  here's the conclusions of the day's research on thyroid: First off, urlLink hypothyroid is pretty common. It means a person’s thyroid isn’t urlLink producing enough hormone. It can be an underlying contributing cause or an outright direct cause to a large number of health problems, including confusion in thoughts or nervous thinking, heart palpitations, heavy sweating, loose stools, weight loss, and serious fatigue. The medical powers that be recommend every adult over 35 get thyroid blood work done every few years. Sometimes when the body is aware that it needs more thyroid hormones, it enlarges the thyroid to up its production. This is called goiter. Goiter results in a full looking lower neck (the area between your collar bones and adams apple). The riskiest complication aside from the general poor health that can result from low thyroid is the development of nodules, which could (very rarely) be cancerous and therefore need to be biopsies.
This seems similar to the way irritable bowel syndrome can develop into polyps, which can very rarely be cancerous. The thyroid doesn’t often go berserk for genetic reasons, it’s too important to human biology for thousands of years of human evolution to let that gene slip by. Instead, it’s susceptible to environmental effects. These range from literally the environment ( urlLink as contaminants often reduce or increase endocrine production in our bodies ), or the dietary minerals absorbed through food.
The thyroid depends chiefly on iodine uptake through the diet. Dietary iodine occurs predominantly via ocean vegetables, ocean fish, and foods grown in iodine-rich soil. This last one is a problem for areas that have over farmed soil, and thus depleted the dirt of its minerals, and areas where the farming soil is very old in geologic terms. That means the most recent huge geological action was hundreds and thousands of years ago, and erosion is the primary geologic force since. Jagged mountain regions--such as the Himalayas or Rockies--are the best examples because in lower areas, floods renew the earth or at least erosion from the highlands does.
(This makes me wonder if man-made flood prevention already has or maybe someday will make food from American soil deplete of vitamins and minerals. Hmm. ) One kind of thyroid problem called urlLink Euthyroid goiter pops up at times of the life where giant hormonal changes are running amuck (read: puberty, pregnancy, menopause). Apparently, people living in hot climates, and people whose lifestyles cause them to sweat a lot are at additional risk for low iodine. It’s a new idea, but urlLink this paper makes a powerful argument . I caught on one correlation in its readings too that makes me also connect the two.
Heart palpitations can be caused by an imbalance of electrolytes, and sweat is the chief cause of electrolyte imbalance in humans. Heart palpitations are also a common effect from low thyroid. One way governments combat low thyroid among the population is by advising (as the US gov’t does) or mandating ( urlLink as the Canadian gov’t does ) salt producers to iodize salt. Currently, 50-70% of the US population consumes iodized salt. Additionally, health organizations and governments alike have launched urlLink social marketing campains to push iodized salt use.
Interestingly, our family had switched to kosher and French sea salt for aesthetic reasons (it tastes so good, you don’t need as much!). A friend of mine went to the doctor for low thyroid and was advised to avoid soy products. A huge percentage of the global population has relied on soy as a dietary foundation for so many generations, that I found myself seriously doubting the validity of the advice. Sure enough, I looked it up and found huge misconceptions regarding soy and thyroid. Anyone whose been through a pregnancy recently knows how important it is to avoid foods high in calcium (chiefly dairy products) around the time of day you take your prenatal vitamin. This is because some vitamin uptake, especially iron uptake, i inhibited by calcium. Iodine uptake is similarly affected by soy products. So while urlLink some irresponsible sources say the isoflavones that make soy one of nature’s most perfect foods are “potent anti-thyroid agents,” they should more accurately say that isoflavones interfere with your colon’s absorption of iodine, which your body needs to maintain a healthy thyroid.
If your diet is already rich in sources of iodine, there is no worry. However, if you have reason to be concerned about your iodine levels, try to eat a source of iodine at least once a day when you haven’t consumed a soy product for an hour or two, and don’t plan to consume it for an hour or so longer.
This harks to the underlying issue of variety in dietary consumption among Americans. If we ate sufficiently varied diets regularly, there would be nothing to worry about. We have to avoid food ruts. The groundwater should also be a source of iodine, but we drink carefully filtered water in an effort to avoid the harmful urlLink environmental polutants common in urlLink metropolitan , urlLink industrial , and urlLink agricultural areas. We're probably filtering out our minerals, too. Recently we began using storebought spring water for drinking (tea, water, etc) and using the fridge filtered water for cooking. The spring water is natural groundwater from sources too deep to typically be polluted, so it should solve both problems for us. 
