with corn (maize); the corn changes the iron, making it very difficult
for the body to absorb it, and can ultimately result in severe anemias.  If
you treat the corn with lime to make hominey, or eat lime at the same time,
then you can (at least partially) neutralize the effects of the corn upon
the iron.  This is one of the reasons eating bone is so healthly; the
calcium and certain amino acids increases the body's absorption of iron.
 
There are many compounds with similar problems, such as when too many
ingested phosphates decreases the absorption of calcium (why osteoporotic
women are supposed to decrease the amount of soda they drink; many contain
phosphoric acid), too much magnesium also decreases absorption of calcium.
Excess calcium and magnesium decreases the absorption of phosphorus.  Too
much potassium decreases the absorption of magnesium.  With iron, the
calcium to phosphorus ratio influences the absorption.  Copper utilization
is reduced if you have too much calcium, and stopped by too much zinc or
molybdenum, resulting in anemias.  To much calcium or phosphorus and the
absorption of manganese is reduced.
 
Besides problems with absorption, many vitamins and minerals can be health
threatening or even toxic in excess.  Too much calcium or phosphorus can
lead to kidney or bladder stones.  Sodium, from salt, is toxic when above
8% of the diet, and results in staggers, blindness, nervous disorders and
hypertension.  Too much copper results in similar symptoms as too little
copper; lameness, anemia, weakened bones, depigmentation.  Selenium can
cause blind staggers, alkali disease or sudden death.  Excess fluorine can
block enzyme action, causes bone and enamel defects and organ degeneration;
it is also an element the body conserves, so it can accumulate and become
toxic over time, even if the daily ingested levels are considered non-toxic.
 
As for the vitamins, most of the problems of toxicity are associated with
the fat-soluble vitamins because the body stores them for future use.
Vitamin A in excess causes much of the same problems as when it is
deficient.  Vitamin D can be in levels so high in the livers of marine
animals that eating the unprocessed liver can be deadly (tip: don't eat most
shark or seal livers) In lower levels, it can cause decalcification of bone
or hardening and calcification of soft tissues.  To much pyridoxine can
cause convulsions and death.  Too much choline and you will have persistent
diarrhea.  Most of the vitamins and minerials not discussed are relatively
nontoxic and excesses are generally swept out of the body in the urine.
Most water-soluble vitamins are non-toxic, especially Vitamin C, and most
fat-soluble vitamins tend to be toxic, except Vitamins E or K.
 
Are any of the macronutrients toxic?  In a way, yes.  Proteins can be toxic
if the lipid levels are too low.  High protein-low fat diets can result in
the utilization of protein for energy, which can result in acidosis, liver
and kidney damage, and a host of nasty side-effects.  This is often called
"rabbit fever," or "rabbit starvation," so named because rabbits tend to be
lean animals, and a diet of only rabbit flesh lacks the essential fatty
acids.  So while the proteins themselves are not toxic, the breakdown
products from using them for energy can be, especially in higher
concentrations.  Most carnivores make at least some of their energy from
proteins, so they are probably more resistant to rabbit starvation that
some other mammals, but you have to evaluate each species individually.
 
One other source of toxins is contamination of the food or water the ferrets
eat.  Toxins tend to concentrate the higher on the food chain you go.  For
example, selenium may be found in the soil in non-toxic level.  As plants
grow, the selenium is taken into the plant, which is, in turn, eaten by
herbivores.  Because a herbivore, such as a deer, can eats tons of plants in
its lifetime, and because the selenium tends to become part of the bones,
the selenium levels can be far greater in these animals when compared to
plants.  It only gets worse for the carnivores dining on the herbivores,
who could ultimately recieve a toxic dose of the mineral.
 
The entire process could be intensified by selenium in the ground water;
not only are you eating high levels of selenium, you are also drinking it,
making the toxins accumulate even faster.  Now selenium is a single
example; similar problems occur with lead, zinc and copper.  The problem
with kibbled diets is you have no idea where the foods originally came
from, so you have no idea if you are feeding your animal foods that have
concentrated toxins.  Some people fear chorine in water; chorine is simple
to remove by allowing the water to stand, for 24 hours, or by running the
water through a reverse-osmosis filter, which is pretty good at removing
most nasties.
 
One last thing to point out. If you read the list of essential minerals
closely, you will notice most of them are extremely toxic in their
elemental state. For example, salt, or sodium chloride, is composed of two
very powerful and toxic chemicals. Breathe chorine, and you might as well
pretend you are Meg Ryan looking at angels. Sodium? Good luck, and bring a
fire extinguisher. However, in their ionic forms, they are required for
life.  Chlorine is a good example; quite toxic, it is an essential
nutrient required for cellular pH balance and production of stomach acids.
 
Bob C and 20 MO Water-Dumping, Food Digging Carpet Monkeys
[Posted in FML issue 2320]