New research in Antarctica shows how thyroid supplementation can raise your spirits
uman beings are basically tropical animals. We evolved on the sunny African savannas, and only through our extraordinary inventiveness and adaptability have we been able to colonize the colder regions of the world. But adaptation does little to change our basic nature, so it shouldn't be too surprising that cold climates with long winters can cause a host of problems for us. One common problem isseasonal affective disorder (SAD), which produces such symptoms as mood disturbances and poor cognitive performance. People who suffer from SAD commonly experience depression, poor concentration, irritability, and impaired memory during the winter months.
SAD appears to be caused by extended periods of insufficient ultraviolet light,1 a common problem during the winter season in much of the world. Other evidence suggests that a cold climate may also contribute to the symptoms of SAD. Low temperatures can reduce the levels of circulating thyroid hormone in the body,2 and it appears, from the available evidence, that SAD is correlated with low thyroid hormone levels.3,4
GOOD NEWS FROM THE SOUTH POLE
Living in Antarctica - one of the coldest, most environmentally challenging regions on the planet - can cause an especially debilitating form of SAD known as polar T3syndrome. This syndrome includes not only the common symptoms of SAD, but also a marked reduction in physical strength and endurance. People suffering from this disorder also have below-normal body temperatures, and their energy requirements rise by as much as 40%, so they typically feel cold and eat more than usual.
Living in Antarctica - one of the coldest, most environmentally challenging regions on the planet - can cause an especially debilitating form of SAD known as polar T3syndrome. This syndrome includes not only the common symptoms of SAD, but also a marked reduction in physical strength and endurance. People suffering from this disorder also have below-normal body temperatures, and their energy requirements rise by as much as 40%, so they typically feel cold and eat more than usual.
By increasing one's circulating
thyroid levels, the brain receives a
more generous supply. This
results in an improvement in
mood and mental skills.
If you happen to have a sluggish thyroid, you might have noticed that polar T3symptoms sound chillingly familiar. Understanding the role of low levels of thyroid hormone, it turns out, is an important clue in solving the polar T3 mystery. A recent study done in Antarctica provides new evidence that low thyroid levels are the underlying cause of many undesirable symptoms associated with this disorder.5 Because low thyroid is easy to treat, this finding is good news not only for those afflicted with polar T3but also for people who suffer from SAD, which appears to be just a less extreme version of polar T3.
YOUR BRAIN NEEDS THYROID HORMONE
The Antarctic study, conducted by Dr. H. Lester Reed and colleagues, measured the thyroid hormone levels in 12 adult individuals while they were living in Antarctica. The study began when the subjects arrived there, and it lasted for 11 months. During the first four months (Period 1), while all the subjects received a daily placebo (an inactive substance), the pooled value for thyroid hormone levels in all the subjects dropped significantly, as did their moods and their performance on tests of mental skills and exercise capacity. At the beginning of the fifth month, half the subjects began receiving daily thyroid hormone supplements (instead of the placebo), while the other half continued to receive a placebo.
The Antarctic study, conducted by Dr. H. Lester Reed and colleagues, measured the thyroid hormone levels in 12 adult individuals while they were living in Antarctica. The study began when the subjects arrived there, and it lasted for 11 months. During the first four months (Period 1), while all the subjects received a daily placebo (an inactive substance), the pooled value for thyroid hormone levels in all the subjects dropped significantly, as did their moods and their performance on tests of mental skills and exercise capacity. At the beginning of the fifth month, half the subjects began receiving daily thyroid hormone supplements (instead of the placebo), while the other half continued to receive a placebo.
At the end of that month, and for the following six months (Period 2), during which the supplementation continued, the test group showed a marked improvement in cognitive performance above the baseline measurements. The control group, however, remained below baseline in their measurements of cognitive performance after the fifth month. Depressive symptoms remained higher in both groups during Period 2, compared with baseline, but the test group reported significantly less fatigue/inertia and confusion/bewilderment than the control group during this period.
The study confirmed that extended winter conditions can lower our circulating thyroid hormone levels, and it appears that this is the principal underlying cause of SAD. Since thyroid hormones control energy metabolism (the process by which oxygen and nutrients are converted to energy for use by the body's cells and organs), and help to regulate body temperature, Dr. Reed has suggested that living in cold climates may cause the muscles to hoard thyroid hormone in an attempt to increase body heat.
Unfortunately, the muscles may be doing this at the expense of the brain. This idea is supported by the fact that thyroid supplementation in the study did not result in improved exercise capacity or increased body temperature. Dr. Reed believes that this is because when the subjects received a dose of thyroid hormone, the supplement may have been shuttled to their brains, where it was most needed. By increasing one's circulating thyroid levels, the brain receives a more generous supply. This results in an improvement in mood and mental skills, but not exercise performance or body temperature, because thyroid-deprived brains are so hungry for the precious hormone.
These results suggest that thyroid supplementation may offer hope to those who suffer from cognitive decline and depression during the winter months. For people who are especially sensitive to cold weather and who suffer from the symptoms of SAD, relieving those symptoms may now be as simple as taking a thyroid supplement - and that is good news.
THYROID HORMONE DECLINES WITH AGE
Thyroid hormone is an iodine-containing compound released by the thyroid gland, a double-lobed, butterfly-shaped organ located in the lower part of the neck, in front of the windpipe. The thyroid gland is part of the body's endocrine system, a network of hormone-secreting glands. (Hormones are chemical substances that travel through the bloodstream to activate organs or groups of cells in parts of the body distant from their site of production.) The thyroid gland is slightly heavier in women than in men, and it increases in size during pregnancy. In addition to affecting body temperature and helping to regulate metabolic processes in all the body's cells, thyroid hormone maintains growth hormone release, stimulates skeletal maturation, and helps to control heart rate. It also promotes central nervous system growth, stimulates the production of many enzymes, and is necessary for healthy muscle tone and vigor.
Thyroid hormone is an iodine-containing compound released by the thyroid gland, a double-lobed, butterfly-shaped organ located in the lower part of the neck, in front of the windpipe. The thyroid gland is part of the body's endocrine system, a network of hormone-secreting glands. (Hormones are chemical substances that travel through the bloodstream to activate organs or groups of cells in parts of the body distant from their site of production.) The thyroid gland is slightly heavier in women than in men, and it increases in size during pregnancy. In addition to affecting body temperature and helping to regulate metabolic processes in all the body's cells, thyroid hormone maintains growth hormone release, stimulates skeletal maturation, and helps to control heart rate. It also promotes central nervous system growth, stimulates the production of many enzymes, and is necessary for healthy muscle tone and vigor.
Because thyroid hormone affects
so many aspects of our
physiology, taking supplements
can have multiple benefits for
people with low thyroid levels.
As with all other hormones, thyroid levels decline with age. Women over forty are the most likely to suffer from low thyroid, but men are also susceptible. Although the extremely low levels that characterize clinical hypothyroidism are treated with thyroid supplements, many physicians view the less severe age-related decline (and the symptoms that go with it) as normal and hence unworthy of treatment. This subclinical hypothyroidism, however, which is characterized by levels that are low but still technically within the normal range according to standard lab tests, can nonetheless cause numerous problems as we get older.
Besides the fatigue, mood swings, and sluggish mental functioning, low levels of thyroid hormone can cause weight gain, low blood pressure, and a loss of libido. But it doesn't stop there. There can also be dry skin, brittle nails, hair loss, constipation, low body temperature, unusually high cholesterol levels, and aching joints. If enough of these symptoms sound all too familiar to you, there is a good chance that you would benefit from taking thyroid hormone supplements. After all, why should you put up with such conditions just because they're considered to be "normal" for an aging person?
Because thyroid hormone affects so many aspects of our physiology, taking supplements can have multiple benefits for people with low thyroid levels. For example, depression that does not respond to antidepressants often does respond to thyroid hormone. In addition to elevating mood and improving cognitive performance, thyroid supplements can also help people with aging thyroid glands to reduce their risk of heart disease6 and to control their weight7 (which, incidentally, also helps to reduce the risk of heart disease).
LOW THYROID CAN LEAD TO CARDIOVASCULAR DISEASE
Studies have consistently shown that low thyroid levels significantly increase the risk of atherosclerosis and cardiovascular disease by decreasing the levels of liver enzymes that break down the amino acid homocysteine.6,8 High blood levels of homocysteine are associated with an increased risk of stroke and other forms of cardiovascular disease,9and they may even be a better predictor of cardiovascular risk than elevated cholesterol levels.
Studies have consistently shown that low thyroid levels significantly increase the risk of atherosclerosis and cardiovascular disease by decreasing the levels of liver enzymes that break down the amino acid homocysteine.6,8 High blood levels of homocysteine are associated with an increased risk of stroke and other forms of cardiovascular disease,9and they may even be a better predictor of cardiovascular risk than elevated cholesterol levels.
Studies have also shown that the B vitamins folic acid, B6, and B12 can significantly lower homocysteine levels, which tend to rise with age.10,11 However, it may not be wise to rely on these B vitamins alone to combat the rising homocysteine levels associated with aging, as a more powerful defense can be maintained by taking them in conjunction with appropriate thyroid supplementation, which offers many other benefits as well.
WHOLE NATURAL THYROID IS THE BEST
Although we have been discussing thyroid hormone in this article as though it were a single substance, in reality there are four distinct thyroid hormones - an important point to consider when contemplating the use of a thyroid supplement. The thyroid gland releases hormone into the bloodstream mainly as thyroxine (T4) and, in smaller amounts, as the four-times-more-potent triiodothyronine (T3). Normally the body also converts some of its T4 into T3 when it needs more, and it converts T4 into two other hormones (called, not surprisingly, T1 and T2) whose precise functions in the body are not yet fully understood.
Although we have been discussing thyroid hormone in this article as though it were a single substance, in reality there are four distinct thyroid hormones - an important point to consider when contemplating the use of a thyroid supplement. The thyroid gland releases hormone into the bloodstream mainly as thyroxine (T4) and, in smaller amounts, as the four-times-more-potent triiodothyronine (T3). Normally the body also converts some of its T4 into T3 when it needs more, and it converts T4 into two other hormones (called, not surprisingly, T1 and T2) whose precise functions in the body are not yet fully understood.
In their treatment of patients with low thyroid, most physicians prescribe synthetic drugs, such as Synthroid®. These drugs consist solely of T4, and we must rely on our bodies to covert it into the other three forms as needed. Some people, however, have a low thyroid condition not because of a decline in hormone production, but rather because of a deficiency in converting T4 to the other forms of thyroid hormone. For these people, taking T4 alone may not produce much improvement, so supplementing with all the thyroid hormones is probably the better course of action. This is accomplished by taking whole, natural thyroid preparations derived from animal thyroid glands, which have an advantage over synthetic drugs: they contain all four forms of thyroid hormone, and the molecular structures of these hormones are identical to those of their human counterparts. They therefore have exactly the same biological activities.
DON'T BE SAD
Because many physicians view age-related hormonal decline as a natural process, subclinical hypothyroidism often goes untreated - thyroid hormone is "just what the doctor did not order." This is unfortunate, because people (of any age) who suffer from low thyroid - whether it leads to SAD or to other symptoms of this disorder - may benefit from this appropriate intervention.
Because many physicians view age-related hormonal decline as a natural process, subclinical hypothyroidism often goes untreated - thyroid hormone is "just what the doctor did not order." This is unfortunate, because people (of any age) who suffer from low thyroid - whether it leads to SAD or to other symptoms of this disorder - may benefit from this appropriate intervention.
Dr. Jonathan Wright believes that everyone over the age of forty, with no overt endocrine disease, should be taking a thyroid supplement, because this is the period in our lives when all the endocrine glands in our bodies are slowing down. So, whether you have a sluggish endocrine system because of cold weather or an aging body, natural thyroid might be just what your brain is hungering for.
References
- Lam RW, Levitan RD. Pathophysiology of seasonal affective disorder: a review.J Psychiatry Neurosci 2000 Nov;25(5):469-80.
- Reed HL. Circannual changes in thyroid hormone physiology: the role of cold environmental temperatures. Arctic Med Res 1995;54 Suppl 2:9-15.
- Sher L, Rosenthal NE, Wehr TA. Free thyroxine and thyroid-stimulating hormone levels in patients with seasonal affective disorder and matched controls. J Affect Disord 1999 Dec;56(2-3):195-9.
- Raitiere MN. Clinical evidence for thyroid dysfunction in patients with seasonal affective disorder. Psychoneuroendocrinology 1992 May-Jul;17(2-3):231-41.
- Reed HL, Reedy KR, Palinkas LA, Do NV, Finney NS, Case HS, LeMar HJ, Wright J, Thomas J. Impairment in cognitive and exercise performance during prolonged Antarctic residence: effect of thyroxine supplementation in the polar triiodothyronine syndrome. J Clin Endocrin Metab 2001;86:110-116.
- Hussein WI, Green R, Jacobson DW, Faiman C. Normalization of hyperhomocysteinemia with L-thyroxine in hypothyroidism. Ann Int Med 1999 Sep 7;131(5):348-51.
- Krotkiewski M. Thyroid hormones and treatment of obesity. Int J Obes Relat Metab Disord 2000 Jun;24 Suppl 2:S116-9.
- Lien EA, Nedrebo BG, Varhaug JE, Nygard O, Aakvaag A, Ueland PM. Plasma total homocysteine levels during short-term iatrogenic hypothyroidism. J Clin Endocrinol Metab 2000 Mar;85(3):1049-53.
- Bostom AG, Rosenberg IH, Silbershatz H, Jacques PF, Sellub J, D'Agostino RB, Wilson PW, Wolf PA. Nonfasting plasma total homocysteine levels and stroke incidence in elderly persons: the Framingham Study. Ann Int Med 1999 Sep 7;131(5):352-5.
- Kok FJ. Folic acid, vitamins B6 and B12: relation to homocysteine and cardiovascular disease. Bibl Nutr Dieta 2001;(55):1.
- Robinson K. Homocysteine, B vitamins, and risk of cardiovascular disease. Heart2000 Feb;83(2):127-30.
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