Food Studies: What You Don't Know About Iodine, the Element of the Moment
How iodine tablets protect against radiation, iodine-laced cattle feed, and "chop-and-die" cassava: Exploring the complex chemistry of iodine.
Food Studies features the voices of volunteer student bloggers from a variety of different food- and agriculture-related programs at universities around the world. Don't miss Amy's first post, in which she describes quitting her ad agency job to go back to school and study nutrition at the ripe old age of 30!
It's perhaps self-evident that, as a student of nutrition and dietetics, I take food pretty seriously. I think carefully about what I eat, where it came from, and how it's going to make me feel.
But even I've been overwhelmed by the sheer range of dynamics that I'm learning to be conscious of when thinking about food. Having been studying for six months or so, I'm starting to be able to put a few pieces of the puzzle together.
I'll take iodine as a random example to illustrate what I mean. It's probably something you've never thought much about before—I certainly hadn't until recently. It's been all over the headlines for the past fortnight because Potassium Iodide (KI) tablets are being distributed to people who might be exposed to radiation from the stricken Fukushima Daiichi plant in Japan. And by pulling together little titbits of information (that I've gathered from my courses in nutrition, physiology, and social sciences), I'm learning that, as with anything to do with food, there's a complex web of stories behind this nutritional element.
Iodine is found naturally in the body, but we also need to consume it in small amounts in our diet. It's found in the highest concentration in fish, while milk contains it in lesser amounts. In the U.K. we tend to eat a lot more dairy products than we do fish, so that’s where we get most of ours. Also, the reason there's iodine in milk at all is because farmers put it into cattle feed to help increase fertility.
Despite the element's presence in a range of foods, iodine deficiency is the world's biggest cause of preventable brain damage (our thyroid gland, the butterfly-shaped gland in our necks, needs iodine to make hormones important in controlling our growth and metabolism). In Ethiopia, for instance, where the trade in iodized salt from Eritrea was cut off when the countries went to war in the late 1990s, 80 percent of Ethiopians are now iodine deficient, exposing them to a range of terrible health problems.
Closer to home, whilst the vast majority of people in the U.K. do get enough iodine—I'm unlikely to treat iodine deficiency when I qualify as an NHS dietitian—people receiving some form of state welfare are up to five times more likely to consume too little iodine than those who are not.
Leaping across continents again, in Nigeria, there's apparently a type of cassava known as "chop and die." Cassava is the major source of energy for some African and Asian populations, but it can disrupt iodine-related processes in the body and cause brain damage. In response, the native population has become well versed in traditional methods of processing cassava, which require up to six days of soaking, mashing, and drying the vegetable to remove its harmful effects.
And right now, for people in evacuation centers in Miyagi Prefecture in Japan, iodine is both a threat and a defense. As the damaged reactors at the Fukushima Daiichi plant release radioactive iodine into the air, it can enter the body through the lungs or contaminate the local food supply (especially leafy greens and milk) and be absorbed that way, potentially causing radiation-induced thyroid cancer. KI tablets contain a stable, non-radioactive iodine salt, and if they are taken in advance of any radiological exposure, the thyroid will absorb so much stable iodine that it will become too "full" to take in any radioactive iodine from either the atmosphere or food.
It's quite awe-inspiring to become aware of so many different ways of looking at food through the lens of a single, fairly obscure trace element. I'll always enjoy food for its own sake, but all these little insights only make me appreciate its power to shape our lives even more.
To be continued...