Home / Food and drink

Ground flax seeds

By the Life in Good Form editors. Updated 2026-10-15.

We research products from makers' specs and health sources; we do not run hands-on tests. Links to Amazon may earn us a commission at no cost to you. How this works.

Why ground instead of whole

A study in the Journal of the American College of Nutrition compared whole flaxseed, milled flaxseed and flaxseed oil baked into muffins, using 30 g of seed or 6 g of ALA in the oil, over a 3 month test period. After 1 month, plasma ALA rose significantly in the oil and milled seed groups, but not in the whole seed group.

All groups had some stomach and gut discomfort early on, which faded in the oil and milled seed groups. Whole seed and oil caused gut effects within 4 weeks severe enough that some people withdrew; no one withdrew from the milled flaxseed group. The authors suggested milled flaxseed may be a good form for getting ALA while avoiding serious side effects. Plasma EPA and DHA, the omega-3s in fish oil, did not rise in any group.

Nutrition: ground vs whole

Details are from two USDA FoodData Central entries that were analyzed separately, so small differences may reflect different samples rather than grinding. A typical spoonful is far less than 100 grams; check your package's Nutrition Facts serving.

What research says about health effects

NCCIH says flaxseed has a long history of traditional use and that flaxseed oil supplements typically contain ALA, an omega-3 fatty acid. Its summary of research is cautious: one trial suggests flaxseed mucilage powder mixed with water might support weight loss in adults with overweight or obesity, some research suggests ALA flaxseed oil might improve fasting measures and insulin resistance in gestational diabetes, and more research is needed on type 2 diabetes.

In the 2008 muffin study, there were no changes in plasma cholesterol or triglycerides in any group. ALA is not the same as the EPA and DHA in fish oil; see our flaxseed oil softgels guide for more on that difference.

Safety

• Do not eat raw or unripe flaxseeds. NCCIH says they may contain potentially toxic compounds; commercial ground flaxseed sold as food is the usual choice.
• Start small. NCCIH says higher doses may cause digestive symptoms such as bloating, fullness and diarrhea, and the 2008 study saw early gut discomfort.
• Medicines. NCCIH notes theoretical reasons flaxseed might interact with drugs, including anticoagulant and antiplatelet drugs. Ask your doctor if you take a blood thinner.
• Pregnancy and breastfeeding. NCCIH says some studies suggest flaxseed is possibly unsafe during pregnancy, though evidence is not conclusive, and little is known about breastfeeding.
• Short-term use. NCCIH says limited amounts may be safe for short-term use, up to 6 months.

How to use and store ground flaxseed

• Stir it into food. Ground flaxseed mixes into oatmeal, yogurt, smoothies or baked goods, as in the muffins used in the study.
• Drink fluids. Flaxseed is high in fiber, so drink plenty of water as you add it.
• Store it cold and sealed. Ground flaxseed is high in fat, so keep it sealed and follow the package's storage directions; many people refrigerate it after opening.
• Grind your own in a coffee or spice grinder if you buy whole seeds.

For other fiber sources, see our psyllium husk powder guide.

Flaxseed and supplements

NCCIH reminds readers that dietary supplements are not approved by the FDA before they are sold, and manufacturers are responsible for their safety and labeling. Ground flaxseed sold as a food is labeled with a Nutrition Facts panel instead. If you want omega-3s from fish, see our fish oil softgels guide, and for a plant protein to pair with flax in smoothies, our plant-based protein powder guide.

What to look for when you buy

Questions people ask

Is ground flaxseed better than whole?

In a 2008 study, milled flaxseed raised blood ALA levels and whole flaxseed did not.

How much fiber is in ground flaxseed?

USDA lists 23.1 g of dietary fiber per 100 grams of ground flaxseed.

Is flaxseed safe during pregnancy?

NCCIH says some studies suggest it is possibly unsafe in pregnancy, though evidence is not conclusive.

Can flaxseed cause bloating?

Yes. NCCIH says higher doses may cause bloating, fullness and diarrhea.

Does flaxseed have the same omega-3s as fish oil?

No. Flax provides ALA; the 2008 study found no rise in EPA or DHA.

Sources

• Flaxseed and Flaxseed Oil: Usefulness and Safety (nccih.nih.gov), National Center for Complementary and Integrative Health
• Bioavailability of alpha-linolenic acid in subjects after ingestion of three different forms of flaxseed (pubmed.ncbi.nlm.nih.gov), Journal of the American College of Nutrition (PubMed 18689552)
• Flaxseed, ground (FDC 2262075) (USDA FoodData Central, FDC ID 2262075), USDA FoodData Central
• Seeds, flaxseed (FDC 169414) (USDA FoodData Central, FDC ID 169414), USDA FoodData Central

Sources checked 2026-10-15.