Wheat, soy, barley, oats, rye and other grains, cereals, corn, grain oils and beans could be causing your migraines.

Yes, that 'healthy' soy milk in that bowl of innocent porridge just may be part of the toxic mix that gives you head-splitting migraines.

Lectins are being pinpointed by a small number of scientists as a common cause of migraines for many people.

But while only a handful of the foodies and ‘healthy living’ websites and publishers are talking about lectins, the recognition of them and their possible role in contributing to bad health continues to grow.

A small number of modern researchers, the leading proponent being Dr Steven Gundry, author of New York Times best-selling book The Plant Paradox, are focusing on lectins in humans, and the roles of lectins in causing so many medical conditions ranging from fatigue and brain fog, depression and anxiety through to autoimmune conditions. And a hundred other modern health problems… Crohn's, Hashimoto's, lupus, multiple sclerosis, chronic fatigue... (Gundry, 2017)

Gundry’s book has given lectins their greatest publicity in what is becoming a growing debate and discussion in nutrition circles. What is also interesting is the numerous anecdotes of the thousands of patients he has treated, and this includes anecdotal reports of clearing migraines.

Dr Loren Cordain has also written extensively and in great detail on the topic and his chapter Cereal Grains: Humanity’s Double-Edged Sword in the book Evolutionary Aspects of Nutrition and Health, Diet, Exercise, Genetics and Chronic Disease makes sobering reading. (Cordain, 1999)

Many writers are dismissive of the spotlight on lectins, some calling it the ‘new gluten’ and that labelling it a new fad, and we take careful note of the criticisms.

At Migraine Escape, we look through the available evidence, read the literature and scientific reports to make our own assessments, and put our findings into layman’s terms, with particular emphasis on their relevance to migraine. There is much smoke, and we found considerable fire! We believe that there is much more worthy of further investigation as we trawled through the material.

Considerable evidence links lectins with migraines, and other health issues in some people. We summarise our findings here, but many volumes more could be written on the topic.

If you have ‘tried everything’ and not had luck with getting to the source of your migraines lectins may be worth investigating.

Let’s look at how and why.

So what exactly are lectins?

Lectins are toxins or poisons that plants produce to stop insects, animals, parasites, moulds and other organisms from eating them!

And you, dear Human, are part of that group.

And all plants produce lectins.

It is part of the genius of Mother Nature's design philosophy.

Simply put, most creatures and organisms in the world are programmed to be reluctant to becoming some other creature’s dinner.

So most creatures, over millions of years and evolution, have developed various forms of self-preservation.

The impala bounds from the sprinting leopard, the bird flies to a tree, the flying fish gets airborne to outpace the pursuing barracuda, the buffalo kicks you or prods you with his horns, the warthog rips your leg open with his razor sharp teeth, the clam clamps his shell shut, the chameleon blends into the surrounding foliage, the cobra spits venom in your eye.

While a plant is unable to slither away like an eel, and unable to box you (or a rabbit) in the ears as you are about to crunch into it, plants have developed an impressive arsenal of self-preservation mechanisms such as husks, shells, skins, acidic peels like a citrus fruit, colour camouflage, spikes and such like.

One of those defences is a really sneaky one, in the form of poisons called lectins, which are sometimes toxic to humans.

They are also called agglutinins. (Peumans & Van Damme, 1995)

These lectins can be fatally toxic to a small insect that decides to lunch on a particular plant.

But another species, like you dear Human, may be able to tolerate a much higher level of many a lectin and its toxin than a tiny beetle.

But it is not just plants that produce lectins. Animals do to, and if you eat their meat, or by-products (e.g. milk) you will consume their lectins. It would seem however that most of our health problems arise from plant lectins.

Size may not matter!

But it is not only related to size. Much of it relates to genetics and evolution. Many a small insect may have a tolerance to the poison of a lectin or anti-nutrient that might sicken a human. One of our favourite animals is the amazing African dung beetle who thrives on elephant dung. Could you, dear Human, swap meals with him?

However what the lectin can do to larger organism, like you, is give you a very upset stomach, and cause vomiting, nausea, cramps, diarrhoea or headache.

Result: The human or affected animal learns to associate that plant with bad karma and therefore avoids it. Much of the plant colony is then able to survive and proliferate and stay on the planet.

Of course most people can probably tolerate most lectins in our diets. But if you are having trouble pinpointing the cause of your migraines or are having issues with inflammation, irritable bowel etc lectins may be in area worth looking into.

You already know the most famous of the lectins…

Gluten.

We all know that many are intolerant to gluten, and that in some particularly sensitive people it causes migraines. But statistics suggest that this only 4% of people.

Dr David Perlmutter in his book Grain Brain also points out that while most of us are not sensitive to gluten in the same way as an individual with celiac (i.e. gastrointestinally) we may all be sensitive to gluten from a neurological standpoint… deep within the quiet confines of our nervous system and brain. (Perlmutter, 2014)

In other words while lectins (and other anti-nutrients in grains) may not rot your guts, they may be rotting your brain and setting you up for Alzheimer’s, dementia, cognitive impairment.

They could also be giving you the fuel for a migraine.

Many studies show that celiac sufferers experience more migraines than non-celiac sufferers.

Recent findings regarding the role of the gastrointestinal microbiota in the gut-brain axis suggest that an unbalanced gut flora (i.e. dysbiosis) can be associated with neurological diseases like migraine. (Rahmoune & Boutrid, 2017)

Pro-inflammatory immune responses have been reported with intestinal disorders associated with dysbiosis and intestinal permeability (leaky gut) ( these are things like irritable bowel syndrome and celiac disease) as well as in migraine patients. (van Hemert, et al., 2014)

Evidence points to changes in gut flora or microbiota being an important contributor to migraine in many people. (Hindiyeh & Aurora, 2015)

But other lectins can be as bad, and some even much worse than the much-maligned gluten!

Researchers point out that gluten is fairly benign compared to its fellow lectin that is also found in wheat – wheat germ agglutinin. This has a far worse effect on the bodies of humans than gluten, but largely escapes the bad rap with the general public! (Cordain, 1999) (Gundry, 2017)

Other lectins

At one extreme, some, like the ricin bean, are so toxic as to make them fatal to any person that should swallow one. ( Yet, fascinatingly, there are insects that can survive a ricin-containing diet indicating that they either can inactivate the toxin or the lectin’s toxins do not bind to the predator’s carbohydrates. (Peumans & Van Damme, 1995)

And some, like peanuts with their lectin peanut agglutinin (arachis hypogaea lectin)  can be immediately fatal to the few people that lack the antibody, but in the rest of us these lectins can build up in the gut causing low level inflammation, gut problems and a host of health problems. They can build up gradually over time until they reach a critical mass, at which point they then inflict their damage.

Some of these lectins actually make your gut gluten sensitive, even if you are not gluten sensitive!

Yes… so if are one of those people who has been tested for gluten sensitivity and have eliminating that as a migraine trigger saying, “I have been tested for gluten sensitivity and I am not gluten sensitive …” well… the consumption and build-up of lectins in your body may include other lectins that make you gluten sensitive when you consume them!

Mother Nature is very clever.

Others make the plant unpalatable until we cook them.

Basically, as a very broad-brush rule, think of almost any plant that we generally do not eat raw, and you will have identified a plant probably packed with lectins.

Think potatoes, beans, peas, wheat, soybeans, corn, grains, rice, wheat, barley, rye and dozens of other foods.

By cooking them we change their molecular structures, and reduce the lectin content to such an extent that they are palatable. But still many of the lectins survive. Some like WGA are heat tolerant and can survive cooking.

Not all lectins are bad!

legume-lectin

Diagram of a lectin from a lentil.
Credit: tomixdf Wikipedia Commons

Of course most of our bodies can obviously tolerate a large number of lectin types otherwise we would not be able to eat so many plants and benefit from them health-wise.

Most of the plants that we eat raw are relatively low in lectins, allowing us to enjoy them as a food source.

But some, like tomatoes and members of the nightshade family – capsicums, eggplants, cucumbers, zucchini  - have lots of lectins in their seeds that can cause some people many health issues.

Often a fruit will have lots of lectins while immature, making them bitter and inedible. Once  they mature the lectins convert from being inedible to being edible, and change from green to a bright attractive colour. Dr Gundry points out that many non-fruit eating animals are colour-blind, as fruit eaters were able to identify ripe fruit by its colour.

Many lectins are both good and bad!

Lectins are in some ways a bit like red wine.

A glass or two can be beneficial to your health but a few bottles in one session may lead to all sorts of problems. Worse still if those sessions occur regularly over long periods.

A lectin that can cause you stomach upset might also have cancer fighting properties.

Or it might cause you a migraine, but in other parts of the body can attack microbes. The bad response to migraines means that you would probably forgo the antimicrobial benefits in favour of a headache-free day.

As examples, research shows that the isoflavanoids from soya may be protective against prostate disease. (Morton, et al., 1997)

Researchers Evans, Morton and Griffiths reported that glycoside genistein found in soy reduced the activity of the enzyme 5 alpha-reductase which converts testosterone to dihydrotestosterone (DHT) – its form that is implicated in prostate cancer and benign prostatic hypertrophy (BHP). (Evans, Griffiths, & Morton, 1995)

5 alpha-reductase activity was reportedly reduced by over 80% by the soy lectin, and was concentrated in the prostate gland in higher levels than blood serum levels. They also postulated that soybean agglutinin (SBA) reduced tumour transformation with breast cancer. (Waran, 2014)

soybean-agglutinin-migraine

Soybean agglutinin, a possible migraine aggravator.
Credit: Olsen et alia. Creative Commons Licence, Wikipedia.

So, biologically, just what is a lectin?

Lectins are proteins. Large proteins.

Sticky proteins.

Lectins like to stick on to sugars.

They stick on to carbohydrates.

So they are carbohydrate binding proteins.

Their other name, agglutinin even sounds like they are made of glue.

Their ability to bind to and stick to sugars is put to use by scientists in the laboratory who use them to isolate a wide range of biochemicals and use them in laboratory processes. (Fluoprobes) (Sigma-Aldrich)

 As you know, our body itself needs all sorts of proteins to run its systems – the organs, muscles, nerves, brain. … everything that makes up a human body.

What happens when we eat lectins?

As soon as a plant enters your mouth the body tries to block lectins by offering them sugars from the mucus in the mouth, saliva and nose. These are called mucopolyshaccarides, and are sugars to which the lectins can bind.

A big word but easy when it is broken into 3 words muco- in the mucus; -poly- many; -saccharides = sugars.

That is why often when you eat certain foods your nose gets clogged up. Or it runs.

The entire tunnel from mouth to the anus, the alimentary canal is coated with a mucosal lining. The mucus acts as a protective coating and blocks foreign bodies, bacteria and germs as they get stuck in its gooey mess, and releases enzymes to kill the unwanted invaders that get stuck in it.

It also acts as a lubricant keeping the mouth, sinuses, throat and digestive system moist and flexible.

What the mucosal lining does to lectins is have a supply of sugars onto which lectins can bind.

The mucus coats the offending lectin and, so covered it makes its way through the alimentary canal and out of the body. Usually…

The lectins that escape this coating then set about trying to break the body’s defence system, while the body does its best to keep them out of the gut lining.

Remember that the gut lining is keeping anything inside the alimentary canal – the gut, oesophagus, intestines etc outside the body itself. So that most of the food that goes through the digestive tract never gets into the body itself, as it is kept out of the body by the wall of the gut.

The digestive system takes the parts out of the food that it wants to use, and pumps the rest out.

Bacteria in the mouth also works on digesting the lectins.

Stomach acid then digests many of the lectins, as does the gut bacteria and flora.

healthy gut lining will block most lectins, and keeps them from penetrating the gut lining and entering the bloodstream and body.

But the lectins are designed to actively attack the gut lining and break through it to enter other parts of the body - the bloodstream, the brain, nerves - where they can go about their God-given business of causing you trouble to try to dissuade you from eating the rest of his family.

What does the lectin then do?

Lectins that are in the body, and have survived the body’s defence systems, try to prize their way through your gut lining and get into the bloodstream and body and cause trouble. They are programmed to give you a bad experience to stop you eating the rest of its family and its offspring.

Lectins vary greatly in their composition but some like the wheat germ agglutinin usually survive the digestive process of the human body and reach the colon in biologically intact form. (Tu, 1992) (Cordain, 1999)

In most healthy individuals the lectins, being relatively big proteins, cannot penetrate the gut lining and its mucosal coatings. Those that survive the saliva and stomach acids, and get through to the intestines, try to bind with cells in the intestinal wall.

The wall itself, also called the endothelial lining, is also protected with things called tight junction proteins. Lectins produce a chemical called zonulin that can change the structure of the tight junction proteins and allow them through the endothelial linings and into the bloodstream and body tissue where they go about inflicting their damage.    (Mu, Kirby, Reilly, & Luo, 2017)

Simplistically put the zonulin prizes open the gaps between the cells, allowing the lectins more room to squeeze through.

As a general rule only up to 5% can squeeze through, but that is enough to cause your body trouble.

Leaky Gut and into the brain

This invasion of lectins into the bloodstream and to other parts of the body is part of the process that we know as leaky gut. Other antinutrients in grains also contribute to leaky gut and for this reason Cordain argues that humans should keep grain consumption to a minimum to maintain optimum health. He argues that those with autoimmune diseases, diabetes, hypertension and obesity issues should wean themselves off most grains. (Cordain, 1999)

He states: Although cereal grains are generally considered to be a wholesome and nutritious food, there is a significant body of clinical, epidemiological and anthropological evidence which demonstrates that cereals are less than optimal foods for humans, and when they are consumed in excessive quantity invariably result in nutritionally related diseases and disorders.

Not only do cereal grains lack essential nutrients required for human nutrition, but they contain many nutrients with low biological availability, as well as numerous anti-nutrients which may impair health. Further, there is an emerging body of evidence which implicates cereal grains in immune-related diseases, particularly in genetically susceptible individuals (Cordain, 1999)

So not only do cereals, grains and legumes contain lectins, they contain other anti-nutrients like phytates, oxalates, tannins, trypsin inhibitors, enzyme inhibitors, protease inhibitors, alpha-amylase inhibitors and alkylresorcinols, and these slow the absorption of certain minerals and vitamins in the body. (Weston Price Foundation)

Through the bloodstream the lectins to other areas of the body including to the brain. They can also travel up the vagus nerve which connects the gut to the brain.

In their intact form lectins are too large to break the blood-brain barrier, but scientists suggest that they do so through a process called adsorptive endocytosis where they bind to sugars called oligosaccharides on certain cell surfaces and the cell membrane then engulfs and swallows the cell to which they have bound, taking it through the blood brain barrier leaving the BBB intact without any rupture. (Broadwell, Balin, & Salcman, 1988)

Also well documented is that lectins and other anti-nutrients in grains decrease intestinal absorption of many key nutrients leading to deficiencies in minerals and vitamins in susceptible individuals. (Cordain, 1999)

A few here and there may not hurt but over time they build up in the body

In small quantities they cause most people little concern, but over time lectins can build up in the body and cause some people a lot of problems, especially those who are genetically more susceptible.

The lectin build up can be rapid in some, but for most it may take years, even decades, and can often only manifest itself in middle age as the efficiency of the body’s immune system starts to wane.

So for example eating bread may not hurt you, but over the years, regular consumption of wheat products could cause susceptible people a lot of problems, including migraines, skin problems, brain fog, hypertension, autoimmune issues, diabetes, leaky gut, weight issues and more. (Cordain, 1999)

Let's look more deeply into lectins and migraines and look at some of the research, and what some of the experts say.

How do Lectins cause Migraines?

Simply put, our immune system is always on the alert for invading foreign bodies that it thinks can cause damage to our systems.

When the immune system detects that foreign bodies like lectins have broken through the endothelial lining of the gut it launches its retaliatory response – the inflammatory response.

We have seen elsewhere that the inflammatory response is the body’s immune system’s response to some attack or injury on it.

In launching this counter-attack the body the body releases an array of chemicals to counter that attack or injury, and soothe the area.

In some people the inflammatory response includes the release of chemicals that lead to a migraine.

In breaking through the gut lining lectins often then mimic other cells fooling the body into thinking that they are not foreign invaders, but are friendly cells. They then set about causing damage within the body.

What can we do to counter lectins?

Dr Gundry and Dr Cordain advise people with health issues like autoimmune issues, brain fog, chronic fatigue, migraines and a myriad of disease, and have been unable to find a cause, to avoid foods that are high in lectins. 

It can take some time to get used to this concept.

The FDA’s food pyramid has for decades recommended grains and cereals to be a substantial part of the daily diet. We now have a major obesity problem over much of the world. Researchers argue that cereals, grains, processed foods, sugars have played a major role in this, and the many diseases that have come with them.

But there are other ways to reduce the effects of lectins if you just cannot live without your high lectin foods.

Being the resourceful folk that we are, humans have, over the centuries developed ways to make foods with lectins more palatable.

Cooking: Firstly we cooked them, reducing the lectin units dramatically.

But of course, some lectins, particularly those in grains are heat stable, and not damaged by heat. Wheat germ agglutinin is one such strong lectin.

Pressure Cooking: Far more effective at destroying some lectins is pressure cooking. These are reportedly very effective against bean lectins but totally ineffective against many of the offending lectins in grains and cereals.

Cooking beans will destroy most of the lectins in them to make them palatable to most people, except those that are most sensitive. But pressure cooking beans destroys virtually all their lectins.

Soaking: This often reduces the amount of lectins in beans, but they still generally require pressure cooking to remove all the lectins.

Remove the skins: Peeling high lectin foods can remove a source of lectins. Tomatoes are one such example.

When humans learned to make wheat into bread they removed the husks and disposed of them, grinding up the grain. But in recent decades we learned that husks had higher fibre to keep you ‘regular’ and eating whole grain flour products became popular. Also there are often more nutrients in the husks. But also more lectins. And here is the problem – for those who are lectin sensitive.

Fermentation: This age-old practice usually destroys most lectins. The Chinese have been fermenting soy beans for thousands of years. Unfermented soy beans can however be a source of great digestive distress.

Sprouting: This also destroys most lectins.

Removing the seeds: Often the highest concentration of lectins is in the seeds. Removing the seeds can reduce your lectin exposure in offending plants. A sliced tomato with the seeds removed just may not look right initially, but in time you can get used to this.

Learn to recognize the effects of certain foods and plants on your body. If after that buffet lunch at a certain restaurant you always have to rush to the bathroom to ‘powder your nose ‘ lectins (or other toxins) could be at work.

Record a diary and see how you feel 2 to 3 days after eating anything. The diary allows you to remind you what you ate 3 days ago and see if there is a link to your wellbeing. Without it most of us forget what we ate for lunch 3 days ago.

While the debate heats up on these topics and their effects our job is to read as much of the research on the matter and make our own lifestyle choices given the evidence as presented.

But there is more on the topic of Lectins and their role in disease

Why GMO plants can be even worse for Lectins and therefore migraines

But the modern GMO plant is even worse than an ordinary plant from a lectin viewpoint!

GMO plants are often designed with ADDED lectins. Scientists take the lectins from one plant that may be highly toxic to insects, and then genetically add them to others so that the GMO plants are more insect resistant. They literally genetically engineer a lectin boost!

They also genetically engineer the seeds by adding genes from more weedicide-resistant plants making the GMO plant to be more resistant to herbicides.

This is done with virtually all modern commercial varieties of grain.

This enables the farmer to spray crops with herbicide, killing the surrounding weeds but enabling the GMO plant to live with fewer weeds. When done, as harvest approaches farmers have found that the plant pumps a last gasp thrust of energy into its seed or fruit, thereby increasing the harvest.

A problem arising from that is the herbicide residues often stay on the harvested crop.

And this is then consumed by humans, and by the millions of commercially farmed animals fed on grain entering the human food chain indirectly through the meat of the slaughter.

Yummy.

Seed manufacturers insist that there is no danger in their seeds genetically modified with lectins.

You should do your own research and you be the judge.

What Foods contain High levels of Lectins ?

Here are the main groups to avoid, should you wish to try a low lectin diet. Consult your health professional before embarking on this.

Most high lectin foods are high protein foods.

Grains

Most grains and cereals are high in lectins. Wheat, barley, rye, oats, quinoa, rice, corn, maize. Also oils derived from grains and cereals are high in lectins. High fructose corn syrup and products with it.
Pressure cooking does not destroy the lectins in wheat, barley, rye, oats.
Sorghum and millet are cereals that are low in lectins and are acceptable to those wanted to adopt a low lectin diet.

Legumes

Soybeans, beans, chickpeas and peas are high in lectins. Cooking destroys most, but pressure cooking destroys virtually all the lectins in legumes. (Gundry, 2017)

Nuts and seeds

Many nuts are high in lectins including peanuts, cashew nuts and chia seeds.
Also sunflower and pumpkin seeds.
Walnuts, almonds and macadamia nuts are low in lectins and are recommended for those on a low lectin diet.

Nightshades

These include tomatoes, eggplants, cucumbers, and in particular the seeds.

Oils

Oils from corn, sunflower, safflower, canola, rape seed, peanut oil are all high in lectins.

Dairy Products

Gundry says to avoid milk, yoghurt, cheese, ice-cream from non-Southern European cows.

Processed and Refined Foods

Pizza, pasta, flour, bread, biscuits, noodles, spaghetti, potato chips, tortillas, corn chips, crackers, sugars, most packaged breakfast cereals, muesli.

Source: (Gundry, 2017)

There won’t be anything left to eat! – Some Coping Strategies

Giving up staples that have formed the basis of life long eating habits can be challenging. While that can be difficult, for anyone with persistent migraines or other health issues that they have just been unable to stop trying, a low-lectin diet is worth trying.

Even cutting back on the above items can bring on positive results.

The modern Western diet involves eating too much nowadays.

This actually is a way to reduce your portion size for those needing to shed a few kilos.

One key statement that Dr Gundry makes is that it is more important what you remove from your diet than what you put into if you are suffering from persistent autoimmune problems, weight problems, brain fog the host of other problems.

Here are some steps to embarking on a low-lectin diet.

  1. Consult your qualified health practitioner or doctor.
  2. Eliminate the foods listed above.
  3. Pressure any cook beans.
  4. Add some probiotics to your diet to get the gut flora.
  5. Keep a food diary and assess how you feel each day.
  6. Avoid sodas, canned soft drinks and fizzy soft drinks.
  7. Avoid fruit juices as they are high in sugars.
  8. Assess how you feel after two or three weeks, and then for 2 months.
  9. Reintroduce foods one by one and assess their impact on your wellbeing. If you get a reaction, withdraw it again.
  10. Take stock of how you feel. A low lectin diet has worked well in reducing migraines for many migraine sufferers. For many, their migraines stop.

If after 2 months you feel no improvement you may have to look elsewhere for your causal factors.

Watch this space

There is a great deal of information in the public domain about this topic, but as a division of science it would seem to be in its relative infancy, and no doubt we will discover more in the coming years.

References

Broadwell, R., Balin, B., & Salcman, M. (1988, January ). Transcytotic pathway for blood-borne protein through the blood-brain barrier. Neurobiology, 85, 632-636. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC279605/pdf/pnas00254-0341.pdf

Cordain, L. (1999). Cereal Grains: Humanity’s Double-Edged Sword. In A. Simopoulos (Ed.), Evolutionary Aspects of Nutrition and Health, Diet, Exercise, Genetics and Chronic Disease (Vol. 84, pp. 19-73). Basel: Karger.

Evans, B., Griffiths, K., & Morton, M. (1995, November). Inhibition of 5 alpha-reductase in genital skin fibroblasts and prostate tissue by dietary lignans and isoflavonoids. Journal of Endocrinology, 147(2), 295-302. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/7490559

Fluoprobes. (n.d.). France: Interchim. Retrieved from http://www.interchim.fr/ft/M/MS902z.pdf

Gundry, S. R. (2017). The Plant Paradox - The Hidden Dangers in 'Healthy' Foods that cause Disease and Weight Gain. New York: Harper Collins.

Hindiyeh , N., & Aurora, S. (2015). What the Gut Can Teach Us About Migraine. Current Pain Headache Report, 19(7), 33. doi:10.1007/s11916-015-0501-4

Morton, M., Chan, P., Cheng, C., Blacklock, Matos-Ferreira, A., & Abranches-Monteiro, L. (1997, July). Lignans and isoflavonoids in plasma and prostatic fluid in men: Samples from Portugal, Hong Kong, and the United Kingdom. (J. T. Isaacs, Ed.) The Prostate, 32(2), 122-128. doi:10.1002/(SICI)1097-0045(19970701)32:2<122::AID-PROS7>3.0.CO;2-O

Mu, Q., Kirby, J., Reilly, C., & Luo, X. (2017, May). Leaky Gut As a Danger Signal for Autoimmune Diseases. Frontiers in Immunology, 8:598. doi:10.3389/fimmu.2017.00598

Perlmutter, D. (2014). Grain Brain - the Surprising Truth about Wheat, Carbs and Sugar - Your Brain's Silent Killers. London: Hodder and Stroughton.

Peumans, W., & Van Damme, J. (1995). Lectins as Plant Defence Proteins - Update on Plant Defence Proteins. Plant Physiology(109), 347-352.

Rahmoune, H., & Boutrid, N. (2017). Migraine, Celiac Disease and Intestinal Microbiota. Pediatric Neurology Briefs, 31(2). Retrieved from http://dx.doi.org/10.15844/pedneurbriefs-31-2-3

Sigma-Aldrich. (n.d.). Sigma-Aldrich Lectin Index. Retrieved from https://www.sigmaaldrich.com/life-science/metabolomics/enzyme-explorer/lectin-index.html

Tu, A. (1992). Handbook of Natural Toxins: Food Poisoning. CRC Press.

van Hemert, S., Breedveld, A., Rovers, J., Vermeiden, J., Witteman, B., Smits , M., & de Roos, N. (2014, November). Migraine associated with gastrointestinal disorders: review of the literature and clinical implications. Frontiers in Neurology, 21(5), 241. doi:10.3389/fneur.2014.00241

Waran, V. (2014). Lectins: The Next Medical Tool? Kuvempu University, Sahyadri Science College. Shimoga: slideshare.net. Retrieved from https://www.slideshare.net/VigneshWaran16/lectins-slideshow

Weston Price Foundation. (n.d.). Living with Phytic Acid. Retrieved from https://www.westonaprice.org/health-topics/vegetarianism-and-plant-foods/living-with-phytic-acid/