But chemists were aware that certain elements had rather similar chemical properties: for example lithium, sodium and potassium or chlorine, bromine and iodine.
Yoghurt is heavyweight nutrition, providing around a third of our daily iodine and calcium, and nearly 15% of our daily protein, which is similar to a boiled egg.
The hormone helps to absorb iodine, which is essential for normal thyroid function.
But additives, such as iodine added to salt, can reduce its shelf life to about five years.
In 1997, the National Cancer Institute reported that the Cold War detonations at the Nevada Test Site had polluted nearly the whole of the country with drifting airborne radioactive iodine, creating somewhere between 10,000 and 75,000 cases of childhood thyroid cancer.
The meal also provides over 100 per cent of the recommended daily allowance of fibre, vitamin A, vitamin C and iodine and is rich in B vitamins, magnesium and zinc - the entire feast meeting the 'five a day' fruit and vegetable recommendation.
Kelp is also a great source of iodine, which speeds up your metabolism, which is perfect if you want to lose weight.
I burst through the doors, the smell of iodine and peroxide hits me, but all I have time to see is two men wearing surgical caps and a woman in green huddling over a gurney.
Before 1920, iodine deficiencies were common in some parts of the country.
As recently as the mid-1990s, China experienced widespread problems of preventable developmental disabilities because of a lack of iodine in children's food supply.
