Some health problems like diabetes can damage the nerve cells and blood vessels that can cause hindrance in the production of semen and its volume when ejaculating.
Sperm output of older men• Zinc has also been found to lower the extremity of prostate cancer and also lower the sex hormone-binding globulin SHBG which basically neutralizes testosterone.
Because the seminal vesicles and the prostate need testosterone to do their job properly, low levels of this vital hormone can lead to decreased secretions from these organs.