Here's How Flaxseeds & Chia Seeds Compare

If you’ve ever perused the grocery store looking for some superfoods to toss into your daily smoothie, then chances are you’ve encountered flax and chia seeds. Both ingredients pack a lot of nutrition into a tiny package, but understanding the benefits of flaxseed vs. chia seeds can help you decide which is the best one to add to your pantry.

Flaxseeds, also known as linseeds, are harvested from the Linum usitatissimum plant and known for their nutty flavor, says Katie Cavuto, MS, RD, a registered dietitian and executive chef for Frutta Bowls. Chia seeds, on the other hand, come from the Salvia hispanica plant, and are smaller and blander-tasting than flax (you may know them through chia seed pudding, where the super-small morsels become little balls that burst with healthy vitamins). Both ingredients are high in nutrients like fiber, omega-3 fatty acids, protein, and more, all of which can help support good digestion and heart health, according to Stephanie Nelson, RD, a registered dietitian and nutrition expert at MyFitnessPal. And they both make an easy addition to most snacks and meals, whether you prefer sprinkling the seeds over oatmeal or grinding them into your juice.

Curious about the small but mighty superfoods? Below, nutrition experts explain the differences between the two ingredients and how to pick the right one for your cooking needs.

The Benefits Of Flaxseeds Vs. Chia Seeds

They’re A Good Source Of Fiber

If you’re aiming to up your daily dose of fiber, both flax and chia seeds have something to offer, says Lauren Minchen, RD, a registered dietitian nutritionist and nutrition consultant for the AI-driven visual diet diary app Freshbit. For context, there are two kinds of fiber: soluble and insoluble. Soluble fibers dissolve in water to form a gel that helps food and waste slide more easily through your digestive tract, she explains, and these make you feel fuller for longer. Insoluble fibers don’t dissolve in water and thus help push waste through your digestive system, according to Nelson.

Flax and chia seeds each contain both types of fiber — in fact, fiber comprises most of the carbohydrates in the seeds (8 and 12 grams of carbs per serving, respectively), says Cavuto. But there’s a difference between the two: Chia has about 11 grams of fiber per serving, with predominately soluble fibers, says Minchen. Flax has about 8 grams of fiber per serving, but is heavier on the insoluble fibers. Both types of fiber support healthy digestion, they just move through your intestines a little differently — think a water slide versus snowplow.

They Improve Digestion

In general, you don’t digest soluble or insoluble fiber like most other food. Instead of absorbing into your body through your digestive tract, fiber stays relatively intact as it travels through you whether it’s in gel form or otherwise. Bacteria feast on it as it moves along your intestines, which supports a healthy balance of microbes in your gut for good digestion, says Nelson. Flax and chia are both solid options to help you reap this benefit, she adds.

The gel that forms in your digestive tract from chia’s soluble fibers can also help relieve diarrhea by sealing waste together into more solid stool, says Minchen. Flaxseed’s insoluble fibers, on the other hand, can ease constipation by moving waste out of your system, she says. Chia also has some insoluble fiber to promote regular poops, but if you’re specifically looking for constipation relief, flaxseed is your best bet, says Minchen.

Chia Helps You Feel Full

Chia expands as it turns into that digestive gel, so eating the seeds can slow digestion to help you feel full for longer compared to flax, according to Minchen. That said, if you have a sensitive tummy, too much high-fiber chia could cause unpleasant digestive symptoms like bloating, notes Cavuto. While flax won’t make you feel quite as full, she says it may be a better option if your intestines give you trouble. In general, she recommends that you “start small and tread lightly” if you’re just starting to eat these fibrous seeds so that your body has time to adjust.

They Can Prevent Blood Sugar Spikes

Since all fiber stays mostly intact as it passes through your intestines rather than absorbing into your body, both flax and chia can help temper how quickly you absorb carbs and sugars from the rest of your food. This can prevent blood sugar spikes after a meal, according to Cavuto.

They Contain Healthy Fatty Acids

Beyond fiber, both flax and chia seeds are also rich in a plant-based omega-3 fatty acid called alpha-linolenic acid (ALA) (about 6,400 milligrams and 4,900 milligrams per serving, respectively), says Nelson. Research shows that consuming this fatty acid regularly could lower your risk for heart disease. If you’re aiming to boost your ALA intake, flax is the way to go, Nelson says — she just recommends eating it in powder form to get the most nutrients possible, since that’s easier to digest than the whole seed.

They’re Nutrient-Dense

The seeds are also packed with other nutrients that help you function your best. Both contain high levels of plant protein, with flax clocking in at about 3 grams per serving and chia at 4 grams, says Cavuto. She also says that both are also good sources of essential minerals like zinc, magnesium, and calcium. That said, of the two, she recommends chia if you’re hoping to boost your calcium intake in particular as it provides about 18% of your daily recommended dose.

Which One Should You Eat?

Both flax and chia are powerhouse seeds — especially in the fiber and plant protein departments — so it can’t hurt to take both, says Minchen. It really just comes down to your taste and cooking preferences, says Minchen. Chia absorbs up to 10 times its weight in liquid, so it can be a great way to add some texture to drinks, says Cavuto. Flaxseed — particularly ground flax — is easy to incorporate into most foods and drinks less noticeably. “This is a great example of the importance of variety, as both seeds offer a variety of nutrients,” she says. Her tip? “Mix it up!”

Studies referenced:

Fleming, J. (2014). The Evidence for α-Linolenic Acid and Cardiovascular Disease Benefits: Comparisons with Eicosapentaenoic Acid and Docosahexaenoic Acid. Advances in Nutrition, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4224228/

Kulczyński, B. (2019). The Chemical Composition and Nutritional Value of Chia Seeds—Current State of Knowledge. Nutrients, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6627181/

McRorie, J. (2015). Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 2. Nutrition Today, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4415970/

Nitrayová, S. (2014). Amino acids and fatty acids profile of chia (Salvia hispanica L.) and flax (Linum usitatissimum L.) seed. Slovak Journal of Food Sciences, http://www.potravinarstvo.com/journal1/index.php/potravinarstvo/article/view/332

Weickert, M. (2008). Metabolic effects of dietary fiber consumption and prevention of diabetes. Journal of Nutrition, https://pubmed.ncbi.nlm.nih.gov/18287346/

Experts:

Katie Cavuto, MS, RD, a registered dietitian and executive chef for Frutta Bowls

Lauren Minchen, MPH, RDN, CDN, a registered dietitian nutritionist and nutrition consultant for the AI-driven visual diet diary app Freshbit

Stephanie Nelson, MS, RD, a registered dietitian and nutrition expert at MyFitnessPal