Lectins & Oxalates - Yay or Nay?
We live in the most nuanced world when it comes to nutrition. Everyone has an opinion and to be honest, everyone should! Every human body is unique in its needs and each person is the expert of their own body. But it sure can become confusing when you’re constantly reading opposing views on the same topic. One person is saying spinach gives you kidney stones, another is saying spinach is one of the richest sources of folate. So, do we eat the spinach, or not?! Let's chat about it.
We often hear “include legumes in the diet, the blue zones of the world eat legumes daily!”. Then the next person says, “avoid legumes entirely, they’re full of anti-nutrients like lectins that destroy your gut!”. Similarly with spinach and kale, once labelled ‘superfoods’ but now demonised for their oxalate content. How do we know what to do with this information, when both views have some valid points?
In today’s blog, we’re going to discuss what lectins and oxalates are, and how best to prepare your foods to reduce the content of these compounds.
Lectins
Lectins are a protein found in many plant foods, mainly beans, legumes and grains. They are considered an anti-nutrient because they cause damage to the gut lining and interfere with nutrient absorption. They do this by binding to carbohydrates on the surface of cells in the digestive tract, disrupting the absorption of nutrients. They also form complexes with some minerals like calcium and iron, which reduces their bioavailability. Lectins can also influence the gut lining, causing inflammation and compromising the intestinal barrier. This can lead to increased permeability or ‘leaky gut’, where larger molecules can then travel through the intestinal barrier that would normally not be able to, which can cause an array of symptoms and associated immune responses.
Knowing this information doesn’t necessarily mean we have to boycott legumes and grains for the rest of our lives. Like mentioned above, people in blue zones all over the world consume large amounts of legumes but the thing is… they do it properly. There are some traditional cooking and food preparation methods that actually aid in the reduction of lectin content and therefore the bioavailability and absorption of nutrients. Not only this, but these methods can also enhance the medicinal effects the food has on our gut lining and microbiome. For example, rinsing and soaking grains and legumes prior to cooking is essential. Soaking them in water with a dash of apple cider vinegar or kefir overnight prior to cooking begins to partially ferment and therefore partially digest the food. This not only removes the lectin content, but makes the food much more bioavailable and easier to digest. When doing this with rice for example, the rice becomes quite medicinal for the gut microbiome.
So, if you find you bloat to legumes or alike, you may find you tolerate them perfectly activated, soaked and/or fermented.
Oxalates
Oxalates are plant compounds found in many foods but mainly things such as dark leafy greens, soy, beetroot, rhubarb and some nuts. Oxalates are understood to aid in the formation of kidney stones, especially in those that are susceptible. They interfere with nutrient absorption by forming crystals with minerals like calcium. In the digestive tract, the oxalates bind to calcium, preventing its absorption and leading to formation to stones, mainly for those already at risk. Genetic predisposition, fluid intake, the gut microbiome and certain medications all contribute to this susceptibility, not just purely from consuming oxalate-rich foods.
To reduce the risk or impact that oxalates have on the body, cooking oxalate-rich foods reduces the content, such as boiling or steaming, where oxalates are released into the water. Fermentation can also aid in their reduction where beneficial bacteria can degrade oxalates, making them less bioavailable for absorption in the gut. Consuming these foods fermented also supports the gut microbiome which is important, as oxalobacter formigenes (a bacteria found in the gut microbiome) actually helps metabolise oxalates in the digestive tract. For example, boiling greens or cooking off spinach in the pan with some water, can be an easy way to reduce oxalates and still reap the nutrient benefits of spinach, such as its folate content!
As you can see, the nuanced world of nutrition can be overwhelming but we urge you to consider how best to consume certain foods, rather than rushing to remove large food groups from your diet entirely, without first considering possible nutritional consequences. Our ancestors have been consuming these foods for hundreds of years, but they were doing it in a way that was intentional, nourishing, not in excess, and not rushed. There are absolutely some cases, depending on your health circumstances/needs, where removing these things from your diet may be necessary in order to heal the gut, calm the immune system, or restore kidney function. If that’s not the case for you, cooking off your greens or soaking grains and legumes overnight is a way to prevent these things from occurring later down the track. It may feel like a lengthy process, but it sure is better for your gut and nutrient absorption than peeling open a packet of pre-made rice!
With so much love,
Jessie, Foraged For You's in house nutritionist.