TPO Antibodies

TPO antibodies (thyroid peroxidase antibodies) target an enzyme the thyroid uses to make hormones. This test is part of the work-up for suspected autoimmune thyroid disease. A positive result can indicate an autoimmune process such as Hashimoto's thyroiditis or Graves' disease, but it does not diagnose a condition on its own — it is interpreted alongside symptoms, thyroid hormone levels (TSH, T4) and other findings. A negative result makes autoimmune thyroid disease less likely. If your result is positive, speak with your healthcare provider about whether further evaluation is needed.

A positive TPO antibody result is most often associated with autoimmune thyroid conditions, particularly Hashimoto's thyroiditis and Graves' disease. Antibodies can be present for years before any change in thyroid function appears, and a proportion of healthy people — more commonly women and those with a family history of thyroid or other autoimmune disease — also test positive. Other autoimmune conditions can co-occur. A positive result signals that your thyroid may warrant monitoring rather than confirming disease.

The antibody itself causes no symptoms; any clinical picture comes from the associated thyroid dysfunction. Underactive thyroid (hypothyroidism, common in Hashimoto's) can cause fatigue, weight gain, cold sensitivity, dry skin, constipation and low mood. Overactive thyroid (as in Graves') can cause palpitations, weight loss, heat intolerance, tremor and anxiety. Many people with positive antibodies have entirely normal thyroid function and no symptoms at all. Any new or persistent symptoms should be discussed with your healthcare provider.

No food changes the antibody level itself, but a balanced, nutrient-rich diet supports overall immune and thyroid health: plenty of vegetables, whole grains, legumes, and sources of omega-3. Adequate iodine (from a varied diet or iodised salt) and selenium (found in fish, eggs and Brazil nuts) support normal thyroid function. If a thyroid condition is confirmed, your healthcare provider will guide any specific dietary advice.

There is no diet that lowers thyroid antibodies, so no foods need to be avoided on the basis of this result alone. Extremely high iodine intake — for example from large amounts of kelp or iodine supplements — is best avoided unless advised, as it can disturb thyroid function in susceptible people. Otherwise, general moderation of ultra-processed foods and alcohol supports overall health. Any tailored restrictions should come from your healthcare provider.