Government of Western Australia
Department of Health
Public Health
Dear Colleague
BonSoy soy milk: information for Medical Practitioners
5 Key points for Medical Practitioners
BonSoy soy milk has been withdrawn from the marketplace following detection of
1.
high levels of iodine in this product. This product should not be consumed.
Several adult cases in NSW have been diagnosed with thyroid conditions
2.
believed to be associated with consumption of BonSoy soy milk.
In addition, a newborn has been diagnosed with hypothyroidism secondary to
3.
iodine excess following maternal consumption of BonSoy during the pregnancy.
Doctors should be alert to seek information about BonSoy soy milk consumption
4.
by any persons presenting or who have presented in the past months with
thyroid conditions.
Medical practitioners should report all suspected cases of thyroid disease where
5.
BonSoy soy milk is involved to the Communicable Diseases Control Directorate
during business hours on tel. 9388 4999 or fax 9388 4848.
BonSoy is a soy milk product distributed nationally in Australia. Tests have shown it to
contain extremely high levels of iodine and consumption has been linked to clinical
thyrotoxicosis and, less commonly, hypothyroidism. Iodine crosses the placenta and may
cause foetal and neonatal hypothyroidism which can cause developmental problems in the
newborn.
Exceeding the safe upper limit for iodine intake may occur when 30ml is consumed per day
by an adult, or 5ml for a child.
Recommended levels of Iodine
The recommended daily intake for iodine depends on age and life stage:
• Younger children (1 to 8 years) – 90µg
• Older children (9 to 13 years, boys and girls) – 120µg
• Adolescents (14 to 18 years) – 150µg
• Men – 150µg
• Women – 150µg
• Pregnancy and breastfeeding – 220µg and 270µg respectively.
The recommended safe upper limit for iodine is:
• Young children (1 to 3 years) – 200µg
• Older children and Adolescents (14 years) – 900µg
• Adults – 1,100µg
Signs and Symptoms excessive iodine intake
Excessive iodine can lead to hyperthyroidism or, less commonly in adults, hypothyroidism.
Infants appear more susceptible to hypothyroidism following excessive iodine exposure.
The commonest symptoms of hyperthyroidism are palpitations, fatigue and weight loss.
Hypothyroidism is often insidious and, in mild cases, may only be detected on routine
screening but it can cause fatigue, weight gain and mental clouding.
Medical Management
• Patients should be advised not to consume the product and to dispose of it either
down the drain or in the garbage bin.
• Iodine has a half life of approximately 30 days.
• When a patient presents with a history of prolonged BonSoy soy milk consumption
together with symptoms or signs listed above, Medical Practitioners should consider
measurement of TSH. If the TSH is abnormal, proceed to measurement of the
urinary iodine level (normal range in children 100-500 ug/L) and thyroid antibodies
and consider referral to an endocrinologist or at least try to obtain phone
consultation with an endocrinologist. There is no need to measure the urinary iodine
level if the TSH is normal (Normal range 0.3-4.0 mU/L, can vary between
laboratories) as stopping the ingestion of the milk will return the body’s iodine levels
to normal within a few weeks.
• Advice to patients who report they have drunk the milk and are pregnant: see your
GP or obstetrician for a TSH measurement. The baby may also need additional TSH
and free T4 measurement after birth (but this is usually routinely done with the
Guthrie heelprick test); If the TSH is abnormal, then thyroid ultrasound and thyroid
scan are indicated. The effect of the high iodine levels will be to block synthesis of
thyroid hormones causing hypothyroidism which in the neonatal period could cause
a permanent loss of cognitive function.
• Suspected cases should be reported during business hours to the Communicable
Disease Control Directorate on 9388 4999, fax number 9388 4848.
Advice for the general public about the recall of BonSoy soy milk product and a fact
sheet about iodine is available on the Food Standards Australia and New Zealand
website: http://www.foodstandards.gov.au/
Thank you for your support in this matter.
Yours sincerely
Dr Tarun Weeramanthri
Chief Health Officer
Department of Health