Around 850,000 Australians have thyroid disease and mood swings often signal an undiagnosed condition. Essential to metabolism and growth, the thyroid produces thyroid hormones from iodine. Getting the right amount is essential.

Too much leads to hyperthyroidism - weight loss, nervous agitation, rapid pulse, tremors, sweating and diarrhoea. Too little slows to hypothyroidism - weight gain, depression, dry skin, puffy face and hair loss.

For Beverly Garside, 54, life was chaos as a teenager as her health and emotional state went from one extreme to the other.
Diagnosed with Hashimoto's thyroiditis at 33, Beverly was advised to have her thyroid removed. 'One week I was manic, staying up late to clean and the next I'd be depressed in bed,' she says. The condition causes swings of metabolism and her antibodies mistakenly attacked her thyroid. 'I'm now on life-long medication of thyroxin but have no symptoms.'

The Facts:
50 per cent of Australian children are iodine deficient, which causes lower IQ and may be a contributing factor in an increase of attention deficit hyperactivity disorder (ADHD). 'Pregnant or lactating mums need 250micrograms (mcg) a day, as opposed to the average daily intake of 130mcg,' says enodcrinologist professor Creswell Eastman, vice- chairman of the International Council for the Control of Iodine Deficiency Disorders. 'Taking iodine in pregnancy helps prevent problems in the crucial stages of foetal development.' He ad.

If you're pregnant you should consult a GP before taking supplements. Non-pregnant women and children need 150mcg a day, which is still slightly more than the daily intake. 'Try iodised salt or eating seafood three or four times a week to reach these levels. If you can't eat salt, consider a lesser supplement such as meat and eggs,' Professor Eastman says.