Your thyroid gland produces hormones that regulate your body's use of energy, especially the use of body fat. The production of these hormones requires the trace mineral iodine. Substances in raw spinach called goitrogens can temporarily decrease your body's ability to absorb iodine from foods. However, eating raw spinach in moderation is unlikely to be problematic unless you have an existing thyroid condition.
Iodine
Iodine is a trace mineral found in dairy, meat, fish, and most fruits and vegetables, although levels may vary depending on the soil conditions during growth. Iodine is also added to table salt, making iodine deficiency in developed nations rare. Your thyroid gland stores ample amounts of iodine in order to produce thyroid hormones.
Thyroid Function
When you don't get enough iodine in your diet, your body cannot produce enough thyroid hormones, resulting in a medical condition called hypothyroidism. Hypothyroidism can have other causes in addition to iodine deficiency. Without enough thyroid hormones, you may gain weight; be sensitive to cold; feel weak and fatigued; experience digestive problems; have brittle hair and nails; and have pale skin. When your thyroid gland is unhealthy, it cannot store iodine efficiently. This may change the amount of iodine you need in your diet. Ask your doctor for specific dietary guidelines specific to your individual needs.
Goitrogens
Goitrogens are chemicals that prevent your intestines from absorbing iodine. Chemicals classified as goitrogenic may also inhibit your thyroid function directly by slowing the production of thyroid hormones. According to a 2002 article in the journal "Thyroid," foods high in goitrogens, such as raw spinach, can increase your risk of developing thyroid disease, but they have not been shown to directly cause it. Other risk factors include pregnancy, low iodine consumption and poor health.
Recommendations
Spinach is high in nutrients and may inhibit the growth of some cancers. There is little need to avoid raw spinach unless you have been diagnosed with hypothyroidism. Even with hypothyroidism, moderate consumption is likely safe if you are taking additional steps to correct any iodine deficiency. Simply taking large amounts of iodine will not treat hypothyroidism, so if you are getting adequate iodine in your diet, raw spinach should not be detrimental.
