The healthy ingredient harming our guts, according to a heart surgeon

It seems official guidelines as to what is and isn’t healthy is permanently changing.

Ten years ago, everyone was obsessed with reducing their fat intake and supermarket chains were brimming with low-fat products.

Now, however, sugar has replaced fat as public enemy number one, and we’ve realised that certain fats - those found in avocado, nuts and olive oil, for example - are actually good for us.

But now a heart surgeon has spoken out to explain that lots of plenty of nutritious foods are not, in fact, 100 per cent healthy.

Cardiologist, heart surgeon, and autoimmune disease expert Steven Gundry says that often the most nutrient-packed foods are the ones causing people digestion issues.

In an article for Mind Body Green, Gundry explains that there’s one particular plant protein creating problems for our guts: lectin.

“These tiny proteins live inside certain plants and act as a defense mechanism by making their predator ill when eaten,” he wrote. “I think they play a huge role in America’s health crisis.”

Lectins are found in foods such as whole wheat flour, cashews, legumes, aubergines, corn, brown rice, tomatoes, and sunflower seeds - so yes, lots of foods that are generally considered healthy.

“A lectin is a type of protein (susceptible to various diseases, bacteria, and viruses) that forces carbs (sugars, starches, and fibres) to clump together and even attach to certain cells in your body when you eat them,” Gundry explains.

“Often, lectins can get in the way of important cells communicating with one another. And when that happens, the body’s response is usually inflammation or some other type of reaction to toxicity, like nausea, diarrhoea, or vomiting.

“A break in cellular communication can also result in symptoms like fatigue or forgetfulness.”

But Gundry believes you may be able to improve your health by decreasing your lectin intake.

Instead of whole wheat bread, he suggests you stick to white. With tomatoes, you should peel off the skin and remove the seeds before eating.

Avoid tinned or processed beans in favour of fresh ones. And instead of cashews (which are actually seeds not nuts), eat pecans, walnuts or macadamia nuts.