kosher salt and iodine deficiency

Dear Kitchenista,

It seems like chefs all over TV and in restaurants use only kosher salt for cooking. Is it just the feel of it, or is it the taste? What’s the difference between kosher salt and regular table salt?  —  B. Dayton, Irvine, CA

Dear B.,

The short answer is: not much. The long answer follows. This is a timely question for me to answer because I recently took a 24-hour long diagnostic test to determine my body’s iodine level. I found out that I was operating with a more than moderate deficiency in iodine which was the likely reason behind many annoying and chronic symptoms I’d been putting up with like bone-aching fatigue, the need to wear sweaters in 80-degree heat, brittle nails and hair, brain fog (some would argue I’ve always had this), and a few others I don’t have to go into here.

I’ve been using kosher salt exclusively since I started culinary school back in 2009. It’s the chef-y thing to do. Chefs love it because of the hand feel of it. You can grab, pinch, hold and see it when you are seasoning something with it. Unlike finely ground table salt, (which is the preferred salt for baking), it doesn’t disappear as soon as it hits its target, so you can more accurately season something, and you are less likely to over-season. When cooking with kosher salt, you would use more (proportionally) than you would of table salt, but that is only due to the size of the grains—they are a larger, less concentrated grain of salt—not the taste. The big difference between kosher salt and most table salts, I learned the hard way, is that kosher salt does not contain iodine. So for the past three years or so, like a third of the world population, I’ve been getting an insufficient amount of this essential-for-health nutrient.

Now, my iodine deficiency is probably not solely a result of my kosher salt usage. Dairy products are a good source of iodine and I don’t consume a lot of those either, due to a lactose intolerance. I eat a moderate amount of fish, but not enough, I guess, and zero amount of kelp, apparently very high in iodine! The fact is that with more and more Americans avoiding dairy due to intolerances and others avoiding salt due to fears of high blood pressure,  many of us don’t get enough iodine.  In fact, iodine deficiency has been a public health problem in this country before. In the early part of the 1900’s the problem was considered epidemic enough that researchers in the field approached major salt producing companies to add iodine to their products to help boost nationwide iodine levels.

This is not a nutrition blog, so I’m not going to even try to go on an on about this subject, but I did want to introduce the information because finding out about my own deficiency and just taking a tiny amount of iodine supplementation has made a big difference in my health and vitality.  A book my husband (the nutritionist) gave me to read about iodine and why we need it might interest you if you too have been plagued with vague symptoms like mine, that aren’t attributable to anything else.

If you like cooking with kosher salt, you may want to use it solely for hands-on seasoning, where being able to see and feel what you’re doing is important. For salting water to cook in, for baking or other measured seasoning that doesn’t depend on “feel” using an iodized salt could help prevent iodine deficiency. The only place in cooking where iodized salt is not recommended is in pickling, fermenting and long-term brining because the iodine content can end up discoloring the food.