Iodine Rich Diet
by Sue Kira, Naturopath & Clinical Nutritionist
The ‘I’ in Iodine should really stand for ‘Increase’ because it can help you to Increase your energy, while insufficient iodine can Increase the size of your thyroid gland, which is called a goiter (lump in your throat).
Both civilized and third world countries commonly suffer from iodine deficiency, mostly due to the lack of consumption of seafood and seaweeds and because soil has very little iodine in it. Processing also removes iodine from foods. Some countries now add iodine to salt to help with this issue, and you will see this on packets of salt labelled ‘Iodized salt’.
According to the World Health Organization (WHO), iodine deficiency is seen as the most prevalent cause of poor cognitive development in children worldwide, with at least 30 million suffering from this easily preventable condition.
Iodine is a trace mineral that is an essential component of the thyroid hormones: triiodothyronine (T3) and thyroxine (T4). The ‘T’ stands for Tyrosine and the ‘3 & 4’ stand for the number of iodine molecules. These hormones regulate the metabolic activities of most cells in our body (not just the thyroid) and play a vital role in early growth and development of most organs, especially the brain, heart, liver and kidneys.
Iodine also influences the absorption of carbohydrates in the small intestines, the breakdown of proteins, the conversion of vitamin A from carotene, and the synthesis of cholesterol…all of which are dependent on thyroxine levels.
Iodine can kill fungus, bacteria and other microorganisms such as amoebas. A specific type of iodine (potassium iodide) is used to treat the effects of radioactive accidents.
Helps control your metabolic rate
Iodine influences thyroid function by helping with the production of hormones that control the body’s metabolism. Our metabolic rate regulates many biochemical processes, including our sleep cycle, absorption of our food and the transformation of what we eat into energy.
Prevents enlarged thyroid gland & supports healthy thyroid function
Iodine deficiency is widely recognized as the primary cause of goiter, an enlargement or swelling of the thyroid. The thyroid hormones, thyroxin and triiodothyronine, influence blood pressure, heart rate, body temperature, protein synthesis and weight stability. A healthy thyroid also helps to support the immune system.
Iodine is a free radical scavenger and it increases the activity of other antioxidants in the body, providing a strong defence against various diseases including cancer and heart disease. Iodine helps protect brain cells from damaging free radicals by bonding to the fatty acids in our cell membranes, leaving less chance of free radicals to have a negative impact.
Iodine also maintains the integrity of the mammary gland and has antibacterial properties, particularly against H-pylori which is a bacterial infection in the stomach associated with gastric cancer.
Helps prevent breast & other cancers
Iodine has a beneficial role in supporting our immunity and also stimulates apoptosis, which is the self-destruction of dangerous, cancerous cells, while preserving healthy cells. Research has shown that iodine-rich seaweed will inhibit the growth of breast tumour development. In parts of the world (e.g. Japan) where women consume a diet rich in iodine such as seaweed, there is a lower rate of breast cancer.
Where low iodine has been detected in patients with various other cancers, especially the reproductive system, some research has shown positive results of taking iodine as part of the treatment. Note: only do this under the direct advice of your primary health care provider.
Supports the excretion of toxic chemicals
Iodine can help the body remove heavy metal toxins like lead and mercury and other biological toxins.
Supports healthy skin, teeth & hair
Iodine helps with the formation of shiny hair, healthy skin and teeth as it is an important trace element. Iodine deficiency can lead to dry, rough, and irritated skin that becomes flaky and inflamed.
Prevents impaired development & growth in babies and children
Studies have shown that iodine deficiency during pregnancy and infancy can interrupt healthy brain development and growth. Babies and infants are more susceptible to poor survival rates and higher risk for neurodegenerative problems if iodine is deficient during their development.
Motor function problems, learning disabilities, low growth rate and a mental form of disability known as cretinism, is more prevalent where there was iodine deficiency during pregnancy and early years of infancy.
Women who are about to conceive or are pregnant or breastfeeding are encouraged to increase their intake of iodine-rich foods, and possibly supplementation under prescription, to prevent these risks.
Insufficient iodine can lead to serious health problems, including the development of tumours of the pituitary, hardening of the arteries, and some have even suggested a link to breast lumps and cancer.
Milder deficiency symptoms include fatigue, weight gain, slow mental reactions, dry hair, and heart palpitations. Anxiety and nervousness are linked to an iodine deficiency which can be coupled with a selenium deficiency.
Here are some health conditions that may be associated with low iodine levels:
- Breast cancer
- Increased cholesterol
- Fertility issues
- Increased infant mortality risk
- Fibrocystic breast disease
Iodine Deficiency Symptoms
- Brain fog
- Cold hands and feet
- Difficulty losing weight
- Dry skin
- Impaired kidney function
- Lethargy or fatigue
- Memory problems
- Menstrual problems
- Muscle weakness and joint stiffness
- Recurrent infections
- Sensitivity to cold
- Shortness of breath
- Thinning hair
Low dietary iodine intake
Iodine is obtained mainly through our diet but can be obtained from iodine supplementation or iodized salt (fortified salt). The consumption of sea vegetables (seaweed) and seafood/fish is the main source of iodine, but it can also be found in small quantities in garlic, onions, nuts, seeds, beans, and turnips – provided the soil contains good amounts of iodine as many soils are already iodine deficient.
Iodine is known for playing a vital role in thyroid health, and selenium is critical to recycle iodine. T4 is converted in the body to T3 and needs adequate levels of selenium for this to happen, so when selenium levels are low, the thyroid must work harder to convert thyroid hormones into forms that can be used by the cells. It’s important to treat both deficiencies to re-establish a healthy thyroid. It is common for those with an iodine deficiency to also have a selenium deficiency.
Eating raw vegetables from the Brassica family (cauliflower, broccoli, kale, cabbage, soy, Brussel sprouts) can adversely affect thyroid function because they contain substances called goitrogens, which are molecules that impair thyroid function.
Steaming these cruciferous vegetables before consumption breaks the goitrogens down. Those with an iodine deficiency are at a higher risk when consuming these foods, but if your iodine level is adequate or you have a healthy thyroid then eating these foods raw or cooked is fine.
Consuming sufficient iodine during pregnancy is important to prevent stunted mental and physical growth and impaired brain functioning (I.Q.) in infants. Combined intake from supplements and food should be 290 to 1,000 mcg (micrograms) a day.
Tobacco contains a compound called thiocyanate which inhibits the uptake of iodide (a form of iodine). Other substances in tobacco that can impair thyroid function are hydroxypyridine metabolites, nicotine and benzapyrenes. Smoking tobacco not only affects thyroid function, but it can also block thyroid hormone action by blocking iodine uptake (amongst other terrible effects).
Fluoridated and chlorinated water
Most tap water contains fluoride and chlorine that can inhibit the absorption of iodine unless you have a filter or water purifier that removes these substances. All three of these compounds (fluoride, chlorine and iodine) are considered to be halogens that all compete for the same receptor sites (parking spaces) on the cells, particularly the thyroid gland. When there is a deficiency of iodine, then fluoride or chlorine or both fill that receptor site, but they are antagonistic to the thyroid, thereby reducing its effectiveness, which in turn can create issues of low thyroid activity.
In infants and children this can be a serious issue (as stated in the pregnancy section). It’s not just about drinking water from a tap; the water in baths, showers, swimming pools, spas and Jacuzzis all contain large amounts of these halogens, and our skin can absorb these compounds that go directly into our blood stream. However, if you have adequate iodine then the receptor sites will be full of iodine and there is nowhere for the other halogens to go except out (excreted).
In a study, researchers used the Wechsler Intelligence Test to determine the IQs of 330 eight to fourteen-year-old children who lived in sixteen villages. All children had low levels of iodine. The water for nine of the villages contained added fluoride, and the water for the remaining seven villages was free of fluoride. The research revealed that the IQs of children from the villages with fluoride in the water were lower than the children from the fluoride-free villages. Interesting!
Hypothyroidism (underactive thyroid) occurs when your thyroid produces too little thyroxin (the thyroid hormone) a condition that is often linked to iodine deficiency. But research has shown if you have too much iodine, it may lead to a sub-clinical version of thyroid disorders that are often missed by standard laboratory tests.
People who have Hashimoto’s Thyroiditis, which is an auto-immune form of hypothyroidism, should speak with their doctor or health practitioner about how much, if any, iodine should be taken through careful supplementation. It is much harder to have too much iodine from diet alone (without iodized salt) unless you eat heaps of seaweed daily.
An iodine overdose exceeding 2,000 milligrams could be dangerous, especially for individuals who have tuberculosis or kidney disease. Excessive iodine can also result in thyroid papillary cancer and hyperthyroidism (overactive thyroid). Pregnant women and nursing mothers should be cautious about taking iodine except in specifically prescribed doses – however iodine from the diet is generally fine.
A healthy balance is needed, however people’s bodies react differently to dosage amounts.
Other sources of iodine that can lead to poisoning are products like Amiodarone or Cordarone (an anti-arrhythmia drug). This also includes Lugol’s iodine, Pima syrup, potassium iodide and radioactive iodine used for certain medical tests e.g. for contrast mediums in radiology tests such as CT scans or thyroid disease treatment.
Symptoms of an iodine overdose
Some symptoms of an iodine overdose can include abdominal pain, shortness of breath, vomiting, delirium and fever. More serious symptoms can occur, depending on the way the iodine overdose occurred.
Although iodine is a necessary element for proper thyroid and metabolic function, elemental iodine from non-food sources can result in very serious side effects, but this is rare if you are getting your iodine from food and sea salt, and only taking supplemental iodine as prescribed.
More is definitely not better when using iodine supplementation.
The following are good food sources of iodine, showing the number of micrograms (mcg) of iodine per serve:
- Baked Cod: ½ cup = 99 mcg
- Cranberries: 1 Tablespoon = 90 mcg
- Potato: 1 medium = 60 mcg
- Shrimp/prawns: ½ cup = 35 mcg
- Navy Beans: ½ cup = 32 mcg
- Egg: 1 large egg = 24 mcg
- Dried Prunes: 5 prunes = 13 mcg
- Seaweed: 1 sheet – commonly around 70-100 mcg. The amount of iodine in seaweed varies greatly depending on the type, where it is grown and if it is cooked/toasted or raw/dried. Nori, the seaweed used in sushi rolls contains the least amount of iodine of all the seaweeds, and dulse and kelp have the highest. 1 sheet of nori contains approx 100mcg and usually makes 2 sushi rolls.
Good levels of iodine are also found in fish and seafood, molasses, brown rice, nutritional yeast, lima beans, mushrooms and sunflower seeds.
The Recommended Daily Allowance (RDA) for iodine
The following list shows the recommended daily allowance of iodine in micrograms. You can use this list and the above list (with some of the foods rich in iodine) to get an idea of the foods you need for your daily requirements:
- 1 to 8 years: need 90 micrograms every day
- 9 to 13 years: need 120 micrograms every day
- 14+ years: need 150 micrograms every day
- Pregnant or breastfeeding mothers: need 290 micrograms every day
Iodine in salt
Iodized salt contains around 45 micrograms of iodine per gram of salt (about 1/8th teaspoon) so it’s easy to add far too much iodine if you like using iodized salt on your food.
Even though iodized salt is one way to get iodine, sometimes it isn’t in a bio-available form that the body absorbs well. It is preferable to use Himalayan or Celtic Sea salt which contains more than 60 trace minerals, including iodine, and it doesn’t pose as much of a risk as iodized table salt. The other minerals in sea salt are very beneficial and taste better.
Before you commence your diet, see your medical or health care professional for qualified guidance about what foods and supplements are best for your body. While on the diet do not stop any medications or supplements previously prescribed unless advised otherwise by your medical or health care professional.
During the early stages of a new diet, you may experience symptoms such as fatigue, headaches, or body aches, which may occur because your body is detoxifying. However, if you are unsure about a symptom at any time, check immediately with your medical or health care professional.