Iodine Deficiency Symptoms, Food Source, Health Benefit

Iodine Deficiency Symptoms iodine is a trace element that is naturally present in some foods, added to others, and available as a dietary supplement. Iodine is an essential component of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Thyroid hormones regulate many important biochemical reactions, including protein synthesis and enzymatic activity, and are critical determinants of metabolic activity. They are also required for proper skeletal and central nervous system development in fetuses and infants.

Iodine and its compounds are primarily used in nutrition. Due to its high atomic number and ease of attachment to organic compounds, it has also found favor as a non-toxic radiocontrast material. Because of the specificity of its uptake by the human body, radioactive isotopes of iodine can also be used to treat thyroid cancer. Iodine is also used as a catalyst in the industrial production of acetic acid and some polymers.

Iodine Deficiency Symptoms

Apart from goiter, hypothyroidism can have the following symptoms:

• Goiter
• Cretinism
• Fibrocystic breast changes
• Fatigue, depression, and forgetfulness
• Hair weakness and hair loss
• Dry skin
• Weight gain
• Cold intolerance
• Constipation

Recommended Intakes of Iodine

Intake recommendations for iodine and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies (formerly National Academy of Sciences). DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and gender, include

• Recommended Dietary Allowance (RDA) – Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
• Adequate Intake (AI) –  Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
• Estimated Average Requirement (EAR) – Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
• Tolerable Upper Intake Level (UL) –  Maximum daily intake unlikely to cause adverse health effects.

Lists the current RDA for iodine. For infants from birth to 12 months, the FNB established an AI for iodine that is equivalent to the mean intake of iodine in healthy, breastfed infants in the United States.

Recommended Dietary Allowances (RDAs) for Iodine 

Age	Male	Female	Pregnancy	Lactation
Birth to 6 months	110 mcg*	110 mcg*
7–12 months	130 mcg*	130 mcg*
1–3 years	90 mcg	90 mcg
4–8 years	90 mcg	90 mcg
9–13 years	120 mcg	120 mcg
14–18 years	150 mcg	150 mcg	220 mcg	290 mcg
19+ years	150 mcg	150 mcg	220 mcg	290 mcg

* Adequate Intake (AI)

The World Health Organization (WHO), United Nations Children’s Fund (UNICEF), and the International Council for the Control of Iodine Deficiency Disorders (ICCIDD) recommend a slightly higher iodine intake for pregnant women of 250 mcg per day.

Food Source of Iodine

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. For these reasons, the values in Table 2 are approximate.

 Selected Food Sources of Iodine 

Food	Approximate Micrograms (mcg) per serving	Percent DV*
Seaweed, whole or sheet, 1 g	16 to 2,984	11% to 1,989%
Cod, baked, 3 ounces	99	66%
Yogurt, plain, low-fat, 1 cup	75	50%
Iodized salt, 1.5 g (approx. 1/4 teaspoon)	71	47%
Milk, reduced fat, 1 cup	56	37%
Fish sticks, 3 ounces	54	36%
Bread, white, enriched, 2 slices	45	30%
Fruit cocktail in heavy syrup, canned, 1/2 cup	42	28%
Shrimp, 3 ounces	35	23%
Ice cream, chocolate, 1/2 cup	30	20%
Macaroni, enriched, boiled, 1 cup	27	18%
Egg, 1 large	24	16%
Tuna, canned in oil, drained, 3 ounces	17	11%
Corn, cream style, canned, 1/2 cup	14	9%
Prunes, dried, 5 prunes	13	9%
Cheese, cheddar, 1 ounce	12	8%
Raisin bran cereal, 1 cup	11	7%
Lima beans, mature, boiled, 1/2 cup	8	5%
Apple juice, 1 cup	7	5%
Green peas, frozen, boiled, 1/2 cup	3	2%
Banana, 1 medium	3	2%

*DV = Daily Value. DVs were developed by the U.S. Food and Drug Administration (FDA) to help consumers compare the nutrient contents of products within the context of a total diet. The DV for iodine is 150 mcg for adults and children aged 4 and older. However, the FDA does not require food labels to list iodine content unless a food has been fortified with this nutrient. Foods providing 20% or more of the DV are considered to be high sources of a nutrient.

The U.S. Department of Agriculture’s (USDA’s) Nutrient Database Web site lists the nutrient content of many foods, but this list does not currently include iodine.

Health Benefit of Iodine

• Iodine deficiency – Taking iodine supplements, including iodized salt, is effective for preventing and treating iodine deficiencies.
• Radiation exposure – Taking iodine by mouth is effective for protecting against exposure to radioactive iodides in a radiation emergency.
• Thyroid conditions –  Taking iodine by mouth can improve thyroid storm and hyperthyroidism. Also, taking iodized salt in addition to thyroxine after surgery for thyroid disease appears to reduce the size of the thyroid.
• Leg ulcers – Research suggests that applying cadexomer iodine to venous leg ulcers along with compression for 4-6 weeks increases the healing rate. Also, applying povidone-iodine in addition to compression seems to help heal leg ulcers and reduce the chance of a future infection.

Possibly Effective for

• Catheter-related infection – Some evidence suggests that applying povidone-iodine reduces the risk of bloodstream infections among people with hemodialysis catheters. However, other research suggests that applying povidone-iodine where a catheter is inserted does not reduce the risk of infection associated with using other types of catheters.
• Conjunctivitis (pinkeye) –  Research suggests that povidone-iodine solutions are more effective than silver nitrate for decreasing the risk of pinkeye in newborns. However, it is not more effective than the medications erythromycin or chloramphenicol.
• Foot ulcers in diabetes – Applying iodine to foot ulcers might be beneficial for people with foot ulcers related to diabetes.
• Inflammation of the uterus (endometritis) – Applying povidone-iodine solution to the vaginal area before a Cesarean delivery reduces the risk of the inflammation of the uterus.
• Painful fibrous breast tissue (fibrocystic breast disease) – Research shows that taking iodine, especially molecular iodine, reduces painful fibrous breast tissue.
• Breast pain (mastalgia) – Taking iodine tablets daily for 5 months reduces pain and tenderness in women with breast pain related to their menstrual cycle.
• Soreness and swelling inside the mouth – Applying iodine to the skin seems to prevent soreness and swelling inside the mouth caused by chemotherapy.
• Gum infection (periodontitis) – Research suggests that rinsing with povidone-iodine during non-surgical treatments for gum infections (periodontitis) can help reduce the depth of infected gum pockets.
• Surgery – Some research suggests that applying povidone-iodine during surgery reduces the risk of infections. However, povidone-iodine seems to be less effective than chlorhexidine at preventing infections at the surgical site.

Insufficient Evidence for

• Bleeding – Early research suggests that washing the tooth socket with povidone-iodine stops bleeding in more patients after having a tooth pulled compared to saline.
• Chile in the urine (chyluria) – Early research suggests that using povidone-iodine in people with chyle in the urine undergoing a pelvic instillation sclerotherapy may be as effective as standard care.
• Eye infection (corneal ulceration) – Early evidence suggests that administering povidone-iodine in addition to standard antibiotic therapy does not improve vision in people with corneal ulcers.
• Fungal skin condition (Cutaneous sporotrichosis) – Potassium iodide is commonly used for cutaneous sporotrichosis. There are reports that taking potassium iodide by mouth alone or with another antifungal treatment is effective for most people with cutaneous sporotrichosis.
• Pneumonia – Early research suggests that rinsing the throat with povidone-iodine decreases the risk of pneumonia in people with severe head trauma who are using a ventilator.
• Wound healing – There is some interest in using iodine agents to promote wound healing. While there is some evidence that applying iodine to wounds is more effective than non-antiseptic dressings in reducing wound size, iodine seems to be less effective than antibiotics.

References

1. https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/
2. https://en.wikipedia.org/wiki/Iodine_deficiency
3. https://www.webmd.com/vitamins/ai/ingredientmono-35/iodine
4. https://www.medicalnewstoday.com/articles/288471.php