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Facing the Consequences of Iodine Deficiency

More than one-quarter of the world's population suffers from some level of iodine deficiency disease. That works out to 1.6 billion people. Of these, 655 million have a goiter, an enlargement of the thyroid that can sometimes be debilitating. Twenty-six million of them have brain damage, and 6 million of those 26 million suffer from cretinism; they are so handicapped by their thyroid conditions that they are completely dependent upon those around them to live. Some researchers believe that for each day we delay treating this vast problem, 50,000 infants are born with decreased mental capacity caused by an iodine deficiency.

The reason so many people suffer is that the food they eat or the ground from which that food comes contains little or no iodine. All soil on earth used to contain iodine. However, over hundreds of thousands of years, the iodine has been leached out of the soil in two major areas of the earth: the high mountains and the plains, far from oceans, that were covered by water in the past.

The high mountains were once covered with glaciers. As the glaciers melted, they carried iodine out of the soil, back to the ocean. In the same way, the flooded plains leached iodine from the soil and carried it back to the ocean as the water flowed away. As a result, high mountains and plains far from oceans are the areas where iodine deficiency disease is most often found.

Crops that grow in such soil are iodine deficient. Animals that feed on these crops become iodine deficient. If the animal happens to be a cow that provides milk, children who drink that milk may be iodine deficient. The meat from that cow is also iodine deficient. The result is a huge public health problem. Even pets such as dogs become iodine deficient.

Focusing on the vastness of the problem

If you looked at a map of the world that shows the areas where iodine deficiency disease is most prevalent, you'd see that vast areas of China, Russia, Mexico, South America, and Africa are rife with the disease. Surprisingly, the United States is not spared. At one time, the iodization of salt and the addition of iodine to bread seemed to solve the problem in the U.S. More recently, as shown in a study in the Journal of Clinical Endocrinology and Metabolism in October 1998, Americans have decreased their iodine intake. Nearly 12 percent of those studied had insufficient iodine in their urine. (The urine test is a reliable measurement of daily iodine intake.) This number compares with only 3 percent with insufficient iodine intake 20 years earlier.

Western Europe, also, used to be virtually free from iodine deficiency, but recent studies among Europeans have shown decreases in iodine intake as well.

Paying the price at every life stage

If your body lacks iodine, it can't produce sufficient thyroid hormone. This deficiency has severe consequences at every stage of life.

Pregnancy

Even before pregnancy, a lack of T4 hormone has a harmful effect. Women who are hypothyroid have greater difficulties becoming pregnant, and they have more miscarriages and stillbirths than women with normal thyroid function.

A fetus doesn't begin to make thyroid hormone until the 24th week of pregnancy. Until then, it's dependent upon the mother's T4. During this time, the fetal brain is developing, and the entire chain of events that produces a normal brain requires T4 at every stage. If this hormone is lacking, the consequences are severe.

If a fetus is deficient in T4 hormone, its brain triggers an increase in the amount of the enzyme that converts T4 to T3 within the brain. This form of the enzyme is not found in other tissues, so the brain may be protected from hypothyroidism while the rest of the body is not.

The entire body's formation is dependent upon adequate T4. If sufficient hormone is not available, congenital anomalies may occur. The infant may not survive much past birth. If it does, it may not live more than a few years. In this nuclear age, it's important to realize that a thyroid gland that is not making enough thyroid hormone will take up large amounts of iodine from whatever source it can. In the case of a nuclear accident where radioactive iodine is released, a hypothyroid mother will concentrate the iodine and pass it on to her growing fetus. If radioactive iodine does not destroy the fetal thyroid, that thyroid will at least be very prone to develop thyroid cancer.

Infancy

A new baby deprived of iodine will have a goiter and show signs of hypothyroidism. Depending upon the severity of the lack, the baby may have cretinism. The brain of a newborn continues to develop up to age 2, so providing iodine starting immediately after birth may prevent retardation. A baby lacking in iodine also shows increased susceptibility to radioactive iodine (or any iodine).

Childhood

Iodine-deficient children often have goiters. They show reduced intelligence and poor motor function, and they may be deaf. Like infants, these children have a tendency to accumulate iodine from any source and are at greater risk in the case of a nuclear accident.

Adulthood

After the iodine-deficient child has grown up, a goiter is often present in an iodine-deficient adult, though not always. He or she is intellectually retarded and may have movement difficulties. This person's thyroid gland is highly susceptible to radioactivity.

As you can see, the costs of iodine deficiency disorder are enormous both for the individual and for society. A village filled with people who suffer from widespread iodine deficiency would not be able to govern itself or provide an economic base to help better the condition of the people, or to take the steps necessary to overcome the problem.

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Pinpointing the Causes of Hypothyroidism

The two most common causes of hypothyroidism are iodine deficiency and chronic thyroiditis. Iodine deficiency is rare in the United States and Europe but very common throughout the rest of the world. Chronic thyroiditis is an inherited condition that is diagnosed by checking the levels of thyroid autoantibodies in the blood.

In addition to these two causes, there are many other reasons that people become hypothyroid. The causes detailed in this article should be ruled out before your doctor starts treating your condition with thyroid hormone replacement.

Removal of the thyroid

If your thyroid has been removed because of cancer or an infection, or in the course of treatment for hyperthyroidism, you will usually become hypothyroid. Only if some tissue is left behind will the thyroid possibly continue to function.

Absence of brain hormones

Anything that destroys the hypothalamus (the part of the brain that secretes thyrotrophin-releasing hormone) or the pituitary gland at the base of the brain (which secretes thyroid-stimulating hormone, or TSH) will produce central hypothyroidism — hypothyroidism originating in the control center of the body, the brain. A trauma, infection, or infiltration (a replacement of brain tissue with other tissue, which can occur when a patient has cancer) could cause this type of destruction. The same result can occur if the pituitary is involved with a destructive lesion that prevents the production and release of TSH, such as radiation treatment to the area of the pituitary gland.

If hypothyroidism is caused by a problem with the hypothalamus or pituitary, some of the signs and symptoms associated with chronic (autoimmune) thyroiditis will not be found. In particular, hoarseness and a thickened tongue occur in autoimmune hypothyroidism but not in hypothyroidism associated with a lack of brain hormones. In addition, the thyroid is not usually enlarged in this instance, because TSH is not stimulating it. Also, the patient's hair and the skin are not coarse in this situation (but they are if the patient has autoimmune hypothyroidism).

Symptoms that result from a lack of other pituitary hormones also help to differentiate central hypothyroidism from failure of the thyroid gland. These include fine wrinkling of the skin of the face and a more pronounced loss of underarm, pubic, and facial hair.

Foods that cause hypothyroidism

Many common foods can cause hypothyroidism if you eat them in sufficient quantities, especially if you have an iodine deficiency. These foods are called goitrogens because they can trigger the enlargement of the thyroid (a goiter) as well as hypothyroidism. They block the conversion of T4 hormone to T3, the active form of thyroid hormone. Among the more common foods that cause this condition are

• Almond seeds

• Brussels sprouts

• Cabbage

• Cauliflower

• Corn

• Kale

• Turnips

If consuming these foods causes your condition, simply removing them from your diet will cure your hypothyroidism. It takes between three and six weeks for your thyroid to return to normal after you stop eating these foods.

Drugs that cause hypothyroidism

Many different medications cause hypothyroidism in the same way as the goitrogens listed in the previous section: They block the conversion of T4 to T3. The drugs you are most likely to run into include

• Adrenal steroids like prednisone and hydrocortisone, which treat inflammation

• Amiodarone, a heart drug

• Antithyroid drugs like propylthiouricil and methimazole

• Lithium, for psychiatric treatment

• Propranolol, a beta blocker

Coexisting autoimmune diseases

Occasionally, a patient with autoimmune thyroid disease has other autoimmune diseases, many of which involve other glands of the body. For example, diabetes mellitus type 1 sometimes occurs together with autoimmune thyroid disease. The cause is the autoimmune destruction of the insulin-producing cells of the pancreas. Another example is Addison's disease, the autoimmune destruction of the adrenal gland. Addison's disease is associated with severe fatigue and low blood pressure and is especially important to identify, because giving thyroid hormone without adrenal hormone to such a patient could be dangerous.

Autoimmune destruction of the ovaries in women or the testicles in men may also occur when a patient has autoimmune thyroiditis. The result for women is failure to menstruate, and for men it is infertility and impotency.

Another gland that may be affected by autoimmune disease is the parathyroid (which actually consists of four parathyroid glands) sitting behind the thyroid in the neck. Loss of parathyroid function results in low blood calcium and the possibility of severe muscle spasms and psychological changes.

Some autoimmune diseases that affect the joints of the body are found together with autoimmune thyroiditis. Rheumatoid arthritis is the most common example, but other diseases with names like Sjogren's syndrome and systemic lupus erythematosis are also diagnosed.

Be aware of a blood disease called pernicious anemia, an autoimmune disease that accompanies autoimmune thyroiditis on occasion. In this condition, cells of the stomach that produce acid are destroyed by autoimmunity. The patient is unable to absorb vitamin B12 and develops an anemia along with symptoms in the nervous system.

On occasion, when these diseases occur together, treatment of one of them treats the other at the same time. For example, treating the hypothyroidism with thyroid hormone may greatly improve the diabetes.

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Clearing Up Common Myths about Thyroid Health

Thanks to the Internet, you have access to incredible amounts of information about your thyroid. Unfortunately, much (perhaps most) of it is not accurate. Much of what you read online is based on the experiences and opinions of one or a few people who took this or that medicine or herb and got better in two weeks. Maintaining a healthy degree of skepticism is important.

Here are a few misconceptions — and myth-busting facts — that may help you understand the real deal behind the little gland with the big reputation.

I'm hypothyroid, so I can't lose weight

If you have hypothyroidism, or if you've been treated for a thyroid condition and the cure resulted in your becoming hypothyroid, you may find that you have a hard time losing weight. The myth is that you can't lose weight if you have hypothyroidism, even when it's properly treated.

The truth is that a large percentage of people who are being successfully treated for hypothyroidism weigh almost the same after being treated as they did before they developed the disease.

Keep in mind that hypothyroidism is associated with fatigue. Many patients with hypothyroidism reduce their physical activity as a result. They may not restore their previous level of activity after the hypothyroidism is treated properly.

The bottom line is that we all follow the principle of conservation of energy. If we take in too much energy compared to what we need, we gain weight. If we take in too little energy compared to what we need, we lose weight.

Another truth is that our metabolic rate declines, as does our tendency to move around, as we age. Both changes tend to make weight loss more difficult, but it's still possible.

I'm hyperthyroid, so I can't gain weight

The myth that hyperthyroidism is always accompanied by weight loss is a source of confusion in making an accurate diagnosis. Although the majority of patients do lose weight when they become hyperthyroid, some patients actually gain weight — the elderly, in particular.

Weight loss, as well as other symptoms of hyperthyroidism, may not always be present, especially in the elderly population. The best solution is to get thyroid blood tests every five years, beginning at age 35.

I have to take thyroid medication for life

Many patients are told that once they are on thyroid hormone replacement, they'll be taking it for life. For many people, this is true. Any treatment that removes or destroys much of the thyroid (such as surgery or radioactive iodine) will require treatment with thyroxine (T4 hormone) for life. However, in certain situations, hypothyroidism is temporary; you may need thyroxine for a time, but you will later stop taking it. Sometimes it may be obvious that you no longer need the medication, but other times you and your doctor may need to attempt a trial period off thyroid for 4 to 6 weeks to see if you still need it.

The following are some of the conditions that require thyroid hormone replacement for a limited amount of time.

• Subacute thyroiditis causes the temporary breakdown of thyroid cells and the release of thyroxine from the thyroid. As this condition improves, thyroxine begins to be made and stored again, and oral thyroxine is no longer necessary.

• Silent and postpartum thyroiditis also cause temporary loss of thyroxine, which is restored with time.

• Acute thyroiditis occasionally requires temporary treatment with thyroid hormone.

Depending on your diagnosis, you may be able to stop thyroid hormone treatment at some point. It's well worth checking, particularly if you are young (under 40).

Thyroid disease is catching

It's not hard to understand why this myth became so entrenched in the minds of the public. Most thyroid disease is inherited; so the likelihood of finding the same disease in two sisters or a mother and her daughter is relatively high, suggesting that their physical closeness to one another causes them to have the same disease. Furthermore, in areas where people don't consume enough iodine, practically everyone has thyroid disease — again suggesting that it may develop.

Another situation that seems to suggest that thyroid disease is catching is the occurrence of thyroid disease after large-scale radiation exposure. Just about everyone comes down with some illness in that situation. Children, especially, often develop goiters, nodules, and thyroid cancers.

An understanding of the way these diseases develop quickly clarifies the situation:

• The hereditary thyroid diseases affect the females of a family, usually sparing the males.

• After iodine is supplied, the incidence of thyroid disease rapidly declines in iodine-deficient areas.

• Children who take iodine pills or avoid exposure to radioactive iodine generally will not get thyroid diseases, while those who do not, will.

You cannot catch thyroid disease, nor can you give it to someone else in the way that germs are passed from person to person.

Iodine deficiency is a medical problem

Because iodine deficiency causes hypothyroidism, goiter, and cretinism (when severe), you would think that it's a clear-cut disease that should respond to medical treatment with iodine. If this were so, the disease would have disappeared years ago.

As with any major medical problem (like AIDS, breast cancer, and prostate cancer), iodine deficiency is a social, economic, and political problem as much as, or more than, it is a medical problem.

To begin with, an understanding about the cause of hypothyroidism in iodine-deficient areas is often lacking. The people are poor, work very hard, and have little time for the intricacies of the cause of disease. Their poverty means that they cannot afford to pay for nurses to give them medication or inject them with iodized oil. They do not understand that certain foods, like cassava, worsen the problem, so they continue to consume large quantities of them.

Sometimes, attempts to solve the problem run up against the realities of salt production. This has been the case in Indonesia, for example, where salt is made by numerous salt farmers rather than a centralized salt production facility (as is done in China). It was easier and more productive to alter the salt production to make enough iodized salt in China than it was in Indonesia.

The instability of poor governments also plays a role. When the problem of iodine deficiency was recognized in Communist East Germany, iodine was provided and the disease was brought under fairly good control. After the reunification of East and West Germany, the combined government neglected the problem, and iodine deficiency began to reappear.

The solution to a clearly medical problem like iodine deficiency may have to involve social, cultural, and economic changes that populations often resist, making a cure exceedingly difficult.