Dr. G - Health Column

Thyroid function and diabetes

How does thyroid function affect diabetics?

Diabetes does not directly cause thyroid disease, however those who already suffer from diabetes are more prone to develop an endocrine disorder. Thyroid function affects diabetics due to its role on the body’s metabolism and can worsen or cause complications such as nerve damage (neuropathy).


How are blood glucose levels affected?

Blood glucose levels are affected by both high and low thyroid levels. Those with high thyroid levels have high blood glucose levels, so the body uses up insulin faster than normal. Those with low thyroid levels have low blood glucose levels, so insulin is used up slowly. If thyroid function is low, it can cause an increase in cholesterol levels and increase the risk of developing cardiac disease.


Type 1 vs Type 2 diabetes

A study showed that women with type 1 diabetes had a higher prevalence of thyroid disease (31.4%) and are at a greater risk of developing thyroid disease. Of the patients with type 2, only 12% had thyroid disease. Researchers also attributed this difference to aging.


What is insulin resistance?

Insulin resistance is the inability of our cells to respond to the insulin hormone. High or low thyroid levels have an impact on blood glucose levels.

How does thyroid function affect this?

As T3 hormone levels rise, so does insulin resistance, blood glucose concentration, A1C (test for average blood glucose levels) and the T3/rT3 ratio. Patients with high thyroid levels generally have a higher A1C over several months.


What research has been done to support this?

A study that compared patients with high thyroid levels (hyperthyroid) to normal thyroid levels indicated that the level of glucose produced by the liver was 20% higher in hyperthyroid patients compared to individuals with normal thyroid levels.

The results showed a larger increase in insulin levels for the hyperthyroid patients compared to the patients with normal levels. This showed that excess insulin had an inhibitory effect on the production of glucose which could indicate liver insulin resistance.

A study compared T3/rT3 ratios of both insulin resistance and insulin sensitive patients. The results showed that the ratio was high in insulin resistant patients as they had a higher proportion of T3 compared to rT3 in their blood.



Dr. G’s solutions



I don’t notice an improvement in symptoms although I am on thyroid medication. Why could this be?

There is a chance that the enzyme DIO2 that converts T4 to T3 has a genetic variation that reduces its conversion ability. In this case, your physician can alter treatment based on information from a genetic test.


ThyroGen examines this conversion ability, giving physicians more information before deciding your treatment.

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