The Healthy Thyroid: What you can do to prevent and alleviate thyroid imbalance. Patsy Westcott

autoantibodies destroy the joints; Addison’s disease, where autoantibodies damage the adrenals; multiple sclerosis, where autoantibodies are directed against the nervous system; and diabetes, where autoantibodies turn against the pancreas.

      It is now established that all of us possess autoimmunity to some degree but, in some people, the immune system seems to have a particular tendency to turn against itself. This might explain why having one autoimmune disorder can put you at an increased risk of developing another. It may also be why, if you have developed an autoimmune thyroid disorder, it is important to be on the look-out for other autoimmune problems.

      Three-quarters of cases of autoimmune disease occur in women. What exactly triggers the immune system in women to attack itself more frequently than in men?

      The Family Factor

      The tendency for autoimmune diseases to run in families provides one clue. It suggests that a faulty gene or genes may be partly to blame. Indeed, scientists have identified a handful of so-called ‘susceptibility’ genes that render some of us more vulnerable to autoimmune attack. They have also pinpointed several areas – ‘susceptibility regions’ – on chromosomes, the 23 pairs of rod-like structures that carry our genes, that appear to confer a greater risk of autoimmunity.

      Many autoimmune diseases, including autoimmune thyroid disease, are strongly associated with a gene for human leukocyte antigens (HLA) found on chromosome 6. Another susceptibility gene, CTLA-4 (cytotoxic T lymphocyte-4), is also involved. Both these genes are known as immune-modifying genes – they alter the way in which your immune system behaves. As well as susceptibility genes, researchers are also finding genes that are specifically involved in autoimmune thyroid problems. These ‘thyroid-specific genes’ are thought to work hand-in-hand with susceptibility genes to trigger an autoimmune attack against the thyroid.

      As to why women are at greater risk than men, scientists have come up with an intriguing theory that suggests that it may be connected with the continued presence of foreign cells from a fetus in the mother’s bloodstream – and vice versa. Another way to acquire cells that aren’t your own is from a twin, even one you didn’t know you had, because it is now known that a number of pregnancies start out as twin pregnancies, but soon lose one of the embryos. Says Dr J. Lee Nelson, the American scientist who pioneered this theory, ‘Our concept of self has to be modified a little bit. We’re not as completely self as we thought we were.’

      Deciphering the Clues

      The presence of thyroid autoantibodies in your bloodstream is an important clue that there has been an immune attack on your thyroid. In fact, it was by studying Graves’ disease that scientists acquired some of the earliest clues of what was going on in autoimmunity. The chief culprit in Graves’ disease is an antibody, first discovered in the blood of Graves’ patients as long ago as 1956, dubbed ‘long-active thyroid stimulator’, or ‘LATS’, because in animals, it stimulated thyroid activity for longer than thyroid-stimulating hormone (TSH).

      Later researchers identified LATS as a type of immunoglobulin G, the main antibody in the bloodstream and, because it stimulates thyroid production by locking onto the TSH receptor, they renamed it TSHR-Ab. This autoantibody is now thought to be responsible for the thyroid overactivity in Graves’ disease, and to play a key role in the development of thyroid eye disease by overstimulating certain cells that line the eye sockets.

      A similar process is involved in Hashimoto’s thyroiditis except that, in this case, the rogue antibodies are directed against thyroglobulin (TG), the protein molecule in which thyroid hormone is stored, and thyroid peroxidase (TPO), a key enzyme involved in the early stages of manufacturing thyroid hormone. The autoantibodies block receptors on both TG and TPO, thereby causing underproduction of thyroid hormone.

       CHAPTER THREE The Out-of-Balance Thyroid

      Given the wide-ranging action of the thyroid, it is hardly surprising that, when something goes wrong, it affects the entire body. Exactly what these effects are depends on whether your thyroid becomes underactive or overactive.

      Hypothyroidism, or the underactive thyroid, can produce a long and bewildering list of symptoms (see Table 3.4, page 42). Most of these are non-specific and easily attributable to some other disorder or simply fatigue – one reason why it often takes so long to get a diagnosis. As Camille recalls:

       I noticed that my mental energy had gone right down, but I kept rationalizing. The tiredness was dreadful, but I persuaded myself it was because I was overdoing it. I kept saying to myself, ‘If only I’d taken two weeks off at Christmas, I wouldn’t be feeling so tired’. It was only the hair loss that got me in for a test.

      Clare has a similar story:

      I just thought I was putting on weight. I put on two-and-a-half stone in as many years. Yet, despite going to Weight Watchers and not cheating, I couldn’t shift it. In retrospect, there were other clues. I developed coarse skin but, because I’d had a baby, and my hands were in and out of sterilizing solution, I just thought it was that. My periods were irregular and I was tired all the time, but I put that down to working and having a family. It was sheer vanity that drove me to the surgery in the end.

      Jennifer, who developed an underactive thyroid after the birth of her second child, remembers:

       My energy levels fluctuated from day to day. I would start the week feeling fine but, by Tuesday, I would be completely exhausted and have to take the day off. I managed to drag myself through Wednesday and Thursday, and Friday I had off. I would spend the weekend in bed. I was so depressed, I would sometimes just lie there and cry. I had constant headaches and sore throats, my muscles ached, my nails were brittle, and I was always getting flu. I couldn’t concentrate; my memory was appalling. I was so cold that, even in the summer, I had to take a hot-water bottle to bed. Our sex life went completely downhill.

      The key characteristic of hypothyroidism is that all your systems slow down as a result of metabolism running on near-empty. Your appetite decreases and what you do eat is converted into energy more slowly. You gain weight and feel permanently cold. The smallest task becomes a supreme effort. Your muscles feel weak and stiff, and ache on the slightest exertion. Just walking up the road can leave you exhausted and breathless. You may experience muscle cramps. Your heart beats more slowly and your pulse is slowed while blood pressure rises. Digestion takes longer and you become constipated. You may also experience joint pain and stiffness. Your kidneys work more slowly, leading to water retention and tissue swelling (oedema). Your liver also slows down, resulting in a rise in levels of ‘bad’ LDL cholesterol and other blood fats known as triglycerides. You may succumb to every passing minor infection as the lack of thyroid hormones takes its toll on your immune system. Cuts and bruises take a long time to heal because of the fragility of your blood vessels. You feel miserable, washed out and overwhelmed with fatigue. As Christine observes, ‘It is total; every body system is affected. People often say, “I just feel so ill, but I can’t put my finger on it.”’

      Appearance Matters

      One of the most distressing aspects of hypothyroidism is the effect on your looks. Even though you have no appetite, the weight piles on unstoppably. Your hair becomes dry, brittle and thin; your skin becomes dry, coarse and puffy. Your waistband nips, your rings become tight and you feel bloated. These symptoms are the result of an autoimmune attack called ‘myxoedema’, where the cells become ‘leaky’, leading to fluid accumulation and mucus deposition beneath the skin. You may become pale due to anaemia, and your complexion may take on a slightly yellowish hue due to the buildup of the yellow pigment beta-carotene in your blood.

      Carol, who was initially diagnosed with depression and went for many years before her underactive thyroid was diagnosed, recalls:

       I developed nasty sores on my skin, mainly on my arms,