Tin (Sn)
Urine accounts for
at least 80% of excreted Tin that is ingested and absorbed from the
gastrointestinal tract. Ingested Tin is not significantly absorbed
if it is an inorganic form. Oxide coatings readily form on metallic
Tin, and salts can quickly oxidize making them insoluble. Organic
Tin, however, is bioavailable and more readily absorbed. Some
organic Tin compounds such as short-chain alkyltins can be absorbed
transdermal and can cause degeneration of myelin. Food and drink
usually provide small daily intakes of (nontoxic) Tin, with amounts
depending upon type of food, packaging, quality of drinking water
and water piping materials. Total daily intake is expected to vary
from about 0.1 to 15 milligrams.
Tin is present in many metal alloys
and solders; bronze, brass and pewter contain the element. Dyes,
pigments and bleaching agents often contain Tin. Anticorrosion
plating of steel and electrical components may also use Tin. "Tin
cans" are Tin-plated steel with a thin outer oxide layer allowing
the surface to be shiny but inert. Modern food-containing cans usually have polymer coatings
that prevent food-metal contact. In the past some toothpastes
contained stannous fluoride, a soluble fluoride source for
strengthening tooth enamel. Currently most brands of fluoridated
toothpastes contain sodium fluoride. Organic Tins, the usually toxic
forms, are: biocides triphenyltin
and alkyltins) used against rodents, fungi, insects and mites;
curing agents for rubbers and silicones (dialkyltin); and methyltin
formed bacteriologically (similar to methyl mercury).
Mildly elevated
levels of Tin in urine may reflect sporadic dietary intake and
excretion; there may be no associated symptoms. A two- or three-fold
increase in urine Tin levels is not uncommon following
administration of EDTA or with sulfhydryl agents (DMSA,
D-penicillamine, DMPS). Early signs of chronic organic Tin excess
can be: reduced sense of smell, headaches, fatigue and muscle aches,
ataxia and vertigo. Hyperglycemia and glucosuria are reported. Also,
for organic Tin exposure, there can be irritation of contacted
tissues (eyes, skin, bronchial tubes, or GI tract). Later, immune
dysfunction may occur with reduced lymphocytes and leukocytes; mild
anemia may occur. Tin is
commonly elevated in urine from autistic patients following
administration of EDTA, DMSA or DMPS.
If you suspect that
you have an elevated Tin level, it is important to determine
total body load. Here at
Chelation Medical Center we can do an IV chelation provoked
challenge, with a
urine collection which will show your total body load of Tin, as
well as other heavy metals. Just give us a call.
