Thyroid and Diabetes:
The Surprising Relationship Between Thyroid Disease and Diabetes
Did you know that people with diabetes (both type 1 and type 2) are at a higher risk of developing a thyroid disease(1, 2)? And individuals who have thyroid disease are at a greater risk of developing diabetes(1, 2).
Both disorders affect the endocrine system- a system of the body that is in charge of releasing hormones that regulate growth, mood, sleep, sexual function, reproduction, and metabolism... It’s a pretty important system! Diabetes is the #1 disorder that affects the endocrine system followed by thyroid disease in the #2 spot (3).
Many people have a combination of these two disorders, which affects just about every organ in the body. It is estimated that 1 in 10 people with type II diabetes have a thyroid condition (2). 30% of women with type 1 diabetes also have a thyroid disease (1).
Why is this?
Thyroid hormones help regulate the metabolism and energy expenditure. The thyroid hormones play a big role in the metabolism of carbohydrates. They also contribute to the function of the pancreas; the organ that produces insulin.
Imbalanced Thyroid and Blood Sugar FLUCTUATIONs
Hyperthyroidism
Hyperthyroidism or an overactive thyroid, can cause higher blood sugar (1). This happens for a few different reasons. The excessive thyroid hormones cause the liver to produce more glucose (sugar) and increase insulin resistance (1). This can lead to hyperglycemia, or high blood sugar.
The increase in the metabolism that is caused my hyperthyroidism also increases insulin needs and dosing (1). This is because the insulin is metabolized or used up much quicker with the excessive thyroid hormones.
Hypothyroidism
Hypothyroidism, or an under active thyroid, can decrease insulin sensitivity which may worsen blood sugar control (2). Hashimoto’s disease is the most common cause of hypothyroidism.
Hypoglycemia, or low blood sugar, is a risk for people with hypothyroidism who take insulin (2). This is because hypothyroidism slows the metabolism. This causes the insulin to not be used by the body as quickly causing the insulin to linger in the blood longer leading to low blood sugar.
Hypothyroidism can also worsen heart disease that is common in people with diabetes(4).
Good news! Treating hypothyroidism can improve blood sugar control (5).
FYI, hypothyroidism may cause false HbA1c readings (5)! Its best to double check with your daily blood sugar readings to see where your HbA1c is likely at.
Treatment options:
Hypothyroidism:
Levothyroxine is the most common treatment for hypothyroidism (6). Once treatment is started, the thyroid hormone TSHs (thyroid-stimulating hormone) is typically monitored every 2 to 3 months until stable. After then, an annual check up it recommended.
Hypothyroidism + Type II Diabetes:
Metformin can help normalize TSH levels while lowering the blood sugar (7).
Lifestyle changes can increase the metabolism and reduce insulin resistance.
Hypothyroidism + Pre-Diabetes:
People with a low functioning thyroid (hypothyroidism) and pre-diabetes are more than twice as likely to develop diabetes compared to someone with a normal functioning thyroid (8). Treating a low thyroid can help control blood sugar, but it is not clear if it helps stop or slow the development of type 2 diabetes(8).
Hyperthyroidism:
Oral Medications such as Tapazole and Propylthiouracil are effective in controlling the production of thyroid hormones (9). Regular blood testing is recommended when taking these medications.
Radioactive Iodine Therapy is the most common treatment for hyperthyroidism in the United States (9). It has a high success rate but there is a chance of developing hypothyroidism (9).
Surgery can be done to partially for fully remove the thyroid (9). Surgery is likely followed by the need for thyroid replacement hormones medication (9).
Hyperthyroidism + Insulin Dependent Diabetes
Insulin needs may be higher. The excessive thyroid hormones cause insulin to be used up quickly, making insulin needs higher (2).
Diabetes with no thyroid disease:
Regular thyroid testing is recommended for people with diabetes because of the higher risk of developing a thyroid disorder. The American Diabetes Association recommends to have testing done every 5 years (2).
Thyroid and Diabetes Diet
Is there a specific diet you should follow?
Unfortunately, there is no one size fits all approach to nutrition with diabetes + thyroid disease. There are many factors to take into consideration including what type of diabetes, type of thyroid disease, and what other conditions are present.
It is best to meet with a dietitian to learn more about your specific nutrition needs.
Luckily, both conditions can be managed with the right medication, diet, and lifestyle combinations!
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