Your Chances of Getting Pregnant Reduced by Iodine Deficiency?

Your Chances Of Getting Pregnant Could Be Cut In Half

Author: Dr. Stephen Chaney

 

Are your chances of getting pregnant reduced by iodine deficiency?

It shouldn’t be happening. The introduction of iodized salt in the 1920s virtually eliminated iodine deficiency in this country. However, in just the past twenty years the incidence of iodine deficiency has increased 3-8-fold in women of childbearing age. Recent studies have estimated that today 30-40% of women of childbearing age are iodine deficient.

How did that happen?

  • We have been told to cut back on sodium. Many Americans have responded by throwing away the (iodized) salt shaker. Unfortunately, we still get a lot of salt from processed foods, and that salt is usually non-iodized.
  • When we do add salt to our foods it is usually the “healthier” designer salts. First it was sea salt. Now it is trendy versions like Pink Himalayan Salt. While sea salt might have some iodine naturally, the trendier versions are non-iodized.
  • The New-Age Whole Food diets often ban salt from the diet. That increases the probability of becoming iodine deficient. For example, a recent study reported that women who followed the Paleo diet for two years became iodine deficient (S. Manousi et al, European Journal of Clinical Nutrition, 72: 124-129, 2018 ).

The consequences of iodine deficiency, especially among women of childbearing age, are alarming. In a previous issue of “Health Tips From the Professor,” The Dangers of Iodine Deficiency During Pregnancy, I reported that iodine is essential for bone and neural development during fetal development and infancy. I also reported that the American Academy of Pediatrics, The National Institutes Of Health, and the World Health Organization have all declared that mild iodine deficiency during pregnancy can prevent normal cognitive development and reduce IQ levels in children.

This study (JL Mills et al, Human Reproduction, doi: 10.1093/humrep/dex379, 2018 ) reports that iodine deficiency also reduces a woman’s chances of becoming pregnant. [I might add, this almost seems to be part of Nature’s plan. If the consequences of iodine deficiency during pregnancy are so detrimental, the fact that iodine deficiency also reduces the chances of a woman becoming pregnant could be considered a good thing.]

How Was The Study Done?

This study recruited 501 couples (ages 18-40) from 16 counties in Michigan and Texas. The women had all discontinued contraception within the previous two months with the intention of becoming pregnant and were followed for an additional 12 months. Women with known thyroid disease were excluded from the study.

Urine samples were collected from each woman at the beginning of the study to determine iodine and creatine levels. The women used fertility monitors to time intercourse relative to ovulation (Basically, that means they optimized their chances of becoming pregnant). They then used digital home pregnancy monitors on the day of expected menstruation to identify pregnancies.

Finally, 90% of the women took either a multivitamin or a pre-natal vitamin during the study (The significance of this will be discussed later).

 

Are Your Chances of Getting Pregnant Reduced by Iodine Deficiency?

chances of getting pregnant iodine deficiency pregnancyThe results of the study were:

  • 3% of the women in the study were iodine deficient (defined as iodine-creatine ratios of <100 mcg/g). This was further broken down to:
  • 8% were mildly iodine deficient (50-99 mcg/g).
  • 8% were moderately iodine deficient (20-49 mcg/g).
  • 7% were severely iodine deficient (<20 mcg/g).
  • That is a total of 22.5% who had moderate to severe iodine deficiency.
  • Women who had moderate to severe iodine deficiency had a 46% decrease in the chance of becoming pregnant over each menstrual cycle compared to the iodine sufficient group.

A simple way of reporting those data would be to say that their chances of becoming pregnant were reduced by 46%, but that would not convey the whole picture. Most of the women did become pregnant during the 12-month study. However, it took the women with moderate to severe iodine deficiency twice as long to become pregnant. Iodine deficiency did not prevent pregnancy from occurring, but it delayed it.

The authors concluded: “In summary, our data show that groups of women with iodine concentrations in the moderate to severe deficient range experience a significantly longer time to pregnancy…The US and European countries where iodine deficiency is common should evaluate the need for programs to increase iodine intake for women of childbearing age, particularly those trying to become pregnant”.

 

Where Can You Get The Iodine You Need?

 

chances of getting pregnant iodine deficiency seafood seaweedThe important question becomes: “Where can you get the iodine you need?”

  • You could start by using old-fashioned iodized salt rather than designer salts in your salt shaker. However, I am reluctant to recommend anything that would increase sodium intake. We get far too much from processed foods already.
  • Seafood (or seaweed, if you are a vegetarian) are the best food sources of iodine. However, our oceans are so contaminated I would recommend consuming those foods only occasionally.
  • You will often see bread and dairy mentioned as good food sources because iodine was used in the preparation of those foods. However, iodine has largely been replaced by other agents, so those foods should no longer be considered good sources. For example:
  • Iodine in commercial breads has traditionally come from the use of iodate as a dough conditioner. Today iodate has largely been replaced with bromide in commercial bread making. Not only does this trend decrease the amount of iodine available in our diet, but bromide also interferes with iodine utilization in our bodies
  • Iodine in milk has traditionally come from the use of iodine-containing disinfectants to clean milk cans and teats. However, they have largely been replaced with other disinfectants
  • Fruits and vegetables are a variable source of iodine, depending on where they were grown. That is because iodine levels in the soils vary tremendously from region to region.
  • That leaves multivitamins and prenatal vitamins as your best source. However, you do need to read labels. You should look for supplements that provide 150 mcg of iodine. Unfortunately, only 50% of prenatal supplements in the United States even contain iodine. Remember, 90% of the women in this study took either a multivitamin or prenatal supplement and 44.3% of them were iodine deficient.

 

The Bottom Line

 

The introduction of iodized salt in the 1920s virtually eliminated iodine deficiency in this country. Now, almost 100 years later, iodine deficiency is back. Recent studies estimate that 30-40% of women of childbearing age are iodine deficient. This is concerning. Previous studies have shown iodine deficiency affects mental development during fetal development and infancy. A recent study suggests that iodine deficiency may also make it more difficult for women to become pregnant. Specifically, the study reported:

  • 3% of the women in the study were iodine deficient. This was further broken down to:
  • 8% were mildly iodine deficient.
  • 8% were moderately iodine deficient.
  • 7% were severely iodine deficient.
  • That is a total of 22.5% with moderate to severe iodine deficiency.
  • Women who had moderate to severe iodine deficiency had a 46% decrease in their chance of becoming pregnant over each menstrual cycle compared to the iodine sufficient group.

A simple way of reporting those data would be to say that their chances of becoming pregnant were reduced by 46%, but that would not convey the whole picture. Most of the women did become pregnant during the 12-month study. However, it took the women with moderate to severe iodine deficiency twice as long to become pregnant. Iodine deficiency did not prevent pregnancy from occurring, but it delayed it.

For more details about why iodine deficiency has reemerged in this country and where we can get the iodine we need, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

The Dangers of Iodine Deficiency During Pregnancy

Does Your Prenatal Contain Enough Iodine?

Author: Dr. Stephen Chaney

 

iodine deficiency during pregnancyA recent study (S.M. O’Kane et al, British Journal of Nutrition, doi.org/10.1017/S0007114516003925)  concluded that 2/3 of Irish women had no idea that iodine was important during pregnancy. In fact, 57% of the women had no idea what iodine was, and 41% were unable to name any health problem related to iodine deficiency. The authors of the study considered this ignorance about iodine to be alarming. I’ll discuss why below.

First, let’s consider the situation in the United States. I suspect ignorance about the importance of iodine is just as widespread in the United States as it is in Ireland. Think about the nutrients we have been told are essential for healthy pregnancy outcomes.

  • We have heard about the importance of iron and calcium for decades.
  • The importance of folic acid and other B vitamins has been widely publicized over the last 20 years.
  • In recent years, we have learned about the importance of omega-3s, especially DHA.

But who has been telling us about the importance of iodine? Almost nobody.

What Are The Recommendations For Iodine Intake?

The RDAs for iodine are:

  • 150 ug/day for adults
  • 220 ug/day for pregnant women
  • 290 ug/day for breastfeeding women

How Common Is Iodine Deficiency During Pregnancy?

iodine deficiency pregnant womenHere are some quick facts about iodine deficiency in the US from a recent American Academy of Pediatrics position paper  and the National Institutes of Health Consumer information site:

  • Approximately 1/3 of pregnant and lactating women in the United States are at least marginally iodine deficient.
  • To meet their RDA requirements for iodine during pregnancy and lactation the American Thyroid Association, The National Academy of Sciences, and The American Academy of Pediatrics all recommend pregnant and lactating women take supplements containing 150 ug of iodine.
  • Although most pregnant and lactating women take supplements:
    • Only 50% of prenatal supplements in the United States contain iodine.
    • Even worse, only 15% of the supplements pregnant and lactating women take contain iodine (some pregnant and lactating women take multivitamins rather than prenatal supplements).
  • Labeling can be deceptive. Most multivitamins and prenatal supplements specify the amount of potassium iodide in the supplement, not iodine. It requires at least 197 ug of potassium iodide to provide 150 ug of iodine.

In short, many pregnant and lactating women in this country are not getting enough iodine from their diet and the supplements they are taking may not provide the iodine they need.

 

Why Are So Many Americans Deficient In Iodine?

iodine deficiencyThe best and most reliable natural sources of iodine are seaweeds and ocean fish. Meats, dairy, and grains can be moderate sources of iodine, but their iodine content is highly variable. It depends on the iodine content of the soil in which they were produced and how they were processed.

Because the soil in the interior of this country is very low in iodine, crops and animals raised in much of our country are also low in iodine. That lead to widespread iodine deficiency in this country prior to the introduction of iodized salt in the 1920s. Iodized salt largely eliminated iodine deficiency in the 1920s. However, since the 1970s, iodine deficiency has been gradually returning to this country for many reasons.

  • In the 1920s most of our food was prepared at home, so most of the salt in our diet was iodized. However, today:
  • Processed foods are replacing home-cooked meals, and the salt used in processed foods is not iodized.
  • Much of the salt we use today is “gourmet” salt that is not iodized. Even sea salt often contains far less iodine than iodized salt.
  • Seaweed has never been considered a delicacy in this country, and increasingly, Americans are avoiding ocean fish because of concerns about our polluted oceans.
  • Iodine in commercial breads has traditionally come from the use of iodate as a dough conditioner. Today iodate has largely been replaced with bromide in commercial bread making. Not only does this trend decrease the amount of iodine available in our diet, but bromide  also interferes with iodine utilization in our bodies.
  • Iodine in milk has traditionally come from the use of iodine-containing disinfectants to clean milk cans and teats. However, they have largely been replaced with other disinfectants.

Together these trends have combined to create the “perfect storm”. Iodine deficiency has, once again, become a major health concern in the US and other developed countries.

 

The Dangers Of Iodine Deficiency During Pregnancy

dangers of iodine deficiency during pregnancyIodine is an essential component of the thyroid hormone. Accordingly, inadequate iodine intake leads to hypothyroidism. Thus, you might expect iodine deficiency to be associated with symptoms like fatigue, sensitivity to cold, dry skin, and unexpected weight gain.

However, you may not have known that thyroid hormone is also essential for bone and neural development during fetal development and infancy. Because of that, thyroid hormone production increases dramatically during pregnancy and lactation (Hence, the increase in iodine requirement for pregnant and lactating women).

I can’t emphasize strongly enough the consequences of iodine deficiency during pregnancy and lactation. Here is what the experts say:

 

The Bottom Line

 

  • Iodine is important for bone and neural development during both fetal development and infancy. Because of this, iodine requirements are significantly higher during pregnancy and breastfeeding.
  • The iodine content of the American diet has decreased significantly since the 1970s. Today approximately 1/3 of pregnant and lactating women in the United States are at least marginally iodine deficient.
  • The National Institutes of Health, the American Academy of Pediatrics, and the World Health Organization all warn that even mild iodine deficiency during pregnancy and lactation can result in cognitive impairment in children.
  • Because of this, the American Thyroid Association and the American Academy of Pediatrics recommend that pregnant and lactating women take a supplement providing 150 ug of iodine. That corresponds to at least 197 ug of potassium iodide (the unit shown on most supplement labels).
  • Only 50% of prenatal supplements and 15% of multivitamin supplements contain iodine. Many that do contain iodine do not provide the recommended 197 ug of potassium iodide.

In short, many pregnant and lactating women in this country are not getting enough iodine from their diet; the consequences of even mild iodine deficiency are significant; and the supplements they are taking may not provide the iodine they need.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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