Wading into the world of gluten is absolutely necessary in any discussion of a Paleo diet. Moreover, in the UK it feels a bit like starting a fight with wheat vigilantes every time you mention that bread isn’t a health food.
Perhaps highlighting how complex and nuanced these arguments are, in the sentence above we have mentioned three different words which are often used interchangeably, though they all describe a slightly different thing. Wheat, gluten, bread – they’re complicated. We’re going to try here to break down the history, the science, the nutrients and the issues…
The Hunter-Gatherer Diet Debate
This is a hot, inconclusive, topic. Grains have been consumed for millennia. Not everywhere, not all grains, not grains in the way we grow, harvest and process them today… but yes, certainly, grains were capable of being harvested centuries ago. Until we had heat we couldn’t do much with them (and therein lies a clue to their digestibility, given that they need to be changed by heat to render them edible) but as soon as we knew how to it seems we were incorporating grains into our nutrition.
As you may already of read, however, we do not approach Paleo with the hope of recreating a perfectly ancestral diet. Our Paleo approach is one of understanding the evolution of humans compared with the evolution of the food environment, and examining the metabolic and biochemical impact of each modern food on our modern bodies. When looking at modern wheat, gluten and bread – what is the impact of these on our human forms – and does gluten, in whatever form, carry more nutrients that anti-nutrients – a key tenet for inclusion on a Paleo or AIP diet? This article will help to explain.
What Is Wheat?
Wheat is a grain crop, it grows in large fields and has many parts to each grain, including an outside husk and an inner seed which contains many nutrients such as B Vitamins and is quite fibrous. Wheat contains lectins, phytates, prolamins, agglutinins etc. (all commonly called “anti-nutrients”) … and it also contains gluten. Gluten is just one of the proteins in grains of wheat (which is also present in barley and rye). Gluten has become a target for those working in modern nutrition – tied not only to the autoimmune disease which it causes (coeliac disease) but with countless other poor health outcomes.
But why? What is it about gluten? What is gluten, exactly? Do we really react so badly if we’re not coeliac (i.e. with an autoimmune disease triggered by consuming gluten)? Should we believe those who tell us gluten is the stuff of the devil? Or should we trust those who say it’s perfectly harmless and a great source of fibre and nutrition?
To understand the truth behind this requires a lengthy explanation of two things: firstly, the mechanism of interaction of gluten with the human digestive system. Secondly, the contexts in which this interaction is problematic.
If you want to stop reading here, the most important thing for you to understand is that, as with most areas of nutritional science, the conflict mainly arises when mechanisms are evaluated out of context and applied generally instead of specifically. We have found that, mostly, people fight about truth because they are attempting to arrive at universal principles. As with all things that we here at Paleo in the UK promote: the impact of gluten is entirely individual.
But let us first begin with the mechanism:
GLUTEN – WHAT IT IS AND WHAT IT DOES INSIDE US
Gluten is actually made up of two smaller proteins, almost ‘weaved’ together. These proteins are called gliadin and glutenin.
The human digestive system works on proteins by breaking them down, with the use of enzymes, to produce individual amino acids. These amino acids can be transported across the wall of the intestines and utilised by the body for its required processes (building blocks of muscle, tissue, neurotransmitters etc.).
Where gluten stands out, and why it attracts so much attention from those interested in digestive mechanisms, is because the enzymes of the human digestive system are only capable of partially breaking down gluten. The reason behind this is because there is a lot of proline in gluten, linked together. Proline is a single amino acid and our enzymes struggle to break down the links between adjacent proline amino acids. Whilst we can chop the long chain of amino acids called ‘gluten’ into smaller strings of amino acids – that’s where our processing of the gluten ends.
The result in our intestines is, rather than individual amino acids, a selection of smaller amino acid strands called gluten ‘peptides’ which are also numbered according to their lengths (a full list is not required for our purposes, but if you’ve ever read a Cyrex gluten panel – the different items being tested are all the different strands leftover from breaking down gluten, coupled with associated enzymes). It must also be noted here that we break down gluten in fairly uniform, regular and familiar ways – so we do it the same every time.
The above ‘incomplete’ breakdown occurs in absolutely every person who consumes wheat and gluten. Everybody ends up with these varying lengths of peptide fragments floating around.
Some of the most notable peptides are the gliadins. Gliadin fragments could be seen as manipulative, in that certain gliadins are able to exert specific actions on the cells lining the intestinal tract. Some gliadin fragments bind to intestinal cells and damage them slightly, changing their barrier function. This allows transport of the gliadin through these cells into the circulation on the other side of the intestinal wall. From there, the gliadin is free to circulate throughout the body.
A more commonly discussed mechanism is that of gliadin increasing the production of something called zonulin.
Zonulin is a protein released internally (from human cells) when a specific sized gliadin protein strand comes into contact with the cells lining the gut.
The gliadin fragment does this by binding to the receptor sites of gut cells called chemokine receptor type 3. (CXCR3) The name is not important, but the function is. The gliadin displaces an inflammatory cell from the CXCR3 – and in a cascade reaction this chemokine receptor attracts T cells (more immune cells) to the site and signals for the cell to release Zonulin.
The mechanism is perhaps scientific, but it has been elucidated nicely by Alessio Fasano et al in research literature.
The most important thing to understand as someone contemplating gluten’s role in the body is to grasp what increased Zonulin levels means.
Zonulin’s role within the body is to open up what are known as ‘tight junctions’ throughout the GI tract. It is SUPPOSED TO DO THIS. Zonulin is absolutely necessary for the absorption of nutrients across the gut barrier. This is actually one of the mechanisms of how we absorb specific nutrients from food. The rapid opening and closing mechanism of tight junctions in the GI tract, regulated by zonulin, is a fundamental part of human physiology.
The problem occurs when something – in this case gliadin fragments – stimulates zonulin release even without the presence of a nutrient that needs absorbing. Gliadin has been shown to increase both the length of time tight junctions are left ‘open’ and also how wide the gap becomes.
Tight junctions are supposed to securely let only certain nutrients through, but the presence of zonulin changes the flux of the GI tract, setting up molecule superhighways flowing out of the GI tract right into our Gut Associated Lymphatic Tissue, or GALT, and into the bloodstream. GALT is the sentry point through which nutrition must pass. Anything that comes into contact with the GALT is presented to the immune system and evaluated for threat level.
In the case of Intestinal Permeability (the scientific name for the process explained above) so many molecules pass through the tight junctions into the GALT that the immune system is stimulated into action. A cascade of immune attacks are put in process against the molecules it has ‘seen’ due to their introduction into the GALT. Disturbing the fine balance of what is allowed past the gut barrier and what is kept inside the GI tract is the start of a dangerous interaction with GALT which very quickly leads to systemic issues such as inflammation, multiple food sensitivities, bacterial dysbiosis and more…
Initially the inflammation is largely localised (i.e. gut-centred). However, once it has begun, inflammation can become a body-wide state – with evidence to suggest that the gut barrier and the blood brain barrier are highly alike in structure and susceptibility to threat. Neuroinflammation (i.e. brain inflammation) is being studied in association with the progression of Intestinal Permeability which leads to systemic inflammation.
Beyond the body-wide inflammation, the immune system is easily dysregulated when faced with the bombardment of molecules that occurs when Intestinal Permeability is in action. Designed to protect us above all things, the adaptive immune system ‘learns’ the strings or shapes of molecules that it sees and tags them as ‘potential threats’. There is great similarity between many food proteins, but also between some of our own organ or joint tissues and the proteins, amino acid strings or molecule shapes that the immune system has seen cross from the gut.
The result is that the immune system may create antibodies not only to the particles of food that are traversing the gut barrier, but also make antibodies to the body’s own tissues. This is autoimmunity, or self-attack.
The tissues targeted in self-attack can include, but are not limited to, thyroid tissue, myelin (wrapping around the nerves in your body and also your brain), brain tissue itself, joints, lungs, liver, GI tract – and on, and on…. Some reactions are more common than others, with thyroid autoimmunity commonly associated due to thyroid tissue’s similarity to gluten proteins themselves. But suffice it to say gluten stimulates production of Zonulin which leads to increased Intestinal Permeability… and from there, the rest of the results can be anyone’s guess and will depend heavily on both genetics and the current health status – immune system, inflammation levels, nutrient status etc.
Beyond just the Zonulin interaction, other gliadin fragments can be toxic to the gut enterocytes themselves, basically changing their function from the inside out and forcing them to die. Rather than manipulate the cells, this is simply killing cells which also has the net effect of creating intestinal impairment. A secondary impact of this is that the cells of the gut are designed to help us absorb nutrients. Any loss of these cells can cause nutrient deficiencies.
It must be stressed here that there are genetic factors which determine sensitivity to gliadin/Zonulin interactions, just as there are genes which predispose for coeliac disease itself. And yet Zonulin fragments have been found in the blood of those who do not carry any genetic predisposition for sensitivity. Why? Because gluten splits into gliadin and can then work to promote zonulin release – in absolutely everyone.
But let us be very real. How badly you react, how affected you are and how quickly you heal from this gliadin-induced ‘permeability’ is mostly genetically determined, as far as we currently know. This means that the mechanism is fairly well validated, but the consequences depend on each individual’s context.
Beyond simple genetics, other factors are fundamental to the repair and strength of the gut barrier. Nutrient status is important because retaining cellular and barrier function integrity requires nutrients such as B Vitamins, zinc (mostly zinc – there’s some intriguing research on how this can tighten tight junctions), short chain fatty acids etc. Additionally, the ability to withstand the Zonulin-mediated permeability has a lot to do with what else your body is currently having to do – fight infections, deal with huge stress at work or in relationships, if you are pregnant, over-exercising (this one particularly causes intestinal issues) under-rested etc. Our ability to tolerate gluten is dependent on many factors – and yet…
The mechanism is not in question.
Which brings us back to the basic tenet of modern Paleo, as we here at Paleo in the UK are framing it. This means – does this foodstuff contain more nutrients than anti nutrients? Thus far, you may have thought that we have made some fairly conclusive arguments that it is mostly harmful… but the case against wheat doesn’t end with gliadin.
Wheat – and notice we say ‘wheat’ here, rather than gluten, because gluten is just ONE of the issues within the wheat grains – along with practically every form of life, contains lectins. Lectins get a lot of attention because some people claim they are the stuff of the devil. Others laugh at the suggestion simply because they are so prolific – and how can anything that is found in literally everything be damaging?!
Lectins are simply carbohydrate-binding proteins and are found EVERYWHERE. And yes, we agree, dismissing wheat because it contains something that is ubiquitous in all forms of life does seem idiotic.
This is why those who are mindful of the anti-nutrient components of wheat (and many other foods) attempt to distinguish between lectins and toxic lectins. What makes certain lectins ‘anti-nutrients’ (i.e. something that takes away from the health of the body) is that they are difficult to digest. What makes certain lectins ‘toxic’ is because their digestibility is challenging enough to the human digestive tract that they have been clinically demonstrated to interact with the brush border enzymes of our gastrointestinal tracts in a negative and damage-causing way.
Still, the word “toxic” is (to our eyes at least) a touch misleading. Lectins aren’t toxic in the way that arsenic is. In only a small percentage of individuals does the damage from ingesting lectins shows up visibly and noticeably. Instead, toxic lectins have a reputation for slower impacts, gradually taking their effect over years, sometimes decades.
The science really breaking down the nitty-gritty on wheat lectins can be found in Sarah Ballantyne’s bible of Paleo/Autoimmune Science, “The Paleo Approach” (pages 91-103). The fact that she takes over 10 pages to explain the multiple interactions these lectins can have on the gut and the immune system is, in itself, indicative of the complexity. More data can also be found in the recent book The Plant Paradox by Dr Stephen Gundry, a leading cardiologist who has made it his mission to spread the words about the poisons in plants (be aware, this is a VERY anti-lectin read).
But here we want to point to one lectin which is most studied in the scientific literature – and not solely by the anti-wheat contingent. That lectin is called Wheat Germ Agglutinin (WGA).
WGA is difficult to digest, cannot be broken down by the acidity in the stomach or by denaturing grains through soaking, sprouting or cooking processes – even at high temperatures. Whilst WGA is not directly toxic to gut cells themselves (as gliadin is, see above) it does interact with the brush border enzymes and increases Intestinal Permeability.
Once across the gut barrier WGA has been demonstrated to seriously aggravate the immune system and, even at low concentrations, stimulate cytokine release (basically WGA cues inflammation to occur). Wheat Germ Agglutinin in compromised individuals has been found at high concentrations extra-intestinally. This means it gets everywhere – even into the peripheral blood supply. It’s toxic, it’s not great for us… and it gets where it shouldn’t be. I’ve included full references below where you can read the studies on WGA and how impactful it can be to many health outcomes.
But if you have read anything on this site thus far you will know that we like to be fair in our assessment of the science.
As far as we are concerned, the whole point about lectins – not just in gluten but also in many grains – is that they are dose specific: i.e. a little is probably fine but too much becomes seriously problematic. This means that once again, how much is too much will be an utterly personal thing – with those in robust health and without genetic predispositions possibly coping better with all lectins than others. But it must be considered that lectins are carbohydrate-binding proteins, which means they are literally within the plants to bind the energy present within them and stop that energy being broken down and utilised. They are toxic to animals (which includes humans) because they are basically the plants’ protection mechanisms. They’re literally designed to make eating foods difficult and digesting foods hard.
Before we branch right out into all lectin-containing foods (and there are many!) let us return to gluten. Based on the lectin content and the Zonulin action, gluten and wheat land up in the ‘more anti-nutrient than nutrient’ category. If a food contains peptides which can destroy your intestinal lining and proteins which are there precisely to stop the nutrients being available we are pretty clear that human consumption is less than ideal and, in many cases, positively damaging.
But there are more factors against gluten and wheat, such as Phytates and Saponins (we have written about these in more depth in our Potatoes and Legumes articles). But wheat is really complicated – much more complicated than its constituent parts. We don’t just eat ‘gluten’ and we don’t just eat lectins – we consume these as foods. Lectins are found in many foods, from legumes, seeds, grains and pseudo-grains to nightshade vegetables like tomatoes and potatoes.
The lectin, saponin, phytate, agglutinin contents of all grains and pseudo-grains is what excludes them from a Paleo Diet. These grains and pseudo-grains require COOKING because their anti-nutrients need to be denatured in some way. Modern sciences shows us that even with modern cooking methods our current human bodies are not well suited to digesting, assimilating and being healthy whilst consuming these foods.
IS IT JUST MODERN WHEAT?
But talking of modern science and modern bodies – is it just the modern breads we try to consume which are causing us such issues?
Obviously, bread is not just gluten. Nor is it just wheat. Depending on the manufacturing method and the flour used, bread can contain a whole host of other ingredients and additives, from the fairly innocuous ‘yeast’, ‘water’ and ‘salt’ (functionally necessary) to a host of preservatives, alternative leavening agents, bleaches and stabilisers. All of these latter ingredients are a requirement of mass production and industrialisation – and the factory/supermarket necessity to provide a basic, carbohydrate staple for large populations.
Conventional, supermarket, mass-produced loaves of bread may contain so many artificial extra ingredients that they are in no way low in anti-nutrients. But what about ancient wheat grains? If Palaeolithic ancestors ate grains (as they likely did in some areas) is the modern wheat different? Is it all the genetically modified grains’ fault? Is it all to do with pesticides…? Is it actually true that ancient wheat contained less gluten?
And what of the evolutionary truth that we have evolved to possess an enzyme called amylase in high quantities which is specifically designed to break down starches? Some anthropologists cite this as evidence that we, as humans, have evolved alongside a grain-heavy environment and are now eminently capable of digesting it – indeed they state that this means we’re supposed to use wheat as a staple food.
These arguments have a grain of truth (excuse the pun!). Ancient grains are likely to have been entirely different to the modern, homogenised wheat species we grow today. Agricultural crops have been bred to make money, not to create nutritional value. Hybridised and/or mono-cropping of wheat is a real contributor to the ‘is modern wheat healthy?’ debate. It is suspected that we have actually bred wheat richer in the anti-nutrients mentioned above through the practices of trying to create hardier, more robust crops (which would make sense – more robust crops require stronger ‘plant protection mechanisms’, the parts that are toxic to humans).
If you want to understand more about the modern wheat growing practices, the documentary to watch is “What’s With Wheat?”
But we’ve been hybridising plants for centuries. Mono-cropping can’t change the wheat that much, can it?
Well, whether it’s the mono-cropping, the intensive production or the hybridised nature of ‘modern wheat’ there is undoubtedly a difference between ancient forms of wheat and modern wheats when they’re analysed in laboratory settings. What difference does this make to the human GI tract?
To understand this, we have to go all the way back to the enzymatic splicing of gluten into strands of component amino acid chains. Remember we mentioned that the resulting strands were quite formulaic and always similar?
It turns out that there is a high likelihood that ancient grains of wheat may have been spliced in a slightly different way. This means that it is actually untrue to say that there is less gluten in ancient wheat. Instead, the ancient grains’ gluten looks like it is broken down into less of the problematic gliadin fragments. The cuts are made in different places, leaving less of the really harmful peptides and resulting in less intestinal permeability, gut enterocyte death etc.
But there are more factors at play here, and to appease the genealogists who may play off the ‘evolved amylase gene’ argument we must cover the enzyme angle. Wheat actually contains what are known as digestive enzyme inhibitors, and in wheat specifically there are particularly high levels of amylase trypsin inhibitors. As the name suggests, these enzyme inhibitors actually block our production of an enzyme called trypsin which is made in the pancreas to break down protein. These inhibitors also block our production of amylase in the saliva and pancreas which would break down starches. On top of their inhibitive functions, these digestive enzyme inhibitors have been shown to cause gut inflammation in and of themselves.
Here is where the modern mono-cropping comes into play. There are approximately 100 times more digestive enzyme inhibitors in modern wheat than there is in either ancient wheat or gluten free grains or pseudo-grains.
CONCLUDING ON GLUTEN
So gluten increases Zonulin which increases gut permeability and creates systemic inflammation and immune dysregulation. It also contains lectins which are basically poisons to the digestive tract. It also contains digestive enzyme inhibitors in vast quantities which limit our ability to digest not only starch but protein. Many of the components of wheat are both inflammatory in and of themselves – and also cause inflammation…
Even after all of this is explained you will still encounter those in the ‘real world’ who will challenge and counter everything listed above – claiming a superior or at least benign nutrient profile for the wheat, flour and bread they consume. Defenders of gluten will cite that bread is rich in a host of B vitamins and also contains protein. And of course, they are absolutely correct – and (like potatoes) bread is not a nutrient-poor food, especially if fortified.
But basically all that these people are demonstrating is an ability to read a nutritional label. They are not demonstrating any ability to understand the complete picture of how food is digested and dealt with by the human body.
When these ‘nutrient rich’ proteins and vitamins are packaged alongside (or inside) something which also contains the ‘anti-nutrients’ listed above, there are strong arguments that gluten is not just benign. To many, it can be positively unhealthy. Those who say gluten is not worth worrying about are simply not looking at all of the available data. That said, those who say gluten is indigestible and will wreak havoc for all are also being a tad extreme.
Ultimately, we all have very individual digestive and immune systems and we all have different genetic predispositions. Even for those who choose a Paleo approach out of preference and a desire to feel optimally healthy, consuming the occasional gluten-containing product may prove completely harmless. Much like with alcohol the ‘wriggle room’ afforded by overall healthy practices might mean that your body is perfectly equipped to handle gluten. (Which, by the way, means that all of the above affects you but that you are deftly able to eliminate any toxins, heal any damage and carry on absolutely unscathed).
And yet for so many others gluten, grains and pseudo grains present real challenges to their bodies. Any vulnerability or preexisting health issue may compromise the capacity to digest, excrete and heal any damage caused by the anti-nutrients in these grains. Additionally, almost all illnesses are exacerbated by inflammation. The mere fact that, in many ways, the consumption of wheat can cause and worsen inflammation is another reason why those who are not completely strong would be wise to avoid these substances.
If you embark upon a Paleo journey, will you be completely unable to have a gluten-containing grain for the rest of your life? That very much depends on your bio-individuality, where you start from, the amount of healing you can do and how far you can build a robust, resilient and healthy body – not just digestively but in terms of lymph flow, liver detoxification, nervous system resilience and hormonal and immune balance.
Where you begin your Paleo (or AIP) journey is never where you end up. There is a great difference between diet as a therapeutic intervention and diet as a lifestyle choice based in safeguarding longevity and health. Therapeutically, gluten is never going to be a health food. AFTER the initial phases and in the scheme of a lifelong nutritional intake the consumption of some, properly prepared and well-cooked gluten-containing grain may be entirely healthy.
The route to being robust enough to trial how well you tolerate certain ‘off-limits’ foods (including gluten) is through the strengthening of your body and all of its systems. This strengthening is the entire point and purpose – and the inevitable outcome – of following the therapeutic intervention of the baseline dietary templates advocated on Paleo or AIP.