A majority of parents in London want to see processed meats cured with nitrites banned from primary schools. More schools are banning red and processed meat in favor of healthy, plant-based foods.

A poll including more than 1,000 Londoners with children between five and 11-years-old found that 69 percent of parents want meat products including bacon and ham removed from school menus. Half of the participants back a complete ban on nitrite-cured meat for health reasons.

In 2015, the World Health Organization (WHO) classed processed meat as a Group 1 carcinogen, meaning it causes cancer in humans. Tobacco smoking and asbestos are also in this category.

WHO stated that eating just 50 grams of processed meat a day could raise the risk of developing colorectal cancer by 18 percent. Fifty grams is equivalent to less than two slices of bacon.

The Global Burden of Disease Project has revealed that nitrite-cured processed meat is to blame for 34,000 cases of bowel cancer every year.

What Are Nitrites?

Nitrites and nitrates are naturally occurring chemical compounds that contain nitrogen and oxygen. They are added to animal products like salami, ham, bacon, and some cheeses to prevent the growth of dangerous bacteria.

Nitrites and nitrates exist naturally in soil, meaning they can also be found in vegetables. However, these are unlikely to be dangerous. Kate Allen, executive director of science and public affairs at the World Cancer Research Fund, explained to the BBC, “It’s not so much nitrates/nitrites per se [that are carcinogenic], but the way they are cooked and their local environment that is an important factor.”

“For example, nitrites in processed meats are in close proximity to proteins (specifically amino acids). When cooked at high temperatures this allows them to more easily form nitrosamines, the cancer-causing compound,” Allen said.

Amanda Cross, a professor of cancer epidemiology at Imperial College in London, says researchers have noted an increased risk of cancer linked to nitrate and nitrites in meats. They haven’t observed an increased risk of cancer from nitrates or nitrites in vegetables.

Schools Banning Meat

More schools are updating their menus to omit meat products. Last month, the Swan School in Oxford opened its doors with a meat-free lunch menu. The school said the move has helped it improve its sustainability.

All New York City public schools — the largest public school system in the world — now participate in Meatless Mondays in an effort to improve student health.

Goldsmiths (University of London) and Cambridge University no longer serve beef while Edinburgh University, Westminster University, University of East Anglia, and Ulster University all promote the consumption of vegan and vegetarian food.