If you've ever been at the grocery store looking for some superfoods to add to your daily smoothies, you've likely come across flax and chia seeds. Both ingredients pack a ton of nutrition into a small package, but knowing the benefits of flaxseeds vs. chia seeds can help you decide on the best ingredient to add to your pantry.
Flaxseed, also called linseed, is harvested from the Linum usitatissimum plant and is known for its nutty flavor, says Katie Cavuto, a registered dietitian and executive chef at Frutta Bowls. Chia seeds, on the other hand, come from the Spanish sage plant and are smaller and lighter-flavored than flax (you may know them from chia pudding, in which the ultra-tiny particles are turned into little balls filled with healthy vitamins). Both ingredients are packed with nutrients like fiber, omega-3 fatty acids, protein, and more, all of which help support good digestion and heart health, says Stephanie Nelson, a registered dietitian and nutrition expert at MyFitnessPal. Whether you like to sprinkle the seeds on your oatmeal or grind them into juice, they can be easily added to most snacks and meals.
Curious about these small but mighty superfoods? Below, nutrition experts explain the differences between the two ingredients and how to choose the one that suits your cooking needs.
Benefits of Flax Seeds vs. Chia Seeds
They are a good source of fiber
If your goal is to increase your daily fiber intake, both flax and chia seeds can provide some help, says Lauren Minchen, a registered dietitian and nutrition consultant for Freshbit, an AI-powered visual food diary app. For context, there are two types of fiber: soluble fiber and insoluble fiber. She explains that soluble fiber dissolves in water to form a gel that helps food and waste move through the digestive tract more easily, which makes you feel fuller for longer. Insoluble fiber doesn't dissolve in water, so it helps move waste out of your digestive system, Nelson says.
Cavuto says both flaxseeds and chia seeds contain both types of fiber—in fact, fiber contains most of the carbohydrates in the seeds (8 and 12 grams of carbs per serving, respectively). But there's a difference: Chia seeds contain about 11 grams of fiber per serving, mostly soluble fiber, Minchen says. Flax contains about 8 grams of fiber per serving, but the insoluble fiber content is higher. Both types of fiber support healthy digestion, they just move in slightly different ways through the gut—think water slides and snowplows.
They improve digestion
Generally speaking, you don't digest soluble or insoluble fiber like most other foods. Rather than being absorbed into the body through the digestive tract, fiber remains relatively intact as it passes through your body, whether in gel form or otherwise. Nielsen says bacteria feed on it as it travels along the gut, which contributes to a healthy balance of microbes in the gut to promote good digestion. She adds that flax and chia seeds are both solid options to help you reap this benefit.
The gel formed in the digestive tract by chia seeds' soluble fiber can also help relieve diarrhea by sealing waste products together to form stronger stools, Minchen says. On the other hand, flaxseed's insoluble fiber can relieve constipation by moving waste products out of your system, she says. Chia seeds also contain some insoluble fiber, which can promote regular bowel movements, but if you're specifically looking to relieve constipation, flax seeds are your best choice, Minchen says.
Chia seeds can help you feel full
Chia seeds expand as they turn into digestive gel, so eating chia seeds can slow digestion and help you feel fuller longer than flax, says Minchen. That said, if you have a sensitive tummy, too many high-fiber chia seeds may cause unpleasant digestive symptoms like bloating, notes Cavuto. While flax won't make you feel full, she says it may be a better choice if your gut is giving you trouble. In general, if you're just starting to eat these fibrous seeds, she recommends "starting small and going light" so that your body has time to adjust.
They prevent blood sugar spikes
Because all fiber remains largely intact as it passes through the intestines rather than being absorbed into the body, both flax and chia seeds can help regulate how quickly you absorb carbohydrates and sugars from other foods. Cavuto said this can prevent blood sugar from rising after a meal.
They contain healthy fatty acids
In addition to fiber, Nelson says flaxseed and chia seeds are rich in a plant-based omega-3 fatty acid called alpha-linolenic acid (ALA) (about 6,400 mg and 4,900 mg per serving, respectively). Studies show that regular consumption of this fatty acid can reduce the risk of heart disease. Nelson says that if your goal is to increase your ALA intake, flax is your best choice—she simply recommends consuming flax in powder form to get as much of the nutrient as possible, since this is easier to digest than the whole seed.
they are nutritious
These seeds are also packed with other nutrients that can help you function at your best. Cavuto says both contain high levels of plant protein, with about 3 grams of flaxseed and 4 grams of chia per serving. She also says both are good sources of essential minerals like zinc, magnesium and calcium. That said, of the two, she particularly recommends chia seeds if you're looking to increase your calcium intake, as it provides about 18 percent of the recommended daily dose.
Which one should you eat?
Both flax and chia are powerful seeds—especially when it comes to fiber and plant protein—so it doesn't hurt to eat both, Minchen says. Minchin says it really depends on your taste and cooking preferences. Cavuto says chia seeds absorb up to 10 times their weight in liquid, so they're a great way to add texture to drinks. Flaxseeds—especially flaxmeal—are easily incorporated into most foods and beverages, but are less obvious. "This is a great example of the importance of diversity because both seeds provide a variety of nutrients," she said. Her tip? "Let's mix it up!"
Research references:
Fleming, J. (2014). Evidence for benefits of alpha-linolenic acid and cardiovascular disease: comparison with eicosapentaenoic acid and docosahexaenoic acid. Nutritional Advances, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4224228/
Kurczynski, B. (2019). Chemical composition and nutritional value of chia seeds—current state of knowledge. Nutrients, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6627181/
McCrory, J. (2015). An evidence-based approach to fiber supplements and clinically meaningful health benefits, Part 2. Nutrition Today, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4415970/
Nitrajova, S. (2014). Amino acid and fatty acid profiles of chia (Salvia hispanica L.) and flax (Linum usitatissimum L.) seeds. Slovak Journal of Food Science, http://www.potravinarstvo.com/journal1/index.php/potravinarstvo/article/view/332
Weikert, M. (2008). Metabolic effects of dietary fiber consumption and prevention of diabetes. Journal of Nutrition, https://pubmed.ncbi.nlm.nih.gov/18287346/
expert:
Katie Cavuto, MS, RD, registered dietitian and executive chef at Frutta Bowls
Lauren Minchen, MPH, RDN, CDN, registered dietitian nutritionist and nutrition consultant for Freshbit, an AI-powered visual food diary app
Stephanie Nelson, MS, RD, registered dietitian and nutrition expert at MyFitnessPal
