Tiny but mighty, seeds are powerhouses of nutrition. And if you want to incorporate the healthiest ones into your diet, you’re likely choosing between chia seeds vs. flax seeds. So, is one of these seeds superior from a nutrition and health perspective?
Meet the experts: Anar Allidina, M.P.H., R.D., a registered dietitian based in Toronto; Vicki Koenig, R.D., C.D.N., a masters-level registered dietitian based in New Paltz, NY.
Here, dietitians share the perks you can expect from eating chia seeds and flax seeds, plus which may help you reach your goals faster (depending on what they may be).
Chia seeds vs. flax seeds: Nutrition
Chia seeds and flax seeds have things in common nutrition-wise, though there are some key differences.
Chia seeds nutrition
A typical serving size for chia seeds is about two tablespoons, or roughly 25 grams (g). Per the U.S. Department of Agriculture (USDA), two tablespoons of dry, raw chia seeds contains:
- 129 calories
- 4 g of protein
- 8 g of fat
- 9.5 g of carbohydrates
- 10 g of fiber
Flax seeds nutrition
A serving size of raw flax seeds is a similar size. According to the USDA, 25 g of flax seeds contains:
- 136 calories
- 4.5 g of protein
- 9 g of fat
- 8.5 g of carbohydrates
- 5.75 g of fiber
Chia seeds benefits
The biggest benefits that chia seeds offer are the ways they impact digestion and feelings of fullness, says Anar Allidina, M.P.H., R.D., a registered dietitian based in Toronto. But they’re so tiny, you may think, how could they possibly affect satiety? “Chia seeds absorb up to 10 to 12 times their weight in water, forming a gel,” explains Allidina. “This gel in our gut slows digestion, helping with fullness, and supports blood sugar balance. And because chia seeds hold onto moisture, they are great for hydration.”
Chia seeds also contain alpha-linoleic acid (ALA), an omega-3 fatty acid that has anti-inflammatory properties, says Vicki Koenig, R.D., C.D.N., a masters-level registered dietitian based in New Paltz, NY. It’s likely the combination of these healthy fats and the impressive dose of soluble fiber that delivers the other benefits of chia seeds. “Numerous studies and meta-analyses indicate that adding chia seeds to your diet produces modest but statistically significant improvements in blood pressure, total cholesterol, LDL cholesterol, triglycerides, central adiposity, and inflammatory biomarkers,” Koenig says.
What’s more, there are many different ways to eat and get the benefits of chia seeds. Adding them to yogurt, oatmeal, or a smoothie and then consuming them right away means they will form a gel-like substance in your stomach to increase satiety. Conversely, you can soak them before eating them, making a chia pudding that may help you feel full even faster after eating.
Potential downsides of chia seeds
“Chia seeds are generally well tolerated but can cause some bloating, gas, and diarrhea in larger amounts,” Koenig says. She adds that because they rapidly absorb liquid when exposed to it, it’s important to eat them with enough fluid (that includes things like yogurt or a blended fruit smoothie). Otherwise, they may pose a choking risk.
Flax seeds benefits
“Flax seeds are another seed that is packed with great nutrition,” says Allidina. Like chia seeds, flax seeds are rich in fiber, though they don’t contain as much. Still, Allidina notes that “flax seeds help support gut motility, which is great for those who suffer from constipation. They also help support metabolic and heart health.” In addition to fiber, flax seeds also contain the omega-3 fatty acid ALA and lignans, which are plant compounds that may support hormone balance. A 2025 review found that eating flax seeds may improve body weight, blood pressure, inflammation, and oxidative stress, among other cardiometabolic risk factors, thanks to the benefits these three nutrients offer.
To get the full health-boosting power of flax seeds, Koenig and Allidina agree that you should choose ground flax seeds as opposed to whole. “Intact seeds may pass through the gastrointestinal tract undigested, reducing bioavailability of beneficial lignans, fiber, and fatty acids,” Koenig explains. “Ground flax can be added to oatmeal, cereal, baked goods, yogurt, and smoothies.”
Potential downsides of flax seeds
As is the case with chia seeds, Koenig says that flax seeds may also cause GI symptoms like bloating, gas, diarrhea, or constipation, especially if you rapidly increase your intake. “Adequate hydration is needed to help push the fiber through,” says Allidina, noting that if you’re drinking plenty of water, you’re less likely to experience side effects.
Chia seeds vs. flax seeds: Which is best for weight loss?
“Both chia and flax are great for weight loss. But chia seeds, especially when soaked, would be your best choice for weight loss,” says Allidina. The key difference is the fiber, with chia seeds boasting almost twice as much as flax. Considering how important adequate fiber intake is for weight loss, this makes chia seeds an excellent addition to your diet if losing weight is your goal.
Chia seeds vs. flax seeds: Which is better for you?
“On a per-tablespoon basis, chia seeds are more calorie-dense and also provide twice the fiber as ground flaxseed,” says Koenig. Still, both are incredibly smart and healthy additions to your diet—they just offer slightly different perks. “If you are looking for more hormonal support, choose flax. If you are trying to stay fuller for longer and reduce appetite, use chia,” says Allidina. “Both can be used daily.”
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