The problem, Mannone explains, is that the make-up of modern wheat differs from its ancestral form. Through intensive crossbreeding, it now contains 42 pairs of chromosomes instead of the original 14, making it higher-yielding but harder for humans to digest. Poorly broken down, gluten can disrupt the gut by feeding harmful bacteria, contributing to dysbiosis and triggering the release of zonulin, a protein that loosens intestinal tight junctions and can lead to “leaky gut.”

While people with Celiac Disease must avoid gluten entirely, according to Mannone, we could all focus on limiting it—particularly modern wheat. He recommends choosing more digestible sources, like breads made from einkorn (an ancient wheat) and natural sourdough, where fermentation partially breaks down gluten and makes it easier to digest.

2. Poor-quality dairy products

Lactose is a carbohydrate that’s made up of glucose and galactose. It’s normally digested by the enzyme lactase, which breaks it down to feed healthy gut bacteria. But in adulthood, many people stop producing enough lactase. Without it, the body struggles to process lactose, which ferments in the gut and can cause symptoms of intolerance—digestive issues, inflammation, skin problems, migraines, joint pain, and more.

Lactose intolerance, however, doesn’t always mean cutting out dairy completely. Hard cheeses like Parmesan, Gouda, or gruyère contain very little lactose, and lactose-free dairy products are often easier to tolerate.

Beyond lactose, dairy also contains casein, its main protein. Some forms of casein (notably A1 beta-casein from hybridised cow breeds) can trigger inflammation, immune reactions, and gut permeability, whereas A2 casein—from goats, sheep, or heritage cow breeds—is considered less harmful.

Equally important is how the milk is produced. Traditional grass-fed cows provided omega-3-rich milk, but today’s intensive farming relies on grain- and soy-based feed that’s high in inflammatory omega-6s. Industrial practices also bring pesticides, antibiotics, hormones, and other residues into the milk supply, all of which may impact human health. Processing methods like pasteurization and UHT further degrade nutrients, and alter proteins in ways that can stress the gut.