Nutritionists Explain the Key Differences Between Chia Seeds and Flax Seeds

Sunflower, pumpkin and sesame seeds have been popular picks for decades, but now, chia and flax seeds are gaining the most traction in the food world. They’re both healthy in their own rights and equally versatile, but there are clear differences in taste, texture and nutrition stats.

To figure out how chia seeds compare to flax seeds traditionally, nutritionally and culinarily, we consulted two top registered dietitians. Below, they explain everything you need to know about chia seeds v. flax seeds so you can make the best choice for your eating plan.

“Chia seeds are edible, tiny black seeds that can grow into a plant that belongs to the mint family. They have been around for centuries and were a staple food for the Aztecs,” says Carmelita Lombera, R.D.N., a clinical dietitian and certified health coach in Sacramento, California. Meanwhile, “flax seeds are edible brown seeds that can be grown into a flowering plant. Their primary origin is France, but it's widely used today throughout the world.”

Flax seeds (L) and chia seeds (R).

Yes, they’re both seeds, but they’re consumed in different ways and offer different nutritional benefits. For instance, chia seeds are known for being able to absorb more than 10 times their size of liquids and acquire a jelly-like texture afterward while flax seeds are often ground up into a powder or turned into an edible oil, Lombera notes.

“Fiber is an excellent nutritional source for heart health and colon health, so regularly incorporating fiber into your diet not only can help regulate your bowels, but can be protective of heart disease and colorectal cancer,” says Sophie Balzora, M.D., a gastroenterologist at NYU Langone. Fortunately, seeds like chia and flax seeds tend to contain quite a bit of fiber.

“Chia seeds are higher in fiber than flax seeds, but both are great choices for anyone trying to increase their fiber intake,” says Lombera. According to the USDA, 2 Tbsp of chia seeds have about 7 g of fiber, but Lombera points out that the fiber content of flax seeds depends on which form of flax seed you’re eating. For example, 2 Tbsp of whole flax seeds have about 5 g of fiber, 2 Tbsp of flax seed meal have about 3 g of fiber, and flax seed oil does not have any fiber.

Our bodies need protein to help build and repair cells, especially in our muscle and bones. In terms of protein content, flax seeds are the winner here, but not by much. USDA data shows that 2 Tbsp of chia seeds have about 3.4 g of protein while 2 Tbsp of flax seeds have around 3.8 g of protein.

Omega-3 fatty acids are the ones you want to prioritize, and both chia seeds and flax seeds contain plant-based ALA omega-3s. Your body converts a limited amount of ALA to EPA and DHA, “which are anti-inflammatory and support heart and brain health,” says Lombera. That said, flax seeds have a leg up here. An ounce of flax seeds contains more than 6,000 mg of ALA while an ounce of chia seeds has 4,900 mg of ALA, according to Bob’s Red Mill, a food company that sells both seeds.

It depends on what vitamins and minerals you’re looking for. Here are some stats from the USDA nutrition database that compare the vitamin and mineral content of 2 Tbsp of chia seeds to 2 Tbsp of flax seeds.

Chia seeds

• Calcium 132.5 mg
• Magnesium 70.28 mg
• Phosphorus 180 mg
• Potassium 85.5 mg
• Zinc 1 mg
• Folate 10.2 mcg

Flax seeds

• Calcium 48.3 mg
• Magnesium 78.1 mg
• Phosphorus 116.8 mg
• Potassium 41.6 mg
• Zinc 1 mg
• Folate 8.6 mcg

Chia seeds contain more antioxidants, but flax seeds contain more of a specific type of antioxidant called lignans. Lignans are phytoestrogens, which may provide hormonal support. “I recommend flaxseed to anyone struggling with low estrogen symptoms such as hot flashes and weight gain,” says Lombera.

“Chia seeds taste great in foods such as oatmeal, yogurt and pudding because the seeds expand to form a gel-like texture but still have a little crunch,” says Lombera. “You can even add chia seeds to peanut butter and jelly to give your PB&J an extra fiber boost. The easiest way to add chia seeds to your diet is to add them to water, but not everyone likes drinking them.”

“Flax seeds pack some of the same nutrients, making it a healthy go-to option, but many note that this seed, compared to chia seeds, has a stronger, sometimes nuttier, flavor than chia seeds,” says Balzora. “You can consume them whole (but be sure to chew them thoroughly), ground or as flaxseed oil.” That said, she notes that grinding the seeds has been known to be most beneficial to access the omega-3-fatty acids.

Both seeds are good add-ins for smoothies and baked goods as well. But no matter how you decide to eat them, make sure you drink plenty of water, especially if your body isn’t used to a high-fiber diet. Increasing your fiber intake too quickly without enough liquid can actually work against your digestive system and lead to constipation.

Both chia seeds and flax seeds are optimal choices if you’re looking to add more high-fiber, nutrient-dense foods to your diet. “Start slow and consult your health care professional if you're not sure how to get started, especially if you're not used to eating a high-fiber diet regularly,” says Balzora. “Don't be afraid to experiment a bit with how you incorporate the seeds into the foods you love. You may surprise yourself, and your health will thank you!”

Medically reviewed byLaura Iu, R.D., C.D.N.

Laura Iu, R.D., is a registered dietitian nutritionist, certified intuitive eating counselor, yoga guide, and owner of Laura Iu Nutrition, a private practice in New York City. She earned her Bachelor of Science in Nutrition and Dietetics from New York University and completed her internship in dietetics at Weill Cornell & Columbia Medical Center of New York-Presbyterian Hospital. She went on to work in New York City’s top hospitals, including Mount Sinai Hospital and NYU Langone Health. She believes that true health is all encompassing — physical, emotional, and mental wellbeing — not an external measure via shape or size.