I just listened to a fascinating podcast about (come on, what did you think?) thyroids. And I took notes, which you will find below.
No no, wait, don't delete this e-mail immediately! Thyroids are really fascinating, and there are reasons you might be interested in them even if yours is doing fine (you might happen to have blood-sugar issues, hormonal imbalances, autoimmune problems, or chronic stress in your life, all of which tie into thyroid dysregulation as explained below) and even though I don't like podcasts at all, I listened to this one twice. Chris Kresser is a naturopath http://chriskresser.com/ , and his wife has had thyroid issues, so he has a personal interest in the topic.
Many thyroid problems are not problems with the gland itself, but stem from autoimmunity, when the body dysfunctionally attacks its own tissues (the thyroid is attacked in the case of Hashimoto's Thyroiditis; other autoimmune diseases are lupus, multiple sclerosis, rheumatoid arthritis, etc.).
Autoimmunity produces chronic low-grade inflammation (Wikipedia says that inflammation is "part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process").
Inflammation, in turn, can do many damaging things, and Chris Kresser specifically describes some of the harmful effects in terms of thyroid disease. Inflammation suppresses the hypothalamic-Pituitary-Thyroid axis, by reducing the body's available stores of TSH (thyroid stimulating hormone, secreted by the pituitary, which acts as a signal to the thyroid), T4 (the body's storage form of thyroid hormone), and T3 (the active form of thyroid hormone, mostly converted from T4 by the liver). The pituitary/hypothalamus also regulates many other hormones, including sex hormones; therefore, taking thyroid hormone medication may alleviate some symptoms of thyroid dysfunction, but will not ameliorate all symptoms (since the hormone supplementation does not address the basic issue if it stems from the pituitary or hypothalamus).
Inflammation can also suppress the number and sensitivity of thyroid hormone receptors throughout the body. All thyroid hormone (in the form of T3) has to be able to get into the body's cells in order to have an effect; if there are not enough cells, or they are not sensitive enough, it doesn't matter how much thyroid meds you take.
Inflammation also decreases conversion of T4 to T3. Ninety percent of the thyroid hormone produced by the body is in the form of T4, but much of that has to be converted into T3 to be used. Which is why T4 thyroid medications are not a great idea--you may end up taking more and more, and you'll definitely get _effects_ from them, but not necessarily the benefits that your body would receive if it were able to convert T4 into T3 and utilize it to begin with.
Basically: autoimmunity is an inflammatory condition, and you must address inflammation in order to heal.
Hypothyroid triggered by problems "upstream," at the pituitary, can have other potential causes: any long-term emotional or physiological stress that taxes the adrenals (which produce chronic excessive cortisol, that stresses the pituitary), and other sources of inflammation (besides the effects seen in autoimmunity, garden-variety inflammation can stem from gut dysbiosis (most common), gut or other infections, yeast infections, etc.). Many of these situations cause the body to produce inflammatory cytokines, and these also suppress pituitary function. In all these cases, one must focus on digestive health and reducing stress.
Underconversion from T4 to T3 can result in a high "Reverse T3" level in the body, which is essentially what the body makes with perceived "extra" levels of T4 in order to get rid of thyroid hormone that isn't converting properly to T3. Underconversion from T4 to T3 is very often due to inflammation from high cortisol levels.
Thyroid hormones are fat soluble, so they can't just get dumped directly into the bloodstream--they must be bound to a protein carrier, otherwise known as Thyroid (Thyroxine) Binding GLobulin (or TBG). If TBG levels are excessive, there will be too-low levels of unbound (or "free") hormones available for use by the body. High estrogen levels can cause elevated TBG, so if someone has excessive levels of TBG, it's wise to look for sources of excessive estrogen: birth control pills are a primary source, along with estrogen replacement therapy. In this scenario, TSH and T4 levels will be normal, but T3 will be low--and TBG will be high. (Another marker to look for is T3 Uptake results, which has an inverse relationship with TBG; if one is high, the other will usually be low, and vice versa.)
Another source of excess estrogen in the body is the liver, which is responsible for getting rid of excess hormones in general. The liver can get bogged down with long-term hormonal imbalance, so it makes sense to support the liver in its daily functions over the long term.
There is another situation that can cause problems with the thyroid, which is thyroid hormone resistance. Similar to the case of insulin resistance (due primarily to consuming a high-carbohydrate diet, when there are too-high levels of glucose in the blood), in thyroid hormone resistance there are high levels of free thyroid hormones, low levels of TBG, and cells are literally, over the long-term, overwhelmed. You might think with so much free hormone available, the body would end up with _hyper_thyroid symptoms, but instead the cells get resistant to hormones (just like in insulin resistance), so you end up with hypo- symptoms instead.
Decreased TBG levels can also be caused by too much testosterone. Women usually do not supplement with extra testosterone, so primarily insulin resistance is responsible for this issue: it sparks an overconversion of estrogen into testosterone, which can have the net result of supplying the body with too much testosterone. This is seen in Poly Cystic Ovarian Syndrome (PCOS), which is also very common in women with Hashimoto's--obviously, reversing the insulin resistance is key.
With thyroid resistance syndrome, hormones are not getting to cells--receptors are too few or too insensitive--so this brings us back to checking on levels of chronic stress and elevated cortisol, which can also cause this. And ANYTHING that throws the body off-balance is a stress. High homocystine levels also contribute to thyroid resistance.
Low T3 syndrome can also be caused by a recently-defined condition known as Autoimmune Hyper Pituitary Syndrome, in which the immune system attacks the pituitary. Studies are suggesting that 40% of those with Hashi's also have AIHP. And obviously, thyroid medications deal with the effects, not the cause of autoimmune dysregulation.
And of course, stress or inflammation that is not autoimmune in origin can also suppress pituitary function. Markers to alert one to the presence of AIHP (tests are not currently available outside of research settings): Low T3, Low T4, Low TSH (with or without the presence of thyroid antibodies in the blood). The best way to diagnose this issue is by exclusion of symptoms--if labs look like those above, and symptoms exist, then it is likely that an issue exists with the pituitary along with the thyroid.
Curing and modulating inflammation cannot be overemphasized in healing autoimmune conditions.
This is very oversimplified, but most autoimmune conditions are due to an imbalance between two branches of the immune system. Picture a teeter totter, and one one side is "cell mediated immunity," and on the other side is "antibody mediated immunity." There should be a dynamic balance on this seesaw, in which both sides are in the air at all times.
In autoimmune conditions, one side of the immune system teeter-totter is dominant, while the other is suppressed--picture a 400-lb. person weighing down one side, sitting opposite a tiny child who can only dangle helplessly up in the air. The 400-pounder can be either branch of the immune system, and sometimes the situation can continually reverse, making the teeter totter bounce wildly. T Regulatory cells are supposed to regulate this process of immune system balance, but in autoimmunity, this process is disrupted, and a problematic feedback loop ensues. To help interrupt and heal this circular process, there are three promising, less-invasive treatments (on top of the extremely important consumption of an anti-inflammatory "paleo" type diet, along with stress management):
1. Optimize vitamin D levels in the blood via supplementation with D3. Inflammation inhibits the body's ability to convert Vit. D from the sun, and of course in people with autoimmune conditions, inflammation is rampant.
2. Optimize glutathione levels, since this helps prevent oxidative damage. Autoimmunity and stress depletes the body's stores of glutathione. (This is a more complicated topic and a challenge to do with supplements...)
3. Low-Dose Naltrexone. This substance appears to have very positive effects on reversing autoimmunity, it supports T-regulatory cell function, and appears to be very, very safe at low doses.
Optimizing fatty acid balance is very important. Omega-six fats promote inflammation, and omega-3 fats are anti-inflammatory. The best way to get omega-3s is to eat a lb. of fatty fish (salmon, makerel, sardines, halibut, herring) per week.
Reducing sources of inflammation is key for overall healing. And STRESS MANAGEMENT AND GUT HEALING are the elephants in the room--these are the two biggest challenges of any treatment. People who find the most success in healing their thyroid conditions must deal with both of these things. Even when one can't reduce stress entirely, stress management is key; and dealing with a leaky gut is crucial in order to heal and quell inflammation.
The following summary found at http://www.sarahwilson.com.au/2011/11/your-thyroid-still-playing-up-i-t… : six basic scenarios in which thyroid medication might not work as well as advertised.
"Hypothyroidism caused by pituitary dysfunction: caused by elevated cortisol from infection, blood sugar imbalances, chronic stress, pregnancy, hypoglycemia or insulin resistance. In your blood tests: TSH will be low but within the standard range but T4 will be low, too.
"Under-conversion of T4 to T3: caused by inflammation and elevated cortisol levels. In your blood tests: TSH and T4 will be normal. But T3 will be low.
"Hypothyroidism caused by elevated Thyroid binding globulin (TBG): caused by high estrogen levels, which are often often associated with birth control pills or estrogen replacement. In your blood tests: TSH and T4 will be normal. T3 will be low and T3 uptake and TBG will be high.
"Hypothyroidism caused by decreased TBG: caused by high testosterone levels. In women, it is commonly associated with PCOS and insulin resistance. In your blood tests: TSH and T4 will be normal. T3 will be high and T3 uptake and TBG will be low.
"Thyroid resistance: caused by chronic stress and high cortisol levels. You can’t test for this.
"Low T3 Syndrome: to better understand how this works, it’s probably best to check out Chris’ posts on the matter http://chriskresser.com/low-t3-syndrome-iv-an-autoimmune-disease-youve-… ."