Much like other plant compounds discussed in the foods highlighted in our “All About” pages, Phytates are perfectly naturally found in plants – both those that we eat, and those that we do not.
When we are talking about ‘Phytates’ we are referring to the stored form of phosphorous (phytic acid) in a plant, chemically bound to a mineral. Phytic acid is stored in whole grains, legumes, pseudo-grains, nuts and seeds – but it is also stored in roots, tubers and most vegetables, though typically in smaller amounts. It is essential to grasp that Phytate content in vegetables is simply a natural part of how plants grow and survive. The binding up of phosphorous with a mineral to create the Phytate (which is known as a salt) is part of how nature allows plants to store and create energy and positively charge ions which allow for multiple chemical reactions to take place within the plant itself. The plants depend on Phytates for their growth and survival.
Unlike other plant compounds, Phytates are less of a direct problem and more a cause for concern because they are salts made by phytic acid BINDING to other minerals within the plants. The minerals bound to are magnesium, calcium, iron, potassium and zinc. The argument is that the binding of these nutrients within the plants makes them NOT bioavailable to humans (non-ruminant animals who lack the enzyme to break down Phytates). This is what gives Phytate its ‘anti-nutrient’ status – because it can render foods less nutritious, when they would otherwise be thought of as nutrient-dense.
The Hunter-Gatherer Diet Debate
If everything we know about biochemistry is correct (and there’s no reason to assume it’s not), hunter-gatherers lacked the enzyme to break down Phytates just as we do. This means that they will undoubtedly have consumed Phytates in every vegetable that they consumed (see above, Phytates are everywhere). However, as you will have grasped from many locations on this website, the ancestral diet was NOT based on the grains, legumes, pseudo-grains and seeds which are richest in Phytates. The reason for this was probably not choice – it was to do with preparation methods.
Consuming uncooked and unprocessed/ground/soaked (etc.) grains, seeds, pseudo-grains and legumes would result in massive gastrointestinal distress and – at an extreme – poisoning and death. These foods were not able to be eaten raw and unprocessed in some way. This, by default, means that until we had discovered fire and began to evolve our diet by manipulating the state in which we consumed the grain and seed foods, nobody would eat them.
So whilst it is absolutely certain that hunter-gatherers would have consumed Phytates in certain quantities, they were not doing so at anywhere near the volume that we would consider eating them today.
The Modern Phytate
The key feature of the modern diet, distinguishing it from the more ancestral template, is the reliance on grains, seeds, pseudo-grains and (in some cultures and geographical areas) legumes. These are all foods that have only been consumed since we discovered how to render them digestible. And yet being able to digest them without them poisoning us and/or creating massive gastrointestinal symptoms does not mean that we are thriving with the inclusion of them in our diet – or that they are consumed without consequences.
The Phytate is held within the outer husk (the outer layer) or the bran of grains and seeds and in the protein-containing outer layer of legumes. The densest sources of these so-called ‘anti-nutrients’ are, therefore, whole grains (which include the husk) and legumes themselves (where you always eat the protein-containing layer).
When you read about Phytates you may be led to believe that the Phytate within these grain- and seed- based foods will bind to minerals inside your digestive tract and remove them from the human body. Erroneous claims are that Phytates will deplete your body of vital minerals because it can bind to them and leech them from your system. This is utter nonsense.
The whole point of consuming Phytates within food is that the phytic acid is already bound – that’s what makes it Phytate. We, as humans, cannot break down the bonds of Phytates so we cannot liberate the minerals that the plants have bound TO the phytic acid. It is in no way true that there is loose phytic acid circulating in the body and binding up any minerals that we need to survive. The phytic acid simply can’t bind to anything else inside us because it’s already bound to a mineral to make Phytate.
In some ways, it’s a blessing that we cannot break that bond…
But in other ways, that is the entire issue with Phytates – we can’t break that bond and access the mineral content of the plant/grain/seed/legume. Eating a nutrient-dense food when all of the nutrients are bound and unaccessible is not a good way to attempt to get nourishment.
To be fair to us humans, we have found a way to access some of the minerals bound by phytic acid. Our microbiome bacteria have been demonstrated to have a certain ability to break down the Phytate – but this seems to be limited. It is postulated that this limit may be why nut consumption – cited as very healthy in almost all circles – only demonstrates benefits up to around 20 grams per day. More than this and the ability to break down and access the beneficial nutrients of nuts seems to be impaired.
For Modern Paleo templates, Phytates are not banned because we would have to then ban all vegetables – and it certainly seems as if, in smaller amounts, we are able to cope with the consumption of Phytates within foods. However, Phytates are just one (of many) reasons why the Modern Paleo recommendation is to steer clear of grains, pseudo-grains and legumes – basically preferring the consumption of other, more nutrient-dense foods – with more bioavailable sources of nutrients.
The Vegetarian and Vegan – Nutritional Deficiencies when Eating Vegetables
Frank nutrient deficiencies due to eating Phytates are unlikely if the diet is broad enough to contain high amounts of the minerals that the phytic acid binds to. However, if a diet is based entirely on cereals, grains, seeds and legumes (i.e. veganism) it is actually quite easy to see where nutritional deficiencies can arise. Whilst on paper the nutrient profile of the legumes/grains etc. may look adequate, it is possible that in practice most of the micronutrients are supposed to be coming from phytic acid-containing foods. This means that those ‘on paper’ nutrients are not available to the human body, in practice.
Other Phytate Complications
If the mineral-binding property of Phytates was the only concern, it possibly wouldn’t factor into the considerations of an overall healthy, nutrient-dense diet. The recommendation would be made to simply ensure that you get enough other sources of micronutrients but that consuming Phytate-laden foods was not too terrible.
And yet, Phytates don’t just bind nutrients – they appear to limit the production and activity of digestive enzymes such as trypsin, pepsin, amylase and glucosidase. If digestive enzyme activity is inhibited by Phytates this creates ongoing digestive issues. Firstly, incomplete digestion means that more ‘intact’ foodstuffs leave the stomach and upper small intestine – delivering more whole foods to the gut bacteria, which contributes to a proliferation of bacteria and bacterial overgrowth.
Secondly, inhibiting enzyme activity will be felt by the body. This will stimulate the pancreas to produce even more of the digestive enzymes which it believes are not being effective. This can ultimately have the net effect of breaking down the gut lining – because those enzymes are designed to break down the cellular structure of foods (fats and proteins in particular) and can, in excess, work to break down the epithelial cells of the human body.
But, to be honest, we at Paleo in the UK think that all of this is incredibly extreme.
As with many things in the diet (and in life, for that matter) – the dose makes the poison. It is very important to consider overall health before determining that Phytates are an issue. Phytates are everywhere – and in some of the most favourite Paleo foods such as nuts and seeds. In someone with impaired gut health, autoimmunity and/or dysbiosis, Phytates may exacerbate any health issues and you may wish to reduce or avoid consumption of them. And yet, in someone with robust digestion, Phytates are not going to be an anti-nutrient that will see you having to rule all Phytate-containing foods out of your diet.
Speaking frankly, the Phytate content of the grains, pseudo-grains and legumes are just one of the complications with them.
Human evolution – the development of the brain, of self-reflected consciousness and of the innovations of industry, agriculture and technology – was possible only because we found more food to eat. We didn’t miraculously invent that food – we invented the ways to make edible the food that we had already found. Ancestral diets did not contain grains because they didn’t know how to do so without dying. Modern man does…
This is why we at Paleo in the UK aren’t adamant about the diet we recommend containing only foods eaten by our ancient ancestors – because that would imply we have not evolved at all. Processing foods to make them edible is, quite simply, fundamental to the progression of the human species.
And yet, if you are going to choose the foods that make the human body thrive, rather than just survive, it is appropriate to seek foods that make the body replete with nutrients used in basic survival – and to do so in as digestively and biochemically suitable way as possible.
In this picture, Phytates in grains, seeds, nuts, legumes and pseudo-grains simply make it much more difficult to be nourished using these foods. In a diet built on creating the path of least resistance to obtain human health and vitality, Phytates are not a foundational piece. Instead, whilst in normal doses they are not going to cause serious harm, we recommend that the diet is built on better sources of vital nutrition – details of which you will find on our Paleo – Foods In page.