I don't personally have thyroid issues, but I've seen a couple of patterns on things (take with a grain of salt if you want):

1. Iodine is known to help hypothyroid. Switching to Paleo or just about any kind of lower carb way of eating usually results in eating less processed food. Less processed food = less iodine from iodized salts = lower thyroid function. The solution is actually pretty easy -- make sure to incorporate more iodine in the diet. Shell fish and sea vegetables have the highest amount of iodine, with non-shell seafood, eggs, and dairy following in a far-behind second.

2. The carbohydrates are a bit of a red herring, depending on the exact issues you're having. As I recall, carbohydrates play a role in TSH, so lower carbs = lower TSH. Though whether or not this is a bad thing is a different story, and TSH isn't generated by the thyroid, but by the pituitary gland (after all, it's the thyroid stimulating hormone), so it's not really a great indicator of thyroid function, anyway (other than response to TSH). It's kind of like the issues of measuring cholesterol -- no one's directly measuring the numbers that matter, but rather not-really-that-great proxies instead (and then wonder why nothing they do to change those proxies help with the issue they're trying to fix).

3. The most common cause of failure (even among people who don't have thyroid issues) on low-carb is not increasing fat and/or not eating enough food in general. Low carb, especially very low carb, generally requires you to increase your calories a little, because fats and proteins aren't as easy to turn into fuel as sugar. This issue is compounded by the fact that fats and proteins are very satiating. Combine all that with the indoctrinated fear of fats (particularly saturated fats) and obsession with stupidly low calorie intakes, and you can have a recipe for disaster. The effects of insufficient fat intake is compounded for hypothyroid patients, because a lot of the symptoms are the same, and often magnified. They then blame it on going low-carb, without taking into consideration their fat and total calorie intake (as well as nutrients from the carbs they do get).

When you say IODINE.. you mean table salt? thats so funny because all my life i was told.. DONT eat salt, dont add salt.. blah blah.. i wonder if low sodium soy is ok.. because i have at least a tablespoon of that a day... I just got total bloodwork back from doc so i was looking up everything.. and one part says SODIUM and it says 139 and so i imagine its ok? I wonder if thats the same as IODINE

2. The carbohydrates are a bit of a red herring, depending on the exact issues you're having. As I recall, carbohydrates play a role in TSH, so lower carbs = lower TSH. Though whether or not this is a bad thing is a different story, and TSH isn't generated by the thyroid, but by the pituitary gland (after all, it's the thyroid stimulating hormone), so it's not really a great indicator of thyroid function, anyway (other than response to TSH). It's kind of like the issues of measuring cholesterol -- no one's directly measuring the numbers that matter, but rather not-really-that-great proxies instead (and then wonder why nothing they do to change those proxies help with the issue they're trying to fix).

Hi DragonWolf,

The resource that I'm using is "The Paleo Approach," by Sarah Ballantyne (a medical biophysicist). If I understand her correctly, she says that for people who are hypothyroid, very low carbohydrate diets may tend to keep insulin levels too low, which is an issue because insulin "supports the conversion of T4 thyroid prohormone (thyroxine) to the active T3 thyroid hormone (triiodothyronine)." (p. 220). So, it might not be altogether a red herring.

Your other points are excellent!

Whoops! I see Nutmeg76 already addressed this point.