The world of Tzu Chi March 2021 (Vol.132)

TZU CHI 132 59 Ng Hui Ling A nutritionist with a Bachelor’s degree in Nutrition and a Master’s degree in Sports Science. She had served with the Singapore Heart Foundation before becoming a self-employed dietary consultant to vegetarians and a contributor for a health magazine. Since I became a vegetarian, I use iodized salt, which I deem the most reliable source of iodine. The sea salts available in vegetarian specialty stores are not cheap, yet do not contain iodine in general. Likewise, some special salts, such as Kosher salt, Himalayan salt and Fleur de Sel, do not have added iodine. So, do look out for iodine in food labels before making a purchase. Dark and light soy sauces as well as miso, are also not reliable sources of iodine. For vegetarians who do not use salt but other seasonings in their cooking, another reliable source would be nutrient supplements that contain iodine. As for vegetarians who love to consume seaweed, refrain from over consumption because one cannot determine the amount of iodine in the seaweed one eats, and excessive iodine in the body can lead to thyroid abnormalities. Hence, it is unadvisable to take large amount of seaweed on a daily basis. Lacto vegetarians may obtain iodine through milk and dairy products. However, for those who do not take dairy products, plant-based beverages such as soy milk, almond milk and rice milk fortified with iodine can be considered. It is imperative to refer to the food label and choose accordingly. Most vegetables and fruits are not good sources of iodine because the iodine contents in them come completely from the soil that they are cultivated in. So iodine content in plants grown from iodine-deficient soil is extremely limited. It is also not possible for us to know the amount of iodine contained in the vegetables we source from supermarkets. Generally speaking, the food that vegetarians consume in large amounts include flaxseed, soy products, cruciferous vegetables such as broccoli, cauliflower and cabbage, and sweet potatoes. These foods contain natural substances called goitrogens, which will reduce iodine absorption into the body, and hence disrupt thyroid hormone synthesis and may cause goitre. While this will not negatively impact vegetarians with sufficient iodine intake, it may exacerbate medical conditions in those who are chronically deficient in iodine. With salt being a common seasoning in daily cooking, using iodized salt is an effective way to prevent iodine deficiency.