Updated: December 30, 2024

Iodine is a chemical element that is naturally present in some foods, added to others, and available as a dietary supplement. As the body cannot produce iodine but requires it for proper functioning, the necessary iodine must come from the diet. Food has very little iodine unless it has been added during processing, such as in iodized salt. Most of the world's iodine is found in the ocean, which is concentrated by sea life, especially seaweed. The thyroid gland needs iodine to make hormones. If the thyroid doesn't have enough iodine to do its job, it can cause an enlarged thyroid gland (goiter), which becomes evident as a swollen neck.

Other consequences of not having enough iodine (iodine deficiency) are also severe. Iodine deficiency and the resulting low levels of thyroid hormone can cause women to stop ovulating, leading to infertility. Iodine deficiency can also lead to an autoimmune disease of the thyroid and may increase the risk of getting thyroid cancer. Some researchers think that iodine deficiency might also increase the risk of other cancers such as prostate, breast, endometrial, and ovarian cancer.

Health Implications of Iodine Deficiency

Iodine deficiency during pregnancy is serious for both the mother and the baby. It can lead to high blood pressure during pregnancy for the mother and mental retardation for the baby. Iodine plays a vital role in the development of the central nervous system. In extreme cases, iodine deficiency can lead to cretinism, a disorder that involves severely stunted physical and mental growth. Iodine reduces thyroid hormone and can kill fungi, bacteria, and other microorganisms such as amoebas. A specific kind of iodine called potassium iodide is also used to treat the effects of a radioactive accident. However, it cannot prevent the impact of a radioactive accident.

Dietary Sources

Nutritional needs should be met primarily from foods. Nutrient-dense foods contain essential vitamins and minerals, dietary fiber, and other naturally occurring substances that may have positive health effects. In some cases, fortified foods and nutritional supplements may be useful in providing one or more nutrients that otherwise may be consumed in less-than recommended amounts.

Seaweed such as kelp, nori, kombu, and wakame is one of the best food sources of iodine, but it is highly variable in its content. Other good sources include seafood, dairy, grain, and eggs. This is because of the use of iodine feed supplements and iodophor sanitizing agents in the dairy industry. Dairy products, especially milk and grain products, are the major contributors of iodine to the American diet. Iodine is also present in human breast milk and infant formulas. Fruits and vegetables contain iodine, but the amount varies depending on the iodine content of the soil, fertilizer use, and irrigation practices. Iodine concentrations in plant foods can range from as little as 10 mcg/kg to 1 mg/kg dry weight. This variability, in turn, affects the iodine content of meat and animal products because it affects the iodine content of foods that the animals consume. The iodine content of different seaweed species also varies greatly.

The Daily Value (DV) for iodine is 150 mcg for adults and children aged 4 years and older. To obtain the daily value, you can include a variety of vegetables, fruits, whole grains, fat-free or low-fat milk and milk products, and oils. Milk is an excellent source of iodine. Fruits, vegetables, and bread also provide small quantities of iodine. Include a variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), nuts, seeds, and soy products. Some fish contain high amounts of iodine. Eggs are also good sources of iodine. Limit saturated and trans fats, added sugars, and sodium to stay within your daily calorie needs.

Iodized salt can also be taken as a dietary supplement.

The U.S. Food and Drug Administration (FDA) has approved potassium iodide and cuprous iodide for salt iodization. At the same time, the WHO recommends the use of potassium iodate due to its greater stability, particularly in tropical climates. According to its label, iodized salt in the United States contains 45 mcg iodine/g. Many multivitamin/mineral supplements contain iodine in the forms of potassium iodide or sodium iodide. Dietary supplements of iodine or iodine-containing kelp (seaweed) are also available. According to some research, potassium iodide is almost completely (96.4%) absorbed in humans.

Dosing Recommendations

Iodine requirements vary by age and condition, with the following daily recommendations:

• Infants (0-6 months): 110 mcg/day

• Children (1-8 years): 90 mcg/day

• Adults (14+ years): 150 mcg/day

• Pregnant Women: 220 mcg/day

• Breastfeeding Women: 290 mcg/day

In emergencies, potassium iodide (KI) is administered to mitigate radiation exposure effects:

• Infants (0-1 month): 16 mg KI

• Children (1 month-3 years): 32 mg KI

• Adults (18-40 years): 130 mg KI

The tolerable upper intake level for adults is 1,100 mcg/day. Exceeding this may lead to thyroid issues or other adverse effects.

Special Precautions and Interactions

• Iodine is likely safe when taken by mouth in recommended amounts or when applied to the skin appropriately using an approved product (2% solution). However, higher doses might cause thyroid problems. Do not exceed 1100 mcg/day if over 18 years old or 900 mcg/day for ages 14-18.

• People with autoimmune thyroid conditions may be more sensitive to iodine's side effects.

• Iodine can worsen rashes (Dermatitis Herpetiformis)

• High doses or prolonged use can worsen hypothyroidism, goiter, or thyroid tumors.

Interactions with

• Antithyroid Drugs: Iodine can over-suppress thyroid function when combined with these medications.

• Amiodarone, Lithium, Potassium-Sparing Diuretics, ACE Inhibitors, ARBs: Combining these with iodine can lead to excessive potassium or thyroid dysfunction.

B2B Opportunities in Iodine-Based Products

Consumer awareness of iodine as a nutrient of concern is well on the rise, thereby opening a great opportunity for business organizations to maintain the general well-being of the public by fulfilling their increasing demands. Several industries can leverage iodine's essential role in health and nutrition:

In healthcare, iodine's role extends beyond thyroid supplements. Launching better formulations designed to meet different requirements of iodine makes it easier for companies to help people suffering from thyroid diseases. Furthermore, it is widely used for imaging in radiography and computed tomography as a contrast medium facilitating correct diagnosis. This application creates opportunities of improving and marketing iodine-based imaging agents to the pharmaceutical producers.

Local antiseptics, including povidone-iodine, have been used for wound treatment for a long time. Yet, taking it to care of skin infections, postoperative disorders, and hospital-acquired conditions can afford broader health care benefits. Iodine's proven efficacy as an antimicrobial agent makes it a valuable resource in infection prevention. In the same way, mouthwash and dental gels containing iodine can serve consumers looking to maintain higher levels of personal oral hygiene and bacterial control, which is a promising but small market category.