Chia seeds vs Flax seeds

The short answer

Two omega-3-rich seeds, both dried. Chia is higher in fibre and calcium and gels in liquid; flax carries a bit more protein and the same omega-3 (best ground to absorb it). Chia for the gel and calcium, flax for a nutty, ground topping.

Chia seeds and Flax seeds, per 100 g and per portion. A gap means USDA has no value for it — not zero.

Chia seeds · per 100 gFlax seeds · per 100 g
Calories486534
Protein16.5 g18.3 g
Fat30.7 g42.2 g
Carbs42.1 g28.9 g
Fiber34.4 g27.3 g
Sugarsno data1.6 g
Sodium16 mg30 mg
Vitamins & minerals — where both carry data
Calcium631 mg255 mg
Folate49 µg87 µg
Iron7.7 mg5.7 mg
Magnesium335 mg392 mg
Niacin8.8 mg3.1 mg
Phosphorus860 mg642 mg
Potassium407 mg813 mg
Riboflavin0.2 mg0.2 mg
Thiamin0.6 mg1.6 mg
Vitamin Ano data0 µg
Vitamin B120 µg0 µg
Vitamin B6no data0.5 mg
Vitamin C1.6 mg0.6 mg
Vitamin Dno data0 µg
Vitamin E0.5 mg0.3 mg
Vitamin Kno data4.3 µg
Zinc4.6 mg4.3 mg
At equal calories (per 100 kcal)
ProteinChia seeds: 3.4 g, Flax seeds: 3.4 g · FiberChia seeds: 7.1 g, Flax seeds: 5.1 g · SodiumChia seeds: 3.3 mg, Flax seeds: 5.6 mg

Generic USDA foods (not brands), so both carry micronutrients. Numbers are per 100 g unless the portion toggle is on. USDA FoodData Central, as of 2026-08-12.

Common questions
Is Chia seeds or Flax seeds better?

Neither is “better” on its own — it depends what you want from it. The table shows where each is higher; the short answer says when each one fits. Compare on the same basis (per 100 g) and pick for your dish and your goal.

How were these numbers worked out?

Straight from USDA FoodData Central for the generic form of each food, per 100 g. We show the portion view too, but portion sizes differ between foods, so per 100 g is the fair comparison.

Why does one column say “no data”?

Because USDA has no value for that nutrient in that food — so we leave it blank rather than print a 0 that would read as “none”. A real zero from USDA still shows as 0.

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