#156 Flax vs. Chia: Which Seed Should You Eat?

Flax vs Chia: Which Seed Should You Eat?

Flaxseeds and chia seeds are both superfoods.  While most health conscientious people now include these seeds in their diet, in the flax vs chia matchup, which seed is best?

Where did flax and chia come from?

Flaxseeds originated from the Middle East.  At one time, flax was considered so holy that ancient Egyptian priests only wore clothes may from flax fibers.

In contrast, chia seeds are the newcomers.  While it seems as if we just discovered chia seeds in the U.S., chia seeds were used anciently by Mayan and Aztec warriors.  It was said that chia seeds could sustain them for days.

Flax vs Chia

Below is a 12-point analysis of which seed is best based on the latest medical studies.

1. Omega 3s

The reason why most people eat flaxseeds and chia seeds is for the omega 3 fatty acids.  Indeed, most of the fat in these seeds are the inflammation fighting omega 3s.

For example, one tablespoon of flaxseeds provides you with 146% of the recommended omega 3s for the day.  Likewise, one tablespoon of chia seeds gives you 132%.

Ounce for ounce, flaxseeds and chia seeds have more omega 3s than salmon.  However, this is the plant form, or ALA form, of omega 3.

In contrast, salmon is packed with the DHA form of omega 3.  When it comes to omega 3s and the prevention of chronic diseases, the DHA form of omega 3 may be more important.

Unfortunately, the body converts little of the ALA form to the DHA form.  Thus, to get all of your omega 3 types, you may need to add in marine algae or fish.

Winner: tie

2. Anti-Inflammatory Effects

Due to the high omega 3 content, flaxseeds and chia seeds have powerful anti-inflammatory effects.  For example, studies show that both flaxseeds and chia seeds reduce C-reactive protein by 25% and 40% respectively.  C-reactive protein, or CRP, is a routine blood test that measures the level of inflammation in your body.  You don’t see this kind of an anti-inflammatory effect from any of the pharmaceutical medications.

Winner: tie

3. Fiber

Fiber is critical to maintaining a healthy weight and a healthy gut.  Fiber may also protect against heart disease and cancer.

Both flaxseeds and chia seeds are loaded with fiber.  For example, one tablespoon of flaxseeds and chia seeds gives you 3 and 5 grams of fiber respectively.  That works out to be 11% of your daily fiber from flaxseeds and 18% from chia seeds.

Calorie for calorie, chia seeds are one of the highest sources of fiber you can find.  Chia seeds also absorb 10 to 12 times their weight in water.

If you are not used to eating much fiber, go slow with chia seeds.  With all of this fiber packed into a tiny seed, there are case reports of where people have obstructed their esophagus or intestines by not drinking enough water.  If you are going to eat these fiber powerhouses, you must also drink copious amounts of water.

Winner: chia seeds

4. Calcium

Both flaxseeds and chia seeds are excellent sources of calcium.  In fact, a tablespoon of flaxseeds gives you 26 mg of calcium (2.6% of your daily needs) and chia seeds 76 mg (7.6% of what you need daily).  For those who can’t tolerate, or wish to avoid dairy, chia seeds are a great option.

Winner: chia seeds

5. Protein

These seeds are high in protein.  By weight, flaxseeds are 18% protein and chia seeds seeds 14% protein.  All nine essential amino acids are found in both seeds.

When it comes to weight loss and satiety, nothing beats protein according to medical studies.

Winner: tie

6. Antioxidants

Antioxidants are substances that protect against oxygen damage or free radicals.  Thus, antioxidants protect against heart disease, cancer, and the aging process.

Studies show that while antioxidant supplements may be harmful, food antioxidants extend life and ward off chronic diseases.  Fortunately, both flaxseeds and chia seeds are extremely high in these protective antioxidants.

Winner: tie

7. Weight Loss

The flaxseed and chia seed should be weight loss champions.  Both are low carb and packed with protein and fiber.  However, in the few weight loss studies done, both seeds have been anything but impressive.

Unfortunately, I could find no study showing convincing weight loss from these seeds.  Two flaxseed studies showed no more weight loss than the control group.  Likewise, two small studies of 90 and 62 people did not show any weight loss from chia seeds.

Winner: neither

8. Cancer Treatment/Prevention

When it comes to cancer prevention and treatment, flaxseeds may be one of the best food sources.  Specifically, one study showed that flaxseeds shrunk tumor size by 48%.  While flaxseeds appear protective against most cancers, the benefit may be the strongest for breast and prostate cancers.

As chia seeds are the newcomer, there are no convincing studies available yet.  However, given the high amount of omega 3 in this seed, studies would predict that chia seeds also fight cancer.

Winner: flaxseeds

9. Cholesterol Reduction

Flaxseeds have long been known to lower cholesterol.  Depending on the study, you can expect a 10-20% reduction in bad cholesterol (LDL) as well as your triglycerides.  While chia seeds reduce cholesterol in animals, those same benefits have not yet been proven in humans.

Winner: flaxseeds

10. Diabetes Treatment/Prevention

When it comes to diabetes, flax seeds may be one of the best treatment options.  Indeed, one study showed that you could lower blood glucose levels by 20% with flaxseeds.

While chia seeds also help with diabetes, the benefit may not be as much.  For example, in a study of diabetics, chia seeds reduced hemoglobin A1C by 4%.

Winner: flaxseeds

11. Blood Pressure Lowering

There have been many studies on the blood pressure lowering effects of flaxseeds.  In a study of Brazilian men at risk for a heart attack, flaxseeds reduced systolic blood pressure by 3 points (mmHg).

Likewise, chia seeds also treat high blood pressure.  In particular, one study showed that chia seeds reduced blood pressure by 6 points (mmHg).   As there are few studies available for chia seeds and blood pressure treatment, it is unclear if the blood pressure lowering effect is better with chia seeds.

Winner: tie

12. Increased Exercise Tolerance

To test the legend that chia seeds allowed ancient Mayans and Aztecs to run for days, scientists put this to the test.  In a fascinating study, researchers compared gatorade to chia seeds in endurance athletes. As expected, the endurance athletes assigned to chia seeds did just as well as the gatorade group.

In contrast, I could find no studies evaluating the exercise effects of flaxseeds.

Winner: chia seeds

Overall Winner

Adding up all 12 categories, flaxseeds came out ahead in three and chia seeds also were better in three categories.  Thus, it is a tie.

Are there any risks of eating flaxseeds or chia seeds?

While both seeds are incredibly healthy, you don’t want to eat too much of them.  For example, flaxseeds contain a potentially dangerous substance, called cyanogenic glycosides.  One study suggested that the maximum amount of flaxseeds you can safely eat in a day is 50 grams or 4.5 tablespoons.

In addition, the phytoestrogen effect of flaxseeds could, theoretically, cause concern with pregnancy.  However, it is this same phytoestrogen effect of flaxseeds which makes them so effective in the treatment of hormonal cancers like breast and prostate cancer.

A side of effect of any omega 3 source is that they also thin the blood.  While this is not a problem in most people, for those taking blood thinners it could increase the risk of bleeding.

As mentioned above, chia seeds rapidly absorb water and can become “glue balls.”  Thus, you must drink enough water when you eat chia seeds.

How do you eat flaxseeds and chia seeds?flax vs chia

Flaxseeds and chia seeds can be worked into almost any recipe.  Put them in smoothies, salad dressings, or on yogurt.

There is now even a Trader Joe’s brand of natural peanut butter that includes both flaxseeds and chia seeds.  This is the main peanut butter we eat in our home.

While flaxseeds may need to be ground first, you don’t have to do this with chia seeds.  Chia seeds also make a great thickener for sauces.

Take Home Message

The key message of this article is that both flaxseeds and chia seeds are incredibly healthy.  Try eating some of these seeds each day to turbo charge the nutritional aspect of your diet.

Are you a flaxseed or chia seed person?  How do you eat these seeds?

Please leave your comments and questions below.  I read and respond to every question.  If you enjoyed this article, please be sure to sign up for my free weekly newsletter and share it with a friend.

Disclaimer Policy: This website is intended to give general information and does not provide medical advice. This website does not create a doctor-patient relationship between you and Dr. John Day. If you have a medical problem, immediately contact your healthcare provider. Information on this website is not intended to diagnose or treat any condition. Dr. John Day is not responsible for any losses, damages or claims that may result from your medical decisions.

  1. Just wanted to say thank you Dr. Day!
    I look forward to your articles on philosophy of life as well as the dietary tips which help me alot with trying to lower my blood pressure.
    Your articles have a lot of wisdom about how to live life in a way that I are inspiring. Love your studies with the Chinese people – fascinating!
    Keep it up!

    • Hi Mary,

      Thank you so much for reading and for your kind comments! Hope your blood pressure is coming down!



  2. Take a tablespoon of chia seeds, put it in your mouth, and then immediately wash it down with a glass of water. Problem with gummy seeds solved.

  3. Interesting article, thanks. Good to have an independent voice when reading about nutrient foods. (Greetings from Scotland)

  4. I use chia seeds in everything except coffee. They are delicious and when cooked, they thicken into jelly-covered little beads. I take flaxseed oil supplements in gelcap form but heading toward buying the seeds and grinding them in a wooden mortar and pestle, for better control of my T2 diabetes. Thanks for this article, Dr. Day – so glad I’m on your email list. Have said it hundreds of times to anyone that hears me – you saved my life and I’ll remain forever grateful.

  5. I grew up having chia seeds almost every day, back home we have a beverage (chan), we make it with water, any kind of natural fruit and chia seed; very refreshing, and you will find it everywhere, also flaxseed we call it linaza in Spanish, we put it in water overnight and then we just drink the water for inflammation or to refresh the stomach, it is part of the Mexican and Central America cultures.

    When I moved here from Central America 35 years ago, we had to have it from California or just a Spanish market, then from wild oats and later on from whole foods, now it is everywhere, which I am glad but now I have read that it is bad for people that have ovarian or breast cancer, or BRCA positive.

    I would like your opinion in this matter. I really enjoy your wife recipes and your newsletter.

    • Hi Sonia,

      Great question. While there is some debate on flaxseeds and cancer risk on the internet, the scientific data is overwhelmingly positive for flaxseeds preventing or treating cancer. While the definitive study on this has not yet been done, if you follow the link below you will see the large number of studies supporting the anti-cancer effects of flaxseeds.


      Of course, if you have been diagnosed with cancer, or are at high risk of cancer, please discuss with your physician if flaxseeds are right for you or not.

      Hope this helps!