Best food groups: Seaweed, seafood, dairy
Also consider: Chocolate ice cream, bread, fish sticks, tuna (canned in oil), prunes, Cheddar cheese, lima beans, apple juice
What is iodine and why is it so important? Iodine is an essential mineral that is required to make protein and enzymes for chemical reactions in the body. It is of particular importance in the thyroid gland as it is needed, along with the amino acid tyrosine, to create thyroid hormones that help regulate metabolism. Iodine is also essential to the skeletal and central nervous systems of developing fetuses. A lack of iodine in the human body causes the thyroid to overreact and swell up in an attempt to capture more iodine. This results in the swelling of the neck, commonly referred to as goiter. Back in the early twentieth century, most brands of salt began to add iodine to prevent the development of goiters, which were prevalent around the Great Lakes area of the United States.
How much is enough?
The DV for iodine is 150 mcg, based on a 2,000-calorie diet.
Typically, food does not contain high enough doses of iodine to have harmful effects; rather, iodine overload comes from chemical exposure. Ironically, high intakes of iodine can cause the same symptoms as a deficiency, namely goiters and hypothyroidism. Excess iodine can stimulate thyroid stimulating hormone (TSH), which can produce a goiter, and excess intakes can also lead to thyroiditis and potentially thyroid papillary cancer.
Did you know? According to the CDC, tincture of iodine (often in the form of inedible povidone-iodine, such as Betadine) is used in presurgical procedures to kill and also prevent microorganisms from growing. It is quite effective in reducing infection rate and increasing wound healing. In chemistry, iodine gas is thought of as being violent. Our mineral name iodine is derived from the term iodes, the Greek word for "violent."
Supplements: Most multivitamins contain iodine but you may purchase them without it, as some people have allergic reactions to iodine or may be on iodine therapy. Vegans may be at risk for low iodine intake, so vegan women of child-bearing age should supplement with 150 mcg of iodine daily.
1. Seaweed
Kombu is known as "the king of seaweeds" and is one of the richest sources of iodine of all of the sea vegetables. It is an essential staple in the Japanese diet and is used to make dashi (stock); it has a wonderful umami taste. It can also be rehydrated or chopped up and added to stews, soups, and casseroles. A strip of it added to a pot of beans, while cooking, reduces the gas-producing carbohydrate called raffinose. Kombu and other brown algae are potent sources of a carbohydrate called fucoidan that possesses anti-inflammatory, antioxidant, and anticancer properties. Fucoidan has been shown to kill human stomach and colon cancer cells, battle immune-related diseases, and keep tumor growth at bay.
2. Cod
Cod is a white, mild-flavored fish that flakes when eaten. In England, cod is the most common fish ingredient in that nation's staple dish, fish and chips. Cod typically weighs between 10 and 25 pounds, but some have been caught as large as 220 pounds. Cod liver oil is an important source of omega-3 fatty acids and vitamins A, D, and E. The fish is an excellent source of iodine and selenium, and a great source of magnesium, niacin, phosphorus, and vitamins B6 and B12. Like chicken and turkey, cod is also an abundant source of the amino acid tryptophan, which has been associated with increased sleepiness. Eating cod, or any fish that is either broiled or baked instead of fried, can help reduce a person's risk of atrial fibrillation, the most common form of heart arrhythmia. Those older adults who had higher plasma levels of omega-3 fats from food sources such as cod were less likely to experience atrial fibrillation later on in life.
3. Yogurt
Boston University researchers found that those subjects who reported eating yogurt and salty fish had the highest level of urinary iodine, compared to those who didn't eat those items regularly.
4. Iodized Salt
Until the 1920s, iodine deficiency was prevalent in the Great Lakes, Appalachian, and Northwestern regions of the United States. Salt was then required to be iodized and shortly afterward, goiters in the United States decreased substantially. Researchers have found wide variation in the iodine content in common foods as well as iodized salt products. Almost 70 percent of all sodium consumed in the United States comes from processed foods; however, producers of commercially prepared food are not required by law to use iodized salt. There is also concern that a call for decreased sodium may also decrease iodine in the diet, so it may be to our best interest to require the use of iodized salt in processed food. Since the 1970s, urinary iodine levels have decreased by nearly 50 percent but average levels still remain in the sufficient range. CDC researchers found that many women are only borderline sufficient in iodine. This may have to do with their not consuming adequate amounts of iodine-rich foods, such as sea vegetables and fish, dairy, and iodized salt.
5. Milk
Back in 2004, a sampling of eighteen different brands of cow's milk in the Boston area revealed that 1-cup samples varied greatly, containing 88 to 168 mcg of iodine per serving.
6. Shrimp
These tasty crustaceans are swimmers, rather than crawlers like their counterparts lobster and crayfish. They are also low in calories and saturated fat, making them a great alternative protein source for more fatty meats. Shrimp are an excellent source of iodine, phosphorus, selenium, and vitamin B12, and also a good source of copper, niacin, vitamin B6, and zinc.
Shrimp are high in cholesterol. But in a peer-reviewed study, researchers found that adding 300 grams (10.5 ounces) of shrimp to the diet per day showed a decreased ratio of total cholesterol to HDL cholesterol. Additionally, the group that ate shrimp lowered their triglycerides by 13 percent!
7. Eggs
Eggs are a great affordable source of high-quality protein. One large egg provides 6.3 g of protein for only 72 calories. Eggs are also vital to food chemistry. We use them for browning, coagulation, emulsification, and foaming of many foods. Adding iodine to the feed of chickens via natural sources such as sea kelp or iodine-rich yeast has been found to triple the amount of iodine normally available in the egg. Unfortunately, this is not common practice, commercially . . . yet!
Source: USDA National Nutrient Database for Standard Reference, Release 24