The Guardian recently highlighted worrying evidence that many women in the UK are unknowingly iodine deficient, with experts calling for the government to recommend that those women planning to conceive, already pregnant or breastfeeding take iodine supplements to help combat the deficiency. So, what are the implications of this evidence and how can people boost their levels of this important mineral?
Why do we need iodine?
The body needs iodine to make thyroid hormones. These hormones control the body’s metabolism, but iodine also has other important functions. The body also requires thyroid hormones for proper bone and brain development during pregnancy and infancy.
Which foods are naturally high in iodine?
Iodine is a component of almost every living plant and animal. No standard measurements of iodine in food exist because iodine concentrations vary across the world. Iodine is only found in certain foods. Most people should be able to get all the iodine they need by eating a varied and balanced diet. In general, foods from the sea contain the most iodine, followed by animal foods, then plant foods. Of all foods, seaweed (like kelp), is the most well known and reliable source of natural iodine, however, the British Dietetic Association discourages consuming kelp or brown seaweed due to the high concentrations of iodine found in both of these (as high iodine levels can also cause thyroid problems). Fish, milk, eggs and dairy products are the main sources of iodine for most people. If you don’t eat fish, salt, meat, or seaweed, your may need consider buying supplements or foods enriched in iodine, or ensure that the plant foods you consume come from parts of the world where the soil is rich in iodine.
Importance of iodine during preconception, pregnancy and when breast feeding
The growing concerns that iodine intake in the UK is inadequate; particularly for women trying to conceive, and pregnant and breastfeeding women, is worrying because this puts an unborn child at serious risk of learning difficulties. A good store of Iodine is required from the early stages of your pregnancy, so you should make sure you have been having enough iodine in your diet for several months before you get pregnant. This will help to ensure that iodine levels are maintained, not only during preconception but also during pregnancy and if you are breast feeding.
Iodine is particularly important during pre-conception and the first 16 weeks of pregnancy to ensure the healthy development of the baby’s brain. Iodine is also important in the development of the skeleton and metabolism. During the first 14-16 weeks of pregnancy, a foetus is entirely dependent on the mother for its supply of thyroid hormone. Severe iodine deficiency can lead to the extreme disability known as cretinism. New mothers should be aware that their breast milk contains iodine for their new born children. The amount of iodine in breast milk will depend on the mother’s diet. This does not necessarily mean that iodine levels need to be increased, as too much iodine can also cause problems, but just to ensure that the correct foods (or a supplement if it is recommended by your GP) are being incorporated into the diet (if you are unsure always check with your health-care provider).
How does iodine affect fertility?
The thyroid gland can be found at the base of the neck. The thyroid gland produces a hormone called thyroxine, which is an important hormone as it controls your metabolic rate. Hyperthyroidism is a condition whereby too much thyroxine is produced by the thyroid gland and hypothyroidism is a condition whereby too little thyroxine is produced by the thyroid gland.
Iodine is most important for women, because it is most highly concentrated in the thyroid, breasts and ovaries. Iodine deficiency can lead to menstrual irregularities, infertility, early menopause, and ovarian diseases. However, it is still vital for men, especially for the prostate gland.
Thyroid gland problems can affect fertility in women in a number of ways including a failure to ovulate and irregular menstrual cycles. Hyper and hypothyroidism can also affect normal ovulation from occurring.
Hypothyroidism can also cause a hormone called prolactin to increase. Prolactin is involved in the production of breast milk and this can also prevent ovulation. Those women with hypothyroidism are sometimes also diagnosed as having polycystic ovary syndrome which can lead to fertility problems.
What are some of the contributing factors leading to low iodine levels (hypothyroidism)?
- Inadequate intake of iodine
- Deficiencies in nutrient cofactors needed for production of thyroid hormones and cell receptors e.g. vitamin A, vitamin B, vitamin C, zinc, copper, selenium, iron and essential fatty acids
- Heavy and toxic metals e.g. lead, mercury, dental amalgams & smoking
- Stress – emotional, physical, chronic allergies, infections, anxiety, poor diet and lack of sleep
- Pesticides
- Fluoride
- Xenobiotics
- Autoimmune disease and genetic susceptibility
- X-rays
- Overtreatment of hyperthyroidism e.g. surgery, drugs and radiotherapy
- Disorders of the pituitary or hypothalamus gland
Top tips of how to boost iodine levels in the body!
- Exercise daily for at least 30 minutes (brisk walking is good).
- Include nutrient-dense diet rich in whole, unprocessed, organic foods, especially plant foods e.g. fruits, vegetables, beans, seeds, nuts and whole grains.
- Eat 2-3 portions of oily fish per week
- Try to sleep for eight hours a night
