The most common cause of hypothyroidism and how to prevent it

The most common cause of hypothyroidism is a deficiency of iodine in the diet. In recent years much attention has been paid to the theory that autoimmune diseases may be the prime driver of hypothyroidism, however according to The Australian Thyroid Foundation, iodine deficiency is still the number one antagonist. And according to the Foundation the situation is more serious than many think:

More than 50% of children and pregnant or breastfeeding women living in Australia have been shown to be iodine deficient, and are at risk of developing thyroid disease.”

Iodine is needed by the body to produce thyroid hormone which is essential for the development and optimal functioning of the brain and nervous system and it also plays an important part in metabolism. When you don’t get enough iodine your body doesn’t produce enough thyroid hormone. This is a particularly dangerous situation when it occurs in pregnant women; their children are at much higher risk of being born with neurodevelopmental disorders and intellectual impairment.

It’s important not to confuse hypothyroidism – where the body doesn’t produce enough thyroid hormone – with hyperthyroidism, where the body produces too much.

Where do you find iodine naturally?

Iodine is found in seaweed (including nori, kelp and wakame) as well as in creatures that live in the sea, particularly oysters and shellfish as well as saltwater fish like cod, tuna, snapper and salmon.

Iodine is also plentiful in seawater, however very few of us are in the habit of consuming much of that!

Many fruits, vegetables and meats contain smaller amounts of iodine, particularly those grown in soils, or grazed on pastures close to the sea.  According to Nutrition Australia, Australian soils are typically low in iodine, which means our fruits, vegetables and meats are lower in iodine also. With this in mind, Nutrition Australia recommends that all Australians should consume iodised salt (see below). Interestingly they say natural sea salt is not a good source of iodine.

Where do you find iodine not-so-naturally

In the 1920s it was discovered that an alarming prevalence of goiters – a swelling of the thyroid gland – in certain inland states in the U.S. was linked to low levels of iodine in the diet. In the affected areas the soil contains no iodine at all, therefore the food grown in it, or on it, also contains no iodine. In response to this public health crisis the U.S. government decided to add iodine to the salt, a practice that was adopted by many western countries including Australia.

Since 2009 commercial bakeries in Australia have been required by law to use iodised salt in their bread – this makes our bread a good source of iodine.

Eggs and dairy can also be a good source of iodine as iodine is added to chicken feed and dairy cattle feed, however the level of iodine in these food products depends on the type of feed used.

Iodine supplements are also available from compounding pharmacies and are a good option for vegetarians, people on low-salt diets or anyone not a fan of seafood. People who have severe iodine deficiency may benefit from iodine supplements however it’s important to consult with your doctor before starting any iodine supplement plan. Taking too much iodine can lead to Hyperthyroidism – where your body produces too much thyroid hormone – and this condition also results in a range of serious health issues.

How do you know if you’re low in iodine?

A urine or blood test ordered by a doctor can flag iodine deficiency however if the situation is advanced a lump or ‘goitre’ may appear on the neck. This is the enlarged thyroid gland making an appearance. It’s important to see your doctor immediately if you find a neck goitre.

Other early symptoms of Hypothyroidism may include:

  • Unexpected weight gain
  • Foggy and muddled thinking – an inability to concentrate
  • Thining hair
  • Breathlessness
  • Feeling unusually cold
  • Fatigue and muscle weakness
  • Puffiness around the face
  • Unusually depressive moods
  • Slow heart rate.

If you think you may have iodine deficiency it’s important to see your doctor straight away as prolonged deficiency can lead to serious heart and other health problems. However if caught in time iodine deficiency can be corrected with changes to diet and/or supplements with no permanent damage to a person’s health.