Understanding Your Thyroid and Diabetes

What do diabetes and thyroid disease have to do with each other?

A lot.

Both conditions are dysfunctions of the endocrine system; they attack the entire body and can fuel each other. They’re also common medical problems. If you have one, you’re more likely to have the other, says Dr. Edward Nicklas II, MD, endocrinologist at Memorial Hermann Medical Group West University and Memorial Hermann Medical Group Pearland.

Problem: Underactive Thyroid

Signs: Hypothyroidism, due to an underperforming thyroid, may spur havoc from your brain to your bowels, slowing metabolism and heart rate, and hiking hunger and cholesterol. Unexplained fatigue, weight gain, drier skin, thinning hair, constipation and an intolerance to cold may occur.

The thyroid, a gland in the neck, also can play a supersized role in glucose control and, if left untreated, can make it harder to harness diabetes.  

Cause: Most often, Hashimoto’s disease, an autoimmune disorder, attacks and sometimes destroys the thyroid. Type 2 diabetes also has been linked to abnormal thyroid-stimulating hormone levels and conversion of the thyroid hormone thyroxine (T4) to triiodothyronine (T3).

Diagnosis: Blood tests show levels of the pituitary’s thyroid stimulating hormone (TSH), which tells the thyroid how much T4 and T3 it should make. Antibodies in the blood detect Hashimoto’s disease. Family history and a physical exam also may be revealing.

Treatment: Many people take a daily pill of synthetic thyroxine and have blood tests at least yearly to make sure thyroxine levels are ideal. If glucose, lipid and protein metabolism are unbalanced, medicine may be needed to address that.

Myth: “The more thyroid hormone medicine you take, the better.”

False: Too much medicine could cause an irregular heartbeat, anxiety or brittle bones, Dr. Nicklas says. “Too much of a good thing is not necessarily better.”

Problem: Overactive Thyroid

Signs: Symptoms that might suggest an overactive thyroid include unexplained weight loss, a racing heart, insomnia, irritability, nervousness, fatigue, diarrhea, hand tremors and more frequent bowel movements. Also, eyes may bulge, and a lump may form on the gland itself.

Cause: Your thyroid is indeed hyper, pumping out too much hormone. The autoimmune disorder Graves’ disease is the most common culprit. Sometimes an inflamed thyroid or taking too much synthetic hormone may cause the imbalance.

Diagnosis: Your doctor may order blood tests to measure T4, T3 and thyroid antibodies. A physical exam or an ultrasound, which uses soundwaves, can detect lumps. An ultrasound can show the thyroid’s size and shape, which may reveal the cause. If your physician suspects you have an overactive thyroid, he or she also may order a radioactive iodine uptake scan, also called a thyroid uptake test, to help determine the cause of the over activity.

Treatment: Antithyroid drugs can block hormone production, while beta blockers can slow a racing heart or steady irregular heartbeats. In some cases, thyroid cells can be killed with radioactive iodine, or the entire gland may be removed surgically.

Myth: “Lucky you: You’ll lose weight.”

False: Not necessarily. Your appetite also increases, so you may eat more, Dr. Nicklas says.

Problem: Type 2 Diabetes

Signs: You may experience unexplained weight loss, frequent urination, excessive thirst, blurred vision, fatigue or weakness.

Cause: Excess weight, inactivity and family history can make the body’s cells fail to respond properly to insulin. Your pancreas pumps out more insulin to try to get cells to react. Eventually, your pancreas is unable to keep up, and your blood sugar rises, setting the stage for higher-than-normal blood sugar. Levels determine whether you’re prediabetic or have type 2 diabetes. Most diabetics are over 45, but with rising obesity rates, an increasing number of adolescents and younger adults are becoming type 2 diabetics.

Diagnosis: A fasting blood sugar test, a blood sugar test two hours after eating or a1C hemoglobin test can reveal excess glucose and how well your body controls blood sugar.

Treatment: A healthy diet and regular exercise can lead to weight loss and lower risk of diabetes or its precursor. “This can be achieved with reduced portions, less processed foods and more fruit, vegetables, nuts, seeds and whole grains in your diet,” Dr. Nicklas says.

Myth: “You’d know if you had diabetes.”

False: One in five people are unaware they have diabetes and four of five don’t know that they have prediabetes, the CDC says.