| Element |
Usual
Food Source |
Function,
if any |
Hazard
Caused by Excess in Food (if known) |
| Aluminium |
From cooking vessels, aluminium-containing
medications, some fruits and vegetables |
Poorly absorbed; no known function |
Decreased phosphate absorption leading
to bone
diseases, altered mental function |
| Antimony |
Foods stored in enamel vessels and
cans |
No known function |
Very low toxicity |
| Arsenic |
Crustaceans and fish, contaminated
water, fruits and vegetables grown in contaminated areas or with spray
residues |
Possibly essential for growth in rodents,
pigs and poultry |
Gut, skin, brain and nerves affected |
| Barium |
Brazil nuts, cereals grown in barium-
rich soil |
No known function; used for X-ray studies |
Very low toxicity |
| Boron |
Plant foods |
Not essential for animals, although
it is for some plants |
Very low toxicity |
| Bromine |
From fumigated grain and its products |
Will replace chloride and so accumulate;
will also be taken up by the thyroid gland instead of iodine |
Adverse effects on brain and thyroid
function |
| Gold |
Information inadequate |
No known function; gold injections
are used in the treatment of rheumatoid arthritis. |
Skin, gut and kidney damage |
| Lead |
Variable content in food; more in
produce grown near highways with vehicles using leaded petrol; more
in food from metal cans than from glass or aluminium containers; some
from reticulated water |
Not essential |
World Health Organisation suggests
tolerable weekly intake of 50 micrograms per kilogram body weight
for adults. Excess affects brain, blood, bone and kidneys. |
| Mercury |
Inorganic mercury to which miners are
exposed; mercurial fungicides contaminating food; organic mercury
in fish from contaminated water, such as near paper mills; from shark,
which is high up in the marine food chain with progressive concentration
of mercury |
Interacts with selenium |
Brain damage, kidney damage |
| Rubidium |
Soya beans, beef |
Can act partly as a substitute for
potassium |
More toxic an low potassium diets,
with effects on growth and reproduction |
| Silver |
From food prepared in silver-plated
vessels, contaminated by silver-lead solders or stored in silver foil |
Not essential |
Low toxicity |
| Strontium |
Plant foods have more than animal foods,
unless bone is a part. More in bran than the remainder of cereal grain. |
Found in bone, and can be replaced
by radioactive strontium from fall-out; interacts with calcium
|
May
affect growth |
