Thyroid and TSH Research

Okay, all you recreationally bloggers feel free to skip this entry. This one is more for my reference as it tracks my research and the inevitable decision not to take Synthroid.

All right let me first state the facts. I am currently borderline hypothyroidal. Here are my Thyroid Stimulating Hormone (TSH) blood test results. (Doctor's visit here. Initial blood results here. My initial reaction here. Actual blood results here.)

~ Collected 6/28/2002: THS = 6.29 MCIU/ML
~ Collected 7/25/2002: THS = 6.50 MCIU/ML

Normal TSH is considered 0.4 – 5.5 MCIU/ML. So I’m just outside the high range. TSH has an inverse correlation to the actual amount of thyroid hormone in the blood (T3 & T4). High TSH levels mean that the pituitary gland is requesting more thyroid hormone from the thyroid. So what should happen is the thyroid will produce more hormone and the pituitary gland will stop signaling the thyroid when it believes there is enough thyroid hormone floating around. Right now, my body is asking for more hormones, but my thyroid isn’t responding. This is my basic and remedial notion of how the thyroid works.

Now the research results:

~ "…even within the reference range of around 0.5-4.5 mU/l, a high thyroid stimulating hormone concentration (>2 mU/l) was associated with an increased risk of future hypothyroidism.” “The thyroidologists by consensus have decided that this test is the most useful for following treatment when in fact it is unrelated to how the patient feels.” “… the TSH value has no clinical correlation except at absolute extremes with the clinical signs or symptoms of the patient.” (here)

~ “The amount of carbohydrates in your diet can have a profound effect, too. It seems that, depending on the person, anywhere from 50 to 120 grams of carbs are needed in order to prevent the decline in T3 during a carbohydrate-restricted diet. Any lower than that, and T3 plummets substantially. It’s likely this effect is simply dependent on glucose levels in the blood.” (here)

~ “The prevalence of unsuspected thyroid disease in healthy people in the general population is very low. Despite the high specificity of thyroid function tests such as the newer TSH assays, their routine use in the asymptomatic general population results in many false-positive results. Because of the low prevalence of unsuspected disease, only 1 in 5-10 persons with abnormal screening tests will prove to have thyroid disease. Given the low risk, the lack of evidence that treatment of subclinical thyroid disease identified by screening results in important health benefits, and the potential adverse effects of treatment, screening the asymptomatic general population is not recommended.” “Examples of (thyroid dysfunction) symptoms include easy fatiguability, weight gain, dry skin or hair, cold intolerance, difficulty concentrating, depression, nervousness, and palpitations.” (here)

~ “We have recently become aware of the complexity of the effects of non-thyroidal illness on the hypothalamic-pituitary-thyroid axis and thyroid hormone metabolism.” This page also has a nice graph showing the fluctuation of hormone and TSH in relation to illness. (here)

~ “The research shows that TSH can naturally rise during colder months, and drop to low normal or even hyperthyroid levels in the warmest months… This seasonal fluctuation can be more pronounced in older people, and in particularly cold climates.” (here)

~ “In humans, severe physical stress also probably inhibits TSH release.” “…it appears that the amount of carbohyrate in your diet rather than the total calories seems to be the most important factor in determining that you might become hypothyroid. In individuals who had become hypothyroid on a starvation diet it appears that simply giving them 200 grams (800 cal) of pure carbos restores them to a normal thyroid state whereas giving them the same amount of calories as either protein or fat does not.” “Alterations in nutritional state, whether short-term or chronic, and whether the result of underfeed, overfeed, or merely a change in substrate mix, affect various aspects of thyroid hormone economy, especially peripheral hormone metabolism. when normal thyroid lean or obese subjects are starved, the serum total and free T3 (thyroid hormone) concentrations decrease abruptly, often into the clearly hypothyroid range.. .. These aspects of peripheral thyroid metabolism are exquisitely sensitive to changes in the carbohydrate content of the diet. The abnormal thyroid concentrations in serum are quickly restored to normal, not only by refeeding with a balanced diet but also by administration of small quantities (800kcal) of pure carbohydrate. Similar quantities of protein have no effect on the serum thyroid level. Calories given as fat are ineffective in restoring normal thyroid hormone. Other evidence of these relationships is that patients receiving low calorie diets composed principally of carbohydrate display little or no change in the serum thyroid hormones.” (here)

All right, here’s the bad news: THS concentrations can be seasonal, meaning my concentrations may get worse with the approaching winter. This kinda makes sense because a reduction in thyroid hormone may lead to weight/fat gain, which would add a layer of adipose insulation for the cold winter months. Some sources say 2.0 MCIU/ML (not 5.5 MCIU/ML) should be the high end of the normal range, which would make me definitely hypothyroidal not borderline.

The good news: Two sources point out that a temporary hypothyroidal state may be induced by a low-carb diet and that a hypocaloric diet may further the problem. I stated this theory a while back. So my chronic hypocaloric carbohydrate restricted diet may be the fiend (note my nutrition log: 1700 cal/day and 80-120 grams of carbs/day). Luckily, the research also says that this state is temporary and will be relieved with the introduction of 200-grams of carbohydrates a day. Research shows that being sick can decrease thyroid hormone production; thus, increasing TSH levels. I was indeed sick the day after my first blood test and I didn’t get better until after my second test (here, here, here, here, here). Lastly, one source believes thyroid dysfunction should be diagnosed based upon symptoms, not blood work. I have none of the symptoms listed: easy fatiguability, weight gain, dry skin or hair, cold intolerance, difficulty concentrating, depression, nervousness, or palpitations.

My course of action: Continue as I have been. My current training regimen (here and here) has me increasing calories today to maintenance levels (2,500 cals) and increasing my carb intake also (200 grams). In two more weeks I increase these levels again and go on 2 - 4 week hypercaloric diet. These levels should allow my TSH levels to normalize, then in six months I’ll get more blood work done (assuming I can work up the courage). At that time I can reevaluate my situation.
...and so it was written, shenry at 8/07/2002 01:58:00 PM.
...and so it was appended with .