Rats are not Little People

Originally Published: July 1, 2011
Last Updated: February 25, 2021

Rats have tails about the same length as their bodies. People don’t. Rats become sexually mature at six weeks. Babies don’t. Men and rats are different internally as well. Humans have gall bladders, rats do not; and, some metabolic pathways are different. In other words, rats are not little people.

People forget this. Reporters forget this. Consumer advocacy groups forget this. Even some scientists forget this.

It’s cheaper, faster, and more ethically acceptable to experiment on rats than on people. Sometimes a compound or treatment seems safe for rats, but with more studies we find it is harmful for people. Sometimes a compound or ingredient is harmful for rats, but with more studies we find it to be safe for people.

Such appears to be the case with the sweetener saccharin. In the early 1970s, studies linked saccharin with the development of bladder cancer in lab rats. As a result, foods with saccharine were required to carry a warning.

But, rats are not little people. Wikipedia explains on its website that “unlike humans, [rats] have a unique combination of high pH, high calcium phosphate, and high protein levels in their urine. One or more of the proteins that is more prevalent in male rats combines with calcium phosphate and saccharin to produce microcrystals that damage the lining of the bladder.” This over time can lead to tumor formation in rats, but not people. In the U.S., the National Cancer Institute confirms this as it reports on its website “…studies in rats showed an increased incidence of urinary bladder cancer at high doses of saccharin, especially in male rats. However, mechanistic studies (studies that examine how a substance works in the body) have shown that these results apply only to rats.” The warning labels on foods came off in 2000.

When foods have saccharin in them, they must say that on their labels in the ingredient statement. This gives consumers a choice. They can choose to eat foods and drink beverages sweetened with sugar, sucralose, stevia, agave syrup, honey, or many other sweeteners including saccharin. This gives people with diabetes or weight concerns an option. Is that bad?

— Claudia O’Donnell, Global Food Forums, a conference and seminar organizer