Opinion of the Scientific Panel on Dietetic Products, Nutrition and Allergies on a request from the Commission related to the Tolerable Upper Intake Level of Tin (Request No EFSA-Q-2003-018) (adopted on 6 July 2005)

The European Food Safety Authority is asked to derive an upper level for the intake of tin from food that is unlikely to pose a risk of adverse health effects.from food that is unlikely to pose a risk of adverse health effects. Tin has not been shown to be nutritionally essential for humans. Tin occurs naturally in foods as stannous and stannic salts, and stannous chloride (SnCl2) is a permitted food additive (E512). Data on tin intake in EU countries are limited. In the UK mean intake in adults from food is estimated at 1.8 mg/day, ranging up to about 6 mg/day, and appears to be decreasing, while in France the mean daily intake was estimated to be 2.7 mg tin/day. The main dietary sources of tin are tinned fruit and vegetables. The absorption of inorganic compounds of tin from the gastrointestinal tract in humans and animals is very low with as much as 98% being excreted directly in the faeces. Because of their limited absorption, inorganic tin compounds have low systemic toxicity in man and animals. In man and animals, gastrointestinal effects are the main acute manifestation of toxicity associated with ingestion of tin. These are caused by the irritant action of soluble inorganic tin compounds on the mucosa of the gastrointestinal tract. In humans, acute effects resulting from consumption of tin-contaminated foods and drinks have resulted in gastrointestinal symptoms, including abdominal distension and pain, vomiting, diarrhoea, and headache. The balance of evidence suggests that the concentration of tin in contaminated foods is critical to the development of acute gastrointestinal effects, and that tin concentrations of 250 mg/kg in canned foods and 150 mg/ kg in canned beverages are more likely to be associated with this. Short term studies in human adults indicate that high intakes of tin ( about 30-50 mg tin/day or per meal) may reduce the absorption of zinc, but not other minerals such as iron, copper, manganese or magnesium. However, the possible long-term effects, if any, of such intake levels on status of zinc or other minerals have not been investigated. The Panel considered that the available data from human or animal studies are insufficient to derive a tolerable upper intake level for tin. The current daily intake of tin in the EU (e.g. ranging up to about 6 mg/day in the UK) appears to be well below the lowest intakes reported to cause adverse effects on zinc absorption. Regulatory limits of 200 and 100 mg/kg for the concentration of tin in canned foods and beverages, respectively, have been established to protect against the occurrence of acute gastrointestinal effects of tin.