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Described as the "superfood of the future" by Forbes, quinoa is one of the most protein-rich foods out there.
Health gurus sing its praises and this ancient, but newly "discovered" grain is gaining popularity worldwide.
Should you be tapping into the health benefits? We take a look at the available science on quinoa.
What is quinoa?
Quinoa (Chenopodium quinoa willd) was called "the mother of all grains" by the Incas.
It's regarded as a pseudograin since it's not a grass like our other grains (wheat, oats, rice, sorghum etc.) and both its seeds and leaves can be eaten. However, the dried seeds (and not the leaves) are generally sold in supermarkets and health shops.
In the ancient civilisations of South America, quinoa was a valued staple food that was so highly regarded that it was deemed sacred. But with the arrival of the western Conquistadores in Peru in the 1500s, quinoa was banned because of the bitter taste of the seeds.
It's only now, after many centuries, that we're "rediscovering" the nutritional value of this food.
What research shows
Recent scientific studies have confirmed that quinoa has remarkable nutritional properties - not only from its protein content (15%), but also from its great amino-acid balance.
Quinoa has been found to contain more lysine (an amino acid that's usually lacking in plant foods) than other cereals. Quinoa also contains vitamins, minerals and compounds such as polyphenols, phytosterols and flavonoids - all of which have antioxidant and protective functions.
Nutritional values published on the internet vary, but the average nutritional composition of a cup of cooked quinoa, based on nutrition data supplied by the USDA SR-21 on the Nutrition Data website (2010), is as follows:
Serving size | 1 cup cooked (185g) | RDA or SDI* | % RDA |
Energy | 932 kJ (222 kcal) | ||
Protein | 8 g | 56 g | 14,3% |
Total fat | 4 g | ||
Total carbohydrates | 39 g | ||
Dietary fibre | 5 g | 20 g* | 25% |
Thiamin (vitamin B1) | 0.2 mg | 1.2 mg | 16,7% |
Riboflavin (vitamin B2) | 0.2 mg | 1.3 mg | 15.4% |
Pyridoxine (vitamin B6) | 0.2 mg | 1.3 mg | 15.4% |
Folate | 77.7 microgram | 400 mcg | 19.4% |
Iron | 2.8 mg | 18 mg | 15.6% |
Magnesium | 118 mg | 420 mg | 28.1% |
Phosphorus | 281 mg | 700 mg | 40.1% |
Potassium | 318 mg | 2000 mg* | 15.9% |
Sodium | 13 mg | 3000 mg* | 0.4% |
Zinc | 2 mg | 11 mg | 18.2% |
Copper | 0.4 mg | 2.3 mg* | 17.4% |
Manganese | 1.2 mg | 3.5 mg* | 34.3% |
RDA = Recommended Daily Dietary Allowance for individuals older than 13 years
SDI* = Suggested Daily Intakes
High energy content
One cup of cooked quinoa is a rich source of energy that supplies about 12% of the daily energy requirements for an adult woman who isn't trying to lose weight, and nearly 15% of the daily energy intake for a woman who is on an energy-reduced diet.
So, while quinoa is an excellent source of readily available fuel, which will make an important contribution to the energy needs of anyone who has a high energy demand (e.g. athletes, children and teenagers), slimmers should only eat moderate portions to prevent weight gain.
Have half a cup of cooked quinoa for breakfast to sustain you for the whole morning.
Macronutrients
Protein
A high protein content (8g per cup), and the fact that quinoa protein contains the nine so-called "essential amino acids", means that quinoa has an advantage over other grains and cereals.
It's particularly useful in the diet of vegetarians and vegans as a source of protein.
Carbohydrates and dietary fibre
Quinoa is also a rich source of carbohydrates and, with a low glycaemic index (GI) of 18, it should provide sustained energy for longer than most other grains. If you suffer from insulin resistance or diabetes, it may be a good idea to have half a cup of cooked quinoa as an alternative to high-GI starches.
The relatively high dietary fibre content will contribute to sustained energy and also prevent constipation.
Finally, the carbohydrate in quinoa is gluten-free, which makes it an excellent choice for people with gluten allergies or coeliac disease.
Fat
The total fat content of quinoa is low (4g per serving of 185g) and, like all cereals and grains, it doesn't contain any cholesterol.
Vitamins and minerals
According to the SA Food Labelling Regulations, any food that contains 15% of the RDA of a nutrient per serving can be regarded as a rich source of the specific nutrient. Quinoa is, therefore, a rich source of B vitamins, namely thiamin, riboflavin, vitamin B6 and folate.
This pseudograin is also rich in magnesium, phosphorus, potassium, zinc, copper and manganese.
The low sodium content of quinoa is regarded as a nutritional advantage, but keep in mind that if you add table salt to quinoa during cooking or food preparation, the sodium content will increase accordingly.
Possible risk
With all its positive attributes, quinoa is a food that can be eaten by most people without risk, but it does contain compounds called oxalates that can be a problem for anyone who struggles with oxalate kidney stones. If you're on an oxalate-reduced diet, it would be better to avoid eating quinoa.
In addition, some people may be allergic to quinoa - the first case report of an anaphylactic reaction to quinoa has already been reported in France. The saponins mentioned below, which need to be carefully rinsed off the seeds before cooking, are classified as toxic glycosides. If you're allergic to alfalfa, hops or soybeans, which also contain saponins, then it's possible that you may have a similar reaction to quinoa.
How to prepare quinoa
According to the WHFoods website, quinoa should be rinsed with water to remove the layer of soapy saponins that cover the seeds. This reduces the bitter taste and removes these potentially allergenic compounds.
Place the seeds in a fine-meshed sieve or colander and rub the seeds while rinsing under flowing water. Taste the washed seeds to see if they need additional rinsing.
Add one cup of quinoa seeds to two cups of water, and bring to the boil. Reduce heat, place a lid on the saucepan, and simmer for 15 minutes until the seeds become translucent.
- (Dr IV van Heerden, registered dietician, June 2015)
References:
- Abugoch JLE (2009). Chapter 1 Quinoa (Chenopodium quinoa, Willd.) Composition, chemistry, nutritional & functional properties. Advances in Food & Nutrition Research, Vol 58:1-31
- Allergy Net (2010)
- Astier C et al (2009). First case report of anaphylaxis to quinoa, a novel food in France. Allergy, Vol 64(5):819-20
- Berti C et al (2005). Effect on appetite control of minor cereals and pseudocereal products. British Journal of Nutrition, Vol 94(5):850-8; Fresh Earth (2010).
- Lee AR et al (2009). The effect of substituting alternative grains in the diet on the nutritional profile of the gluten-free diet. Journal of Human Nutrition & Dietetics, Vol 22(4):359-363; Nutrition Data (2010).
- Ruales J, Nair BM (1992). Nutritional quality of the protein in quinoa (Chenopodium quinoa, Willd) seeds. Plant Foods for Human Nutrition, Vol 42(1):1-11; WHFoods (2010).)
