MODERN-DAY food fads are responsible for the rise of the goitre, a deformity that was rife 300 years ago.
The gross swelling of the thyroid gland at the base of the neck is caused by a lack of iodine, a trace element found in seafood, and fruit and vegetables grown in iodine-rich soil.
However large parts of the UK have very little natural iodine and soil levels in a swathe of England from the South-west up to the Peak District are so low that in the past one in three children there developed goitres. It was once so common in the Midlands it was known as “Derbyshire neck”.
In the Forties, iodine intake in the UK diet began to climb, if only by accident. Iodine-based disinfectants were adopted by dairies and traces of the element began to find their way into milk supplies. As a result, today one cup of milk provides half our daily iodine requirement.
Iodine levels in milk have remained constant for at least 30 years but a survey carried out for the British Thyroid Foundation has revealed the deficiency is on the rise again.
More than two-thirds of the 737 teenage girls checked were low in iodine and one in five was dangerously low. Dr Mark Vanderpump who conducted the study says: “There has been no change in the amount of iodine in milk so it must be that we are drinking less of it.”
European Union figures confirm between 1991 and 1996 alone milk sales fell by seven per cent.
The study focused on girls approaching child-bearing age because they are the most at risk but there is no reason to believe levels are any better in the wider population.
Dr Vanderpump, a consultant based at the Royal Free Hospital in London, warns: “The significant public health impact of these findings needs to be addressed.”
Iodine deficiency impairs growth and mental development in babies and children. Even a mild deficit can damage an infant’s brain. In fact it is the most common cause of preventable brain damage in the world.
Widespread deficiency is also likely to lead to an increase in goitres. Dr Vanderpump explains: “The thyroid is good at making the most of a limited amount of raw materials and it swells to accommodate the fact there is not enough iodine.”
One in four of us has a thyroid problem and because of its role in regulating the metabolism, symptoms such as tiredness, feeling the cold or becoming forgetful are often vague.
H owever the British Thyroid Foundation, a patient-focused charity, warns it is an area shrouded in mystery. For instance, one website offering “educational information” suggests you can test for deficiency by painting iodine on to your skin and seeing if the substance disappears.
“Nonsense,” says Dr Vanderpump. Blood tests are required for an accurate diagnosis and even then they can be difficult to interpret. “It’s a very subtle biochemical abnormality.”
Kelp and other iodine supplements are as likely to cause thyroid problems as they are to cure them.
The butterfly-shaped thyroid uses iodine to make hormones that regulate how quickly the body uses energy, how sensitive it is to other hormones and aids production of essential proteins.
If this chemical production is too fast it causes hyperthyroidism or overactive thyroid. Symptoms include weight loss, palpitations, rapid pulse, sweating, feeling hot, tiredness, muscle weakness, mood swings, thirst, itching and an enlarged thyroid gland.
Hyperthyroidism can be triggered by the immune system turning on itself, by kelp supplements and by medicines such as lithium which is used to treat mood disorders.
If production is too slow it causes hypothyroidism or underactive thyroid. Symptoms include fertility problems, depression, sluggishness, sensitivity to the cold and dry skin or hair.
Goitre (a thyroid infection) and Graves’ disease (an auto-immune disorder) are common causes of hypothyroidism. Both are treated with drugs to suppress or increase production of thyroid hormones and require expert medical care.