Phytates & Toxic Lectins in Grains, Legumes, Nuts & Seeds, and How to Avoid Them

Posted on September 27, 2014 by Cat

By Cat, Nov 2007; (Photo, right, from FitElement (8))

Edible Seeds

This article was previously titled: “Soaking, Sprouting & Fermenting Grains, Nuts & Seeds (About/Intro).” Its original title was “The Humble, Un-sprouted Seed.”

The seeds of plants are designed to survive all insult (including ingestion by humans and other predatory animals), thus protecting its vulnerable nutrients from assailants and from each other, until conditions are just right for germination.  Germination of the seed produces a new plant to ensure survival of the species. This includes all seeds: grains, legumes, nuts and fruit/vegetable seeds.

Just think about this.  The seed must survive chewing, harsh stomach acids, alkaline bile salts, intestinal churning, action by hungry bacteria; and then depart the body in the stool, whole and  unharmed, so that it can still germinate and produce a new plant. Totally amazing! So then, how do we benefit from their nutrients? We can crush them, but even then most of the nutrients are protected from digestion and absorption.

Seeds protect themselves by several mechanisms including: Phytates (that keep minerals from activating the seed’s enzymes before conditions are ripe for germination); and lectins (toxins that make the predator – including humans – sick in the gut and other parts of the body). But all is not lost; soaking, sprouting, fermentation and high-pressure cooking are things you can do to begin the breakdown of the lectins.

Note: this is a fairly long post.

The humble, unsprouted seed: the problem of phytates & lectins

All seeds have a hard, nearly impermeable shell or husk that, unless broken by crushing or other damage, will ensure passage of the seed through the digestive system intact.

To keep the seed from germinating until the time and place are “just right,” the seed contains phytates that bind the minerals in the seed to keep them from activating the enzymes involved in germination. While phytates are not usually toxic, they do keep you from accessing the minerals that are bound by them.

To protect the un-sprouted seed from predators (including humans), the seed – especially its hull – contains “lectins,” which cause illness in the predator when the seed is eaten. Considered “sticky,” lectins work by binding to sugars such as those bound to fats or proteins on the cell wall. In the gut, they bind to the intestinal lining that is only one-cell thick; this can cause what is commonly known as “leaky gut,” when the lectins bind to the side of the cell abutting another cell, creating a gap. One of the most well studied lectins is WGA (wheat germ agglutinin) in wheat germ. Gliadin – one of the two components of gluten – is sometimes called a lectin because it causes openings in the intestinal lining, as lectins do; indeed, it is a close cousin.

Seeds that contain particularly problematic phytates and lectins for humans include: grains, legumes (beans, cashews, peanuts), and night-shades (tomatoes, peppers, potatoes and eggplant). The process of germination begins the breakdown of phytates and lectins in the seed, making the seed much less toxic.

Germination

When conditions are ripe for germination – a warm, moist environment – rapid changes occur in the seed:

  • The enzyme inhibitors are deactivated, releasing and activating the enzymes.
  • Among the first to be released are the phytase enzymes, which release the minerals from their phytate jailor. The minerals then are free to activate other enzymes. An overnight soak (what I call a “pre-soak”) is sufficient to release the minerals.
  • Some enzymes produced by sprouting the seed convert its starches to vegetable sugars, to provide energy for growth of the young plant. Others break down some of the proteins into peptides and amino acids. When you eat the sprouted seed, these enzymes help you digest starches, vegetable sugars and proteins from the rest of your meal.
  • Others create new amino acids from the sugars and starches, or form new proteins from free amino acids.
  • Still others produce cofactors and vitamins and other active components of the living plant. Among the vitamins are carotenes (vitamin A family), vitamin B-complex, and vitamin C, that are essential for the health and growth of the young plant, but also benefit your health when you eat the sprouted seeds.

Germination is a very active, magical time. The seed forms a sprout, and grows roots that interact with the soil’s microbiome to absorb more moisture and nutrients from the soil, which in turn support the growth of the young plant above ground.

Germination/sprouting provides a great bonus for those who consume the germinated seed:  it makes the nutrients in the seed more bio-available by making the nutrients not only more bountiful, but also more easy to digest.

If you eat the seed (including grain, nut, legume) as it is (whole or ground but not germinated), you risk exposure to these toxic lectins, and will not get the benefit of many of its nutrients which are locked-in because you cannot digest them (see “Nutrition of germinated/sprouted seeds” section, below).

Or you can take advantage of the germination process by soaking the seeds in lightly-acidic water at room temperature with minimal exposure to light; these conditions cause the seeds to germinate, just the same as if they were planted in soil. If  you continue to expose them to water, they will sprout in 1 – 4 days.  Once sprouted by soaking, the nutrients in the seeds are more digestible and bio-available.

Health benefits of the germinated seed

The seed’s many vital nutrients that are not available for digestion and absorption when you eat the seed; they only become available after germination. This includes:

  • Minerals are needed to activate the enzyme, but must be kept apart from the enzymes until it is time to germinate; otherwise, the seed would germinate when conditions are not ripe.  To prevent this, the minerals are bound by a chelator (jailer) called phytic acid, to make phytates.  It takes just the right conditions to free the minerals, but this will not happen in the human digestive system. More on this, below.
  • Enzymes are needed to make certain vitamins and for other functions that support growth of the young plant, such as producing energy. But in the ungerminated seed, that enzyme activity is not wanted, and the enzymes are inhibited to keep the seed from sprouting.  For example, at germination, the phytase enzyme breaks the link between phytic acid and minerals such as magnesium, calcium and zinc, to release the minerals. The freed minerals then combine with the inactive enzymes to activate them, which in turn causes the seed to sprout.
  • While seeds do have some vitamins and co-factors (in storage rather than active form), many of the vitamins needed by the young plant are not formed until after germination.  For example, vitamin C.  Once again, it is to our advantage to consume the seeds AFTER they have sprouted (germinated), if we want these precious nutrients. More on this, below.
  • Sugars that are used as fuel for growth of the young sprout, are stored as complex starches and fibers (very long chains of sugars) that our bodies cannot digest. But upon germination, enzymes are activated to break down these starches into shorter-chain vegetable starches (called oligosaccharides) and simple sugars that we can digest.  We have the ability (with the aid of our gut microbiome — probiotics living in our gut) to digest these shorter chain carbs and sugars, so it is to our advantage to consume the seeds AFTER they have sprouted (germinated).
  • Proteins used for various functions of the young sprout are also in a storage form before germination, but then are activated upon germination. For example, the gluten in wheat is formed from two proteins, gliadin and agglutinin.*  One function of agglutinin in the un-sprouted seed is to discourage predators (primarily birds) from eating the seed, as it is toxic to their digestive systems, and may also be toxic to many humans. Upon germination (or exposure to moisture), these combine to form gluten.*  Typically – as for gluten – the activated form is more digestible for us humans, which is an excellent reason to  ferment grains (as in sourdough).

*To see an animation of the formation of gluten, check out the Bread Science (1) website.  Scroll down to the link for ‘gluten animation.’

On a side note, phytic acid is related to one of the B-vitamins, inositol (B-8). Inositol is a ring of 6 carbons with an alcohol (OH) group bound to each carbon. Phytic acid is formed by replacing the alcohol groups with phosphate groups, as a storage form for phosphate. Because it binds the minerals in the seed, it is considered an “anti-nutrient,” which has positive and negative consequences (16). On the positive side, it:

  • helps prevent hardening of the arteries and platelet formation;
  • may improve kidney health and prevent stones when excreted in urine;
  • plays a role in pancreatic function and insulin secretion. And it may reduce the glycemic response from meals, meaning you feel full for longer;
  • binds free iron and other free radicals; and can protect against or reduce the consequences of hemochromatosis (iron overload).

On the negative side, it can bind essential minerals in the gut, making it difficult to absorb them.

Nutrition of germinated/sprouted seeds

Sprouted seeds are more nutrient dense than unsprouted seeds.  For example, sprouted whole wheat, compared with non-sprouted whole wheat, has (3):

  • 28% more thiamine (B1);
  • 315% more riboflavin (B2);
  • 66% more niacin (B3);
  • 65% more pantothenic acid (B5);
  • 111% more biotin (B7);
  • 278% more folic acid;
  • 300% more vitamin C;
  • Predigested protein resulting in shorter peptide chains and free amino acids;
  • Predigested starches resulting in oligo-saccharides and sugars.

This transformation is not limited to wheat; all grains undergo similar transformation, resulting in a more digestible and absorbable food.

About Soaking & Sprouting

NOTE: Unsprouted nuts and seeds eaten in small amounts probably do not cause digestive upset, but eaten in larger quantities can cause the formation of considerable gas, and constipation. A simple overnight soak, rinse and drain is all that’s needed if you eat small amounts of the seeds.

Both soaking and sprouting begin with a soak in slightly acidic water, during which the seed softens and increases in size. (Depending on the seed type, the duration of soak can be from as little as 20 minutes to 12 hours). The beginning steps toward germination happen during the soak; primarily, the acidic moisture activates the phytase enzyme, which then breaks down the phytates that lock-up the minerals, releasing the minerals so they can activate other enzymes.

After this soak, the seeds are rinsed and drained (very important), and then can be:

  • Used as-is in recipes or dried (dehydrated) for a light toasting; however, for most seeds, soaking doesn’t deactivate the lectins which can cause digestive harm.
  • Allowed to germinate/sprout fully over 1 – 4 days, to form a sprout by repeatedly rinsing and draining 2 – 3 times daily. The amount of time depends on the type of seed and how long a sprout is desired; you can stop when you first see a tiny tail growing from the seed, or wait until the tail grows and eventually adds a leaf. The sprouted seed is even more nutritious than the soaked seed, and can be eaten as is (I add them to my morning smoothie), or used in recipes such as for porridge or cooked beans (with a greatly reduced cooking time), or can be planted to form the plant. Sprouting the seed begins the deactivation of lectins. See my post: Sprouting Grains, Legumes, Nuts & Seeds for Eating or SproutPeople: Sprouting Basics for more detail (17).

Soaking grains, legumes, nuts and seeds begins the processes of germination; the longer the soak, the more benefits for the human diet:

  • Makes their minerals more available for absorption (by unlocking them from phytic acid).  This includes not only minerals in the soaked item, but other dietary minerals as well.
  • Breaks down the starches into shorter-chain vegetable starches and sugars;
  • Breaks down some of the proteins into peptides and amino acids;
  • Forms new proteins, vitamins, and other active components of the living plant.
  • For beans and other legumes, soaking shortens cooking time; sprouting shortens it even further.

It is not advisable to sprout soy or kidney beans, but they can be soaked prior to cooking.  These beans contain a toxin that is destroyed only by high temperature/pressure cooking.

“Kidney beans should be soaked for at least 8 hours in enough cold water to keep them covered. After soaking, drain and rinse the beans, discarding the soaking water. Put them into a pan with cold water to cover and bring to the boil. The beans must now boil for 10 minutes to destroy the toxin.” (from Vegetarian Society on pulses (6)).

What seeds can be sprouted at home?

Almost all seeds can benefit from sprouting; for example, grains, nuts, pumpkin and sunflower seeds; some benefit more than others.   Unsprouted nuts and seeds eaten in small amounts probably do not cause digestive upset, but eaten in larger quantities can cause the formation of considerable gas, and constipation.  Sprouting and drying the nuts and seeds renders them more digestible, without altering flavor.  It’s a bit of a bother, so I recommend doing a large quantity at one time, and then store them in the refrigerator, or a cool & dry place in your pantry.

NOTE:  Some seeds cannot be sprouted in the kitchen, or are difficult to sprout.  These include:

  • Flax seeds (they get too mucilaginous to rinse properly; however, they are low in physic acid when not sprouted, and so should not cause problems if consumed in small quantities);
  • Oat seeds will not sprout once separated from their outer hulls; however, they do benefit from soaking and/or long, slow cooking, as in old-fashioned porridge;
  • irradiated seeds and spices

NOTE:  Some grains do not have sufficient phytase enzyme to deactivate the phytates in the seed, even after a long soaking period.  These include oats, millet, corn and sorghum. To improve phytate deactivation, mix a bit of fresh-ground wheat or rye (which are high in phytase enzyme) with these low-phytase grains when sprouting, to increase phytate deactivation and thus increase available minerals (4).

How to Sprout Seeds

See Sprouting Grains, Legumes, Nuts & Seeds for Eating, for instructions; it also includes the process for making porridge from sprouted grains.

See also related articles:

High-pressure cooking (in pressure cooker)

Using a pressure cooker to cook (or can) seeds like legumes helps to break down the phytates and lectins. Why is this important? Because (12):

Ingesting lectins can cause flatulence. Consuming legumes and grains in their raw form can even result in nausea, diarrhea and vomiting. Indeed, researchers speculate that many apparent causes of bacterial food poisoning may actually be lectin poisoning. …

This GI distress happens because lectins can damage the intestinal lining.

As food passes through the gut, it causes very minor damage to the lining of the GI tract. Normally the cells repair this damage rapidly. Since the purpose of the gut lining is to let the good stuff past and keep the bad stuff contained, it’s important for the cellular repair system to be running at full efficiency.

But lectins can blunt this speedy reconstruction. Our cells can’t regenerate as fast as they need to in order to keep the intestinal lining secure. Thus, our natural gut defenses are compromised after the damage occurs and the gut can become “leaky,” allowing various molecules (including stuff we don’t want) to pass back and forth amid the gut wall. We may also not absorb other important things, such as vitamins and minerals, properly.

When enough lectins are consumed, it can signal our body to evacuate GI contents. This means vomiting, cramping and diarrhea. It’s similar to consuming large amounts of alcohol, which can damage the GI lining and cause GI evacuation.

This damage to the intestinal wall can lead to auto-immune diseases, as undigested proteins and peptides never intended to be absorbed into the blood, do so before they can be broken down into their respective amino acids. These proteins and peptides then alert the immune system which then attacks not only these large molecules, but also the body’s organs that have similar amino acid sequences on their surface.

The solution to avoid all this trouble down the road, is to break down the lectins prior to ingesting them. For legumes, the best method is high-pressure cooking. It may also work for grains – as for porridge or gruel – but if you want to use the grains for baking, fermentation/sourdough is a better method.

Fermentation and Sourdough

Fermentation of the seed takes the process one step further by modifying critical proteins such as gluten in grain seeds, and lectins in most seeds, to remove or minimize their toxicity. People with IgG-type gluten sensitivity can then safely eat the fermented grain. Most people with Celiac can also tolerate grain that is allowed a long fermentation time – 12 to 24 hours, once they have healed their gut by avoiding gluten for a long period of time, and balancing their microbiome. From Grains of Truth by Stephen Yafa (9):

“Published in 2007 in the peer-reviewed Applied and Environmental Microbiology (10), one study found that long fermentation in wheat bread reduced gluten levels from 75,000 parts per million (ppm) to 12 [ppm], way below the 20 ppm that is considered gluten-free.”

In a 2010 Italian clinical study on sourdough’s effect on gluten levels published in Clinical Gastroenterology and Hematology (11), patients with a diagnosis of celiac disease who took part were separated into two groups: one group received partially hydrolyzed wheat flour while the patients in the second group, unlike the other, received baked goods completely degraded by the lactic acid bacteria (LAB) found in sourdough. Those patients had no clinical complaints, and their celiac-related antibodies did not increase. The researchers concluded that a “sixty-day diet of baked goods made from hydrolyzed wheat flour manufactured with sourdough lactobacilli and fungal proteases, was not toxic to patients with CD.”

Biopsies for the second group revealed a change in their intestinal lining, although those patients had no clinical complaints. But the most significant change showed up in the third group. Blood levels for immune markers that signal an adverse reaction to wheat did not rise for the celiac patients who ate baked goods made from wheat flour fully broken down by sourdough’s lactic bacteria; after sixty days, biopsies on each participant showed no intestinal lining deterioration.

NOTE: if you have been diagnosed with Celiac disease, introduction of fermented grains (sourdough) should be done only under the close observation of a practitioner licensed to treat Celiac and other auto-immune disease.

My Articles about Sourdough and other Natural Leavens: 

Canning Beans and other Legumes

Canning legumes in a pressure cooker will break down the lectins; see high-pressure cooking, above. The remainder of this section has been moved to Canning Beans & Other Legumes.

References

  1. Bread Science on gluten: exploratorium.edu/cooking/bread/bread_science.html
  2. Nourishing Traditions, by Sally Fallon and Mary G. Enig
  3. Creating Heaven website (creatingheaven.net/eeproducts/eesfc/)
  4. Rebuild From Depression website (rebuild-from-depression.com/simplechange/simplechange/grains-legumes-nuts-seeds.html) or rebuild-from-depression.com/resources/book/Chapter13.pdf)
  5. Vegetarian Society on pulses: vegsoc.org/info/pulses.html (link no longer works)
  6. msuextension.org/publications/HomeHealthandFamily/MT198329HR.pdf
  7. (6) Nutrition data on spelt: nutritiondata.self.com/facts/cereal-grains-and-pasta/10355/2; and on whole wheat: nutritiondata.self.com/facts/cereal-grains-and-pasta/5744/2
  8. FitElement photo: fitelement.com/the-difference-between-grains-and-seeds
  9. Grains of Truth by Stephen Yafa, copyright 2015 by Stephen Yafa and published by Avery; author cites two articles about sourdough and Celiac (10 and 11)
  10. Rizzello, C. G., et al.; “Highly Efficient Gluten Degradation by Lactobacilli and Fungal Proteases During Food Processing: New Perspectives for Celiac Disease.” Applied and Environmental Microbiology 73. no 14 (July 2007): 4499-507 (aem.asm.org/content/73/14/4499.full).
  11. The Clinical Gastroenterology and Hematology article is not cited in his references section; I believe it is the following article: Luigi Greco, et. al.; Safety for Patients With Celiac Disease of Baked Goods Made of Wheat Flour Hydrolyzed During Food Processing, January 2011, Volume 9, Issue 1, Pages 24–29  (cghjournal.org/article/S1542-3565(10)00987-0/abstract)
  12. Precision Nutrition: precisionnutrition.com/all-about-lectins
  13. Yogitrition: yogitrition.com/soaking-grains-beans-nuts-and-seeds-101
  14. Mercola article, “Limit the Lectins” has a great summary of the issue and how to avoid/minimize lectins in your diet: articles.mercola.com/sites/articles/archive/2018/01/07/limit-lectins.aspx)
  15. shieldnutra.com/gluten-lectin-leaky-gut-connection/
  16. precisionnutrition.com/all-about-phytates-phytic-acid
  17. sproutpeople.org/growing-sprouts/sprouting-basics/ 

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