They are both called superfoods. Both are on every list of "healthy foods" you can find online. But if you could only add one seed to your diet, chia or flax, which one would help you reach your goals more?
There is a good reason why chia seeds and flax seeds are so well-known. Chia has become very popular since the early 2010s, thanks in part to pudding bowls and smoothie toppings that look good on Instagram. Flax, on the other hand, has been a quiet staple in health-conscious kitchens for decades, long before the term "superfood" was even used in marketing.
But just because something is popular doesn't mean you should buy it. Using data from USDA FoodData Central, this guide compares chia and flax seeds on all the important factors, including protein, omega-3, fiber, calories, calcium, iron, magnesium, and more. By the end, you'll know exactly which seed is best for you.
II. Quick Comparison TableFull Nutrition Table for Chia and Flax Seeds
Here is the full comparison for a standard serving size of 28g (1 oz). You can also change the serving sizes and see charts with our comparison tool.
| Nutrient | Chia Seeds (28g) | Flax Seeds (28g) | Winner |
|---|---|---|---|
| Calories | 138 kcal | 150 kcal | Chia |
| Protein | 4.7 g | 5.1 g | Flax |
| Total Fat | 8.7 g | 12 g | Chia |
| Carbohydrates | 11.9 g | 8.2 g | Flax |
| Fiber | 9.8 g | 7.8 g | Chia |
| Omega-3 (ALA) | 5,060 mg | 6,380 mg | Flax |
| Calcium | 179 mg | 71 mg | Chia |
| Iron | 2.2 mg | 1.6 mg | Chia |
| Magnesium | 95 mg | 110 mg | Flax |
Chia wins 5 categories, Flax wins 4. But as you'll see below, the winner really depends on which nutrients are most important for your goals.
III. Macronutrient BreakdownBreakdown of Macronutrients
Chia has fewer calories (138 vs. 150)
Chia seeds have 12 fewer calories per ounce than flax seeds. That's not a big difference, but if you're not getting enough calories, every little bit helps, especially if you're adding seeds to your meals every day. That's about 360 fewer calories from chia over the course of a month.
Flax wins by a small amount (5.1g vs. 4.7g) in protein
Flax has 0.4 grams more protein per ounce than chia. To be honest, the difference is so small that neither seed should be your main source of protein. Hemp seeds (9.5g per ounce) are much better than either of these if protein is your top priority.
Chia has less fat (8.7g vs. 12g)
Per serving, flax seeds have 38% more fat than chia seeds. Both have healthy unsaturated fats, but if you're watching how much fat you eat, chia has less fat per serving and more nutrients.
Flax has fewer carbs (8.2g vs. 11.9g)
Flax has 31% fewer carbs, which is good for people who are on a keto or low-carb diet. But most of chia's carbs come from fiber (9.8g out of 11.9g), so the net carbs are about the same: chia has about 2.1g net carbs and flax has 0.4g.
Chia has a lot more fiber than flax (9.8g vs. 7.8g)
This is the best thing about chia. Chia has 9.8 grams of fiber per ounce, which is almost 40% of the daily fiber intake that is recommended. That's 26% more fiber than flax. When chia's soluble fiber mixes with liquid, it forms a gel that helps with fullness, blood sugar control, and regular digestion.
The Big Difference: Omega-3 Fatty Acids
If you looked up "chia vs flax seeds" just for omega-3, here is your answer: flax wins by a long shot.
Flax seeds have 6,380mg of ALA (alpha-linolenic acid) per ounce, which is 26% more omega-3 than chia seeds, which have 5,060mg. Flax seeds are the best plant food for getting ALA omega-3 fatty acids.
What does omega-3 do? The American Heart Association says that getting enough omega-3s can lower the risk of heart disease, lower inflammation, and improve cholesterol levels. It has been shown that ALA lowers blood pressure and triglyceride levels.
The Problem of Conversion
Keep in mind that both chia and flax contain ALA omega-3, which is different from the EPA and DHA forms found in fish oil. Research published in the British Journal of Nutrition says that your body can change ALA into EPA and DHA, but the rate of conversion is low—usually only 5–10% for EPA and less than 1% for DHA.
This doesn't mean that plant-based omega-3 is useless; ALA has its own benefits. If you only eat seeds for omega-3, you might want to think about taking an algae-based DHA supplement with your seeds.
V. Vitamins & MineralsComparison of Vitamins and Minerals
Chia has more calcium than anything else (179mg vs. 71mg)
Chia seeds have 2.5 times as much calcium as flax seeds: 179mg per ounce compared to 71mg. One serving has about 18% of your daily value, while a glass of milk has 300mg. Chia seeds are one of the best plant-based sources of calcium if you don't eat dairy, are vegan, or can't tolerate lactose.
Chia has more iron (2.2mg) than flax (1.6mg)
Chia has 37% more iron in each serving. That's about 12% of the daily value for men at 2.2mg. Pumpkin and sesame seeds have about twice as much iron as other seeds.
Flax has more magnesium (110mg vs. 95mg)
Flax has a little more magnesium than the other plant, 110mg vs. 95mg. Both are good sources (23–26% of daily needs), but if you want magnesium, hemp seeds (210mg) are the best seeds.
Other Important Micronutrients
- Manganese: Both seeds are great sources of this mineral, which is good for bone health and metabolism
- Phosphorus: Flax has a little more, which is good for your teeth and bones
- Thiamine (B1): Flax is very high — 31% of the daily value per ounce. This is important for how your body uses energy
- Zinc: Both give a small amount, but pumpkin seeds have more of it
Which Seed Will Help You Reach Your Goal?
Chia Wins for Losing Weight
It has fewer calories (138 vs. 150), more fiber (9.8g vs. 7.8g), and it makes a gel that keeps you full longer. If you're trying to lose weight, chia is the better choice.
Flax Wins (Barely) for Building Muscle
It has a little more protein (5.1g vs. 4.7g) and magnesium to help muscles recover. But really, neither seed is a good source of protein. If you want protein, add hemp seeds.
Flax Wins for Heart Health
26% more omega-3 (6,380mg vs 5,060mg ALA) and lignans, which are plant compounds that studies have linked to a lower risk of heart disease. The American Heart Association says that foods high in omega-3s are good for your heart.
Chia is better for Bone Health
More calcium (179mg vs. 71mg) and iron (2.5 times more). Chia provides 18% of the daily calcium needs per ounce. This is important for bone density, especially for women over 40.
How to Eat Flax and Chia Seeds
Chia Seeds: Simple and Useful
- Chia pudding: mix 3 tablespoons of chia with 1 cup of liquid and chill overnight
- Thickener for smoothies: To get more fiber, add 1 tbsp to any smoothie
- Egg substitute: To make a "chia egg" for baking, mix 1 tablespoon of chia with 3 tablespoons of water
- Sprinkle raw: Just sprinkle it on yogurt, oatmeal, or salads — no need to prepare it
Flax Seeds — First, grind them
- Oatmeal boost: Add 2 tablespoons of ground flax to your morning oats to give them a boost
- Baking: Use ground flax instead of some of the flour in muffins, pancakes, or bread
- Smoothies: Mix 1 to 2 tablespoons of ground flax into smoothies; you won't taste it
- Egg substitute: One "flax egg" is made by mixing 1 tablespoon of ground flax with 3 tablespoons of water
Cost and Availability
You can find both seeds in grocery stores, health food stores, and online stores. You can usually expect to pay this much:
| Seed | Avg. Price (per lb) | Cost per Serving (1 oz) |
|---|---|---|
| Chia Seeds | $8 – $12 | $0.50 – $0.75 |
| Flax Seeds (whole) | $3 – $6 | $0.19 – $0.38 |
| Flax Meal (pre-ground) | $5 – $9 | $0.31 – $0.56 |
Flax seeds are a lot cheaper — often half the price of chia. If you're on a budget, flax is a great value for the money. Buy whole flax seeds and grind them yourself for the freshest and cheapest option.
IX. Final VerdictFinal Decision: Chia or Flax?
After looking at all the numbers, we honestly think you should use both.
They can't be used in place of each other. Chia is great for fiber, calcium, and being easy to use (no grinding needed). Flax has more omega-3, more protein, and costs a lot less. They cover up each other's weak points.
If you had to choose just one:
- Choose chia if you want more fiber, calcium, and iron, or if you want something easy to eat (no prep needed)
- Choose flax if you want the most omega-3 for heart health, if you're on a budget, or if you need more protein and magnesium
Me? I have both of them in my pantry. I put chia seeds in my smoothies and pudding that I make the night before. I put ground flax in my oatmeal and when I bake. For $15 a month, you can get fiber, omega-3, calcium, and iron all in one daily habit.
🔬 Compare Chia vs Flax Yourself
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⚡ Open Compare ToolFrequently Asked Questions
Can I eat both chia and flax seeds every day?
Yes. There's no nutritional conflict between them. Many nutritionists recommend combining them since they have complementary profiles — chia for fiber and calcium, flax for omega-3. A typical daily amount is 1-2 tablespoons of each. Start with smaller amounts if you're new to high-fiber foods to avoid digestive discomfort.
Which has more protein — chia or flax?
Flax seeds have slightly more protein: 5.1g vs 4.7g per ounce. The difference is small (0.4g). If protein is your main goal, neither is ideal — hemp seeds deliver 9.5g of complete protein per ounce, nearly double either option.
Do I need to grind chia seeds?
No. Unlike flax seeds, chia seeds can be eaten whole and your body will still absorb the nutrients. Grinding chia may slightly improve absorption, but it's not necessary. Soaking them in liquid (for pudding or drinks) also works well.
Which seed is better for constipation?
Chia seeds are generally better for constipation relief. They have 26% more fiber (9.8g vs 7.8g) and their soluble fiber absorbs water, forming a gel that adds bulk and softness to stool. Drink plenty of water when eating chia seeds to maximize this effect.
References
- USDA FoodData Central — Chia Seeds, dried (NDB #170554). fdc.nal.usda.gov
- USDA FoodData Central — Flaxseed, ground (NDB #169414). fdc.nal.usda.gov
- American Heart Association. "Fish and Omega-3 Fatty Acids." heart.org
- Burdge GC, Calder PC. "Conversion of alpha-linolenic acid to longer-chain polyunsaturated fatty acids." British Journal of Nutrition. 2005;93(3):331-42.
- National Institutes of Health. Office of Dietary Supplements — Calcium, Iron, Magnesium Fact Sheets. ods.od.nih.gov