Unexplained Weight Gain: Is your thyroid to blame?

Is your thyroid to blame?

When someone tries to blame their beer gut or cream-pie thighs on anything other than too many calories and too little exercise, we tend to roll our eyes and put the excuse-maker in the "can't face facts" box. But for the 1 in 14 Australians diagnosed with some form of thyroid disease, an underactive thyroid is a very real cause for unexplained weight gain.

Your thyroid is a small gland with a big job. It is located at the base of your neck, just below your Adam's apple, and is shaped like a butterfly. The thyroid affects not only your body weight, but also your energy levels, muscle strength, skin health, menstrual cycle, memory, heart rate, and cholesterol level; it is essential to your body's overall wellbeing.

One of the thyroid's main roles is to release the hormones which control your metabolism. When you suffer from hypothyroidism, the thyroid does not produce enough of these hormones. A lack of thyroid hormones in your body means that your metabolism slows down - and that equates to weight gain.

Read on to find out what causes an underactive thyroid, what the symptoms and risk factors for the condition are, how hypothyroidism is diagnosed and treated, and what you can do about the weight gain.

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What causes underactive thyroid?

Hypothyroidism (having an underactive thyroid) occurs when your thyroid gland stops producing enough thyroid hormones. This happens for a number of reasons including thyroid disease, iodine deficiency, thyroid gland surgery, injury to the thyroid, and genetic predisposition. Hashimoto's disease - inflammation of the thyroid gland - is the most common cause of hypothyroidism. This is an autoimmune disease which means that, for some reason, your body thinks your thyroid is a foreign invader and tries to destroy it with antibodies. The outcome is that your thyroid gland is inflamed and can no longer produce hormones effectively.

Thyroid hormones are responsible for all aspects of your metabolism; from how quickly you burn calories, to how fast your heart beats. Without enough thyroid hormones, your metabolism cannot function properly. When your metabolism is sluggish from lack of thyroid hormones, it's easy to gain up to 9 kg in weight.

But weight gain isn't the only worrying outcome. Underactive thyroid has also been shown to increase LDL ("bad") cholesterol, leading to subsequent heart disease. Untreated, the disease can also cause depression, slow mental processes, muscle weakness, osteoporosis, and infertility, as well as coma and death in extreme cases. Babies born to mothers with hypothyroidism are also more at risk for intellectual and developmental problems and birth defects including cleft palate, heart, brain and kidney problems. If the condition goes untreated a goiter can form from the swollen thyroid gland. Goiters can affect your appearance and may interfere with swallowing and breathing.

What are the symptoms and risk factors?

Weight gain, increased cholesterol, depression and slow mental processes are all symptoms, as well as health problems, associated with underactive thyroid. There are also several other signs to watch for. Keep in mind that these symptoms can be subtle and are often easily overlooked as signs of normal aging.

Early symptoms of the disease include:

Fatigue
Muscle weakness
Sluggishness
Swollen tongue
Puffy face

As metabolism continues to slow you may experience:

Feeling cold when others don't
Constipation
Coarse hair
Brittle nails
Heavy menstrual periods
Slower pulse
Husky voice
Pale, dry skin
Raised blood cholesterol level
Weight gain of up to 4.5 - 9 kg
Depression
Forgetfulness
Mood swings
Irritability
Goiter
Decreased sexual desire

The condition is more common in women, particularly following pregnancy, around menopause, or after age 60. Diabetes is also a strong risk factor, as is genetics. If you have a close family member with the disease you are at greater risk.

How is it diagnosed?

If you are showing symptoms of an underactive thyroid, your doctor will administer a simple blood test called the TSH (thyroid stimulating hormone) test. For a more complete analysis you can request a thyroid panel. These tests are now so effective that doctors can often diagnose thyroid disorders even before symptoms are experienced. Adults 35 and older should have a TSH test every 5 years. Testing when pregnant is also wise.

How is it treated?

Underactive thyroid is treated using the oral medication Oroxine, which contains the essential hormone Thyroxine. Tertroxine may also used with Oroxine, and occasionally it may be prescribed on its own. These medications are slow-acting, and it can take weeks or months for you to feel their affects.

Antioxidants and essential fatty acid foods and supplements are a great way to naturally maintain a healthy thyroid. Whether or not you have an underactive thyroid, try to include omega-3 fatty acids, vitamins, zinc, selenium, and a moderate amount of iodized salt in your diet to help keep your thyroid healthy. Salt water fish and seaweed are good natural sources of iodine.

What about weight gain?

Thyroid hormones are responsible for all aspects of your metabolism; from how quickly you burn calories, to how fast your heart beats. So it is possible for an underactive thyroid to be responsible for weight gain.

However, the amount of weight gain from hypothyroidism is generally only 4.5 - 9 kg, most of which is fluid. Dietitians warn that only a very small percentage of weight gain cases are due to underactive thyroid. When it comes to weight gain, it's just as important to check your eating habits, calorie intake, and exercise level as it is to take a thyroid test.