Iodine in Diet

Iodine in Diet

Introduction

Iodine Deficiency (ID) is the most prevalent preventable cause of mental impairment. Iodine is important for normal development because it is an essential component of thyroid hormone, which is indispensable for growth and metabolism. Although recent attempts have been made to eradicate ID, the threat still persists, especially in developing countries.

A Brief History of Iodine

First discovered in 1811 by a French chemist

Signaled the “birth” of Western medicine.The use of iodine for treating goiter was the first time that a single element (iodine) was used to treat a specific illness (goiter),More than 100 years ago, iodine was calle“The Universal Medicine”

Iodine in diet

Definition  :Iodine is a trace mineral and an essential nutrient found naturally in the body.

Function  :Iodine is needed for the normal metabolism of cells. Metabolism is the process of converting food into energy. Humans need iodine for normal thyroid function, and for the production of thyroid hormones.

Need for Iodine

Iodine is an essential component of thyroid hormones

Daily needs calculated from balance studies, hormone replacement; represent safe average

Major effects of iodine deficiency come from hypothyroidism

Why Do We Need Iodine?

Every cell in the body contains and utilizes iodine

White blood cells cannot effectively guard against infection without adequate amounts of iodine

Iodine is concentrated in the glandular systemThyroid, breasts, salivary glands, parotid glands, pancreas, cerebrospinal fluid, brain, stomach, skin, lacrimal glands, etc

Where Does The Iodine Go?

Thyroid – 3% (50 mg)

Fat and Muscle– 70%

Skin – 20% (Helps you sweat!)

Iodine is needed for much more than just prevention of goiter!

Why is Iodine So Beneficial?

Elevates pH (Iodine is an alkalinizing agent)

Necessary for the production of thyroid hormones

Necessary for the production of all the hormones of the body (adrenals, ovaries, testicles, etc.)

Responsible for the formation of the normal architecture of the glandular tissue, e.g. breast, thyroid, ovary, & prostate

Iodine’Therapeutic Actions

Alkalinizing agent

Antibacterial

Anticancer

Antiparasitic

Antifungal

Antiviral

Detoxifying agent

Mucolytic agent (like Guaifenesin

Conditions Treated With Iodine

Asthma

Atherosclerosis

Fibrocystic Breast Disease

Cancer

COPD

Diabetes

Excess Mucus Production

Hemorrhoids

Headaches

Hypertension Infections

Keloids

Liver Diseases

Ovarian Cysts (PCOS)

Parotid Duct Stones

Sebaceous Cysts (Acne)

Thyroid Disorders (hypo, autoimmune, and cancer)

Food Sources

Iodized salt -- table salt with iodine added -- is the main food source of iodine. Seafood is naturally rich in iodine. Cod, sea bass, haddock, and perch are good sources. Kelp is the most common vegetable seafood that is a rich source of iodine. Dairy products also contain iodine. Other good sources are plants grown in iodine-rich soil.

Iodine in foods: examples

Milk – 8 oz contains 116 mcg iodine

Bread – wide variation; most has little, but some has >300 mcg per slice

Seafood – variable, moderate content

Meat – good source, depends on animal feed

Grains – variable

Recommended Daily Iodine Intake (FNB,2001)

Adults                        150 mcg

Pregnant                     220

Lactating                    290

Infants 0-6 mos          110

Infants 7-12 mos       130

Children 1-8 y            90

Children 9-13 y        120      

Consequences of Iodine Deficiency

Decreased child survival

Defective child

Reproductive complications

Hypothyroidism

Goiter

Side Effects

Lack of enough iodine (deficiency) may occur in places that have iodine-poor soil. Many months of iodine deficiency in a person's diet  may cause goiter or hypothyroidism. Without enough iodine, the thyroid cells and the thyroid gland become enlarged.

Deficiency happens more often in women than in men, and is more common in pregnant women and older children. Getting enough iodine in the diet may prevent a form of physical and mental retardation called cretinism.

A 1/4 teaspoon of iodized table salt provides 95 micrograms of iodine. A 6-ounce portion of ocean fish provides 650 micrograms of iodine. Most people are able to meet the daily recommendations by eating seafood, iodized salt, and plants grown in iodine-rich soil. When buying salt make sure it is labeled "iodized."

Iodine & The Hormonal System

It is impossible to balance the hormonal system without iodine sufficiency

 Thyroid

 Adrenals

 Sex hormones

Iodine Deficiency andThe Thyroid

Associated with goiter, nodules, hypothyroidism, hyperthyroidism.

Inorganic iodine therapy will decrease the size of a goiter, and also the size of nodules.

Inorganic iodine therapy will repair hypothyroidism and hyperthyroidism. 

BEWARE that some people are very iodine sensitive and may become hyperthyroid when exposed to iodine.  (Your doctor should check iodine levels at 1 month!)

Symptoms of Hypothyroidism

Brittle nails

Carpal tunnel syndrome

Cold hand and feet

Cold intolerance

Constipation

Depression

Difficulty swallowing

Dry skin

Edema

Elevated cholesterol

Essential hypertension

Eyelid swelling

Fatigue

Hair loss

Headaches

Hoarseness

Hypotension (low blood pressure)

Inability to concentrate

Infertility

Irritability

Menstrual irregularities

Muscle cramps

Muscle weakness

Muscle and joint pain

Nervousness

Poor memory

Puffy eyes

Slower heartbeat

Throat pain

Weight gain

Underscored items were my symptoms –many of which were labeled “fibromyalgia”

Iodine excess

Tolerable upper limit 1100 mcg (adults)

Often no effects from much higher doses

Increase in autoimmune thyroid diseases

Occasional iodine-induced hyperthyroidism

Occasional hypothyrodism

Possible increase in papillary cancer

Assessing Iodine Nutrition

Median urinary iodine concentration

Thyroid size in school-age children, by ultrasonography

Neonatal screening by TSH for hypothyroidism

Serum thyroglobulin

Urinary Iodine in USA

NHANES I (1970s) – median 321 mcg/L

NHANES III (1988-94)-median 145 mcg/L

NHANES 2001 –median 161 mcg/L

WHO et al – median >99 mcg/L = sufficiency

Iodine Nutrition in Pregnancy

Developing brain most vulnerable target for iodine deficiency

Fetus gets almost all iodine from mother

Renal iodine threshold lower in pregnancy

NHANES III small subset of pregnants suggested some may have low urinary iodine (<150 mcg/L)

Iodine Nutrition: Neonatal Screening

Routine to detect neonatal hypothyroidism

Occurs in ~1/4000 in iodine sufficiency

Incidence of transient hypothyroidism increases with iodine deficiency

In US, incidence about 1/4000

Iodine Nutrition: Thyroid Size

Thyroid enlarges in iodine deficiency (goiter)

Thyroid size by ultrasound in US similar to that of iodine-sufficient populations

Goiter of pregnancy not typically seen in US

Recommendations

Add iodine to all vitamin/mineral preparations in pregnancy, lactation, and infant formulae

Encourage iodized salt use in those unlikely to get adequate iodine from other sources

Summary

Iodine deficiency can have severe consequences, especially on reproductive outcome

Iodine supplements should be given routinely in pregnancy