In 2016, I had been having trouble losing weight as well as experiencing highly variable performance. I just could not make sense of it. Then I came across information with several key points:
- Iodine can be depleted in an athlete training regularly.
- The USA RDA of iodine is woefully low, at least in the context of regular exercise.
- Ordinary iodized salt rapidly loses its iodine content.
Also, I struggled with all these symptoms of iodine deficiency this year: weight gain (an inability to drop body fat), sluggishness, fatigue, cold extremities. I particularly noted a problem this year with feeling cold when the temperature was reasonable, and particularly cold hands and feet. See my weight loss chart after I started eating for iodine.
According to Wikipedia:
An opened package of table salt with iodide may rapidly lose its iodine content through the process of oxidation and iodine sublimation.
According to Iodine uptake and loss-can frequent strenuous exercise induce iodine deficiency? at nih.gov:
Most of the daily dietary iodine intake (approximately 90 %) will be excreted in the urine; measurement of urinary iodine excretion is thus routinely used as an index of dietary iodine intake. However, urinary excretion is not the only means of iodine loss.
Subjects such as athletes or those participating in vigorous exercise can lose a considerable amount of iodine in sweat, depending on environmental factors such as temperature and humidity. In areas of lower to moderate dietary iodine intake, loss in sweat can equal that in urine. Although electrolyte loss in sweat is well-recognized and replacement strategies are adopted, there is less recognition of potential iodine loss.
Crude calculations reveal that if sweat iodide losses are not replaced, dietary stores could be depleted in an athlete undergoing a regular training regime. The significance of these losses could be increased in areas where dietary iodine intake is lower in the summer months. Although there is little doubt that excessive sweating can induce a relative iodine deficiency state, there is no case as yet for iodine supplementation in those that take vigorous exercise. However, sustained iodine loss may have implications for thyroid status and possibly consequences for athletic performance.
What I did
I figure that 90 minute a day of vigorous exercise along with 7 double centuries in ~5 months qualifies me as being at high risk for iodine deficiency. See also Excessive Sweating, Athletic Performance, and Iodine Deficiency – Is There a Connection? and iodine lost during exercise.
I felt that there had to be a connection, so I started eating sheets of seaweed nori, and taking kelp tablets. Not long after starting, my weight began to plummet and my performance bumped up strongly.
I now use Himalayan pink salt*, which is claimed to be high in iodine and other trace minerals. And it has a goo texture and taste (some iodized salts are too fine, and taste harsh to me). A one pound bag in my local grocery store cost me $4.99. That amount lasts me a long time, so it’s plenty cheap—and it’s a good texture and taste also.
* Set aside the trendy (and moronic) labels on salt as being “gluten free and GMO free”. This catering to the scientifically ignorant is a sad state of affairs, but vendors recognize that nitwits buy stuff too, and thus have to make it easy for irrational pea brain customers too.