If a nutrient is not in the soil, it cannot be in the food. Unfortunately, New Zealand soils do not contain iodine so locally grown produce reflects this, and studies have shown evidence of iodine deficiency re-emerging in New Zealand. Iodine is essential for the production of thyroid hormones, which control the basic activity of each cell in the body, including metabolism, growth and development.
Thyroid issues can affect fertility, so optimal iodine intake is important when trying to conceive. During pregnancy, iodine is needed for normal brain development in the foetus, and even subclinical hypothyroidism due to iodine deficiency in the mother can lead to irreversible brain damage.
Iodine is found in seafood, seaweed and iodised salt. Not all salt is iodised, so it’s important to check the label. During pregnancy, you need about 1.5 times the amount of iodine an adult normally requires, and the Ministry of Health recommends taking an iodine supplement daily. You only need a small amount of iodine each day to meet your needs. If you have any preexisting thyroid conditions, it’s essential that you consult with your qualified medical professional before supplementing iodine.
Dr Libby is a nutritional biochemist, best-selling author and speaker. The advice contained in this column is not intended to be a substitute for direct, personalised advice from a health professional. See drlibby.com