DEAR DR. ROACH: In 2003, I had surgery for throat cancer, followed by radiation treatments. I have been negative ever since. My salivary and thyroid glands were damaged. Does the thyroid gland control bowel movements? I’ve been constipated a lot. I’ve tried different laxatives without good results. — J.
ANSWER: Radiation therapy, though it can be lifesaving, often has side effects. In the case of head and neck cancers, you have had two common side effects: damage to salivary glands and to the thyroid gland. Both can affect bowel function.
There are three major salivary glands: the parotid (in the cheeks), the submandibular (under the jaw) and the sublingual (under the tongue). Low amounts of saliva can cause severe dental damage, but saliva is helpful in several other ways: Saliva has enzymes that help break down food, and the liquid swallowed helps the food move through the digestive tract. Without adequate saliva — whether it’s due to radiation treatment, medical conditions like Sjogren’s disease or a side effect from medication — constipation is more likely.
Low thyroid levels are a frequent cause of constipation, and radiation damage to the thyroid predisposes you not only to low thyroid levels but also to thyroid cancer, so your thyroid gland needs to be periodically examined. You should have a lab test to check your thyroid function.
Most constipation improves with increased dietary fiber and water.
DEAR DR. ROACH: I’m an 80-year-old woman with very few ailments. The only medication I take is for low thyroid. About two weeks ago, I woke up feeling tired, lightheaded and with a poor appetite. My granddaughter took me to my primary care doctor, who did a checkup, including a urine test. He told me that my symptoms were due to the “super moon.” It affects people in flat-roof dwellings, and he said my symptoms would last only three days.