Quinoa: the Controversial Seed

By Andrew.

Quinoa gets major attention in health food circles. Some foodies hail it as a "super food," while others assert it is a threat to gastrointestinal health. Quinoa is often misidentified as a grain, but I wanted to learn if there is anything besides this confusion that concerns those on a gluten-free or grain-free diet.

Quinoa is Not a Grain
A "grain" is the word commonly applied to the botanical term "caryopses." All cereal grains (such as wheat, oats, barley, rye, rice, etc.) are members of the grass family and produce caryopsis/grain. The "pericarp" (the external wall) is fused to a single "carpel" (the structure that encloses the "ovule").
 Quinoa is not part of the grass family. It is a flowering plant in the "chenopod" family. Other members include beets, chard, and spinach. The quinoa seed is not fused to its pericarp. Based on these two criteria, quinoa can not be called a grain.
 Confusingly, the agricultural term "grain" is based only on the appearance of a food product. As a result, packaging, articles, advertising, etc. may refer to "quinoa grain." The term "pseudocereal" is also applied to quinoa, because the plant's appearance and use is similar to that of true grains. Botanically speaking quinoa is a grain-free food.

Quinoa and the Gluten-Free Diet
Quinoa is gluten-free. There are rumors saying that quinoa has similar protein to gluten that causes digestive problems. A recent study showed that quinoa does not cause immune reactivity, confirming it is safe for celiacs. I have not found any research suggesting a problematic quinoa protein. The confusion is probably based on concerns with "saponin" (see bellow).

Quinoa and the Paleo Diet
The Paleo Diet avoids grains, quinoa is not a grain, so one would think it should be allowed. However this is not the case. It seems that the Paleo Diet's problem with quinoa stems from one paragraph from one prominent author, Robb Wolf. On page 87 of The Paleo Solution he writes:

Well, you’ve likely heard the expression, “If it looks like a duck and quacks like a duck…” [although entertaining, this colloquialism does not support a scientific argument] Quinoa is botanically not a grain, but because it has evolved in a similar biological niche [How are the climates/plant-life of the mountainous Andes and Mesopotamian grasslands similar?], Quinoa has similar properties to grains, including chemical defense systems that irritate the gut [the gluten in grains is not a defense against animal consumption]. In the case of Quinoa, it contains soap-like molecules called saponins. Unlike gluten, which attaches to a carrier molecule in the intestines, saponins simply punch holes in the membranes of the microvilli cells. [at what levels do saponins need to reach for this to happen? Wolf does not cite a reference.] Yes, that’s bad. Saponins are so irritating to the immune system that they are used in vaccine research to help the body mount a powerful immune response. [a recently published study specifically looked at quinoa's effect on the immune system and found that there is no such immune reponse] The bottom line is if you think grains or grain-like items like Quinoa are healthy or benign, you are not considering the full picture.

[The brackets in the quote above are my notes.]

One problematic chemical found in quinoa is listed here. The bitter-tasting saponins are an irritant to animals and people, however they are easily removed from the quinoa we eat. Quinoa's pericarp contains 2 to 6 % saponin (depending on the variety). This pericarp is physically removed from quinoa sold in N. America, and remaining residue can be easily washed from the seed (quinoa flakes do not contain saponins). As a slight aside, I find it interesting that Wolf so easily dismissed quinoa, yet he advocates mercury-toxic fish.
 Three other books, The Paleo Diet, Every Day Paleo, and The Paleo Diet for Athletes all disallow quinoa, but do not offer a reason why.

Quinoa and the Specific Carbohydrate Diet
Quinoa is high in starch, so it's a no-no on the SCD.

Benefits:
Quinoa has been cultivated in the Andes Mountains since 3000 B.C. It offers a complete protein (rare among plants) and all nine essential amino acids. Quinoa is high in calcium, magnesium, phosphorus, potassium, and iron. It is a complex carbohydrate which digests slowly (it will not spike blood sugar levels).

Quinoa in our Family
I respect that some people choose not to eat quinoa, and I acknowledge that not everyone can tolerate quinoa, like not everyone can tolerate nuts, meat, or other foods. In our family Kelly is celiac, Ashley is allergic to gluten, and Zoe and I are gluten-intolerant. Thankfully, we all do very well with quinoa.

References:

1. Ellen Douglas. "Quinoa & Paleo Diet"

2. Nathan Gray. Millet, Ammaranth, and Quinoa deemed gluten-free after the study Paolo Bergamo, et. al. "Immunological evaluation of the alcohol-soluble protein fraction from gluten-free grains in relation to celiac disease" published in Molecular Nutrition & Food Reseach, vol 55, issue 8. August, 2011.

3. Duane L. Johnson and Sarah M. Ward. "Quinoa" pages 219-221. In: J. Janick and J.E. Simon (eds.), New Crops. Wiley, New York.

4. E.A. Oelke, D.H. Putnam, T.M. Teynor, and E.S. Oplinger. "Quinoa." Alternative Field Crops Manual. University of Wisconsin Extension and University of Minnesota. January 20, 2000.

5. Rachel Venokur-Clark. "Quinoa Vegetable Protein"