Weight Gain, Depression & Other Often-Mistaken Symptoms Could Signify Thyroid Disease, Harvard Reports

“The symptoms of thyroid diseases are so wide-ranging—affecting your mood, energy, body temperature, weight, heart, and more—that it may be difficult to get the correct diagnosis right away,” according to the authors of a recent Special Health Report on Thyroid Disease published by Harvard Medical School.

“The risk of thyroid disease increases with age. Yet thyroid disease is most difficult to detect in people over 60 because it often masquerades as another illness, such as heart disease, depression, or dementia. Misleading symptoms are one reason many Americans who have thyroid disease—mostly women—do not yet know they have it,” the Harvard authors state.

The Harvard Special Health Report, “Thyroid Disease: Understanding hypothyroidism and hyperthyroidism,” is written by the editors of Harvard Health Publications of Harvard Medical School in consultation with Jeffery R. Garber, M.D., who is an Associate Professor of Medicine at Harvard Medical School, Chief of Endocrinology at Harvard Vanguard Medical Associates, a Physician at Beth Israel Deaconess Medical Center, and an Associate Physician at Brigham and Women’s Hospital.

The Report is available online from Harvard Health Publications, Harvard Medical School.

What is Thyroid Disease? Who Has it? How Common is it?

The Thyroid Gland and Its Function

The thyroid gland is a “small, butterfly-shaped gland” that weighs less than an ounce, which, when functioning normally, “perches unobtrusively with its wings wrapped around the front of your windpipe (trachea), below your voice box (larynx),” the Harvard Report states in an introductory chapter, “Your Thyroid Gland“.

“Its slight size could easily fool you into underestimating the thyroid’s importance to your health. Yet this gland influences the rate at which every cell, tissue, and organ in your body functions, from your muscles, bones, and skin to your digestive tract, brain, heart, and more,” the Report states. “It does this primarily by secreting hormones that control how fast and efficiently cells convert nutrients into energy— a chemical activity known as metabolism — so that the cells can perform their functions.”

The Report goes on to provide a more detailed explanation of what is metabolism, how the Thyroid gland works in controlling that key life process, and how the thyroid gland is regulated by hormones produced in your brain and pituitary gland.

“Throughout life, this busy gland is constantly producing hormones that influence your metabolism. So when disease causes your thyroid gland to slack off and underproduce thyroid hormone, or overwork and produce too much of it, you’ll know something isn’t right,” the editors summarize in a description of the report provided by the publisher.

How Common is Thyroid Disease? Who Does it Affect?

“Estimates of how many people have thyroid disease vary widely, ranging from 10 million to 30 million,” according to the Harvard Report.

“The most reliable number available comes from the third U.S. National Health and Nutrition Examination Survey (NHANES III) of people ages 12 and older. The survey showed that nearly 6% of the U.S. population has thyroid disease [which by today's U.S. population number would mean about 18.9 million people].” “But the population is aging, and the proportion of people with thyroid conditions is increasing,” the authors state.

Thyroid disorders tend to run in families, and are far more prevalent in women than in men, according to the Harvard Report. “The Association of Clinical Endocrinologists (AACE) reports that women are as much as five to eight times more likely than men to suffer from thyroid disease,” the Harvard authors point out.

“Hypothyroidism is common in people over age 60, and the risk of hypothyroidism increases steadily with age, especially among women,” the authors state.

Types of Thyroid Disorders: Hypothyroidism and Hyperthyroidism

“Within [the 18.9 million people estimated to suffer from thyroid diseases], about 80% have hypothyroidism. A much smaller number, close to 20%, have hyperthyroidism,” the authors state.

As they explain, “hypothyroidism” is a condition in which the thyroid gland is underactive and does not produce enough thyroid hormone (which mostly means T4 thyroid hormone).

On the other hand, “hyperthyroidism” is a condition in which the thyroid gland is overactive, and produces too much thyroid hormone. The Report explains in greater detail what these conditions are and what are their possible causes.

“An out-of kilter thyroid gland causes a variety of puzzling symptoms and many people and doctors mistake them for signs of another disease or normal aging,” the editors state.

What are the Signs and Symptoms of Thyroid Disease — Hypothyroidism or Hyperthyroidism?

The Harvard Report explains in some detail the many and varied symptoms that may accompany thyroid disorders — hypothyroidism (an underactive thyroid gland, not producing enough thyroid hormone) or hyperthyroidism (an overactive thyroid gland, producing too much thyroid hormone).

The authors caution that symptoms vary person to person, and thyroid disease manifests differently in different people. So no one should jump to conclusions based upon a summary list of symptoms. If you recognize several of these symptoms, you should see your doctor, and if appropriate, your doctor may refer you to a specialist in this area (an endocrinologist).

Following are summary lists of some of the signs and symptoms of Hypothyroidism and Hyperthyroidism provided by the authors of the Harvard Special Health Report:

Risk Factors — Who is Most At Risk For Thyroid Disease?

Here is a summary list of Risk Factors for Thyroid Disease provided by the Harvard authors:

The Effects and Risks of Iodine

You might be surprised by the last risk factor listed above — indicating that you may be at elevated risk for thyroid disorder if you “are taking medications that contain high levels of iodine.” The role of iodine in the proper function of the thyroid gland is crucial but complicated, as the Harvard authors explain.

They explain that the thyroid gland needs and uses iodine in the production of thyroid hormones (T4 and T3) that are needed by your body. “The only significant dietary contributor to thyroid disease is iodine. Too little or too much iodine can trigger a thyroid problem,” the authors state.

The addition of iodine to salt and other food products has largely eliminated the problems of dietary insufficiency of iodine in the U.S. and other developed countries. “Iodine defiency is generally not a problem in the United States, but it still plagues numerous developing countries,” the authors state.

However, if you are taking supplements (such as Kelp) or other medications that contain large amounts of iodine, you could be getting too much iodine, and putting yourself at risk of thyroid disorders.

According to the U.S. National Institutes of Health (NIH), Office of Dietary Supplements, “High intakes of iodine can cause some of the same symptoms as iodine deficiency — including goiter, elevated TSH levels, and hypothyroidism—because excess iodine in susceptible individuals inhibits thyroid hormone synthesis and thereby increases TSH stimulation, which can produce goiter.”

“Iodine-induced hyperthyroidism can also result from high iodine intakes, usually when iodine is administered to treat iodine deficiency. Studies have also shown that excessive iodine intakes cause thyroiditis and thyroid papillary cancer,” the NIH, Office of Dietary Supplements states.

Medications that May Interfere with Thyroid Function, Thyroid Tests, or Thyroid Medications

The Harvard Report (page 23) presents a table with a long list of “Drugs and foods that interact with thyroid medications.” These “medicines and therapies can influence the effectiveness of thyroid medicines in one or more of the following ways: by interfering with the absorption of thyroid hormone, by binding thyroid hormone to binding proteins, and by interfering with thyroid hormone metabolism,” according to the authors.

Other Scientists have identified long lists of medications that they have reported may not only interfere with thyroid medications and thyroid tests, but also may induce thyroid disorders. According to a paper found in the PubMed database of the National Institutes of Health, on How medications affect thyroid function, by Dr. Betty J Dong and colleagues at the University of California, San Francisco School of Pharmacy, “Drug-induced thyroid illness is associated with the use of iodides, iodide-containing preparations, lithium, and interferon alpha treatment.”

Dr. Dong and her colleagues state, “Iodides are hidden in many preparations, including prescription (for example, amiodarone [which, according to Dr. Dong, "is being increasingly used for the management of a number of cardiac conditions, including atrial fibrillation and congestive heart failure"], radiocontrast dyes, povidone iodine, and iodinated glycerol) and nonprescription items (for example, cough and cold preparations, kelp tablets, herbal preparations, and dietary supplements).”

Even over the counter skin remedies such as hydrocortisone (which, according to Drugs.com, “is in a class of drugs called steroids”), may, in certain dosages, have some effect upon the thyroid gland. According to drug facts published by Drugs.com, “Steroid medication can weaken your immune system,” and “If you have any of these other conditions [a long list, which includes "a thyroid disorder], you may need a dose adjustment or special tests to safely take hydrocortisone.”

The bottom line appears to be, ask your doctor about potential side effects of any medications you are taking — including potential side affects on thyroid function. This may be especially important, if you recognize in yourself some of the symptoms of potential thyroid disorder listed above.

Diagnosis and Treatment of Thyroid Disorder

The Harvard Report explains in detail the types of blood tests which doctors use to diagnose potential thyroid disorder, and how they measure potential thyroid function based on your levels of thyroid-related hormones, such as TSH, T4 and T3.

According to the Harvard authors, “If you’ve been diagnosed with hypothyroidism, a sigh of relief may be warranted—your symptoms have been explained, and treatment is usually a simple matter of taking the correct amount of thyroid medication.”

“If you were diagnosed with hyperthyroidism by your primary care doctor, you will most likely be referred to an endocrinologist or thyroidologist who specializes in the treatment of thyroid disease,” the Harvard Report states.

“The goal of hyperthyroidism treatment is to stop the thyroid from over functioning.  There are three different ways of doing this: radioactive iodine may be used to destroy part of the thyroid; medication may be used to block your thyroid’s ability to produce hormone…; or surgery can remove all or part of the thyroid,” according to the Harvard authors.

Living with Thyroid Disorder

In a final section of their Report, Living well with thyroid disease, the Harvard authors present tips on how to live a healthy life after you are diagnosed with thyroid disorder.

Here is a summary of further tips for living a healthy life with thyroid disorder that are discussed in greater detail in the Report:

• Medications. “The most important thing to know about living with thyroid disease is that you will probably need to take thyroid hormone replacement for the rest of your life,” the authors say. “Whether you spontaneously developed hypothyroidism or you were treated for hyperthyroidism and became hypothyroid, you’ll need to stay on a regimen of daily medication and regular thyroid tests,” they state.

  “The good news is that once medication puts your thyroid hormone levels within normal ranges, you are, in a sense, cured and can go on with your normal life, as long as you continue your medication,” they say.

  Avoid the Drugs and foods that interact with thyroid medications (which, as discussed above, are listed on page 23 of the Report), the authors advise;

• Regular Check-ups. Go to your doctor for regular check-ups, the Report advises;
• Diet:
• Foods to Avoid: According to the authors, “There is no special diet you must follow while on thyroid hormone medication,” however, they advise that you should “Avoid foods high in soy protein, which can interfere with the absorption of thyroid hormone. If your thyroid was not removed or destroyed and you still have a substantial portion of your thyroid, avoid excessive amounts of iodine, either in medications or supplements, as this could trigger more problems with your thyroid. Most iodine-rich foods, such as iodized products or fish, are acceptable, but kelp and other thyroid supplements should be avoided.”
• Eat a Healthy Diet: The authors advise that, as always, you should eat “a healthy diet that includes lots of fruits, vegetables, and whole grains.” A healthy diet includes:
• “Eat nutritious foods.” Limit intake of “drinks, potato chips, candy, crackers, and other junk foods that are high in calories and low in nutrition;”
• “Cut down on “bad” fats.” Reduce saturated fats and trans fats in your diet to a minimum. “Many processed foods and snacks contain trans fats, so you may be consuming them without realizing it,” the authors state. “Instead, choose fats that help reduce LDL cholesterol. These include monounsaturated and polyunsaturated fats from vegetable oils, and omega-3 fats, found in certain kinds of fish. Seeds, nuts, and legumes are also healthy choices,” the authors advise.
• “Limit dietary cholesterol.”  “The American Heart Association recommends limiting dietary cholesterol to no more than 300 mg a day,” the authors point out. “If your cholesterol levels are high, try to consume no more than 200 mg per day,” they advise. “Sources high in cholesterol include animal fat, eggs, and full-fat dairy products.”
• “Increase dietary fiber.” “Dietary fiber helps improve digestion. Eating whole-grain foods and a variety of vegetables and fruits helps ensure that you have an ample supply of dietary fiber.”

• “Exercise.” “People who exercise tend to live longer because exercise increases the heart’s pumping ability and the body’s oxygen use.” In addition to burning calories and keeping your weight down, “Just walking 30 minutes a day on most days can help prevent heart disease and stroke and promotes general good health,” according to the Harvard authors.

More Information

The complete Harvard Special Health Report, “Thyroid Disease: Understanding hypothyroidism and hyperthyroidism,” is available online from Harvard Health Publications, Harvard Medical School.

For further information on thyroid disorders, see:

Thyroid Diseases: MedlinePlus - a medical and health information website for patients and consumers maintained by the National Library of Medicine, part of the National Institutes of Health, U.S. Department of Health & Human Services.

Hypothyroidism and Hyperthyroidism – Cleveland Clinic;

Thyroid Problems: Information About Thyroid Disease … – MedicineNet

See also related HelpingYouCare^® reports on:

Harvard Guide to Women’s Health Fifty and Forward Focuses on Prevention

Preventing Depression Misdiagnosis of Women

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