Video spreads false claims about human body cell regeneration rates

Context
A video posted on Facebook by discredited Australian naturopath Barbara O’Neill with the caption “Do you know our body is capable of healing on its own” has amassed over 7.5k likes and 1.8k shares. An archive link of the post can be accessed here.

In the video, O’Neill claims, among other things, that human eye cells are remade every 1-2 days, that humans have "new bones" every three months, and a new liver every six weeks. She also says, “After two years we have a new body.”

O’Neill also claims that cells in the gastrointestinal tract replace themselves every 3-5 days. This is not entirely false as it is close to the figure of 5-7 days given by The Harvard Gazette. She also says “We’ve got a new skin every month”, which is also close to four weeks as reported in an article on the U.S. National Institute of Health (NIH) website. 

In fact

On consulting various experts and multiple studies, we concluded that several of the other claims made by O’Neill in relation to different cell regeneration rates for the human body are false. 

Do human eye cells regenerate every 1-2 days?

Contrary to O’Neill’s claims, not all eye cells regenerate every 1-2 days. An article published in Nature says the corneal epithelial surface constantly renews itself to maintain an unblemished and uniformly refractive surface, but the story is different for retinal cells.

According to a report from the National Institute of Health (NIH) dated January 24, 2023, once eye cells die, they do not regenerate. It says, “These (eye) cells capture light or send visual information to the brain. Their loss can eventually lead to reduced vision or even blindness.” An article in BBC’s Science Focus magazine says that “cells in the middle of your eye lenses last a lifetime.”

Dr. Santosh Bhide, President of the Maharashtra Ophthalmological Association and Ophthalmologist at Ruby Hall Clinic, Pune, told Logically Facts, “The endothelial cell layer of the cornea, which is essential for clarity of the cornea, does not replace or regenerate. Similarly, certain cells in the retina cannot regenerate once dead, just like neurons in the brain cannot regenerate. Corneal epithelial cells on the other hand do replace themselves approximately every 7-10 days.”

Do bones regenerate every three months?

According to a book on the NIH website, cellular activity in the bone consists of removal and replacement at the same site in a process called remodeling. In contrast to O’Neill’s claims that humans have "new bones" every three months, the book adds, “Remodeling continues throughout life so that most of the adult skeleton is replaced about every 10 years.”

Similarly, rheumatologist Chad Deal, MD, Head of Cleveland Clinic’s Center for Osteoporosis and Metabolic Bone Disease, explained in an article on the Cleveland Clinic website, “Your skeleton is completely new every five to 10 years.” 

Orthoinfo, a website by the American Academy of Orthopedic Surgeons also says, “The body's skeleton forms and grows to its adult size in a process called modeling. It then completely regenerates — or remodels — itself about every 10 years.”

The liver

O'Neill claims that the liver regenerates every six weeks. Research published in Cell Systems suggests that on average the liver is three years old in people of all ages. However, Doctor Olaf Bergmann of the Center for Regenerative Therapies states that "Typical cells renew approximately once a year, while the cells richer in DNA can reside in the liver for up to a decade," said.

Dr. Mandar Doiphode, senior consultant gastroenterologist at Sahyadri Hospital, Pune told Logically Facts that the liver does not regenerate every six weeks. He said, “If that was the case, all my hepatitis patients would get better after six weeks as they would have a new liver. This is completely untrue.” He added that liver cells die and get replaced like red blood cells but that does not mean that a completely new liver is formed in six weeks, as O’Neill claims. 

A new body every two years?

O'Neill claims that the human body is completely regenerated every 2 years. According to Scientific American, some cells like red blood cells last for 120 days, while other cells like muscle cells last for 30-70 years. As discussed earlier, some cells in the retina of the eye do not replace themselves at all. 

This contradicts O’Neill’s claim that the human body is completely new every 2 years.

The verdict
Experts and research confirm that eye, bone, and liver cells do not regenerate at the rate claimed by O’Neill. Therefore, we have marked this claim as false.