What Is An Anti-Nutrient Anyway? (And Is Modern Paleo Based On Mechanism, Not “Health Outcomes” Evidence?)
One of the things we have made really clear everywhere within this site is the overriding ethos behind Modern Paleo which motivates us to be part of this website and promote the Paleo diet/lifestyle.
As we have regularly heard Robb Wolf, a leader of the Paleo movement from the start, state: the terminology is unfortunate, but the idea that it promotes is always going to be a good one – removal of processed foods and sugars, avoiding highly refined products (from carbs to oils) and limiting inflammatory foods.
Until the last part of this sentence, almost everybody would be behind the concepts. It is the question of what precise foods are deemed inflammatory that seems to garner the most attention, and create the most conflict.
We have referred to the concept of ‘nutrients’ vs. ‘anti-nutrients’ a LOT on this site, because it influences precisely this determination of what can be classed as inflammatory and what cannot. This is basically the underlying mantra behind Modern Paleo: scientifically established nutritional evaluation which contrasts nutrients with anti-nutrients and fills the diet with foods which squarely sit in the ‘high-nutrient’, ‘low-anti-nutrient’ category.
But What Is An Anti-Nutrient?
If you have read any of our All About Pages you will have seen terms such as Lectins, Saponins, Glycoalkaloids and Phytates – and we also reference Salicylates, Histamine and Oxalates. All of these could be considered Anti-Nutrients. But they’re also just ubiquitous plant compounds which can be relatively benign.
In our Modern Paleo world, anti-nutrients are anything that either blocks our access to the usable nutrition within food and/or creates cellular, immune and inflammatory damage upon consumption. Many foods eliminated on a Paleo diet do both.
What Do Anti-Nutrients Do?
(Hand drawn images on this page are extracted from ThePaleoMom.com – simply because she’s the queen of this science and they show mechanism very well…)
Anti-nutrients, in a nutshell (that’s a Lectin in-joke, btw), can cause dysregulation because they have the capacity to interfere with human biology in a variety of ways. Most ofthese anti-nutrients interact with the lining of the gastrointestinal tract because they are capable of binding to the cells which surround the gastrointestinal tract. By binding to these cells, anti-nutrients can create cell damage, cause intestinal permeability and thereby trigger immune system involvement. Alternatively they can directly interfere with the open/close function of the tight junctions of the gut – keeping these little gaps open too long which allows molecules through the gut, also triggering immune system activity. And lastly, anti-nutrients can make the breakdown of food difficult through a host of mechanisms. This results in improper digestion and, if serious enough, can also contribute to an overall inflammatory and immune burden.
Anti-nutrients are so-called because they do not give nutrition to those consuming them. The anti-nutrients listed above are what make certain these plants indigestible and undesirable to humans and other animals. The anti-nutrients in the outer walls of seeds or cases of beans mean that the nutrients inside move through digestive systems largely intact. In the animal kingdom, these seeds and skins would be excreted whole into soils, thereby spreading the genes of these plants.
In humans, this obviously does not happen. However, the plant protection mechanisms remain. Anything that moves through digestive systems intact is a relatively poor source of nutrients because the inner contents (where the protein, carbs and fats that we can use for energy and health are) are inaccessible, sometimes referred to as having low ‘bioavailability’. Different anti-nutrients resist digestion in a slightly different way. By being slightly poisonous and toxic, animals are put off eating these plants because of the effects they can have on them – everything from nausea and vomiting to neurological and cellular issues.
In the animal kingdom these would be strictly avoided. As humans we have strived to make these foods digestible for many reasons, using cooking/soaking/heating/sprouting/milling/fermenting etc. to render previously indigestible compounds less toxic to the human body. Many would argue that whilst we will therefore not die from eating these products (many beans are poisonous raw) we are merely ‘coping’ with their consumption, rather than thriving on it.
For us here at Paleo In The UK, and for those advocating the Modern Paleo-style approach, it is the immune system and inflammation involvement that we are keen to avoid. Cell damage and/or disruption in the gastrointestinal tract can create localised inflammation and, through the immune tissue immediately surrounding the GI tract, an up-regulation of immune alertness. Intestinal Permeability is a state in which particles which should be kept inside the gut are able to cross the gut barrier, and this is interpreted as invasion of antigens by the immune system. (Doubt the science of Intestinal Permeability? Our founder, Victoria, did a withering take-down of sceptics of this concept in a recent blog article.)
In the human body, things being where they shouldn’t be become immune targets. In a state of an immune flare, inflammation is the result. And inflammation is the bedrock of many chronic diseases – linked to everything from heart disease, to diabetes, obesity, metabolic syndrome, neuro-degeneration, anxiety, depression and other mental health conditions and autoimmune conditions, which span the gamut of health concerns from hypothyroidism to Multiple Sclerosis and beyond.
It is universally recognised that inflammation has a Goldilocks zone, as do many elements of health. A little is good, short bursts of a lot are well managed and responded to by our bodies. A LOT of inflammation or chronic, underlying, long-term inflammatory states contribute to – and sometimes cause – poorer health outcomes overall.
Now, we will freely admit that not all anti-nutrients are created equal. Moreover, not all plant products contain the same level of anti-nutrients. And – most importantly – not all people respond to anti-nutrients in the same way. But you also have some people insisting that anti-nutrients aren’t really a ‘thing’ at all, rendering the Paleo ethos complete nonsense.
Mechanism vs. Real-Life Outcomes: a Primary Criticism of the Anti-Nutrient Concept
The reason that people challenge the concept of anti-nutrients is because of the data that we have available about their effects. No-one doubts the biology of the plant, and relatively few will refute the science of the impact of certain plant lectins on the cells of the gut lining – and their ability to move systemically throughout the bloodstream.
In our All About Nightshades page we explain how tomato saponin has been found to cross the gut barrier and interfere with lymphocytes in humans and lectins in hot spices influence permeability of the human intestinal gut lining. In our All About Gluten page you will read the extensive science about the role of wheat lectins in creating intestinal permeability and systemic inflammation (irrespective of diagnosed coeliac disease in which the mechanism of gluten’s impact is very different). In our All About Potatoes page you’ll discover that glycoalkaloids can act like soap eroding the surface of cells and creating permeability in the intestines with inflammatory and immune effects. In our All About Legumes page we share the research behind a host of different beans and pulses, discussing the various anti-nutrient and toxic components of this plant family and how they interfere with digestion, potentially causing both inflammatory responses and also malnutrition. And we even have a whole page on Phytates which discusses this other anti-nutrient and how it can interrupt the absorption of minerals from the food.
You’d be forgiven for thinking that with this host of science, the elimination of plant anti-nutrients from the diets would be uncontroversial for those who care about nutrient absorption, digestibility, bioavailability and inflammation. The criticism, however, is that all of the data here is mechanistic. By this it means that we have established the mechanism of action and the potential consequences of the consumption of these plant foods. However, such mechanistic data has not been conclusively linked to poorer health outcomes, overall. In fact, many studies which take epidemiological data regarding the healthiest diets often include whole grains and legumes in particular – two food groups notoriously high in what the Paleo community would call anti-nutrients.
It’s difficult to rebut the assertion that all of the data is mechanistic evidence. Because, quite frankly, a lot of it is. Real randomised controlled trials about whole dietary styles can be conducted, though it’s expensive and tricky. Epidemiological studies occasionally have to do, in which populations are studied retrospectively, using notoriously unreliable self-reporting. It makes truly understanding the impact of certain foods very challenging. Because no food is eaten in isolation, we struggle to divorce individual effects from the impact of the overall balance of the diet.
This has been true of many ‘meat’ studies, which link red meat consumption to all manner of complicated health outcomes, from heart disease to bowel cancer. The reality is that ‘red meat’ isn’t just one thing. It matters what meat we’re discussing (red meat includes a host of animals, not just cows). It matters what that meat has been fed, how long it has lived, the environment in which it lived (i.e. free to roam or caged in a factory). It matters what CUT of meat you use. And most importantly, it matters what the rest of the diet contains, how much of the meat is consumed and how frequently. It is also important to assess the balance of fats, fibres, proteins, carbohydrates… and basically everything else that ISN’T the food in question.
So when it comes to science, sometimes mechanism is actually the perfect tool to understand the biological impact of a single food. Doing the complex, multi-faceted nutritional analysis proves ultimately far too complicated – because if we’re really going to crown the Mediterranean diet the “King Of Diets” (which many do), we also have to assess whether this is just in the Mediterranean where climate, sleep, socialisation and stress levels are fairly optimal (and protein is used sparingly, with fasting entered into regularly as part of religion or habit). Or is this the Mediterranean Diet as consumed by the CEO doing CrossFit 6 times a week and training for an Ultra-Marathon? Are the health outcomes the same?
We doubt it.
It’s not that mechanistic studies are the best data… it’s just that understanding mechanism helps us to personalise nutritional intake. This doesn’t mean that mechanisms can prove a detrimental health outcome. It just means that if you understand your current health picture and how many stressors you are currently under you can gauge how many additional stressors or things to deal with you literally pile onto your plate. The mechanistic data is not enough to suggest that in all people, all the time, negative health consequences occur as a result of eating foods high in anti-nutrients.
Instead, it illuminates how our biology interacts with certain compounds of the plant world and the demands that digesting certain foods place on the human body. In understanding this we can make a decision: are you in a place and a state of health in which the more ‘challenging’ foods (i.e. those with anti-nutrients) are going to present a stress to your body and your immune system which may contribute to an inflammation burden and, either immediately or somewhere down the line, contribute to poorer health outcomes?
And when it comes to trials and studies of longer-term health outcomes, it is the multiple-intervention studies that interest us here at Paleo In The UK. This is becoming more popular because science is starting to recognise that studying things in vacuums isn’t applicable to real life. So instead of using JUST diet, we have emerging evidence that a whole Autoimmune Protocol (including diet and lifestyle advice) has shown improvements in Inflammatory Bowel Disease. Additionally, The Wahl’s Protocol (again utilising nutritional tools as well as lifestyle, meditation and mindfulness tips) is demonstrating success with Multiple Sclerosis cases. Lastly, the multi-intervention model from Dr Dale Bredesen is revealing both mechanisms AND solutions for neurodegenerative disease such as Alzheimer’s.
How To Decide For Yourself
These studies’ success where single-intervention drug studies have failed proves that changing one thing is not sufficient. But they are extreme. They include and promote whole life changes which affect overall disease progression. At least two of the above strategies choose to eliminate anti-nutrient containing foods – but not just because of their anti-nutrient quantity. It’s more a choice which selects more nutrient-dense sources of bioavailable nutrition. Evaluated on this scale, the legumes and grains will lose out every time.
The problem with multiple interventions is that we cannot establish whether it is the removal of anti-nutrients, the inclusion of high amounts of vegetable matter, fibrous foods, fermented foods, the change in meat sourcing or all of the lifestyle measures and supplementation with vitamins such as vitamin D which makes the difference.
There is no doubt that the Paleo and AIP interventions are coming from the ‘better safe than sorry’ point of view. But when it comes to healthcare, sometimes being prudent is the best approach.
We will always state that your susceptibility to anti-nutrients is going to be based on your individual point of health and resilience at each moment in time. Some people cope well with legumes, nightshade vegetables and grains and the mechanisms demonstrated by the data have no overtly damaging effects. Others visibly notice the difference in their health symptoms when they consume foods containing anti-nutrients. That’s why the Paleo Template is a customisable baseline from which individuality can be established: because no two people are the same.
The bedrock of Paleo is nutrient density, and we can only eat so much food in the day. If you are aiming to have a nutrient dense diet, the simple lack of bioavailable nutrition from the plants and grains which contain anti-nutrients is enough to mean that these foods should not be a dietary staple. Depending on your point of view – even if you believe that foods high in anti-nutrients may not directly lead to poorer health outcomes overall, you cannot doubt that foods higher in nutrients will always lead to better overall health outcomes. Faced with the choice between protein sources and carbohydrate sources it becomes a question of what are you going to choose to include. In this dietary evaluation the animal proteins and vegetable (as opposed to grain) carbohydrates will always be superior. (Do click on this link, it’s an amazing Chris Kresser video on nutrient density of a variety of foods… including organ meats and herbs and spices… all the way through to grains.)