Obesity affects brain and leads to low sperm count: Study

According to a study, obesity may reduce sperm count by impacting the hypothalamus, the brain centre responsible for reproduction and signalling when to stop eating. Researchers found that changes in the hypothalamus, which oversees survival-related behaviours, could interfere with the production of hormones essential for creating testosterone and sperm. This study was conducted on mice.

Researchers at the University of California Riverside, US, discovered that feeding mice a high-fat diet led to lasting alterations in their brains, interfering with the signals that indicate sufficient energy intake, thereby inhibiting the urge to stop eating. Additionally, the study, published in the Journal of Neuroscience, revealed that these mice had decreased testosterone levels and a lower sperm count.

Djurdjica Coss, the lead author, explained that reproduction is regulated by a feedback loop involving the hypothalamus and pituitary gland in the brain, along with the gonads in the reproductive organs. The hypothalamus is responsible for controlling behaviours essential for



survival, such as eating and reproducing. Meanwhile, the pituitary gland manages the production of testosterone and sperm in males and estrogen and ova in females.

According to Coss, the hypothalamus communicates with the pituitary gland to regulate the production of hormones that control the levels of testosterone or estrogen. In obese mice, this communication was found to be impaired, leading to reduced hormone production by the pituitary gland and lower testosterone levels.

"When these neurons in the hypothalamus are not functioning properly, as in obesity, it causes lower hormone levels from the pituitary gland and lower testosterone and sperm production," said Coss. "To our surprise, we found the primary site of obesity's effects is the brain, rather than the testes or pituitary, in disrupting the normal functioning of the neurons that regulate reproduction," she added.

Researchers said more studies would be needed to make sense of the latest results. Obesity results in fewer sperms being produced and lowering of libido is not fully understood.