A Complete, Gluten-Free ProteinJuly 2015
By Michael Downey
People everywhere are turning to quinoa for an excellent, meat-free, complete source of low-fat protein.1-3
The high-protein content of this vegetable seed—often mistakenly called a grain—means quinoa has a much lower carbohydrate content than grains,2 as well as a lower glycemic index.4 It is also low in sodium5 and unlike some grains, is completely gluten-free.2,6
Quinoa contains a range of nutrients including riboflavin (vitamin B2),6 quercetin,7 tocopherols,8 polyphenols,3,8 saponins,8 phytosterols,3 minerals,3 vitamins,3 free-radical fighting molecules,7,9 fiber,10 and highly potent compounds like hydroxybenzoic acids and arabineans.9
Scientists continue to find evidence that this versatile grain substitute may inhibit inflammation,9 reduce cholesterol,8,9 quench free radicals,7 improve glucose levels,7-10 promote cellular energy production,10 support weight loss,10 act as a prebiotic,11,12 and potentially help prevent cancer and heart disease.13
In fact, NASA scientists have suggested quinoa as a possible crop for cultivation on long-duration manned space flights.14 And the United Nations officially declared 2013 to be the International Year of Quinoa, with UN Secretary-General Ban Ki-moon declaring, “Quinoa is now poised for global recognition.”15
A Protein Powerhouse
Quinoa was a dietary staple in South America as long as 4,000 years ago.16
However, it wasn’t until 1955 that scientists concluded, “While no single food can supply all the essential life-sustaining nutrients, quinoa comes as close as any other in the plant or animal kingdom.”17
Prominent among these nutrients is its high-quality protein.2,3,9,10,18 The seed of this vegetable, related to spinach and beets, is one of the most protein-rich foods we can eat.10
It is possible for plant foods to include all nine of the essential amino acids—those that must be derived from diet. But one or more of these protein-building blocks is generally in short supply, limiting the amount of usable protein.1,6,9 This means that vegans have very limited options for quality protein.
For instance, grains often lack sufficient amounts of lysine and isoleucine, rendering their protein contribution incomplete.6 But quinoa contains ideal levels of these and all of the other essential amino acids6—making it the only grain-like food that is a complete protein.9
The gluten molecules in wheat, barley, and rye trigger an autoimmune response in celiac patients. However, quinoa—which can be eaten like a cooked grain—is gluten-free and safe for celiac patients, as well as those with gluten intolerance.19
Compared to grains, quinoa provides a substantially higher proportion of protein relative to carbohydrate.2,18 The concentration of protein is highest in the germ, and the quinoa germ comprises up to about 60% of the quinoa seed—while the wheat germ makes up less than 3% of the wheat kernel.2 This makes quinoa ideal for low-carb and low-glycemic diets.
Many people consume grains because they can be a good source of fiber. But quinoa is fiber-abundant,10 with just one cup delivering 21% of your recommended daily fiber intake.5 The fiber content of quinoa is significantly greater than that of either whole wheat or brown rice.18
Quinoa is recognized as a “functional food.” That is, its balanced content of protein, minerals, vitamins, and fatty acids deliver such a strong contribution to nutrition that it may lower the risk of a broad range of diseases. Let’s examine a few of these main health effects.
Protecting Against Cardiovascular Disease
Researchers continue to find that quinoa provides significant cardiovascular benefits.
In a University of Milan study, scientists compared various gluten-free foods. Quinoa stood out in the study for producing lower free fatty acid levels and triglyceride concentrations than other foods studied, including gluten-free pastas and breads.20
Quinoa is high in magnesium,21 which can reduce blood pressure22 by relaxing blood vessels.
Quercetin, abundantly found in quinoa, has been shown to target blood pressure in hypertensive subjects.23 Quinoa also delivers a significant fiber punch, which may help lower high blood pressure, as well as decrease cholesterollevels.10
Substantial levels of potent phytochemicals in quinoa—such as saponins and phytosterols—support significant cholesterol reduction. In a 2010 animal study at Jagiellonian University in Krakow, Poland, scientists concluded that quinoa decreased total cholesterol by 26%, LDL cholesterol by 57%, and triglycerides by 11%, compared to controls. And while the control group suffered a significant decrease in beneficial HDL, quinoa inhibited this effect in the first group.8
The fat content in quinoa is higher than in cereal grasses such as wheat, and includes valuable amounts of heart-healthy fats such as oleic acid, a monounsaturated fat. Quinoa also provides small amounts of alpha-linolenic acid (ALA), an omega-3 fatty acid.24-26
Studies have demonstrated a remarkable fact: Quinoa does not get oxidized as rapidly as might be expected given its higher fat content. As a result, cooking quinoa doesn’t appear to significantly compromise the quality of its fatty acids. This oxidative protection may be due to quinoa’s diverse array of polyphenols, various members of the vitamin E family such as alpha-, beta-, gamma- and delta-tocopherol, as well as flavonoids such as quercetin and kaempferol.24,27
Controlling Blood Sugar
Quinoa is at the low end of the glycemic index,4 which makes it a great grain substitute for those with blood sugar issues. Its magnesium content may also reduce the risk of type II diabetes by promoting healthy blood sugar control.10
The high fiber content of quinoa can contribute to lower glucose levels and may promote weight loss10—which in turn, may further reduce the risk of diabetes. A University of Milan study found that quinoa has a higher Satiating Efficiency Index (SEI) than wheat or rice,20 meaning it promotes a feeling of fullness that can block the weight gain associated with increased diabetes risk.
Investigators showed that “quinoa seeds can reduce most of the adverse effects exerted by fructose on lipid profile and glucose level.”8
In 2009, scientists at the University of São Paulo in Brazil studied 10 traditional Peruvian grains and legumes for their potential to inhibit type II diabetes-relevant hyperglycemia. This in vitro study concluded that quinoa could possibly be developed as dietary strategy for managing type II diabetes.7
Reducing Cancer Risk
High levels of bioactive compounds in quinoa have the potential to lower the risk of cancer.
The Journal of Agricultural and Food Chemistry published a study in 2011 that employed sophisticated laboratory techniques to determine levels of phenolic compounds in quinoa.28
The researchers identified in quinoa the following compounds: genistein, quercetin, kaempferol, epigallocatechin (the anti-inflammatory polyphenol present in green tea) and other phenolic substances that have the capacity to suppress new blood vessel growth (antiangiogenesis) and inhibit the proliferation of cancer cells.28 In fact, the concentration of quercetin and kaempferol in quinoa sometimes exceeds their concentration in high-flavonoid berries such as cranberry and lingonberry.24,29
Quinoa also contains a range of potent compounds known as saponins. These bitter-tasting chemicals provide strong antitumor, apoptotic (cell death), and tumor antiangiogenic effects.30 They are sometimes used as an adjunct to chemotherapy.30
The saponins in whole quinoa flour have been found to be so abundant that they constitute between 5.6 and 7.5% of the flour’s total composition.28
Quinoa provides substantial anti-inflammatory effects.
A 2014 study in the Journal of Food Science tested some of the many saponins in quinoa on rodent macrophage cells for anti-inflammatory effect. The researchers found that these compounds decreased the production of nitric oxide, an inflammatory mediator. The quinoa saponins also inhibited the release of inflammatory cytokines, including tumor necrosis factor-alpha and interleukin-6. This study concluded that, “These results suggest that quinoa saponins may be used as functional food components for prevention and treatment of inflammation.”31
Beyond saponins, research has been identifying a greatly expanded list of anti-inflammatory components in quinoa. The unique combination of these phytonutrients in quinoa may explain the results of animal studies indicating that daily ingestion of quinoa decreases the risk of inflammation-related health issues, including obesity.24,32
Potent inflammation-inhibiting phytonutrients found in quinoa are now known to include hydroxycinnamic and hydroxybenzoic acids; polysaccharides such as arabinans and rhamnogalacturonans; the flavonoids quercetin and kaempferol; and novel saponins, including molecules derived from oleanic acid, hederagenin, and serjanic acid. Quinoa also provides a form of vitamin E called gamma-tocopherol and small amounts of alpha-linolenic acid, an anti-inflammatory omega-3 fatty acid.9,27,29,33
Gluten-free quinoa is increasingly recognized as a superfood as scientists continue to confirm that its high content of fiber and high-quality protein—combined with a vast array of potent compounds—delivers diverse and powerful health benefits. The saponins, phytosterols, polyphenols, polysaccharides, free-radical fighting molecules, minerals, vitamins, and other constituents in quinoa provide strong protection against cardiovascular disease, diabetes, cancer, and inflammation.
If you have any questions on the scientific content of this article, please call a Life Extension® Health Advisor at 1-866-864-3027.
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- Ranilla LG, Apostolidis E, Genovese MI, Lajolo FM, Shetty K. Evaluation of indigenous grains from the Peruvian Andean region for antidiabetes and antihypertension potential using in vitro methods. J Med Food. 2009 Aug;12(4):704-13.
- Paśko P, Zagrodzki P, Bartoń H, Chłopicka J, Gorinstein S. Effect of quinoa seeds (Chenopodium quinoa) in diet on some biochemical parameters and essential elements in blood of high fructose-fed rats. Plant Foods Hum Nutr. 2010 December;65(4):333-8.
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- Available at: http://www.forbes.com/sites/juliewilcox/2012/06/26/7-benefits-of-quinoa-the-supergrain-of-the-future/. Accessed August 4, 2014.
- Bianchi F, Rossi E2, Gomes R3, Sivieri K2. Potentially synbiotic fermented beverage with aqueous extracts of quinoa (Chenopodium quinoa Willd) and soy. Food Sci Technol Int. 2014 Jun 23.
- Carrion R, Murphy K, Ganjyal G, Kowalski R, Noratto G. Quinoa as source of bioactive compounds with potential for intestinal health. FASEB J. 2014 April;28(1):18.
- Gawlik-Dziki U, wieca M, Sułkowski M, Dziki D, Baraniak B, Czy J. Antioxidant and anticancer activities of Chenopodium quinoa leaves extracts - in vitro study. Food Chem Toxicol. 2013 Jul;57:154-60.
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- Moralesa M, Barberenab R, Belardic JB, et al. Reviewing human–environment interactions in arid regions of southern South America during the past 3000 years. Palaeogeogr, Palaeoclimatol, Palaeoecol. 2009 October;281(3-4):283-95.
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- Dixit AA, Azar KM, Gardner CD, Palaniappan LP. Incorporation of whole, ancient grains into a modern Asian Indian diet to reduce the burden of chronic disease. Nutr Rev. 2011 Aug;69(8):479-88.
- Lee A, Newman JM. Celiac diet: its impact on quality of life. J Am Diet Assoc. 2003 Nov;103(11):1533-5.
- Berti C, Riso P, Monti LD, Porrini M. In vitro starch digestibility and in vivo glucose response of gluten-free foods and their gluten counterparts. Eur J Nutr. 2004 Aug;43(4):198-204.
- Nascimento AC1, Mota C, Coelho I, Gueifão S, Santos M, Matos AS, Gimenez A, Lobo M, Samman N, Castanheira I. Characterisation of nutrient profile of quinoa (Chenopodium quinoa), amaranth (Amaranthus caudatus), and purple corn (Zea mays L.) consumed in the North of Argentina: proximates, minerals and trace elements. Food Chem. 2014 Apr 1;148:420-6.
- Volpe SL. Magnesium in disease prevention and overall health. Adv Nutr. 2013 May 1;4(3):378S-83S.
- Edwards RL, Lyon T, Litwin SE, Rabovsky A, Symons JD, Jalili T. Quercetin reduces blood pressure in hypertensive subjects. J Nutr. November 2007;137 (11):2405-11.
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- Alvarez-Jubete L, Holse M, Hansen Å, Arendt EK, Gallagher E. Impact of Baking on Vitamin E Content of Pseudocereals Amaranth, Quinoa, and Buckwheat. L. Cereal Chem. 2009 September/October 2009;86(5):511-15.
- Gómez-Caravaca AM, Segura-Carretero A, Fernández-Gutiérrez A, Caboni MF. Simultaneous determination of phenolic compounds and saponins in quinoa (Chenopodium quinoa Willd) by a liquid chromatography—diode array detection—electrospray ionization—time-of-flight mass spectrometry methodology. J Agric Food Chem. 2011;59:10815-25.
- Repo-Carrasco-Valenciaa R, Hellströmb JK, Pihlavac J, Mattilab PH. Flavonoids and other phenolic compounds in Andean indigenous grains: Quinoa (Chenopodium quinoa), kañiwa (Chenopodium pallidicaule) and kiwicha (Amaranthus caudatus) Food Chem. 2010 May;120(1):128–33.
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- Yao Y, Yang X, Shi Z, Ren G. Anti-inflammatory activity of saponins from quinoa (Chenopodium quinoa Willd.) Seeds in lipopolysaccharide-stimulated RAW 264.7 macrophages cells. J Food Sci. 2014 May;79(5):H1018-23.
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