Q:I would be very interested to know your views on the Barnes Basal Temperature Test for diagnosing slight hypothyroidism. I first heard of this when I consulted a nutritionist last year. Recently I read about it in an article.
I have been taking my underarm temperature first thing in the morning for a few weeks and have found temperatures ranging from 97 degrees to 98.2 degrees!
The article states that the most accurate readings are taken on days two and three after a period starts, but doesn't mention the best days for men or postmenopausal women. D K, Langdon Hills.......
A:Taking your Basal Temperature can be an initial indicator of possible hypothyroidism (underactive thyroid), since low body temperature is one symptom.
The Basal Body Temperature is the lowest temperature that you achieve during the day. The test entails placing a thermometer under your armpit for 10 minutes on waking and before rising out of bed. Supposedly normal readings are between 97.8 and 98.2 degrees Fahrenheit (36.6 and 37 degrees Celsius); anything lower is supposedly abnormal. It is the same test used for natural family planning in women since female hormones cause the body temperature to fall slightly just before ovulation and then rise just after.
But we stress that it is only an indicator. The danger is relying on any single test or factor to determine thyroid function or, for that matter, health. Recently, Diana Holmes, one of our readers, sent in a paper excoriating doctors for relying totally on blood tests for hypothyroidism. She based some of her fascinating conclusions on the work of Dr Broda O Barnes, who studied hypothyroidism for some 35 years.
Currently, doctors tend to assess thyroid function by performing blood tests to measure three thyroid hormones in the blood. These tests examine the amount of thyroid stimulating hormone (TSH), the hormone released from the pituitary gland to cause the thyroid to secrete thyroid hormones and also the hormones themselves: T4 (thyroxine) and T3 (triiodothyronine), which regulate your metabolism by setting the rate at which reactions take place in individual cells.
As Diana points out, the blood tests are very limited because they will show accurate levels of thyroid hormone in the blood, but not how much the body is able to use or how much is necessary for an individual patient's health. No test has yet been devised to show how much hormone is actually present inside each cell in the body. Furthermore, the tests are based on a cross section of so-called normal people's thyroid function, when many of those comprising the "normal" range may themselves not really be normal. The test may also show as "low normal" many people whose true health demands that they be in the higher range of normal.
Measuring levels of hormone in the blood also won't show whether there is exhaustion of adrenal glands, which will effect hormone uptake, or malfunction at receptor sites, she says, or whether the conversion of one hormone to another is adequate. There is also the problem inherent in all laboratory work: human error or the margin of error built into the test. Our Alternatives columnist Harald Gaier says that when he orders up blood tests for thyroid and they come back as abnormal, he often will request a new set from another lab, just to be sure.
The other problem with the test is that it will register as "underactive" patients whose low output is perfectly adequate for their needs. By relying solely on a test, doctors also adopt a simplistic solution, believing that simple replacement of the "low" hormone will sort out the problem. This one-dimensional approach may be why thyroxine replacement therapy so often doesn't work.
In one University of Birmingham study of 102 patients, nearly half given replacement therapy had levels of TSH outside normal levels (The Lancet, January 19, 1991). Furthermore, thyroxine replacement therapy often doesn't do any good. A Danish study divided up a group of 206 patients who'd had surgery for goitres (swelling due to inadequate thyroid uptake of iodine), and gave half thyroxine and half no treatment. After nine years, the group which received nothing had no higher recurrence of goitre than those who'd received the hormone. And of course if you're given thyroxine for spurious reasons, such as for overweight, your own production of the hormone will decline; if you haven't had a thyroid problem when you started, you'll certainly end up with one.
This is one reason why tests, in Dr Gaier's view, should comprise only one marker of this disease but must be consistent with the entire clinical picture, which can vary tremendously between patients. The main symptom is a decrease in metabolic rate, which is evidenced by general slowing of mental and physical function feelings of tiredness, cold, weight gain, general pains, forgetfulness and lack of ability to concentrate. Even the pulse is slow.
One blood test he does find useful examines for autoimmune diseases by assessing whether the body produces anitibodies that attack its own thyroid tissue. These tests would confirm suspected autoimmune disease, such as Hashimoto's thyroiditis and Grave's disease.
It's also wise to keep in mind that there can be many complex causes of thyroid dysfunction and an entire range of solutions. Sometimes a low thyroid will need nothing more than supplementing with kelp; in other cases, further investigation may reveal that the problem has to do with something else in the endochrine system. Oftentimes women with unbalanced hormone levels will have thyroid problems, since both TSH and sex hormones are regulated by the pituitary gland in the brain; as soon as the sex hormone imbalance is corrected, the thyroid often functions much better.