# Flaxseed: ALA, lignans and why grinding changes everything

> Flaxseed is sold as a plant-based omega-3 source - the picture is more nuanced. What ALA actually does in the body, why lignans need your microbiome, and why whole seeds often pass straight through.

Flaxseed has a reputation as the omega-3 source for people who don't eat fish. True - but only half true. The fatty acid in flaxseed is not the one in salmon, and your body converts it only at a considerable loss. What makes flaxseed interesting is something else: the combination of ALA, viscous fibre and lignans.

## ALA is not the same as EPA and DHA

**Alpha-linolenic acid (ALA)** is an essential omega-3 fatty acid with 18 carbon atoms. Your body cannot make it, but it can rebuild it - via desaturases and elongases into EPA and further into DHA. That conversion is the bottleneck. Burdge and Calder (2005) summarised the isotope studies: in men roughly 5 to 8 percent of ingested ALA is converted to EPA, and less than one percent reaches DHA.

So if you specifically want EPA and DHA, flaxseed won't get you there. If you want ALA, you will struggle to find a denser source: [WOO® Leinsamenmehl](/en/shop/woo-flaxseed-flour-bag) provides 4.75 g of omega-3 per 100 g, meaning 0.71 g per 15 g serving.

## The cholesterol claim and its condition

There is an authorised health claim for ALA: ALA contributes to the maintenance of normal blood cholesterol levels. Condition: 2 g of ALA per day. One serving covers around a third; the rest realistically comes from rapeseed oil or walnuts.

Pan et al. (2009) evaluated 28 intervention studies: flaxseed measurably lowered total and LDL cholesterol - more clearly with whole or ground seed than with flaxseed oil alone. An indication that it is not the fatty acid working in isolation, but the matrix of fibre and lignans.

## Lignans need your microbiome

Flaxseed is the richest known dietary source of **secoisolariciresinol diglucoside (SDG)**. It only becomes active through your gut bacteria, which convert SDG into the enterolignans **enterodiol** and **enterolactone**, credited with antioxidant and weakly phytoestrogenic properties. How much is produced depends on your individual microbiome - the spread between people is substantial.

Kuijsten et al. (2005) tested the decisive practical question: ground flaxseed produced markedly more enterolignans in plasma than whole seed. The hard seed coat is a mechanical barrier - and it holds.

## Fibre: 36.5 g per 100 g

Flaxseed contains two fibre fractions. The soluble mucilage swells in water into a viscous gel: delayed gastric emptying, longer satiety, binding of bile acids. The insoluble fibre increases stool volume and transit speed. A 15 g serving delivers 5.5 g - around a fifth of the 30 g daily recommendation. Reynolds et al. (2019) demonstrated a clear dose-response relationship between fibre intake and cardiometabolic endpoints.

## How WOO® Leinsamenmehl puts this into practice

WOO® Leinsamenmehl is 100 % flaxseed flour, no additives. The grinding is exactly the point: whole flaxseeds frequently pass through the digestive tract intact, and the flour removes that problem. The downside is more surface area and therefore more exposure to oxidation of the ALA - which is why it should be stored dry, cool and sealed.

One serving is 15 g; the 450 g pack covers 30 servings - for baking, in muesli, in a smoothie.

## Frequently asked questions

**Does flaxseed flour replace fish oil?**
No. The conversion rate to EPA, and especially to DHA, is too low. For those, oily sea fish or algae oil are the sources.

**How much per day makes sense?**
15 g is a good starting point. If you currently eat little fibre, increase slowly and drink enough alongside it - viscous fibre needs water.

**Can I heat it for baking?**
Fibre and lignans are heat-stable, ALA less so, though relatively protected inside a dough. If the fatty acid is your priority, use the flour cold.

## Sources

Burdge GC & Calder PC (2005), Reproduction Nutrition Development - Conversion of alpha-linolenic acid to longer-chain polyunsaturated fatty acids in human adults.
Pan A et al. (2009), American Journal of Clinical Nutrition - Meta-analysis of the effects of flaxseed interventions on blood lipids.
Kuijsten A et al. (2005), Journal of Nutrition - The relative bioavailability of enterolignans in humans is enhanced by milling and crushing of flaxseed.
Reynolds A et al. (2019), The Lancet - Carbohydrate quality and human health: a series of systematic reviews and meta-analyses.

*WOO® Leinsamenmehl - in the NEMAPO shop.*