Kim Kardashian
Kim Kardashian is a vocal advocate of eating placentas Dimitrios Kambouris/Getty Images

The modern trend for new mothers to eat their own placentas has no medical justification and "borders on cannibalism", an expert gynecologist has claimed. A host of celebrities, including Kim Kardashian, have eaten their own innards while championing the health benefits.

The practice is widespread in the animal kingdom, and now more and more Western women are snacking on their own placentas, which are a source of nutrients and have been claimed to ward off postnatal depression.

But an academic review of the apparent superfood argues that the new mums should stop. Science has not shown a link between placenta consumption and better moods or increased lactation.

"Medically speaking, the placenta is a waste product. Most mammals eat the placenta after birth, but we can only guess why they do so," said author Dr Alex Farr from the University of Vienna.

However, the doctor then went even further, suggesting that women who do eat their own placentas are behaving similar to primitive flesh-eating tribespeople.

"Eating the placenta borders on cannibalism," he claimed. Cannibalism is illegal throughout the developed world.

Farr acknowledged that placentas contained nutrients, but added that their levels of zinc, iron and selenium were not "available in sufficient concentrations to justify eating".

He even claimed that consumption could be harmful due to "high concentrations of heavy metals" accumulating in the organ during pregnancy. He pointed to the case of an American mother who contracted life-threatening blood poisoning after embracing the health trend.

Like Kardashian, the woman had her placenta steamed, dehydrated, ground and converted into pill form. This is preferred by most new mothers, rather than the ultra-natural approach of chewing through the raw sac.

"Because placentophagy is potentially harmful with no documented benefit, counselling women should be directive: physicians should discourage this practice," Farr said.

"Health care organisations should develop clear clinical guidelines to implement a scientific and professional approach to human placentophagy."

In January 2015, after the birth of her first daughter, North West, Kim Kardashian tweeted: Yummy...PLACENTA pills! No joke...I will be sad when my placenta pills run out. They are life changing! #benefits #lookitup."