A warning has been issued to everyone drinking Coca-Cola and Pepsi after a scientific study revealed a new health impact.

According to the study, drinking the fizzy drinks increases testicle size and testosterone production.

Researchers at the Northwest Minzu University in China carried out the study.

Previous research had suggested the drinks could reduce sperm count and have a harmful impact on reproduction functions.

The study focused on the impact drinks had on fertility in mice, with one group given only water and the remaining groups drinking different levels of Coca-Cola and Pepsi.

The Northern Echo:

The results found that the testosterone levels increased, and testicle size grew in the mice drinking the fizzy drinks.

The authors wrote: “The outcome demonstrated a high dose of Pepsi or Coca-Cola could promote testis growth and development.

“The concentrations of serum testosterone in all mice were enhanced after the Pepsi-Cola and Coca-Cola treatment.

“This indicated that high doses of Pepsi and Coca-Cola could improve testosterone secretion of male mice.

“In conclusion, drinking Coca-Cola and Pepsi-Cola could promote testis development, enhance testosterone secretion, increase serum EGF concentrations.

“Our findings provided the scientific basis for fully understanding [carbonated beverages] effects and their mechanism on development and reproduction functions of humans, but also benefit to prevent prostate dysfunction and cancer."

The researchers said their findings contradict previous studies carried out.

One study of 2,500 men, found that sperm quantity reduced by 30 per cent after drinking one litre of carbonated drinks every day.

Another study found the drinks could have an impact on hormones that affect ovulation.