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minerals (nutrition)
tin (Sn)
Nutrition

definition

Tin:
» overview:
• Tin was first found to be an essential growth factor in rats who were made deficient on an ultra clean chemical diet in the early 1970's.
• Its highest concentrations are found in the liver and spleen. People living in cities have a higher concentration in their tissues.
• Little or no tin is found in fetuses or newborns. It accummulates progressively after birth.

» metabolism:
• Tin is very poorly absorbed, depending upon the intake. At low intakes as much as 50% may be absorbed and at higher intakes less than 3% gets absorbed.
• It is excreted in the bile and in small amounts in the urine.

» function:
• Little is known about the function of tin in the body, but it may be involved in electron transport systems and in protein binding.

» requirements:
• Estimated safe and adequate daily dietary intake (ESADDI): none
• Average intake in the U.S.: 3-4 mg per day.
• Intakes may be up to 38 mg per day for people eating a lot of canned foods.

» food sources:
• Most tin comes from the consumption of canned foods. Tomato, pineapple and orange juices are often placed in unlacquered tin cans, therefore they may contain as high as 50 mg of tin per container.

» deficiency:
• A deficiency in rats results in stunted growth and anemia.

» therapeutics:
• None known.

» toxicity:
• Oral tin has very low toxicity.
• A 50 mg per day. tin intake may have a negative effect on zinc balance.
• Decreased hematocrits, hemoglobin and serum iron in rats fed equivalent of 170mg per day tin has also been noted.
• Organo-tin compounds tend to much more toxic because they may be absorbed more efficiently.
• In humans inhalation of tin has been associated with a mild benign pneumoconiosis.


footnotes

Marz, Russell. Medical Nutrition From Marz. Second Edition. Portland, OR. 1997.