How Much Iodine Do I Need?

By Dr. Mercola – How Iodine Deficiency May Affect Your Child’s Brain Function and IQ <–Content Source

In this fascinating video, taped at last year’s Restorative Medicine Conference in Portland, Oregon, Dr. Jorge Flechas, MD discusses the importance of total body iodine sufficiency, and how lack of iodine might severely affect your child’s brain and intellectual prowess. Iodine is an essential trace element required for the synthesis of hormones, and the lack of it can also cause or contribute to the development of:

  • Hypothyroidism
  • Goiter
  • Mental retardation
  • Cretinism (severely stunted physical and mental growth and deafness due to untreated congenital hypothyroidism)
  • Certain forms of cancer

Iodine is used by your thyroid gland to help regulate metabolism and development of both your skeleton and brain, among other things. But how much iodine do you need, really? There’s quite a bit of contention on this issue.

Some, like Dr. Flechas insists severe iodine deficiency is rampant, while others claim this is not the case at all, and that taking higher doses of iodine can be harmful. I don’t proclaim to have the answer to this question… There’s no doubt you need iodine. But it’s difficult to say precisely how much.

I suspect the dosages recommended by Dr. Flechas, Dr. Brownstein, and others, may be too high, so I would encourage you to do your own research, and adopt a sensible, middle-of-the-road approach when it comes to iodine.

I also want to clarify the difference between Iodine and Iodide. Iodine is the molecule that is taken up by cells in the body. However, Iodine is a gas and is not very available in food and supplements. Instead, it is the iodide form that is more stable and can be consumed. In the body, Iodide converted into Iodine which is the active form.

Why Is Hypothyroidism More Prevalent in Women than Men?

There is simply no question that optimizing your iodine levels is essential for thyroid health. Hypothyroidism disproportionately affects women at a rate of about 9 to 1 in the US. The reason for this is that the female hormone estrogen inhibits the absorption of iodine.

According to Dr. Flechas, hypothyroidism is associated with up to 80-90 percent free estrogen levels, compared to the normal value of 40-60 percent free estrogen. Hyperthyroidism is associated with only 20 percent free estrogen levels, and low iodine intake can lead to a hyperestrogenic state. In his lecture, Dr. Flechas explains the interplaying dynamics of estrogen, thyroid hormones, and iodine at greater depth, so for more information, please set aside 40 minutes to watch the video above.

Your Body Needs Iodine for More than Just Your Thyroid

Dr. Flechas presents a number of interesting facts about iodine that is not widely known. For example, did you know that thyroid hormones are created not just in your thyroid, but also in a woman’s ovaries (thyroid T2), and in the white blood cells of your bone marrow? Furthermore, iodine is not only required for proper function of your thyroid. Other tissues that absorb and use large amounts of iodine include:

~ Breasts | Salivary Glands | Pancreas | Cerebral Spinal Fluid | Skin | Stomach | Brain | Thymus ~

Salivary glands = inability to produce saliva, producing dry mouth Iodine deficiency, or insufficiency, in any of these tissues will lead to dysfunction of that tissue. Hence the following symptoms could provide clues that you’re not getting enough iodine in your diet. For example, iodine deficiency in:

  • Skin = dry skin, and lack of sweating. Three to four weeks of iodine supplementation will typically reverse this symptom, allowing your body to sweat normally again
  • Brain = reduced alertness, and lowered IQ
  • Muscles = nodules, scar tissue, pain, fibrosis, fibromyalgia

How Much Iodine Does Your Body Need?

According to Dr. Flechas, researchers have determined that the average dietary intake of iodine for Japanese women is 13.8 milligrams (mg) per day. He recommends 12.5 mg/day, especially for his pregnant patients to optimize their child’s intelligence. He shares a couple of success stories in his lecture, where iodine supplementation at higher doses resulted in children with remarkably advanced intelligence.

Hypothyroidism, which is one of the first ailments to develop in response to iodine deficiency, is indeed particularly troublesome during pregnancy. One 1999 study found that thyroid deficiency during pregnancy can lower your child’s IQ by about seven points. The researchers noted that for the first 12 weeks of pregnancy, before the unborn child’s thyroid becomes active, the mother is the sole source of thyroid hormones. Studies suggest that these hormones play an important role in brain development. Overall, compared with other children, the offspring of thyroid-deficient mothers had impaired school performance and lower scores on tests of attention, language, and visual-motor performance.

But pregnant women aren’t the only ones who need to be concerned with the iodine content of their diet. According to Dr. Flechas, your thyroid alone needs about 6 mg of iodine per day; the breasts of a 110-pound woman will need about 5 mg/day (larger women or women with larger breasts need more); and other body tissues, such as your adrenals, thymus, ovaries, hypothalamus, and pituitary gland, need about 2 mg/day.

Here are a few more interesting facts:

  • In total, the human body can hold 1,500 mg of iodine
  • Your thyroid can hold a maximum of 50 mg of iodine
  • 20 percent of the iodine in your body is held in your skin (if your skin is depleted of iodine, you will not be able to sweat)
  • 32 percent of your body’s iodine stores are in your muscles (if muscles are depleted, pain and other fibromyalgia symptoms can develop)

Although he makes a compelling argument, I am not yet convinced that such large amounts may be necessary. Dr. Brownstein and others would label this as iodinophobia, but I believe caution may be appropriate here before swallowing mg amounts of iodine on a regular basis. Personally, I am not yet convinced and do not take such high doses in supplemental form.

The US RDA May Be Insufficient for Many

It is important to realize that the current US daily recommended allowance (RDA) for iodine are not in milligram doses but in micrograms:

  • 150 micrograms (mcg) per day for adult men and women
  • 220 mcg for pregnant women
  • 290 mcg for lactating/breastfeeding women

However, this RDA was set with the intention to prevent goiter only. Dr. Flechas makes a compelling argument for it being completely insufficient for overall physical health and prevention of diseases such as thyroid disease, fibromyalgia, and cancer. Iodine actually induces apoptosis, meaning it causes cancer cells to self destruct. Dr. Flechas is adamant that absence of iodine in a cell is what causes cancer, and statistics tend to support this view. In his lecture, he shows the results of a number of NHANES surveys.

For example, between 1971 and 2000, the average iodine levels declined by 50 percent in the US. During that same time, cancers specifically associated with iodine deficiency—such as cancer of the breast, prostate, endometrium, and ovaries—increased.  He also points out that the RDA completely ignores the presence of increasing amounts of goitrogens in the environment. The following halides compete for the same receptors used in your thyroid gland and elsewhere to capture iodine, so if you’re exposed to too many of these, your thyroid hormone production can be severely disrupted, resulting in a low thyroid state:

  • Bromide / bromine (Bromide can be found in several forms. Methyl bromide is a pesticide used mainly on strawberries, found predominantly in the California areas. Brominated vegetable oil (BVO) is added to citrus drinks to help suspend the flavoring in the liquid. Potassium bromate is a dough conditioner found in commercial bakery products and some flours)
  • Chlorine
  • Fluoride

Could High-Dose Iodine Be Dangerous?

As I mentioned at the beginning, while Dr. Flechas provides very compelling arguments for using doses as high as 12.5 milligrams (mg) per day, which is a far cry from the RDA of 150 micrograms (mcg), I’m hesitant to make such a recommendation. I think the jury is still out, and we need more research to determine the health effects of too much iodine.

As reported by Reuters at the beginning of this year1, a recently published study has cast some doubts on high-dose iodine supplementation. The study, published December 28, 2011 in the American Journal of Clinical Nutrition, randomly assigned one of 12 different dosages of iodine (ranging from 0 to 2,000 mcg/day) to healthy adults for four weeks.

When diet was factored in, those taking 400 mcg/day were receiving a total of about 800 mcg of iodine per day.

At doses at and above 400 mcg of supplemented iodine per day, some of the study participants developed subclinical hypothyroidism, which appeared to be dose dependent. At 400 mcg/day, five percent developed subclinical hypothyroidism; at the highest dose—2,000 mcg/day—47 percent of participants were thus affected. Subclinical hypothyroidism refers to a reduction in thyroid hormone levels that is not sufficient to produce obvious symptoms of hypothyroidism (such as fatigue, dry skin, depression or weight gain, just to mention a few common tell-tale signs).

So, these findings suggest it might not be wise to get more than about 800 mcg of iodine per day, and supplementing with as much as 12-13 mg (12,000-13,000 mcg’s) could potentially have some adverse health effects.