The Effects of Smoking on Sperm

A study published in the British Journal of Urology International indicates that smoking affects male fertility, and not in a good way.
 
Researchers from São Paulo Federal University studied the impact of smoking on fertility by comparing the sperm of 20 smokers and 20 non-smokers.

They found that the sperm of smokers is more likely to suffer DNA damage, with some showing partially or completely inactive mitochondria. Mitochondria are part of sperm cells that produce the energy needed to complete tasks, such as fertilizing an egg.

Smokers' sperm also had more defects in the acrosome, which is located near the head of the sperm cell and contains the digestive enzymes needed to break down the egg cell membrane during fertilization.

Scientists also examined 422 proteins in the sperm of the subjects. Proteins are essential for every cell, playing roles in structure, function, and regulation of cellular processes. When comparing the two groups of men, researchers found that the smoking group lacked one protein, had insufficient expression of 27 proteins, and overexpression of 6 proteins. This can lead to inflammation of the seminal vesicles (which secrete fluid) and the testes. Inflammation, in turn, reduces sperm integrity and increases DNA damage.

Researchers believe that oxidative stress is a key reason for the impaired fertility of smokers. Oxidative stress is caused by excessive free radicals (molecules) damaging cells. The body is overwhelmed by so many aggressive molecules that it cannot counteract this damage. Components in cigarettes, such as nicotine and cadmium, increase the levels of oxygen ions and these free radicals in the body.

Overall, the study shows that male fertility is sensitive to environmental factors. So, while smoking may seem like a temporary indulgence, it can have a much larger impact than you might think before you start a family.