Thyroid Antibodies Range for Optimal Health and Longevity

Antibodies are a natural molecule created by our immune system. They help attack invaders such as viruses, and inactive them before they can make us sick. So in themselves, antibodies are great! However, antibodies that are programmed to attack our own body are one of the hallmarks of autoimmune disease, and cause the immune system to attack our own organs. One of these self-antibodies is anti–thyroid peroxidase antibody (TPO-Ab). It is the known cause of autoimmune thyroid disease, most commonly of ‘Hashimoto’s’ (R).

Even without overt thyroid disease such as Hashimoto’s or Grave’s disease, the presence of thyroid auto-antibodies has been shown to predict a higher risk of thyroid disease in future. And even outside of the effects on thyroid function, there is evidence that women with elevated TPOAb and/or TgAb are at increased risk of infertility even if the thyroid hormone level is within a normal range. It has been reported that positive thyroid antibodies could increase the probability of decreased ovarian reserve function. The decreased ovarian reserve function not only has a negative impact on the fertility of women of childbearing age, but also affects the success rate of in vitro fertilization-embryo transfer pregnancy aid. This may be the reason for the increased risk of infertility caused by positive thyroid antibody (R).

Furthermore, thyroid antibodies have also been shown to contribute to atherosclerosis (= cardiovascular disease) and breast cancer development, likely due to their pro-inflammatory effects (R).

Why TPO antibodies in normal ranges do not necessarily mean they are optimal

What we consider to be ‘normal’ thyroid antibodies might in fact already be contributing to issues. Research suggests that anti-TPO  in normal, yet on the high end of normal, ranges, triggers low grade inflammation, and with it atherosclerosis (an inflammatory condition of the arteries), even in individuals with normal thyroid hormone levels (R, R).   

Research suggests the optimal cutoff points for TPOAb were 18.38 and 14.77 IU/mL for predicting clinical and subclinical hypothyroidism, respectively (R).

Another study even went that far to state that any presence of anti-TPO is linked to an increased risk of atherosclerosis (R).

Mayo Clinic considers values above 9.0 IU/mL to be associated with autoimmune thyroiditis, but elevations are also seen in other autoimmune diseases (R).