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Iodine: are you getting enough?

Linked to thyroid issues, poor brain function and cancer, a lack of iodine could be a disaster, says nutritionist Christine Bailey

Linked to thyroid issues, poor brain function and cancer, a lack of iodine could be a disaster, says nutritionist Christine Bailey

When it comes to getting your daily intake of vitamins and minerals it’s not often you hear about iodine. Yet this nutrient is found in every single organ and all tissues and, without adequate levels in the body, life is not possible. Iodine plays a vital role in thyroid function, brain development and female hormone health, not to mention being associated with reducing the risk of cancers.

Despite this, iodine deficiency is one of the three most common micro-nutrient deficiencies in the world today. It has increased more than fourfold in the past 40 years and it’s now estimated that over 70 percent of adults don’t consume enough. Plus, it’s not just adults who are missing out. A 2011 study published in the Lancet found that more than two thirds of teenage girls in the UK are iodine deficient and so could be putting their long-term health at risk.

WHY IODINE?
Most of us will be aware that this nutrient is essential for the production of thyroid hormones, which is why the most visible symptom of deficiency is goitre – the swelling of the thyroid gland. But even sub-optimal levels can influence your thyroid health – which works by controlling your metabolism, regulating everything from body temperature and cognitive health to heart rate and cholesterol.

Iodine also plays a really crucial role in female health, as breast tissue actually contains higher concentrations of the nutrient than the thyroid gland! Low levels have been linked to breast cancer and fibrocystic breasts (density, lumps, bumps). What’s more, if you get sore breasts before menstruation, you may be deficient as this is linked as well. Japanese women whose diet is high in iodine-rich seaweed (with intakes 25 times higher than the average western women) have breast cancer rates roughly one third of those found in American women. Supplementation has actually been shown in numerous studies to reduce the size of tumours and relieve the symptoms of fibrocystic breast disease.

Pregnant woman need to pay particular attention to their levels, as deficiency is thought to be a cause of stillbirth and spontaneous abortion, and can result in mental impairment of babies. A lack can result in growth retardation, decreased fertility, hypothyroidism, certain cancers and reduced cognitive function. Iodine fulfils a number of other roles too – it removes toxic metals and chemicals from the body, supports immune health and has antimicrobial properties.

WHY ARE WE DEFICIENT?
There are several reasons why many of us don’t get enough. Soil worldwide is generally deficient in iodine, which in turn leads to only trace levels found in most foods. And, unlike other countries, iodine is not added to salt in the UK. There is also concern that toxins could be impacting iodine levels. For example fluoride and bromide (known as halides), have a similar structure to iodine, competitively inhibiting iodine absorption and binding in the body. So, the increasing levels of toxins in the environment and in food mean larger amounts of iodine are necessary to correct the deficiency.

For some people, especially those with hypothyroidism, excessive amounts of goitrogen-rich foods may also reduce iodine levels by interfering with its uptake. Such foods include soy, cassava, cabbage, broccoli, cauliflower, and other cruciferous vegetables, although cooking cruciferous vegetables seems to reduce this effect. Deficiencies of iron and of vitamin A have a similar result, making it difficult for the body to absorb iodine.

EASY IODINE FIXERS
One of the best food sources of iodine is seaweed but only certain types have sufficient levels – top of the list are kelp, arame and hijiki. Other good sources include fish, shellfish, certain dairy products (when the animals are fed with iodized feed) and eggs. Salt-water fish are iodine rich, in particular sea bass, haddock, cod and perch. Himalayan crystal salt naturally contains a range of minerals and trace elements including iodine. Don’t be fooled into thinking refined sea salt is a good source, though; most is highly processed and devoid of iodine.

The iodine RDA for adults (14 years and older) is 150mcg, with a slightly higher intake of 220mcg during pregnancy and 290mcg for lactating women. However the Japanese daily diet, high in seaweed, may contain up to 13mg (13,000mcg) of iodine per day. Many researchers, complementary and alternative practitioners, including Dr David Brownstein (author of Iodine: Why You Need It), believe even this level is inadequate and recommends doses as high as 50mg per day (subject to diagnosis) to counter deficiencies.

Article by

Lucy Trevallion

Article by

Lucy Trevallion