Excess iodine has been found to be associated with decreased testosterone concentrations in men
Men with normal and high concentrations of iodine in their urine had markedly lower levels of testosterone in their blood than those with low concentrations of the trace element. Scientists believe that excess iodine may provoke diseases unrelated to the thyroid gland, including androgen deficiency.
Scientists from the University of L'Acquila in Italy studied the relationship between the level of iodine in the urine and the concentration of testosterone in the blood in men. The results of the study published the portal MedpageToday with reference to the journal JAMA Network Open.
The analysis showed that men with low urinary iodine concentration had significantly higher testosterone levels than those with normal and high iodine levels. Men with low urinary iodine concentrations had an average total testosterone level of 446.7 ng/dL, while those with normal and high concentrations had mean levels of 398.68 ng/dL and 398.5 ng/dL, respectively.
The same relationship was observed when free testosterone levels were measured. Among participants with low, normal, and high urinary iodine levels, blood testosterone levels were 75.8 pg/mL, 72.1 pg/mL, and 67.2 pg/mL, respectively.
In addition, the authors noted that people with low iodine levels were less likely to have thyroid dysfunction compared to participants with normal and high concentrations, although the difference was not statistically significant.
They analyzed data from 2934 men who participated in the NHANES National Health and Nutrition Examination Survey at different years. The mean age of the participants was 47.1 years. The relationship between urinary iodine concentration and plasma testosterone levels was assessed, taking into account body mass index, blood pressure, glucose, triglycerides, high-density lipoprotein cholesterol, and creatinine levels. An iodine concentration of less than 10 µg/L was considered low, 10-299 µg/L was considered normal, and 300 µg/L and above was considered high.
According to Arcangelo Barbonetti of the University of D'Acquila, iodine was previously thought to be harmless or even beneficial. However, research has shown that an excess of this trace element can have adverse health effects and even cause diseases not related to the thyroid gland, including androgen deficiency.