Gluten-free diets should not be encouraged among people who do not have coeliac disease, according to a new study. Researchers at Harvard University found that not only did going gluten-free not cut the risk of heart disease, but it also lowered the intake of grains that are known to be beneficial for the heart.
But there's a new food fad that could soon be taking gluten-free's place. In his new book, The Plant Paradox, Dr Steven Gundry argues that the secret to losing weight and leading a healthier life isn't removing gluten from your diet, but getting rid of lectins instead.
The book aims to explain "how plants defend themselves from being consumed by humans, and how eating the wrong ones at the wrong times immeasurable hurts our health."
What are lectins?
Lectins are a type of protein found naturally in plant foods such as tomatoes, lentils peas and legumes and also inside certain dairy products. They bind together cell membranes and cannot be digested properly by humans.
What's the problem?
Lectins are thought to have toxic and inflammatory properties. Consuming certain types of lectins can be harmful and can result in vomiting, diarrhoea and abdominal pain.
Raw kidney beans, for example, contain high quantities of a toxic lectin called 'phytohaemagglutnin'. While cooked kidney beans contain between 200 to 400 hau (the unit of toxin measurement), raw kidney beans contain between 20,000 to 70,000 hau.
Eating just five raw kidney beans could bring on the symptoms from lectin poisoning, though recovery usually happens within four hours.
However, there are some cases in which lectin ingestion could prove fatal. Just a small dose of ricin, a naturally occurring lectin produced in the seeds of the castor oil plant, could kill an adult human.
Gundry writes: "[Lectins] are designed by nature to protect them from predators (including humans). Once ingested, they incite a chemical warfare in our bodies, causing inflammatory reactions that can lead to weight gain and serious health conditions."
How to avoid them?
In the book, Gundry offers tips for removing or lessening lectins in your diet, including properly peeling your vegetables as "most of the lectins are contained in the skin and seeds of plants" and shopping for fruit in season as fruits "contain fewer lectins when ripe".
He also recommends swapping brown rice for a white as "whole grains and seeds with hard outer coatings are designed by nature to cause digestive distress and are full of lectins."
Other methods for reducing the lectin content in your diet include soaking your beans and grains before you cook them. Soaking beans, peas and grains overnight and draining them before cooking can help to neutralize the lectins further and bring its hau measurement to a safe level.
Fermenting foods with a high lectin count is also a great way of bringing the hau measurement to a consumable level as it causes helpful bacteria to digest and convert the harmful lectin.
These methods don't completely destroy the lectin in the foods, but generally bring the levels of lectin down to a consumable degree that won't cause any harmful side effects.
So what can I eat?
As lectins are found in many foods that have typically been thought to be beneficial to our health, learning that they could potentially be toxic will leave many wondering what they can actually eat instead.
In his book, Gundry offers a host of alternatives that he says you should be eating regularly: "Olives and olive oil, leafy greens (kale, Swiss chard, spinach), cruciferous vegetables (cauliflower, Brussels sprouts, broccoli) and avocados."
The bottom line?
Research has shown that while lectins have the potential to be harmful to humans, this is dependent on the type of lectin, the amount of lectin consumed, how the lectin has been prepared and the individual themselves.
Speaking to The Times, Dr Megan Rossi, a research associate at King’s College London and spokeswoman for the British Dietetic Association, says that most of us don't need to reduce our lectin intake as we are already dealing with it properly: "There is a lot more to lectins than we are being told. For one, it is relatively easy to get rid of them by cooking and preparing food in the right way."
Though she also added: "Despite limited research in human studies, a lower lectin diet may work for some individuals.
"We used to think a wheat intolerance was linked to gluten sensitivity, but preliminary investigations indicate that for some people the problem might lie with a sensitivity to agglutinin, a lectin found in wheat."
Gundry insists lectins play a huge, and potentially detrimental, role in our health and suggests that if you're experiencing symptoms that cannot be explained by other intolerances "then lectins could be to blame."