We all know that eating flax, chia, and hemp seed is good for our health (even if we aren’t entirely sure why). In a nutshell – or should I say, a “seed” shell – flax, chia, and hemp all contain alpha linolenic acid (ALA for short); the parent fat of the omega 3 family. Susan Macfarlene here to discuss these important omega 3 sources.
Omega 3 is an essential fat because our body is unable to make it (although we can convert small amounts of ALA into DHA and EPA, the type of omega 3 found in algae and animals that eat algae). The heart healthy benefits of consuming omega 3 have been well-established, although most of these benefits have been attributed to EPA and DHA. In a recent review (1), ALA was found to have a modest benefit in the prevention of heart disease, diabetes, and osteoporosis, and demonstrated the following health-promoting properties (1):
- Reduced hardening of plaque
- Lowered blood cholesterol
- Promoted healthy artery walls
- Prevented clots from forming
- Prevented arrhythmia
- Lowered inflammation
However, what research on ALA does not answer is what the best source is between the popular choices of chia, flax, and hemp seed.
One of the first crops domesticated by humans, flax has been commercially produced in the United States since 1753 and is used today for both its oil and seed (2). By weight, flax is 41% fat, 20% protein, and 28% fibre (containing both soluble and insoluble fibre), with a highly desirable omega 6 to omega 3 ratio of approximately 0.3:1 (3). In addition to being a good source of vitamin E (3), flax seeds also contain calcium, magnesium, and phosphorus. The nutritional composition of 100 g and 1 tbsp of ground flaxseeds seeds can be viewed below (USDA database):
|Nutr. Info||100 g||1 tbsp (7 g)|
|Omega 3 (g)||22.8||1.6|
|Omega 6 (g)||5.9||0.4|
Flax seeds are also rich in bioactive substances, most notably lignans, which exert health-promoting properties as a phytoestrogen and antioxidant (3). For example, lignans from flax seed have been shown to decrease biomarkers of breast cancer in premenopausal women (4), as well as supress the growth of tumours (5). Furthermore, the bioactive substances in flax may lower cholesterol (especially in post-menopausal women), reduce the risk of comorbidities associated with obesity, and mitigate inflammation (3).
Chia seeds are a relative of the mint family and were traditionally used in Central and South America as a medicinal and staple food (6). In North America, chia seeds gained popularity in the 1980s as “Chia Pets”; terracotta figurines that sprouted chia seeds to resemble an animal’s fur or hair. Nowadays, people are more likely to consume, rather than grow, chia seeds, thanks in part to their impressive nutritional profile.
By weight, chia seeds are 53% fat, 35% carbohydrate, and 12% protein (containing all nine essential amino acids) and are a good source of both insoluble and soluble fibre (6). In addition, chia seeds are high in antioxidants and contain the minerals calcium, magnesium, phosphorus, potassium, and selenium. Unlike flax seeds, which in their whole form will pass through digestion unabsorbed, chia seeds can be digested and absorbed in their whole form (6). The nutritional composition of 100 g and 1 tbsp of chia seeds can be viewed below (USDA database):
|Nutr. Info||100 g||1 tbsp (11 g)|
|Omega 3 (g)||17.8||2.0|
|Omega 6 (g)||5.8||0.6|
There is a lack of high-quality evidence to support the use of chia seeds in the prevention and management of chronic diseases. Nonetheless, a few studies have suggested that chia seeds may help prolong satiety (7), reduce blood pressure and inflammation, and keep post-meal blood sugars stable (8).
Hemp seed has seen its fair share of controversy since it hails from the same plant as marijuana. Because of this, both Canada and the United States had regulations that limited, or outright banned, the growing of hemp seed, despite its very low content of THC (~0.2%), which is effectively removed by processing and cleaning (9,10). Thankfully, these bans have been lifted, allowing North Americans to reap the nutritional benefits of these hearty seeds.
By weight, hemp seeds are 20% to 25% protein, 20% to 30% carbohydrate, 25% to 35% fat, and 10% to 15% insoluble fiber (11). In addition, they are a good source of magnesium, phosphorus, iron, and manganese, and contain incredibly high levels of antioxidants (11). The nutritional composition of 100 g and 1 tbsp of chia seeds can be viewed below (USDA database):
|Nutr. Info||100 g||1 tbsp (10 g)|
|Omega 3 (g)||8.7||0.9|
|Omega 6 (g)||28.7||2.9|
Hemp seeds are unique in that they contain stearidonic acid (SDA); an intermediary in the pathway that converts ALA into the longer-chain EPA and DHA (11). Because of the presence of SDA, it is possible that an increased amount of EPA and DHA could be made from hemp seeds (compared to other plant sources of omega 3), but this has yet to be proven through research.
Similar to flax and chia, the fatty acid profile of hemp seeds exerts a favourable effect on lipid profile and markers of cardiovascular health (11). Furthermore, hemp seeds and oil contain phytosterols, which are plant-derived compounds that resemble cholesterol but have an LDL-lowering effect (12, 13).
Which to Choose – Hemp, Flax, or Chia Seed?
What’s clear is that flax, hemp, and chia seeds are all an excellent choice and provide a good source of plant-derived ALA, along with an array of nutrients and antioxidants. Of the three, flax provides the highest source of ALA and most ideal ratio of omega 6 to 3. On the other hand, hemp is the highest in protein and provides an excellent source of zinc, while chia seeds are the highest in calcium and fibre. To me, there is no clear winner among the 3, which is why I recommend including all of them in your diet. Just keep in mind that because of the high antioxidant and polyunsaturated content of these fats, it’s best to store them in your fridge or freezer and be mindful of cooking practices that could introduce free-radicals, such as high-temperature cooking.
Remember to signup at cronometer.com to see the complete nutritional breakdown of all your food.
- Rajaram S. Health benefits of plant-derived α-linolenic acid. Am J Clin Nutr. 2014 Jul;100 Suppl 1:443S-8S. Abstract from: https://www.ncbi.nlm.nih.gov/pubmed/24898228.
- Oplinger ES, Oelke EA, Doll JD, Bundy LG, and Schuler RT. Flax. Alternative Field Crops Manual, University of Wisconsin-Extension, Cooperative Extension, University of Minnesota: Centre for Alternative Plant & Animal Products and the Minnesota Extension Service. 1997 Nov. Available from: https://hort.purdue.edu/newcrop/afcm/flax.html.
- Cardoso Carraro JC, Inês de Souza Dantas M, Rocha Espeschit AC, Stampini Duarte Martino H, Machado Rocha Ribeiro S. Flaxseed and Human Health: Reviewing Benefits and Adverse Effects. Food Reviews International. 2012;28:2, 203-230. Abstract from: https://www.tandfonline.com/doi/abs/10.1080/87559129.2011.595025.
- Fabian CJ, Kimler BF, Zalles CM, Klemp JR, Petroff BK, Khan QJ, et al. Reduction in Ki-67 in benign breast tissue of high-risk women with the lignan secoisolariciresinol diglycoside. Cancer Prev Res (Phila). 2010 Oct;3(10):1342-50. Abstract from: https://www.ncbi.nlm.nih.gov/pubmed/20724470.
- Saggar JK, Chen J, Corey P, Thompson LU. The effect of secoisolariciresinol diglucoside and flaxseed oil alone and in combination, on MCF-7 tumor growth and signaling pathways. Nutr Cancer. 2010;62(4):533-42. Abstract from: https://www.ncbi.nlm.nih.gov/pubmed/20432175
- Santora Zimmerman J. Health Benefits of Chia — Learn About Its History, Nutrient Composition, and Current Research Regarding Its Health Benefits. Today’s Dietitian. 2017 Jan;19(1):44. Available from: http://www.todaysdietitian.com/newarchives/0117p44.shtml.
- Vuksan V, Jenkins AL, Dias AG, et al. Reduction in postprandial glucose excursion and prolongation of satiety: possible explanation of the long-term effects of whole grain Salba (Salvia Hispanica L.). Eur J Clin Nutr. 2010;64(4):436-438. Abstract from: https://www.ncbi.nlm.nih.gov/pubmed/20087375.
- Vuksan V, Whitham D, Sievenpiper J, et al. Supplementation of conventional therapy with the novel grain Salba (Salvia hispanica L.) improves major and emerging cardiovascular risk factors in type 2 diabetes: results of a randomized controlled trial. Diabetes Care. 2007;30(11):2804-2810. Abstract from: https://www.ncbi.nlm.nih.gov/pubmed/17686832.
- Cherney JH, Small E. Industrial hemp in North America: production, politics and potential. Agronomy. 2016;6(4):58.
- Leson G, Pless P, Grotenhermen F, Kalant H, ElSohly MA. Evaluating the impact of hemp food consumption on workplace drug tests. J Anal Toxicol. 2001;25(8):691-698. Abstract from: https://www.ncbi.nlm.nih.gov/pubmed/11765026.
- Hultin G. Health Benefits of Hemp Seeds. Today’s Dietitian. 2018 May;20(5):44. Available from: http://www.todaysdietitian.com/newarchives/0518p44.shtml.
- Leizer C, Ribnicky D, Poulev A, Dushenkov S, Raskin I. The composition of hemp seed oil and its potential as an important source of nutrition. J Nutraceuticals Funct Med Foods. 2000;2(4):35-53. Abstract from: https://www.tandfonline.com/doi/abs/10.1300/J133v02n04_04.
- Lee MJ, Park SH, Han JH, et al. The effects of hempseed meal intake and linoleic acid on Drosophila models of neurodegenerative diseases and hypercholesterolemia. Mol Cells. 2011;31(4):337-342. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/21331775.