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Food Safety Focus (74th Issue, September 2012) – Incident in Focus

Iodine in Infant Formula

Reported by Ms. Shuk-man CHOW, Scientific Officer,
Risk Communication Section,
Centre for Food Safety

On 8 August, two Japanese brands of infant formulae were voluntarily recalled from market after being found to have low iodine content. The testing is part of a two-year programme (2012-2013) of the Centre for Food Safety (CFS) to test the nutritional composition of infant and follow-up formulae available in the local market. As of 19 September 2012 , seven out of the 61 powdered infant formulae tested were found to have low level of iodine content to an extent that may cause health problems to those infants who have been solely fed on them.

Seven infant formulae were found to have low iodine content which may affect the normal function of the thyroid gland of infants solely fed on them
Seven infant formulae were found to have low iodine content which may affect the normal function of the thyroid gland of infants solely fed on them

Iodine for Infants

Iodine is an essential nutrient necessary for the production of thyroid hormones which are responsible for normal growth and development. Diet is the major source of iodine intake for humans. For exclusively formula-fed infants, infant formula is their only food source of dietary iodine. Iodine content in infant formulae will affect the daily iodine intake of these infants. A prolonged deficiency in iodine may affect the functioning of the thyroid gland. If thyroid function is significantly affected, there may be potential impact on brain development of infants.

Findings on Iodine Content of Infant Formulae

Iodine content in infant formula available in the market varies from brand to brand. The Codex Alimentarius Commission (Codex) sets a standard of 10 to 60μg/100kcal of iodine for infant formula. However, Codex only specifies the desirable level of iodine in food. Detected level below Codex standard does not necessarily mean the consumer’s health is at risk.

When assessing whether a product may pose health risk to the consumer, risk assessment has to be conducted to determine if the level of iodine in the diet meets the World Health Organization (WHO) recommended daily nutrient intake (the amount of a nutrient a person should consume in a day). According to WHO, infants might have lowered thyroid function with the risk of brain damage when the iodine intake is about one-third of this value.

Follow-up Measures

In view of the potential reliance on infant formula as the sole source of dietary intake for infants, as a precautionary measure, the CFS has advised the public to stop feeding infants with the concerned infant formulae and the trade should stop selling the affected products. The relevant importers were informed of the test results and voluntarily withdrew the products from market. To allay concerns associated with the incident, the CFS has set up a hotline (3978 0600) to provide information to concerned parents and handle any related enquires from the public. In addition, a dedicated website has been developed with frequently asked questions regarding iodine in infant formula, iodine levels in selected infant formulae available in Hong Kong, and the announced test results uploaded for the public’s information and reference.

Although seven infant formulae were found to have low iodine content which may affect the normal function of the thyroid gland of infants, as at 17 September 2012 , among the 111 blood samples tested by the Department of Health, only two were found to have thyroid hormone levels outside the normal reference range. According to specialists of the Hospital Authority (HA), both results were less likely caused by consumption of the iodine-deficient infant formulae. Nonetheless, the infants concerned were referred to the HA paediatric specialist clinic for follow-up.

Given the above surveillance finding, the CFS will continue testing on the nutritional composition of infant and follow-up formulae in the local market with respect to the Codex standard. Relevant testing results will be released in phases. The CFS will take appropriate follow-up actions if the findings indicate any potential health impact on infants. In view of the latest development, the Government will expedite preparatory work for legislation to regulate the nutritional composition and nutrition labelling for infant formulae.

Key Points to Note:

  • Iodine deficiency may result in lowered thyroid function, which in turn may affect growth and brain development in infants.
  • Use the nutrition label on infant formula to find out its iodine content.
  • So far, there have been no apparent clinical cases of abnormal thyroid function due to the consumption of the concerned infant formulae.

Advice to Trade

  • Stop selling the products of concern.
  • Formulate infant formula in accordance with Codex standards. Ensure the composition poses no health risk to the local population.
  • Provide labelling information according to Codex standards to allow consumers to make informed choices.

Advice to Consumers

  • Follow WHO’s recommendation on exclusive breastfeeding for the first six months after birth, with safe and appropriate complementary foods and continued breastfeeding for up to two years or beyond.
  • Stop feeding infants with the concerned products and switch to other infant formulae with adequate iodine content.
  • Read the nutrition information on the product label when choosing infant formula.
  • Consult family doctors or paediatricians if in doubt.
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    Last Revision Date : 19 -09-2012