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Nuts & Seeds · Seeds
Flax Seeds
97/ 100
Also known as: flaxseed, linseed, ground flax
Flax seeds are nutrient-dense whole grains rich in plant-based omega-3 fatty acids (ALA), soluble fiber, and lignans, making them a powerful functional food for cardiovascular and metabolic health.
Variants (2)
Nutrition · per ~28 g serving · ≈ a small handful
🔥 Calories
150/ 2000 kcal day
🥩Protein5.1 g10% DV
🍞Carbs8.1 g3% DV
🥑Fat11.8 g15% DV
🌿Fiber7.6 g27% DV
≈ 0g net carbs · carbs − fiber
Vitamins
- Thiamin0.46 mg38% DV
Minerals
- Copper0.34 mg38% DV
- Manganese0.69 mg30% DV
- Magnesium109.8 mg26% DV
- Phosphorus179.8 mg14% DV
Other
- Omega36386.8 mg
BioactivesEstimated
- Lignans~8.4 mg
- Inulin / Prebiotic fibre~840 mg
- Omega-3 (ALA/EPA/DHA)~420 mg
- Polyphenols~42 mg
Estimated typical amounts — derived from this food's profile, not measured for this item. Real bioactive content varies widely by variety, ripeness, storage and preparation; use as a rough guide only.
Source: USDA · 169414
Score · 97/100
Nutrient Density35.0 / 35
Vitamins & minerals packed in relative to calories — the single biggest driver of the score.
Protein Quality11.5 / 15
How much protein it delivers, by absolute grams and per calorie.
Fiber Content10.0 / 10
Dietary fiber for gut health, satiety and steadier blood sugar.
Healthy Fats9.5 / 10
Fat quality — unsaturated vs saturated, and trans-fat free.
Bioactives14.0 / 15
Polyphenols, flavonoids and other beneficial plant compounds for this food group.
Glycemic Impact10.0 / 10
Low sugar with a high fiber-to-carb ratio scores best — gentler on blood sugar.
Top Nutrients
- Thiamin137% DV
- Copper136% DV
- Manganese108% DV
- Magnesium93% DV
- Phosphorus51% DV
Overview
Flax seeds (Linum usitatissimum) have been cultivated for millennia and are among the richest plant sources of alpha-linolenic acid (ALA), a short-chain omega-3 fatty acid essential for human health. Per 100g, flax provides 22.8g of omega-3s, 27.3g of fiber, and substantial amounts of phosphorus, magnesium, and manganese. The seeds contain unique bioactive compounds called lignans—polyphenolic phytoestrogens with antioxidant and anti-inflammatory properties. For longevity, flax seeds support cardiovascular health through cholesterol reduction, promote healthy lipid profiles, and support hormone balance and gut microbiota diversity via their high soluble fiber content. The combination of omega-3s, fiber, and polyphenols makes flax particularly valuable for reducing cardiovascular disease risk, improving insulin sensitivity, and supporting healthy aging. However, bioavailability of omega-3s and lignans depends significantly on seed preparation—grinding whole seeds increases nutrient accessibility. Flax also contains small amounts of cyanogenic compounds that are neutralized through heating or soaking, making proper preparation important for safety and efficacy.
Health Benefits (5)
- Improved cardiovascular health and cholesterol reductionstrongALA omega-3s and soluble fiber (mucilage) reduce LDL cholesterol oxidation and triglycerides, while lignans exhibit anti-inflammatory effects on arterial walls
- Enhanced insulin sensitivity and glycemic controlmoderateHigh soluble fiber content slows glucose absorption and reduces postprandial blood sugar spikes; lignans may improve beta-cell function
- Gut microbiota enhancement and improved digestive healthmoderateInsoluble and soluble fiber serve as prebiotic substrates for beneficial bacteria, increasing short-chain fatty acid production
- Reduced systemic inflammation and oxidative stressmoderateLignans (especially secoisolariciresinol diglucoside) act as potent antioxidants and modulate inflammatory cytokines including TNF-α and IL-6
- Support for hormonal balance and bone healthemergingLignans may modulate estrogen metabolism; high phosphorus and magnesium content supports mineral density and bone turnover
Food Pairings
- ·Pair with vitamin C-rich foods (citrus, berries, tomatoes) because ascorbic acid enhances conversion of ALA to EPA/DHA and improves polyphenol bioavailability
- ·Combine with fatty fish (salmon, sardines) because combined ALA and preformed EPA/DHA create synergistic anti-inflammatory effects on cardiovascular tissue
- ·Mix with fermented foods (yogurt, kefir, sauerkraut) because live probiotics work synergistically with flax's prebiotic fiber to expand beneficial microbiota diversity
- ·Pair with turmeric and black pepper because curcumin and piperine enhance absorption of flax lignans and create combined anti-inflammatory effects
Practical Tips
- ·Grind whole flax seeds immediately before consumption using a coffee grinder; ground seeds have 3-4x higher lignan and omega-3 bioavailability than whole seeds, but oxidize within hours
- ·Store whole seeds in an airtight container in the refrigerator or freezer (up to 6 months) to prevent oxidative degradation of omega-3s and preserve lignan content
- ·Consume 1-2 tablespoons (15-30g) daily; higher intakes may cause digestive distress without adequate water intake, as the mucilaginous fiber requires hydration
- ·Soak or lightly toast seeds before eating to reduce cyanogenic compound content and improve digestibility without destroying heat-sensitive nutrients
- ·Add ground flax to smoothie bowls, oatmeal, yogurt, or baked goods rather than heating above 350°F (175°C), which may degrade some bioactive compounds
Optimal Timing
🌅
morning
Best with food
Consuming flax seeds in the morning supports stable blood glucose throughout the day via soluble fiber, enhances satiety for appetite control, and allows adequate hydration for fiber metabolism. The timing also allows optimal lignan absorption through normal digestive processes.
Avoid
- · Immediately before or during intense exercise (high fiber may cause gastrointestinal distress)
- · With iron or calcium supplements taken simultaneously (may reduce mineral bioavailability)
Ground flax can be added to smoothies upon breaking fast, but whole seeds should be consumed with meals to minimize digestive upset
Systems supported
body systems this food feedsPathways supported
biochemical reactions enabled by this foodHow flax seeds stacks up
Compared to other nuts & seeds
Per 100 g of the default form. Bars show how much higher or lower flax seeds is than the average across 18 peer foods in this category. Green means a favorable direction; amber means the opposite.
Calories#2 of 19
534kcalvs588kcal avg
-9% below category average
Protein#11 of 19
18.3gvs18.2g avg
+1% above category average
Fiber#3 of 19
27.3gvs12g avg
+127% above category average
Thiamin#1 of 12
1.6mgvs0.8mg avg
+108% above category average
Copper#12 of 17
1.2mgvs1.6mg avg
-21% below category average
Manganese#8 of 18
2.5mgvs3.1mg avg
-19% below category average
Magnesium#4 of 18
392mgvs284mg avg
+38% above category average
Common questions
What people ask about flax seeds
What is flax seeds?
Flax Seeds is classified as a seeds (nuts & seeds). Flax seeds are nutrient-dense whole grains rich in plant-based omega-3 fatty acids (ALA), soluble fiber, and lignans, making them a powerful functional food for cardiovascular and metabolic health.
Is flax seeds healthy?
Flax Seeds scores 97/100 in Formulate, making it an exceptional choice. Its strongest contributions come from Thiamin, Copper, Manganese. The score blends nutrient density, fiber, healthy fats, protein quality, bioactive compounds, and glycemic impact.
Is flax seeds high in protein?
Not particularly. A 28 g serving provides about 5.1 g of protein (~10% of the 50 g daily value).
Is flax seeds high in fiber?
Yes — it's a high-fiber food. A 28 g serving provides about 7.6 g of fiber (~27% of the 28 g daily value).
What vitamins and minerals are in flax seeds?
In a 28 g serving, flax seeds is highest in Thiamin (~38% DV), Copper (~38% DV), Manganese (~30% DV), Magnesium (~26% DV), Phosphorus (~14% DV).
Is flax seeds keto-friendly?
Yes — it fits comfortably in most keto plans. A 28 g serving has about 0.4 g of net carbs (8.1 g total minus 7.6 g fiber).
When is the best time to eat flax seeds?
Best in the morning. Consuming flax seeds in the morning supports stable blood glucose throughout the day via soluble fiber, enhances satiety for appetite control, and allows adequate hydration for fiber metabolism. The timing also allows optimal lignan absorption through normal digestive processes.
How much flax seeds should I eat?
A typical serving is around 28 g (~150 kcal), based on the FDA's Reference Amount Customarily Consumed for this food category. There's no fixed daily target — most adults benefit from rotating flax seeds alongside several other nuts & seeds sources.
Is flax seeds an allergen?
Flax Seeds falls into the tree nut / seed group, which is a common allergen. If you have a known allergy or sensitivity in this category, avoid it and consult a clinician before adding it back.
What pairs well with flax seeds?
Flax Seeds pairs nicely with: Pair with vitamin C-rich foods (citrus, berries, tomatoes) because ascorbic acid enhances conversion of ALA to EPA/DHA and improves polyphenol bioavailability; Combine with fatty fish (salmon, sardines) because combined ALA and preformed EPA/DHA create synergistic anti-inflammatory effects on cardiovascular tissue; Mix with fermented foods (yogurt, kefir, sauerkraut) because live probiotics work synergistically with flax's prebiotic fiber to expand beneficial microbiota diversity; Pair with turmeric and black pepper because curcumin and piperine enhance absorption of flax lignans and create combined anti-inflammatory effects.
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Connect the dots
Signature nutrients in Flax Seeds
These are the nutrients flax seedscontributes meaningfully toward (≥10% DV per 100 g serving). Click one to see what it does in the body, which supplements concentrate it, and which other foods are top sources.