Nutritional Considerations
Zinc, vitamin E and vitamin A function together in many body processes including the manufacture of thyroid hormone. In addition to iodine, a deficiency of any of these nutrients would result in lower levels of active thyroid hormone being produced. Low zinc levels are common in the elderly, as is hypothyroidism. The B vitamins riboflavin (B2), niacin (B3), and pydidoxine (B6), and vitamin C are also necessary for normal thyroid hormone manufacture. The trace minerals zinc, copper, and selenium are the required cofactors for iodothyroinine iodinase, the enzyme which converts T4 to the far more active T3. There are several different forms of this enzyme, each requiring a different trace mineral. Supplementation with zinc (the second most common mineral deficiency) has been shown to re-establish normal thyroid function in hypothyroid patients who were zinc-deficient, even though they had normal serum T4 levels. Dental mercury removal and heavy metal detoxification will restore many vitamin, mineral and trace elements to normal levels as well.
Similarly, selenium supplementation may be important, as those living in areas of the world where selenium is deficient have a greater incidence of thyroid disease. Of particular significance is the fact that while a selenium deficiency does not decrease the conversion of T4 to T3 in the thyroid or the pituitary, it does result in a great decrease in this conversion in the other cells of the body. People with a deficiency of selenium have elevated levels of T4 and TSH.
Supplementation with selenium results in a decrease in T4 and TSH and normalization of thyroid activity. Selenium is deficient in about 50% of people's diets, which, along with the high incidence of mercury toxicity, may account for the large number of people with low thyroid activity. Research demonstrates that a selenium deficiency results in low thyroid activity in the cells even though hormone levels are normal or even elevated,and provides some support for Barnes' contentions.
Basal Temperature Test
The Barnes test or basal temperature test is a simple measurement of oral temperature--"at rest"--taken with an ordinary oral thermometer. The basal temperature test is a better index of hypothyroidism and need for thyroid therapy than the basal metabolic rate test. It costs nothing. Any patient can self-administer the test at home in ten minutes. It is done upon waking in the morning while the body is completely at rest, before engaging in any activity or eating anything, before getting out of bed, even to urinate. The thermometer should already have been shaken down the night before so as not to create heat from the muscle activity of shaking the thermometer. The thermometer is placed in the mouth for ten minutes by the clock while resting quietly. Body heat depends upon the amount of foodstuffs burned. Thyroid hormone is essential for the oxidation or burning of fuel in the body, and in the thyroid-deficient person body temperature falls below normal because of inadequate oxidation.
The normal range of basal temperature is between 97.8 and 98.2 degrees Fahrenheit, if there is no sinus or throat infection present. A reading below this normal range suggests low thyroid function. If it is above the normal range, one must be suspicious of some infection or an overactive thyroid gland. In women of menstruating years, because temperature can be elevated with ovulation, basal temperature is best measured on the second and third days of the period after flow starts. Before the menarche or after the menopause, the basal temperature may be taken on any day. When symptoms of thyroid deficiency are present, the basal temperature may be one, two, or even three degrees below normal. With thyroid therapy, the temperature will start to rise toward normal.