Goitrogens and Thyroid Health: Are You Protected or at Risk?

Linda J. Dobberstein, Chiropractor, Board Certified in Clinical Nutrition

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Goitrogens and Thyroid Health: Are You Protected or at Risk?
Goiters, or enlargement of the thyroid gland, are a common problem experienced despite today’s modern world of iodized salt. Several factors can trigger this enlargement or swelling of the thyroid gland. These factors include goitrogenic foods, common chemical exposures and nutritional deficiency. The impact of goitrogenic foods and chemical exposures are reduced and even avoided when thyroid health and nutritional status is up to par. Understanding these factors and being mindful about them can help turn energy on, relieve fatigue, fluid retention, and weight gain from a hampered thyroid.

Symptoms of a goiter may make one feel like there is a lump in the throat or the throat feels tight. The voice may be hoarse. There may be trouble swallowing, breathing, or a chronic cough. Sometimes there may be a noticeable swelling at the base of your neck below the Adam’s apple. Not all goiters create symptoms.

The swollen thyroid gland, or goiter, is often linked with both overproduction (Grave’s disease) and underproduction (Hashimoto’s disease). The swelling can turn into nodules, either single or multiple. These nodules may be benign and related with inflammation, or less common, related with thyroid cancer. Any thyroid swelling or nodules found should be properly and thoroughly evaluated as the incidence of thyroid cancer has increased significantly worldwide over the last several decades.

Goiter Inducing Foods


Goitrogen by definition is a food, chemical, or even a medication that disrupts the production of thyroid hormones by interfering with iodine uptake within the thyroid gland. The risk of goiter development is influenced by daily dietary habits, nutritional status, and compounded with chemical exposures. Tolerance to these foods and compounds is increased with sufficient intake of iodine, selenium, iron, zinc, and vitamins A and B12.

There are a number of foods that contain goitrogenic compounds. When these foods are eaten in excess or in raw forms, they can stress the thyroid and increase the occurrence of goiters. Cruciferous vegetables or the Brassicae plant family are considered goitrogen foods. They contain a compound called thiocyanate. High intake of thiocyanate and its related compounds affects iodine use and uptake and can lead to a swollen thyroid gland and eventually to goiter development. Cooking de-activates the majority of these compounds making them overall non-threatening. This vegetable family includes cabbage, cauliflower, kale, broccoli, rutabaga, kohlrabi, spinach, and Brussels sprouts, etc.

Other foods that contain thiocyanate include cassava, lima beans, linseed, bamboo shoots, and sweet potatoes, butter beans, lentils, black-eye peas, garbanzo beans/chick peas, millet, buckwheat, sorghum, lima beans, and peanuts. Many of these foods are consumed cooked which negates the issue. Periodic consumption is not an issue; it is the routine daily intake with inadequate iodine stores that is the concern for your thyroid tolerance.

These foods are wonderful, vibrant healthy foods with many benefits. The form of these foods, i.e. raw versus cooked, and frequency of consumption dictate the risk of a swollen thyroid and goiter development relative to iodine intake for thyroid. We are creatures of habit. Once in a pattern, it is easy to get locked into a routine. We often assume that if a certain food or food group is great for us, more is better. So this is a consumer be aware statement for those who are locked into a diet heavily populated with these foods especially in raw form, have started on a New Year’s resolution with daily raw kale or cruciferous vegetable green drinks and have inadequate iodine for the thyroid. This is most problematic when the foods are consumed raw, daily, and in excess of what your thyroid can tolerate. It is even more problematic when thyroid protective minerals are lacking. Specifically, if you are lacking iodine, selenium, zinc, and/or iron, these foods can dampen thyroid activity despite how wonderful the food is. It also means, we need to mindful about daily and weekly food patterns to make sure that there is a wide variety of foods interspersed with raw and cooked. Trouble occurs when doing the same thing over and over again.

Soy based foods and nutrients like genistein and daidzein can contribute to goiter problems and generally are stressful to the thyroid. The risk of goiter development is again related to the health of your thyroid, your iodine and other mineral nutritional status, and the amount and forms of these foods taken in routinely. If you are consuming soy on a daily basis as your primary source of protein with a kale and spinach smoothie every day, this may stress the thyroid leading to nodule or goiter development.

Celiac disease and gluten intolerance can also trigger goiter or thyroid nodule development even in the absence of digestive symptoms. This is an autoimmune inflammatory response and is different than the response from thiocyanate rich foods. If you are gluten intolerant and have thyroid problems, gluten abstinence is mandatory.

To be clear, the goiter inducing vegetables listed above are not unhealthy in the context of a diet that has a wide variety of many different types of vegetables and are consumed both cooked and raw. It is the fixed, locked in patterns and lack of variety that can cause trouble. This will be worsened if iodine or other minerals necessary for thyroid health and protection are lacking.

Cigarette Smoke and Thyroid


There are other sources of thiocyanate found within the environment including cigarette smoke. Researchers found that smokers who were deficient in iodine had a much higher occurrence of goiters and thyroid nodules compared to those who had adequate iodine levels. Thiocyanate found in cigarette smoke competes with iodine uptake in the body just like the thiocyanate found in the foods above. The cigarette smoke exposure affects not only the smoker but expectant mothers and those exposed to second-hand smoke. If you grew up in an environment where a parent was a smoker and you now have thyroid or thyroid-related problems like infertility, this may be a hidden cause.

Perchlorates Cause Goiters


Perchlorate is a goitrogen-causing chemical and very toxic to the thyroid. Perchlorate is a chemical used in rocket fuel and several other items like fireworks, matches, car air bag inflators, batteries, chlorine, chlorine based cleaners, pool chlorination chemicals, military munitions, paint, fertilizers, chewing tobacco, aluminum refining and more. As a result of common industrial use, this toxin is found in low levels in the groundwater and therefore the food supply. Groundwater exposure brings it to animals and vegetarian food sources alike, no matter if it was grown using organic or conventional growing methods. The worst areas of contamination in the United States are found in California, Texas, the East Coast, and the Southwest.

Other Common Chemicals and Medications


Various other goiter causing chemicals consist of nitrates found in well water contamination from nitrogen application in farming. It is also found in foods with nitrates added or naturally occurring in green leafy and root vegetables. Bromine (brominated flour), chlorine and fluorine (fluoridated water and products are problematic too. Fluoride is not just found in the water supply or dental treatments. Fluoride-based pesticides may be used on grape crops in California.

In addition to the environmental chemicals, medications like lithium carbonate (Lithobid), immunosuppresants, antiretrovirals, and the heart drug- amiodarone (Cordarone, Pacerone, etc.) may increase the risk of goiter development.

Thiocyanate, Perchlorate, and Insufficient Iodine – Oh My!


Many of these factors have been known for some time. But the word is still not getting out. The issues of goiters, thyroid problems and thyroid cancer are rising. In a study by the Council on Environmental Health, published June 2014, found that only 15 percent of pregnant and breastfeeding women take a supplement containing adequate iodide to meet the minimal needs for the expecting mother and baby. This means that 85 percent of women in this group do not get adequate iodine. This is a thyroid disaster waiting to happen. This puts them and their children at much higher risk of thyroid dysfunction and autoimmune disorders from thiocyanate, perchlorate and other toxins. This also greatly prevents children from attaining their full intellectual potential.

A study published just weeks ago shows that poor nutrition is not just a third world problem. Scientists measured blood and urine samples of 284 healthy women at 10-14 weeks into pregnancy living in New York City. They found presence of perchlorate, thiocyanate, and nitrate in all individuals. The women who had the greatest amounts of these compounds found in their lab samples had increased TSH (thyroid stimulating hormone) which showed decreased thyroid function. Perchlorate found in the highest concentration subsequently impacted the thyroid the most.

In the Journal of Clinical Endocrinology and Metabolism November 2014, researchers analyzed information from 487 mothers with their children. They evaluated the mothers during pregnancy for perchlorate levels and thyroid function. Urinary tests revealed that all of the mothers had detectable levels of perchlorate and low levels of iodine. The researchers then evaluated the children at three years of age. The mothers who had the highest amount of perchlorate in the body during pregnancy had significantly increased odds of children at three years of age of having children with the lowest IQ. The children’s health outcome did not matter if the mother had been on levothyroxine or thyroid hormone. This was the first study, using direct patient data, that showed that mothers who had high perchlorate levels during pregnancy had children with impaired cognitive development in direct proportion to the perchlorate exposure. Prescription thyroid medication that helped the mother did not protect the child from the perchlorate exposure and consequential challenged brain development.

Animal studies show that exposure during pregnancy to thiocyanates affect the offspring’s thyroid and pituitary for at least one month after birth. In this study, it was found the cells in the pituitary that produce the signal for the thyroid gland (TSH cells) were blunted and thyroid cells enlarged. This study did not measure perchlorates or nitrates individual or combined effect.

Autism and Anti-Thyroid Compounds


Mounting evidence from recent animal studies shows that maternal thyroid hormone deficiency as challenged by these food and environmental compounds increases the risk of autism spectrum disorders by four-fold. The development of the brain is negatively impacted by the lack of thyroid hormone and the environmental chemicals that disrupt the production and function of thyroid hormone in the offspring. When the mother is exposed to anti-thyroid compounds like thiocyanate, perchlorate, and nitrate that disrupt the thyroid even temporarily, it can change the neurological developmental process in the offspring.

Thyroid Cancer in Adults, Developmental Problems in Children


The detriment of these chemical compounds that lead to goiters and poor thyroid development affects all ages. Researchers have noted a distinction between different parts of life. The main risk for the unborn and young children is the impact on intelligence, cognitive function, and behavior. Adults experience a different set of problems – autoimmune thyroid disease (Hashimoto’s and Grave’s disease), and benign or cancerous nodules.

Thyroid cancer is the most common endocrine cancer and has been rapidly increasing over the last three decades. A recent review article reviewed dietary habits of adolescents and middle-age adults over a span of several years. After evaluating diet diaries, they found that higher consumption of goitrogenic foods was associated with a two-fold increased risk of thyroid cancer. Other studies in men and women and different ethnic groups have reported on this relation. This presents a conundrum with these very healthy foods as it is well-established that cruciferous vegetables like broccoli provide powerful anti-cancer benefits.

Dietary and Nutritional Solutions


Before throwing out the broccoli, kale and other wonderful foods, it is important to understand key principles. Frequent daily consumption of raw cruciferous vegetables and other thiocyanate rich foods may contribute to goiter or nodule development if your thyroid is compromised and not protected with adequate minerals. Cooking these foods reduces or eliminates most goiter inducing compounds, except in foods like millet. Iodine is a critical mineral essential for a healthy thyroid gland. Iodine protects against goitrogenic or thiocyanate compounds found in foods as well as goiter inducing compounds in the environment.

Too much iodine in the wrong form can also cause thyroid dysfunction. Extremely high doses of potassium iodide may cause trouble. Use a water soluble form of iodine such as Iosol iodine that is easily utilized and managed by the body. The basic RDA dose of iodine is 150 micrograms, but that dose is not sufficient to resolve a deficit or to provide enough protection in the chemical loaded environment we live in. The Institute of Medicine recommends dosage of iodine for pregnancy at 500 -1100 micrograms per day. More may be beneficial to ensure fetal protection and brain development especially with deficits and toxin exposure. Even in 2015, the CDC estimates that 2 billion people worldwide have insufficient iodine intake. Make sure you are not one of them.

Insufficient vitamin A, selenium, iron, vitamin B 12 and zinc also affect how the body manages these goiter producing compounds. In addition, gut bacteria balance plays a role, but it unclear exactly how gut bacteria manage the metabolism of these thyroid challenging compounds. High dose vitamin C was found to inhibit nitrate induced goiters. Research shows that turmeric or curcumin protects against goiters too. Thus, cooking with turmeric together with some of the foods listed above may alleviate the conundrum of what to eat when there is a goiter or thyroid problem.

Take a look at your lifestyle. The average person consumes the same 20 foods on a routine basis. If your diet consists primarily of these foods in their raw state and you have less than optimal thyroid function or a goiter has developed, simply changing your dietary patterns may just wake up the thyroid. Protect your thyroid from the chemical insults of perchlorates, nitrates from well water or high nitrate content foods, cigarette smoke, chlorine, fluoride, and medications that are known to induce goiters. Avoid these substances or use filters to remove as much of these compounds from daily exposure. Ask for medication alternatives if possible. Ensure sufficient intake of iodine, selenium, iron, zinc, vitamins A, C and B12. Iodine, zinc, and selenium provide front-line protection. These choices help put you in the driver’s seat of your thyroid health.

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