Flax, Chia and Hemp - what is the difference?

A doctor friend of mine asked for advice about changing up his morning smoothie recipe.  He currently uses almond milk, banana, spinach or kale, and ground flax seed.  He asked what I thought about chia and hemp seeds.  Here is my reply.

Aside from dark green leafy vegetables, seeds are one of the most nutritious foods humans eat.  The seed provides all the building blocks necessary to generate a brand new baby plant - so it makes sense that seeds are packed with healthy fats, digestible proteins, vitamins, minerals and fiber.  Eating seeds contributes to a healthy diet - but each type has a slightly different nutrient composition.

Per 1 tablespoon, flaxseeds contain 1.9 g protein, 2.8 g fiber and 2.96 g polyunsaturated fatty acids (PUFA).

In contrast, 1 tablespoon chia seeds contain 1.7 g protein, 3.5 g fiber and 2.74 g PUFA.  Hemp seeds contain 3.3 g protein, 1 g fiber and 3.3 g PUFA.

Note: The nutrients listed for flax and chia can be found on the USDA Nutrient Database.  Not surprisingly, hemp seeds are not included in the USDA Nutrient Database, so I used the Nutrition Facts panel on a sample of Manitoba Harvest Hemp Hearts instead.

If your goal is to get more protein, hempseeds are a better choice than flax or chia.

If you goal is to get more fiber, chia seeds win.

If your goal is omega-3 fatty acids, both flax and chia are better than hemp - as they have more ALA (an omega-3 fatty acid) and a better w6:w3 ratio (read: more anti-inflammatory).

Food	Serving Size	ALA (% of FA)	LA (% of FA)	Ratio of w6:w3	ALA (g/serving)
Chia seeds	2 T/30 ml (20 g)	61	20	0.33:1	4
Flaxseed oil	1 T/15 ml (14g)	57	16	0.28:1	7.8
Flaxseeds, ground	2 T/30 ml (14 g)	57	16	0.28:1	3.2
Flaxseeds, whole	2 T/30 ml (20.6 g)	57	16	0.28:1	4.8
Greens, mixed	1 C/250 ml (50-60 g)	56	11	0.19:1	0.1
Hempseed oil	1 T/15 ml (14 g)	20	61	3:1	2.8
Hempseeds	2 T/30 ml (20 g)	20	61	3:1	1.2
Walnuts (English)	1/4 C/60 ml (28 g)	14	58	4:1	2.6

Table from an article in Today's Dietitian (Feb 2010).