Many Hongkongers are not getting enough iodine from their diet and this could be making them tired, depressed or overweight, health officials warned on Thursday.

The Department of Health (DH) said it questioned more than 16,000 people aged 15 and over between November 2020 and February 2022, and did urine checks on 2,000 of them, for the first ever territory-wide survey on iodine intake.

It found that on average, over 35s are not getting the amount recommended by the World Health Organisation, although the shortage is not massive.

The Centre for Health Protection’s Head of Non-Communicable Disease Branch, Dr Rita Ho, said the results are in line with overseas studies that have found that as people age, their intake of iodine tends to decrease, with women aged 55 and above particularly at risk of iodine deficiency.

"Because in general, the female energy requirement and the total amount of food intake is less than that of males," Ho explained.

“Iodine is required for normal thyroid function, growth and development, therefore we recommend that all people should keep and maintain their adequate iodine intake," she said.

“Inadequate iodine intake may lead to hyperthyroidism and goitre and for hyperthyroidism there are various symptoms such as tiredness, excessive weight gain, prone to depression and also low in response and movement.”

Ho said people should consume more iodine-rich food such as seaweed, fish, egg and dairy products, or use iodised salt instead of sea salt, but only up to one teaspoon a day.