Can eating peas and peanuts really lead to brain fog?

VeGeTABLeS and whole grains have long been seen as the key to good health. But could some of these actually be doing us harm? That’s the claim made by U.S. heart surgeon, Dr Stephen Gundry, in his book, The Plant Paradox. He says some plants not only use thorns to deter predators, they have other defences too: large, sticky proteins called lectins.

‘Because plants’ first predators were insects, some developed lectins that would paralyse any bug that tried to dine on them,’ says Dr Gundry. He claims that as humans have more cells than insects it is only after years of consuming lectins that the damaging effects to health become apparent — causing, he suggests, problems such as allergies, brain fog, fatigue, irritable bowel syndrome, and even autoimmune diseases such as rheumatoid arthritis.

‘Lectins enter our our joints, our nerve junctions, the lining of our blood vessels and our brain where they incite inflammation and autoimmune diseases,’ says Dr Gundry.

‘ I’m now convinced that all arthritis, most coronary artery disease, acne, eczema, and the autoimmune diseases are all caused or worsened by lectins.’

He says they are the ‘ No 1 biggest danger in the Western diet’.

Lectins were first discovered in the 1880s by German microbiologist Peter Hermann Stillmark. He isolated and distilled proteins from the castor tree into the poison ricin.

In the past 20 years, hundreds more have been discovered. Now the idea that lectins may not be good for health has gained interest in celebrity circles. The supermodel Gisele Bündchen’s private chef has reportedly said he limits her intake of tomatoes as they cause ‘inflammation’ — a claim also made by Dr Gundry.

Lectins are more concentrated in foods that are themselves seeds in pods, such as peas, kidney and soy beans, cashews and peanuts, but are also in the seeds of tomatoes, cucumbers, red peppers and aubergines.

Dr Gundry says wholegrains contain other types of lectins, such as wheat germ agglutinin. Which is why, he says, wholemeal baked goods — traditionally seen as healthier because of their high fibre content — should be swapped for white bread, which has been stripped of these seed husks.

He sells supplements on his website said to counteract the effects of lectins — one, Lectin Shield, costs more than £60 for a month’s supply. But should we take all this with, well, a large pinch of salt?

‘There are small amounts of lectins in some foods, but they are well tolerated by the vast majority of people,’ says Dr Megan Rossi, a dietitian and research associate at King’s College London. She points out that peeling and deseeding veg and fruit such as tomatoes to reduce lectin intake, will also reduce the amount of antioxidants — substances that help keep the body’s cells healthy — as well as fibre content.

‘Less than half the UK population are getting enough fibre, so the last thing we want to be doing is reducing our whole grains and vegetables,’ she adds.

Yet some experts believe lectins warrant further investigation.

‘To date, the majority of the studies have indicated that if lectins have an effect on the gut it i s more often harmful than beneficial,’ says Peter Whorwell, a professor of medicine and gastroenterology at the University of South Manchester.

He believes lectins might have a role to play in sensitivities to cereals and breads.

‘When I take fibre out of the diets of patients with irritable bowel syndrome, they almost always improve,’ he says. ‘It’s possible their guts have been irritated by lectins, found in the husks of the wheat these foods contain.

‘But while some lectins are overtly poisonous, studies have also found they improve the gut lining by JoN triggering cell regeneration.’

RHoDeS, emeritus professor of medicine at the University of Liverpool, has carried out research into lectins and says they have many effects, including increasing or decreasing cell division. The most intriguing research, he says, is the possible link to Parkinson’s disease and loss of nerve cells in the brain.

In April, the journal Neurology published a study that suggested Parkinson’s starts in the gut and spreads to the brain via the vagus nerve that stretches from the abdomen to the brainstem.

And a study l ast year at Louisiana State University found lectins can get into the vagus nerves of roundworms.

Yet Professor Rhodes says: ‘The only diet for which there is a reasonable body of scientific evidence showing it’s good for you is the Mediterranean Diet — which recommends eating plant- based foods, wholegrains, legumes and nuts — the opposite to a lectinfree diet.’