Curious About Iodine, Half 1: Simply the Fundamentals

The usage of iodine dates again to 4th century China the place seaweed and burnt sea sponge had been successfully used to deal with goiter. It was not till 1811 that iodine was remoted as a selected aspect that exhibited properties just like the opposite halogens of bromine, chlorine, and fluorine. In 1829, Jean Guillaume Auguste Lugol, MD, launched potassium iodide as an efficient remedy for the results of tuberculosis, and John Murray, MD, used iodine to deal with croup, bronchial asthma, consumption, and different respiratory illnesses (1).

Tincture of iodine has been a staple in each first help package for the remedy of wounds to forestall an infection and help therapeutic. Surgeons scrub up with a betadine resolution and paint it on the physique of these present process surgical procedure to guarantee the pores and skin is freed from microbes. Over its lengthy historical past, iodine has been used as an efficient remedy for goiter, higher respiratory infections, bronchial asthma, and croup. It has additionally been used as an antiseptic, disinfectant, an expectorant, an amoebicide, and an anti-syphilitic treatment. Iodine has additionally been used topically for the remedy of assorted pores and skin problems (1).

Iodine Deficiency Dysfunction is the commonest endocrinopathy on the earth and can also be probably the most preventable.

Iodine is a really versatile aspect in that its mechanism of motion is considerably decided by the place it’s saved within the physique. The thyroid gland wants iodine to make thyroid hormones, which help development, metabolism, and cognitive improvement, however iodine can also be concentrated in quite a few extrathyroidal tissues the place it acts intracellularly as an antioxidant, helps mobile differentiation, has anti-inflammatory results, and helps apoptosis (2). 

Roughly 30% of the worldwide inhabitants is iodine poor on account of lowered consumption and publicity to meals and environmental elements that inhibit iodine absorption. Let’s discover a number of the fundamentals about iodine – the place we get it, widespread kinds, signs of deficiency, and the way a lot we really need, not solely to forestall deficiency, however to optimize tissue ranges past what is required to help thyroid operate.

Sources of iodine

The oceans are the world’s important repository of iodine with some deposition in coastal soil on account of volatilization of ocean water from ultraviolet radiation. Little or no of the earth’s iodine is definitely present in soil and the additional we’re from the coast, the decrease the iodine content material (3). Meals sources of iodine are seaweed (kombu, nori, kelp, wakame), seafood, iodized salt, dairy, eggs, baked items made with iodate dough conditioner, breast milk, toddler method, beef liver and rooster (4).

Iodine versus iodide

Though iodide and iodine are used interchangeably, they’re structurally and functionally completely different. Iodine and iodide are intently associated phrases as a result of iodide is derived from iodine; nonetheless, iodine is a chemical aspect whereas iodide is an anion (5).

• Iodine (I²) – Iodine hardly ever happens as the one aspect seen on the periodic desk. Iodine as I² is molecular iodine through which two atoms of iodine are sure collectively.
• Iodide (I¯) – Iodide is the anion of iodine and sometimes binds to different components to type a salt reminiscent of potassium iodide or sodium iodide. Iodide is shaped from iodine with the addition of an additional electron.

Iodine deficiency

Iodine Deficiency Dysfunction (IDD) is the commonest endocrinopathy on the earth and can also be probably the most preventable. The latest knowledge means that no less than one-third of the world’s inhabitants is iodine poor (6). In accordance with knowledge from the Nationwide Well being and Diet Examination Survey (7), the median urinary iodine focus of adults within the U.S. decreased by over 50% from the early Seventies to the late Nineties (8). Decreased consumption of dietary iodine within the U.S. is probably on account of variations within the iodine content material of dairy merchandise or avoidance of dairy, the removing of iodate dough conditioners in commercially produced bread, new suggestions for lowered salt consumption for blood strain management, and use of non-iodized salt (8).

Iodine deficiency outlined

Iodine ranges are measured within the urine as a lot of what we devour is eradicated by the kidneys. To find out regional iodine deficiency, the measurement of urinary iodide is finished throughout giant populations and doesn’t contain using a excessive loading dose of iodine. The American Thyroid Affiliation defines iodine deficiency as a median urinary iodide focus lower than 100 mcg/L in a nonpregnant inhabitants, or <150 mcg/L in pregnant girls (9).

Signs of iodine deficiency

A lot of the systemic results of iodine deficiency are the results of deficiency of thyroid hormones (3). Although many tissues focus iodine and all cells of the physique make the most of iodine, it’s the thyroid that will get the lion’s share from dietary sources. Deficiencies are most pronounced inside the thyroid gland with extenuating results on different iodine-concentrating glandular tissues. Frequent signs of iodine deficiency embrace weight achieve, mind fog, psychiatric problems, lowered mental capability, most cancers (breast, abdomen, prostate), prostate enlargement, melancholy, fatigue, goiter, menstrual points, polycystic ovary syndrome (PCOS), saliva deficiency, thyroid nodules, migraines, miscarriages, and stillbirths (3).

Absorption of Iodine

The assorted types of iodine that we devour in meals or by supplementation is lowered to iodide within the abdomen and higher small gut earlier than absorption. Iodide is actively transported into cells primarily by the sodium-iodide symporter (NIS). Within the thyroid, the operate of the NIS is regulated by thyroid-stimulating hormone, thyroglobulin, and iodide concentrations. The NIS can also be expressed in different tissues that focus iodide. These tissues embrace the tear ducts, salivary glands, choroid plexus, abdomen, intestines, lactating breasts, kidneys, placenta, the ovaries, and cells of the immune system (10).

The sodium iodide symporter (NIS) is a plasma membrane protein that facilitates the energetic transport of iodide into the thyroid gland and numerous extrathyroidal tissues.

Along with iodide transport, the NIS can even transport different chemical compounds that will inhibit iodide absorption and NIS operate. Perchlorate is a standard environmental chemical that inhibits NIS operate and impairs iodide absorption. Perchlorate is pervasive within the atmosphere and our meals chain as it’s generally present in fertilizers, rocket gas, missiles, fireworks, and different explosives, leaving remnants to settle into the soil and groundwater (11).

Nitrates can even inhibit the NIS and although they’re generally present in greens, meat, and dairy, greater concentrations are present in fertilizers that saturate the soil and seep into groundwater. The energetic element of goitrogenic meals is thiocyanate. It’s present in excessive concentrations in raw cruciferous greens, millet, soy, and candy potatoes, and is one other widespread inhibitor of the NIS and iodine absorption (11).

Bromine, chlorine, fluorine, and iodine are a part of the household of halogens on the periodic desk, so that they have related properties. Like iodine, the halogens can exist of their ionic type as bromide, chloride, and fluoride. These halides exist in meals, water, drugs, and the environment and competitively inhibit the absorption of iodine.

How a lot iodine do we want?

The Beneficial Dietary Allowance (RDA) for iodine is 150 mcg for an grownup, 220 mcg throughout being pregnant and 290 mcg for lactating girls with the higher day by day restrict set at 1100 mcg per day (12). Iodine deficiency is primarily from lack of iodine consumption, however we’re additionally uncovered to parts in meals and the atmosphere that inhibit the assimilation of iodine into the tissues that want it probably the most.

Iodine ranges are measured within the urine as a lot of what we devour is eradicated by the kidneys.

The RDA of 150 mcg was proposed a long time in the past as the quantity of iodine wanted to forestall goiter. Given the presence of naturally occurring and man-made chemical compounds in the environment which have the potential to inhibit iodine absorption, our want for iodine could also be higher than the RDA. In a 2011 evaluation of iodine  consumption in Japan, Zava and Zava decided that the common iodine consumption, largely from seaweed, averaged 1000-3000 mcg/day (13).

Compared to the RDA, residents of Japan who devour a conventional weight loss plan, ingest between 7-20 instances our RDA and the Japanese Ministry of Well being has set the higher restrict of iodine at 3000 mcg/day (14). The elevated consumption of iodine might have a major impact on the decrease charges of breast, gastric and prostate most cancers in Japan as in comparison with the U.S.

Further vitamins to help iodine

Meals sources with the next iodine content material could also be higher tolerated than greater ranges from dietary supplements as iodine is mixed with extra vitamins that help absorption and utilization. Selenium, iron, zinc, copper, magnesium, and vitamin A are all supportive of thyroid operate and hormone manufacturing. Combining iodine supplementation with these vitamins helps the enzymes wanted to make thyroid hormone, reduces oxidative stress, and helps conversion of T4 to T3 (15).

The paradoxical impact of an excessive amount of iodine

Learn any literature on using iodine and you’ll encounter the cautionary story of the Wolff-Chaikoff impact. It is a actual phenomenon, and it happens when an excessive amount of iodine enters thyroid tissue and has an inhibitory impact on thyroid hormone manufacturing and launch. As talked about above, the NIS is partly regulated by iodine focus inside thyroid cells. An excessive amount of iodine decreases the exercise of the NIS, leaving the thyroid in a state of lowered exercise for anyplace between 2-15 days. Ultimately, the thyroid might return to regular operate however in these with an underlying thyroid dysfunction reminiscent of subclinical hypothyroidism or Hashimoto’s, the thyroid might not return to regular operate and ongoing remedy with thyroid medicine could also be crucial (13).

Although many tissues focus iodine and all cells of the physique make the most of iodine, it’s the thyroid that will get the lion’s share from dietary sources.

Excessive dosages of iodine can even trigger hyperthyroidism particularly in populations which have been dwelling in a state of iodine deficiency the place nodules can type an extreme quantity of thyroid hormone from supplemented iodine (14). It’s at all times essential to keep in mind that in excessive doses, vitamins can have a drug-like impact. Simply because somewhat is sweet doesn’t imply extra is best.

Measuring iodine standing

ZRT Laboratory measures iodine by a dried urine pattern taken upon waking and earlier than mattress. This check doesn’t require a excessive loading dose of iodine previous to gathering the urine pattern and is extra consultant of day by day consumption. The choices for testing urine iodine embrace a standalone Iodine Panel; as a part of a Complete Thyroid Profile; or together with different important minerals and heavy metals, in both the Urine Poisonous & Important Components or the Complete Poisonous & Important Components.

Up subsequent

To additional our understanding of the numerous advantages of enough iodine, I might be wanting into the position that iodine performs in extrathyroidal tissues in addition to a better take a look at thyroid operate and iodine standing. If IDD is the commonest endocrinopathy, what are the results of iodine deficiency on fertility, PCOS, pores and skin problems, immune operate, fibrocystic breasts, and breast, prostate, and different cancers? Keep tuned…

References

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7. Nationwide Well being and Diet Examination Survey. Nationwide Heart for Well being Statistics. Heart for Illness Management and Prevention. 1999-2008
8. Leung AM, Pearce EN, Braverman LE. Enough iodine consumption throughout being pregnant: simply do it. Thyroid. 2013;23(1):7-8.
9. Iodine deficiency. American Thyroid Affiliation. 2022.
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11. Pearce EN, Braverman LE. (2017). Environmental Iodine Uptake Inhibitors. In: Pearce EN (eds) Iodine Deficiency Problems and Their Elimination. Springer, Cham.
12. Truth Sheet for Well being Professionals. Nationwide Institutes for Well being. Workplace of Dietary Dietary supplements. 2022.
13. Zava TT, Zava DT. Evaluation of Japanese iodine consumption based mostly on seaweed consumption in Japan: a literature-based evaluation. Thyroid Res. 2011;4:14.
14. Iodine testing in dried urine. ZRT Information Sheet. ZRT Laboratory. 2022.
15. ​Triggiani V, Tafaro E, Giagulli VA, et al. Function of iodine, selenium and different micronutrients in thyroid operate and problems. Endocr Metab Immune Disord Drug Targets. 2009;9(3):277-294.