Amaranth (Amaranthus spp.) is a traditional grain used in South America dating back to the Inca, Maya and Aztec civilizations. In some cases the leaves of the young plants can be used in salads, but most commonly it is the grain of the Amaranth plant that is used in breads and other baked products (1).
Recently amaranth has become popular in North America because of its nutraceutical properties and low risk of an allergic reaction. There are several proposed health benefits associated with amaranth consumption including: an improved nutritional profile, cholesterol reduction, antitumor effects, improvements in blood glucose levels, and anti-allergic properties. But does amaranth *really* have health benefits above and beyond the more commonly consumed grain products?
Amaranth appears to have a superior protein content and composition than several of the more traditional grains. Typically grains tend to be low in two essential amino acids, lysine and methionine; comparatively, amaranth has a higher concentrations of both of these amino acids (2). Amaranth grain also has a significant amount of unsaturated fatty acids as compared to many other grains (3). As with many other whole grains, amaranth also contains insoluble fibre and a small amount of soluble fibre, as well as vitamins and minerals.
Iron deficiency is one of the most common nutritional deficiencies around the world; consequently grain products are often fortified with iron to improve dietary intakes. Amaranth cereal naturally contains a small amount of iron (~ 3 mg per 125 ml), however, the cereal can also be fortified to increase the iron content (1). Rat studies have found that iron-fortified amaranth has good biological availability (read: it’s well absorbed) and regular consumption improved hemoglobin levels as well as iron levels in the liver and blood (4). In addition to iron, amaranth is also a decent source of calcium – 60 mg per 1/2 cup of cooked grain. You can see the complete nutritional profile of cooked amaranth grains from the Canadian Nutrient File.
Currently health claims exist for several different grain-based fibres with respect to their ability to lower cholesterol levels, specifically oat fibre and psyllium fibre. Although no health claim yet exists for amaranth, several animal studies have found that amaranth has cholesterol-lowering abilities. Furthermore, there is at least one human study to show that consuming of 18 ml per day of amaranth oil (just over 1 tbsp) for three weeks improved cholesterol levels in patients with cardiovascular disease (3). Exactly how amaranth oil lowers cholesterol is unclear but it may be due to one or several of the following properties: the unsaturated fatty acids, the phytochemicals (namely phytosterols – a plant product that is similar to cholesterol, tocotrienols, tocopherols, and squalene), inhibition of cholesterol synthesis and/or the amino acid composition of the protein component (1).
Antitumor Effects/Antioxidant Properties
The waters of diet and cancer are murky and amaranth is no exception! Recently, cancer cells have been used to evaluate the potential antitumor properties of an isolated protein from a strain of amaranth. The authors report that the amaranth protein extract suppressed cell division and increased tumor cell death (5). Amaranth also has antioxidant properties (6), therefore, may play a role in the prevention of several chronic diseases including cancer. Although promising, further studies are required before any conclusions can be made regarding the antitumor/antioxidant effects of amaranth. Furthermore, there is no indication of the dose necessary to induce health improvements in humans, if any truly exist.
As with all grains, the effects of amaranth on blood glucose levels should be carefully considered. On one hand, animal studies have found that when diabetic rats were given amaranth their blood glucose levels decreased and their insulin levels increased (7). Conversely, others are concerned about the effects of amaranth on blood glucose levels as its starch component is highly digestible giving it a high glycemic index rating. Foods that have a high glycemic index increase blood glucose levels and subsequently insulin levels, theoretically promoting cardiovascular disease and type 2 diabetes.
At present, although several studies support its classification of a high glycemic index food (8), the effects of chronic consumption on blood glucose regulation remains to be determined, particularly when having amaranth as a part of a meal. Given the paucity of studies regarding amaranth and blood glucose regulation, no definitive conclusions can be made. However, it is recommended that people with diabetes closely monitor their blood glucose levels if they are consuming amaranth on a regular basis, just as with most grains.
Perhaps the most promising feature of amaranth is its low risk of causing an allergic reaction. Amaranth does not contain gluten and is therefore an excellent grain choice for those with celiac disease or those simply wanting to decrease the gluten content of their diet (1). Interestingly, amaranth may actually have anti-allergic actions. Hibi et al. (9) found that amaranth contains components that can actually suppress allergic responses.
No Baloney’s advice? Amaranth certainly appears to be an excellent choice for those who cannot consume other gluten-containing grains. Additional research is required to make definitive claims regarding its health benefits but, other than the high glycemic index, it appears to be a highly nutritional grain – we say go ahead and give it a go! It can never hurt to increase the variety of grains in your diet. Stay tuned for Wednesday when Kristin will post one of her amazing amaranth recipes.
- Caselato-Sousa VM and Amaya-Farfan J. State of knowledge on amaranth grain: a comprehensive review. J Food Sci 2012; 77: R93- R104.
- Bressani R. The proteins of grain amaranth. Food Rev Intl 1989; 5:13-38.
- Martirosyan DM, et al. Amaranth oil application for coronary heart disease and hypertension. Lipids Health Dis 2007; 6:1-12.
- Ologunde MO, et al. Bioavailability to rats of iron from fortified grain amaranth. Plant Foods Hum Nutr 1994; 45:191-201.
- Barrio DA and Anon MC. Potential antitumor properties of a protein isolate obtained from the seeds of Amaranthus mantegazzianus. Eur J Nutr 2010; 49:73-82.
- Pasko P, et al. Effect of amaranth seeds in diet on oxidative status in plasma and selected tissues of high fructose-fed rats. Food Chem 2011; 126:85-90.
- Kim HK, et al. Antioxidative and antidiabetic effects of amaranth (Amaranthus esculantus) in streptozotocin-induced diabetic rats. Ann Nutr Metab 2006; 50:277-81.
- Capriles VD, et al. Effects of processing methods on amaranth starch digestibility and predicted glycemic index. J Food Sci 2008; 73:H160-4.
- Hibi M, et al. Amaranth grain inhibits antigen-specific IgE production through augmentation of the IFN-gamma response in vivo and in vitro. Cytotechnology 2003; 43:33-40.