For some people, quinoa is a new and nutritious food recently available at their local supermarket or favourite restaurant as a substitute for many commonly eaten grains. While this may be true in many areas of the world, quinoa was a major food crop of the pre-Columbian cultures in Latin America, and still remains an important food for the Quechua and Aymara peoples of the rural areas in the Andes region of South America.1 In the Quechua language, quinoa is called chisiya, meaning ‘mother grain’.2
Quinoa is unique in that it is a seed eaten in a manner similar to a grain. It is often either cooked and added to soups, or made into flour to be used in bread, drinks or porridges. Regarding quinoa’s nutrition, it is comparable in energy to similarly eaten foods such as beans, maize, rice or wheat as shown in Table 1. In addition, quinoa is notable as a good source of quality protein, dietary fibre, polyunsaturated fats and minerals. While quinoa is a good source of many nutrients, it is important to consume it as a part of a balanced meal with many other food types to obtain good overall nutrition.
Quinoa’s protein quantity depends on the variety, with a protein range of 10.4 to 17.0 percent of its edible portion.3 While generally higher in protein quantity than most grains, quinoa is known more for its protein quality.4 Protein is made up of amino acids, of which eight are considered essential for both children and adults. As shown in Table 2, when compared to the FAO’s recommended essential amino acid scoring pattern for 3 to 10 year old children, quinoa exceeds the recommendation for all eight essential amino acids. In contrast to quinoa, most grains are low in the essential amino acid lysine, while most legumes are low in sulphuric amino acids methionine and cysteine.5
A recent study of four quinoa varieties found the dietary fibre in raw quinoa to range from about 13.6 to 16.0 grams per 100 grams dry weight.6 Most of the dietary fibre was insoluble, with a range of 12.0 to 14.4 grams compared to 1.4 to 1.6 grams of soluble fibre per 100 grams dry weight. Similar to quinoa’s total protein value, its dietary fibre value is generally higher than that of most grains, but lower than that of legumes. Dietary fibre is the indigestible portion of plant foods, and it is important for good digestion and to prevent against constipation.
As shown in Table 1, quinoa contains more fat (6.3 g) per 100 grams dry weight than beans (1.1 g), maize (4.7 g), rice (2.2 g) and wheat (2.3 g). Fat is an important source of calories, and aids in the absorption of fat soluble vitamins. Of quinoa’s total fat content, over 50 percent comes from essential polyunsaturated fatty acids linoleic (omega-6) and linolenic (omega-3) acid.3 Linoleic and linolenic acid are considered essential fatty acids because they cannot be produced by the body. Quinoa’s fatty acids have been shown to maintain their quality because of quinoa’s naturally high value of vitamin E, which acts as a natural antioxidant.7
On average quinoa is a better source of minerals than most grains as shown in Table 3. Quinoa is especially a good source of iron, magnesium and zinc when compared to the daily mineral recommendations. A lack of iron is often one of the most common nutrition deficiencies. However quinoa, like all plant foods, does contain certain non-nutritive components that can reduce its mineral content and absorption. Most notable are its saponins, which are found on the outer layer of the quinoa seed and are usually removed during processing to remove their bitter taste. Quinoa is also high in the compound oxalate, which can bind to minerals such as calcium and magnesium, reducing their absorption in the body.8
Quinoa is also a good source of B vitamins riboflavin and folic acid compared to other grains, similar in amounts of thiamine, but lower in niacin on average as shown in Table 4. It also contains significant amounts of vitamin E, though the quantity seems to decline after processing and cooking (Koziol, 1992). In general, quinoa’s vitamin content is not affected by removing its saponins as the vitamins are not found in the pericarp of the quinoa seed (Koziol, 1992).
1 Abugoch James, L.E. (2009) Quinoa (Chenopodium quinoa Willd.). Advances in Food and Nutrition Research. 58.
2 National Research Council. (1989) Lost Crops of the Incas: little known plants of the Andes with promise for world-wide cultivation. Washington, DC: National Academy Press.
3 Reyes Montaño, E.A., Ávila Torres, D.P. and Guevara Pulido, J.O. (2006) Componente nutricional de diferentes variedades de quinua de la región Andina. AVANCES Investigación en Ingeniería.5, 86-97.
4 Repo-Carrasco, R., Espinoza, C. and Jacobsen, S.E. (2003) Nutritional value and use of the Andean crops quinoa (Chenopodium quinoa Willd.) and kañiwa (Chenopodium pallidicaule). Food Reviews International. Vol. 19, Nos. 1 & 2, 179-189.
5 Koziol, M. (1992) Chemical composition and nutritional evaluation of quinoa (Chenopodium quinoa Willd.). Journal of Food Composition and Analysis. 5, 35-68.
6 Repo-Carrasco-Valencia, R. and Serna L.A. (2011) Quinoa (Chenopodium quinua, Willd.) as a source of dietary fiber and other functional components.” Ciencia e Tecnologia de Alimentos. 19 (1), 225-230.
7 Ng, S., Anderson, A., Cokera, J. and Ondrusa, M. (2007) Characterization of lipid oxidation products in quinoa (Chenopodium quinoa). Food Chem. 101(1), 185-192.
8 Siener, R., Honow, R., Seidler, A., Voss, S. and Hesse, A. (2006) Oxalate contents of species of the Polygonaceae, Amaranthaceae and Chenopodiaceae families. Food Chem. 98, 220-224.