I often promote quinoa as a wonderful gluten-free plant-based complete protein. In addition to the nutritional benefits we gain from eating quinoa, it is relatively affordable and simple to prepare and incorporate into our gluten-free meals.
For quinoa basics like varieties, preparation methods and serving suggestions read this article.
But today, let’s talk about a different aspect of quinoa – saponins. Saponins in quinoa have come under question in regard to their possible toxicity to our bodies. For a better understanding about this component of quinoa, let’s turn to research-based facts.
Saponins are a group of naturally occurring chemical compounds present in more than 100 varieties of plants and in some marine life (like the starfish and sea cucumber).
Common dietary sources of saponins are legumes like soybeans, chickpeas, mung beans, peanuts, kidney beans and lentils. Saponins are also found in oats, leeks, garlic, asparagus, certain teas, spinach and of course, quinoa.
So, just like I tell you certain foods contain vitamins and minerals – oranges are high in vitamin C, tomatoes are rich in lycopene, etc. – I’m telling you some foods have saponins inside.
Chemically speaking, saponins are a type of glycoside. That simply means molecules with a sugar group bound to some other chemical group. There are many types of glycosides in nature, each with their own specific qualities.
Here are a few examples of glycosides most of us are familiar with (even if we didn’t realize it):
- The sorghum plant (the same one used to make naturally gluten free sorghum flour) contains cyanogenic glycosides in its roots, making it resistant to root worms.
In this case, the glycoside is acting as a natural pesticide.
- The stevia plant contains steviol glycosides, which are used as natural sweeteners.
In this case, the glycoside is acting as a natural sweetener.
- Many, many plants contain flavonoid glycosides, which we value for their protective antioxidant effects on our cells.
In this case, the glycoside is acting as a natural cell protectant in our bodies.
As I said before, saponins – present in all those foods listed above – are a type of glycoside.
In chemistry, the primary characteristic differentiating saponins from other glycosides is their distinctive foaming quality. In fact, saponins get their name from the soapwort plant – it’s botanical name is Saponaria and its root was once used to make soap.
The soapy characteristic is evident in the white foam that results when quinoa seeds are rinsed before cooking. (Note: Some quinoa is pre-washed to remove saponins; if so, this is stated on the outer packaging.)
Removing saponins from quinoa by rinsing prior to cooking also removes the bitter taste, caused by saponins on the outer seed coat layer of quinoa.
Now, just as there are a variety of glycosides, there are also several different varieties of saponins, each with slightly different properties. We’ll focus on quinoa saponins to answer Rebekah’s question.
According to research, the primary saponin-related compounds in quinoa include:
- Oleanolic acid
- Phytolaccagenic acid
These compounds, when extracted from the quinoa plant (some from the leaves, some from the seeds) have a variety of uses.
Some Uses of Quinoa Saponins
Saponins have many medicinal uses as:
- Antifungal agents (derived from the White Yam, native to Africa)
- Antiviral medicines (found in the Scarlet Pimpernel of the Primrose family of flowering plants)
- Antibacterial compounds (found in the Purple Fruited Pea Eggplant, a relative of the potato and other nightshade plants)
- Agents to help our immune systems respond more efficiently to certain vaccines and medicines (Research from the University of Saskatchewan, Saskatoon, Canada).
Further, Belgian researchers recently reported on oleanolic acid’s potential pharmacologic uses in humans as:
- A liver protectant
- An anti-inflammatory agent
- An antioxidant
- An anticancer compound
(Note: Health-promoting oleanolic acid is mainly found in the seed of the quinoa plant, the part we eat.)
Of course, there are also instances where the repellent effects of saponins in quinoa are used.
Perhaps the best example of this is the product Heads Up Plant Protectant, categorized by the US Environmental Protection Agency as a biopesticide, approved primarily as a treatment on potato seed pieces.
Now, before we panic about consuming a pesticide by eating quinoa, let’s put this in perspective.
Remember, saponins are a plant’s natural defense against pests. What the makers of Heads Up Plant Protectant have done is isolate these saponins and concentrate them to amplify their impact as a natural pesticide.
We do not consume isolated, concentrated saponins when we eat rinsed, cooked quinoa seeds. (If you’re wondering, rinsing is shown to remove the majority of the saponin on the quiona seed.)
Of course, we cannot ignore what science tells us about saponin toxicity. After all, we need this information to make our own personal decision about whether quinoa is something we choose to consume on our gluten free diet.
What Research Says about Saponin Toxicity
In terms of saponin “toxicity”, research (repeated studies spanning 40 years) confirms the degree to which a substance can damage a particular organism varies by:
- Type of saponin
- Saponin concentration
- Method of administration
While some research suggests saponins in quinoa are toxic when the compounds are administered intravenously (IV), the same study shows that toxicity is significantly lower when the extracted saponin compounds are administered orally. As long as we avoid the quinoa IV, I suppose we’re OK there. ;)
Other studies suggest saponins are not absorbed in the gut and are in fact destroyed by certain saponin-specific enzymes in mammals, including humans.
Research also indicates there is low bioavailability of saponins in humans, meaning those compounds aren’t readily absorbed through the intestines into the bloodstream, but are instead excreted as waste.
And while it is true certain saponins are used for their toxic properties as:
- Insecticides (like in the Heads Up Plant Protectant described above.)
- Anthelmintics (for their anti-parasitic qualities in livestock)
Also keep in mind many compounds contained in items we regularly consume, when concentrated, could lead to health issues.
Take alcohol as an example. It is a known toxin to the human liver, with excessive consumption resulting in cirrhosis, fatty liver and/or alcoholic hepatitis. Further, there is minimal, if any, health benefit gained from consuming alcohol; however, many of us enjoy the occasional cocktail.
My point? What is not toxic to most of us in moderation can be deadly in excess.
This is why I often say our journey to optimal health is all about balance and moderation. It really is.
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