VEGETARIAN diets have been linked to the soaring number of Scots suffering chronic weight problems.
A lack of iron and large amounts of soya in some vegetarian meals has contributed to an increase of more than 300% on Scotland’s drug bill for treating thyroid problems.
Experts believe the combination of too little iron and too much soya can cause the thyroid to malfunction, causing rapid weight gain or loss in patients.
The latest official figures show that NHS Scotland spent £8m treating thyroid conditions in 2011 compared with just £2.2m in 2001.
Over the same decade, the number of prescriptions for thyroid problems soared from 1.2 million to 2.2 million, according to NHS Scotland.
The thyroid gland controls the body’s metabolism and problems including fatigue, loss of libido and female infertility can also result when it goes wrong.
It is now estimated that as many as one in five Scots will suffer from a thyroid condition during their lifetime.
Lyn Mynott, Chief Executive of charity Thyroid UK, said a lack of proper nutrition and a meat-free diet were contributing to a rise in numbers of people seeking support for thyroid-related disorders.
She said: “We know there is an increase in cases of thyroid problems as we have an increasing number of people coming to us for support. You can also look at prescription cost analysis to see this trend.”
Junk food is an important factor because vitamins are essential to the healthy functioning of the thyroid, she said.
More surprising is the threat some vegetarians are posing to their own health.
She said: “Your thyroid needs iron and a lot of people don’t eat meat and are eating a lot more soy.”
Ms Mynott said soy acted as an “endocrine disrupter”, interfering with the working of the thyroid.
“When people are put on medication for thyroid conditions, in most cases they will be on it for life,” she said.
“This is certainly a bigger problem than it used to be.”
Endocrine disrupters are chemicals that interfere with the body’s hormone system, and can cause cancerous tumours, birth defects, and other developmental disorders.
Soya falls into a category of foods known as goitrogens that promote the formation of a goiter, or an enlarged thyroid. Some goitrogens also appear to slow thyroid functions and in some cases trigger thyroid disease.
The thyroid is the largest gland in the neck and makes the thyroid hormone, which in turn regulates the body’s metabolism.
Symptoms of an underactive gland include tiredness, weight gain, female infertility, depression and constipation.
An overactive thyroid can cause severe and sudden weight loss, increased heart rate, loss of libido, fatigue, skin problems, muscle and other organs.
Peter Taylor, senior lecturer in physiology at Dundee University, agreed that a diet with high levels of soya, and low in foods containing iodide, can be a cause of thyroid problems.
He said: “If your diet is low in iodide and iron selenium and you have very high levels of soya in your diet then it is possible that this will contribute to thyroid problems. Soya can compete with your body’s ability to process iodide.”
Low iron levels are more common in people who with underactive thyroids, compared with the rest of the population.
A lack of iron can lead to hair loss, dizziness, bruising and leave you feeling tired and weak.
Dr Damian Dowling, of New Medicine Group, in London, said a lack of iron and the consumption of soya products could negatively impact on the thyroid.
He said: “There are things in soya that can limit the body’s intake of iron and other important nutrients and minerals as well.
“Soya can disrupt the hormone function, particularly in woman, and can disrupt the thyroid directly.”
The popularity of soya products is on the rise in Scotland, and currently around two-thirds of all manufactured foods contain ingredients made from soya.
Soya can be ingested as whole beans, soya flour, soya sauce or soya oil, and soya flour is widely used in foods including, breads, cakes, processed foods, ready meals, burgers and sausages, and baby foods.
William Shand, chairman of the Scottish Vegetarian Association, defended the vegetarian diet, accusing Thyroid UK as “scaremongering”.
He said: “The vegetarian diet is far healthier than a meat-based diet and these claims don’t worry me at all, this is just another example of scaremongering.
“A vegetarian diet is full of vitamins and minerals and doesn’t contain dangerous chemicals, such as antibiotics, that people absorb into their diets through eating animal products.
“A vegetarian diet is low in fat and can actually help people to lose weight. I don’t believe any of these claims that avoiding meat can make you suffer weight problems.”