By Dr. Mercola
Pregnant women are often told of the importance of consuming enough folate during pregnancy in order to prevent birth defects. You may also be aware of the importance of consuming omega-3 fats for your baby's brain and vitamin D for both baby and maternal health.
Some health care providers now recommend probiotics to their pregnant patients to protect against allergies in their children and more. Few pregnant women are aware of the importance of iodine, however, even though it's estimated that 67 percent of women do not get enough via their diet alone.1
Iodine is a vitally important nutrient that is detected in every organ and tissue in your body. Along with being essential for healthy thyroid function and efficient metabolism, there is increasing evidence that low iodine is related to numerous diseases, including cancer.
Iodine might also severely affect your child's brain and intellectual prowess, as it is important for healthy brain development. New research now suggests an iodine supplement during pregnancy might help to boost children's IQ scores while benefitting the economy.
Iodine May Boost Children's IQ and Lead to Economic Benefits
Research published in 2013 showed that mild iodine deficiency during pregnancy lead to decreased intellect in children. Those born to mothers with low iodine in early pregnancy had lower IQs at age 8, by an average of three points, compared to those born to mothers with healthy iodine levels. The children of low iodine mothers also had worse reading ability at age 9.2
Building on this research, the latest study revealed that if all women took iodine supplements before conception, during pregnancy, and while breastfeeding, children's IQ scores would be raised by an average of 1.22 points.3
In turn, the boosts in IQ would lead to nearly $7,000 in higher earnings and lower education costs for children for each pregnant woman choosing to take an iodine supplement. Meanwhile, savings to the UK's National Health Service were estimated at over $310 per pregnant woman. The researchers concluded:
"Iodine supplementation for pregnant women in the UK is potentially cost saving. This finding also has implications for the 1.88 billion people in the 32 countries with iodine deficiency worldwide.
Valuation of IQ points should consider non-earnings benefits — e.g, health benefits associated with a higher IQ not germane to earnings."
Why Low Iodine During Pregnancy Is Detrimental to Baby's Brain
For the first 12 weeks of pregnancy, before the unborn child's thyroid becomes active, the mother is the sole source of thyroid hormones, which are required for optimal brain function and development in children. Hypothyroidism is one of the first ailments to develop in response to iodine deficiency, and it is particularly troublesome during pregnancy.
One 1999 study found that thyroid deficiency during pregnancy can lower your child's IQ by about seven points. 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.4
According to Dr. Jorge Flechas, MD, 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 for adults, but especially for his pregnant patients to optimize their child's intelligence.
He shares a couple of success stories in his lecture above, where iodine supplementation at higher doses resulted in children with remarkably advanced intelligence.
Although he makes a compelling argument, I am not yet convinced that such large amounts are necessary. 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. Personally, I am not yet convinced and do not take such high doses in supplemental form.
For comparison, the World Health Organization advises that pregnant women should have 0.25 mg of iodine a day,5 so I would encourage you to do your own research and adopt a sensible, middle-of-the-road approach when it comes to iodine.
It's Not Only Pregnant Women Who Need Sufficient Iodine
Iodine is necessary for your thyroid, which in turn produces hormones crucial for brain development. However, other tissues also absorb and use large amounts of iodine, including:
Breasts Salivary glands Pancreas Cerebral spinal fluid Skin Stomach Brain Thymus
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:
- Salivary glands = inability to produce saliva, producing dry mouth
- 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, and fibromyalgia
Iodine actually induces apoptosis as well, 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. Unfortunately, iodine levels have significantly dropped in the US in recent decades due to several factors, including:
- Bromine exposure: When you ingest or absorb bromine (found in baked goods, plastics, soft drinks, medications, pesticides, and more), it displaces iodine, and this iodine deficiency leads to an increased risk for cancer of the breast, thyroid gland, ovary, and prostate – cancers that we see at alarmingly high rates today
- Declining consumption of iodine-rich foods, such as iodized salt, eggs, fish, and sea vegetables
- Soil depletion
- Less use of iodide in the food and agricultural industry
- Fluoridated drinking water
- Rocket fuel (perchlorate) contamination in food, which can impair the uptake of iodine into your thyroid
Too Much Iodine May Be Harmful
The jury is still out on whether iodine in supplemental form is safe, especially at higher doses. For instance, while sea vegetables are a naturally rich source of iodine, the British Dietetic Association recommends against the use of kelp and seaweed supplements, particularly by pregnant women, because they may contain harmful amounts.6
Even consuming sea vegetables regularly could potentially put you over a healthy limit. The George Mateljan Foundation recommends that anyone consuming one tablespoon or more of sea vegetables on a daily basis might want to evaluate their intake of iodine to see if it exceeds the Tolerable Upper Limit (UL) of 1,100 micrograms.7
While taking extremely high doses of iodine could lead to acute symptoms such as mouth pain, nausea, and vomiting, there is also concern that high-dose iodine supplementation might lead to subclinical hypothyroidism. The study, published 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.8
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, 5 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 telltale 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 to 13 mg (12,000 to 13,000 mcgs) could potentially have some adverse health effects.
How to Test Your Iodine Levels
In the US, low iodine is widespread, such that virtually everyone needs it. But there is, unfortunately, no foolproof lab test to find out if your levels are low. However, if you are interested in being tested for iodine deficiency, ask your health care provider about the urine iodine challenge test. This test involves taking iodine tablets and collecting your urine for 24 hours to determine how much is stored in your tissues and how much is excreted. This can give you an idea of whether your levels are sufficient or not.
Another simple way to ensure you're getting enough iodine is to get an inexpensive prescription from your physician for SSKI, which is a super-saturated potassium iodine. You simply apply three drops to your skin and rub it in, once a day. If when you touch something with slightly wet fingertips it leaves a yellowish stain, then the iodine is coming out of your skin, indicating your body is saturated, i.e. you're getting enough iodine.
What Are the Best Ways to Optimize Your Iodine Levels?
Toxin-free sea vegetables and spirulina are likely the ideal natural sources from which to obtain your iodine — however, make sure that these are harvested from uncontaminated waters (especially if you're pregnant!) and be careful not to overdo it. Consuming sea vegetables comes with the added benefit of also providing valuable minerals and even modulating your gut flora such that it alters estrogen metabolism and lowers your risk of breast cancer.9 (One study even found that consuming a sheet of nori a day may cut a woman's risk of breast cancer in half.10)
Other sources of seafood, such as wild-caught scallops, sardines, salmon, and shrimp, contain iodine as well, as do raw milk, eggs, and even strawberries. At the same time, you'll want to avoid all sources of bromine as much as possible, as this appears to play a large role in the rising levels of iodine deficiency. Here are several strategies you can use to avoid bromine and thereby help optimize your iodine levels naturally:
- Eat organic as often as possible. Wash all produce thoroughly to minimize your pesticide exposure.
- Avoid eating or drinking from (or storing food and water in) plastic containers. Use glass and safe ceramic vessels.
- Look for organic whole-grain breads and flour. Grind you own grain, if possible. Look for the "no bromine" or "bromine-free" label on commercial baked goods.
- Avoid sodas. Drink natural, filtered water instead.
- If you own a hot tub, look into an ozone purification system. Such systems make it possible to keep the water clean with minimal chemical treatments.
- Look for personal care products that are as toxin-free as possible. Remember – anything going on you, goes in you.
- When in a car or a building, open windows as often as possible, preferably on opposing sides of the space for cross ventilation. Utilize fans to circulate the air. Chemical pollutants are in much higher concentrations inside buildings (and cars) than outside.
If you're pregnant, keep in mind that some prenatal supplements contain added iodine as well, so you should factor that into your total daily intake. Even if you're not pregnant, adults can also consider an iodine-containing whole food supplement in addition to the dietary sources mentioned above.