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