So what exactly are lectins?
Lectins are a type of naturally occurring protein found in many foods including legumes, grains, seeds and certain vegetables with smaller amounts present in eggs and dairy products.
They act as a glue binding carbohydrates together, which can help cells interact and communicate with each other.
What is the premise of a lectin-free diet?
Dr. Steven Gundry says that plants use lectins to protect themselves against being eaten. He claims that in humans, eating these lectins results in Leaky Gut Syndrome and causes a range of unpleasant symptoms and autoimmune issues.
While there’s little science to back up this link, it’s true that some lectins can be harmful to humans. But it’s down to how they’re consumed.
“In some cases, it causes irritation of the gut lining and can lead to symptoms such as bloating, vomiting and diarrhoea,” Charlene Grosse, accredited practising dietitian and spokesperson for the Dietitians Association Australia, told Women's Health.
“This can particularly be seen when eating raw/uncooked legumes, as the lectin in these foods bind to and effect the lining of the gut, causing vomiting and diarrhoea in the consumer. However the reality is, that we don’t often eat food high in lectin (e.g. kidney beans) in their raw state, and once soaked and cooked, the lectin content is significantly reduced.”
What does the diet involve?
The lectin-free diet removes out high lectin foods like grains, quinoa, legumes, and nightshade vegetables like tomatoes, peppers, and eggplant. It also advocates ditching dairy, out-of-season fruit, and conventionally-raised meat and poultry.
Instead, they suggest piling your plate with low-lectin foods like leafy greens, cruciferous veggies like cauliflower, broccoli, and asparagus, mushrooms, nuts and seeds, millet, pasture-raised meats, and wild-caught fish.
Gundry also offers a variety of supplements that claim to neutralise or reduce the negative effect of lectins.
Are there science-backed health benefits of this diet?
Some research has shown both negative and positive effects of lectin, but the majority of studies have been done with isolated lectins, not actual foods, and have been conducted in test tubes or in animals, not in people.
“There is strong scientific evidence to support the health benefits of foods such as legumes, vegetables, nuts etc," Charlene says. "However there is very little evidence surrounding the harmful effects of lectin.”
What are the risks associated with following a lectin-free diet?
“Removing lectin filled foods over a long period of time is likely to result in potential deficiencies, due to the vast array of vitamins, minerals and nutrients that these foods contain,” Charlene says. “Therefore the benefits of consuming these foods far outweigh any concern for the level of lectin that they contain in their raw state.”