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Vegetable

Fennel

90/ 100

Fennel is a low-calorie cruciferous vegetable rich in fiber, potassium, and vitamin K, with a subtle anise-like flavor that supports digestive and cardiovascular health.

Nutrition · per ~85 g serving · ≈ ¾ cup chopped

🔥 Calories
26/ 2000 kcal day
🥩Protein1.1 g2% DV
🍞Carbs6.2 g2% DV
🥑Fat0.2 g<1% DV
🌿Fiber2.6 g9% DV
Vitamins
  • Vitamin K53.4 mcg44% DV
  • Vitamin B60.20 mg12% DV
  • Vitamin C10.2 mg11% DV
  • Folate22.9 mcg6% DV
  • Niacin0.54 mg3% DV
  • Vitamin E0.49 mg3% DV
  • Riboflavin0.03 mg2% DV
  • Choline11.2 mg2% DV
  • Vitamin A40.8 iu<1% DV
  • Thiamin0.01 mg<1% DV
Minerals
  • Potassium351.9 mg7% DV
  • Manganese0.16 mg7% DV
  • Copper0.06 mg6% DV
  • Iron0.62 mg3% DV
  • Magnesium14.4 mg3% DV
  • Phosphorus42.5 mg3% DV
  • Calcium41.6 mg3% DV
  • Sodium44.2 mg2% DV
  • Zinc0.17 mg2% DV
  • Selenium0.59 mcg1% DV
Other
  • Polyunsaturated Fat0.14 g
  • Saturated Fat0.08 g
  • Monounsaturated Fat0.06 g
BioactivesEstimated
  • Quercetin~13 mg
  • Polyphenols~128 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 FDC · 169385

Score · 90/100

Nutrient Density31.7 / 35

Vitamins & minerals packed in relative to calories — the single biggest driver of the score.

Protein Quality8.7 / 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 Fats5.0 / 10

Fat quality — unsaturated vs saturated, and trans-fat free.

Bioactives11.0 / 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
  • Vitamin K52% DV
  • Vitamin B614% DV
  • Vitamin C13% DV
  • Potassium9% DV
  • Manganese8% DV

Overview

Fennel (Foeniculum vulgare) has been cultivated for millennia across Mediterranean and Asian regions, traditionally used both as food and herbal medicine. This versatile vegetable—composed primarily of water and fiber—delivers exceptional nutrient density with only 31 calories per 100g. Its bulb, stalks, and seeds all contain bioactive compounds including anethole and fenchone, which have demonstrated anti-inflammatory and antimicrobial properties in research. The high potassium content (414mg per 100g) supports cardiovascular regulation and blood pressure management, while vitamin K (62.8mcg) is essential for bone mineralization and vascular health—critical factors in longevity. Fennel's soluble fiber promotes healthy gut microbiota composition, potentially enhancing metabolic health and reducing systemic inflammation. The vegetable's low sodium and caloric density make it ideal for weight management, while its documented diuretic properties may support kidney function. Emerging research suggests fennel's phytochemical profile may have estrogenic and antioxidant effects, though human clinical trials remain limited. For aging populations specifically, fennel's combination of bone-supporting nutrients, cardiovascular benefits, and digestive support positions it as a valuable staple in longevity-focused nutrition.

Health Benefits (5)

  • Improved digestive function and reduced bloating
    moderate
    Anethole and fenchone compounds stimulate digestive enzyme secretion and promote smooth muscle relaxation in the GI tract, while soluble fiber (3.1g per 100g) feeds beneficial bacteria and increases stool bulk
  • Enhanced bone health and fracture resistance
    strong
    High vitamin K content (62.8mcg, ~79% daily value) activates osteocalcin, a protein required for bone mineralization; potassium content reduces urinary calcium loss
  • Improved cardiovascular function and blood pressure regulation
    moderate
    Potassium (414mg) acts as a vasodilator and regulates sodium-potassium balance; fiber content helps reduce LDL cholesterol; anti-inflammatory compounds reduce arterial stiffness
  • Reduced inflammation and oxidative stress
    moderate
    Quercetin and kaempferol flavonoids, along with anethole, inhibit pro-inflammatory cytokine production and neutralize free radicals
  • Supported estrogen metabolism and hormonal balance
    emerging
    Phytoestrogens in fennel may modulate estrogen receptor signaling; research suggests potential benefit during menopause, though human evidence is limited

Food Pairings

  • ·Pair with olive oil because fat-soluble vitamin K (62.8mcg) requires dietary lipids for optimal absorption, and polyphenols are enhanced by lipid co-ingestion
  • ·Combine with citrus (lemon, orange) because vitamin C enhances iron bioavailability from fennel while supporting collagen synthesis and antioxidant status
  • ·Eat with fatty fish (salmon, mackerel) because omega-3 fatty acids synergize with fennel's anti-inflammatory compounds to reduce systemic inflammation and support cardiovascular function
  • ·Pair with leafy greens (spinach, kale) because both are vitamin K-rich, creating a potent combination for bone mineralization and vascular health

Practical Tips

  • ·Store fennel in the refrigerator's crisper drawer wrapped in damp paper towels for up to 10 days; discard any brown-spotted or mushy sections before use
  • ·Slice fennel thinly (1-2mm) and eat raw in salads to preserve heat-sensitive vitamin C and maximize enzyme activity for digestion
  • ·Roast fennel bulbs at 200°C for 25-30 minutes with olive oil and sea salt to caramelize natural sugars and enhance sweetness, making it palatable for fennel-averse individuals
  • ·Use fennel fronds (the feathery tops) as a fresh herb garnish to capture additional fiber and volatile oils often discarded; 1-2 tablespoons adds minimal calories with concentrated flavor
  • ·Consume fennel with meals containing fat (not as a standalone snack) to optimize vitamin K absorption and provide satiety through fiber while remaining very low-calorie

Optimal Timing

☀️
midday
Best with food

Consuming fennel at lunch or dinner alongside protein and fat sources maximizes nutrient absorption and digestive enzyme stimulation when digestive capacity is highest; the diuretic effect is less disruptive during daytime than evening

Avoid
  • · Late evening (within 2-3 hours of bedtime) due to mild diuretic properties that may disrupt sleep with nighttime bathroom visits

While fennel is extremely low-calorie (31 kcal/100g), vitamin K absorption is significantly impaired without concurrent dietary fat; consume with meals containing fat sources for optimal bioavailability

Systems supported

body systems this food feeds
BonesBrainCardioEnergyEyesGutHormonesImmuneJointsKidneyLiverMuscleReproductiveSkinSleepStressLongevity

Pathways supported

biochemical reactions enabled by this food
AMPKAntioxidantATP / MitoBoneClottingCollagenDetoxDopamineGlucoseGlycolysisHematopoiesisHPA AxisInsulin SignalingLipidsMembranesMethylationmTORNAD⁺NeurotransmitterSerotoninSteroidogenesisThyroidUrea CycleVitamin D Activationβ-OxidationKetogenesisVascular NO
How fennel stacks up

Compared to other vegetables

Per 100 g of the default form. Bars show how much higher or lower fennel is than the average across 137 peer foods in this category. Green means a favorable direction; amber means the opposite.

Calories#63 of 138
31kcalvs52.1kcal avg
-40% below category average
Protein#101 of 138
1.2gvs2.6g avg
-52% below category average
Fiber#36 of 138
3.1gvs2.9g avg
+6% above category average
Vitamin K#28 of 71
62.8mcgvs157mcg avg
-60% below category average
Vitamin B6#50 of 109
0.2mgvs0.5mg avg
-55% below category average
Vitamin C#72 of 129
12mgvs27.6mg avg
-56% below category average
Potassium#46 of 138
414mgvs382mg avg
+8% above category average
Common questions

What people ask about fennel

What is fennel?

Fennel is classified as a vegetable. Fennel is a low-calorie cruciferous vegetable rich in fiber, potassium, and vitamin K, with a subtle anise-like flavor that supports digestive and cardiovascular health.

Is fennel healthy?

Fennel scores 90/100 in Formulate, making it an exceptional choice. Its strongest contributions come from Vitamin K, Vitamin B6, Vitamin C. The score blends nutrient density, fiber, healthy fats, protein quality, bioactive compounds, and glycemic impact.

Is fennel high in protein?

Not particularly. A 85 g serving provides about 1.1 g of protein (~2% of the 50 g daily value).

Is fennel high in fiber?

Not really. A 85 g serving provides about 2.6 g of fiber (~9% of the 28 g daily value).

What vitamins and minerals are in fennel?

In a 85 g serving, fennel is highest in Vitamin K (~44% DV), Vitamin B6 (~12% DV), Vitamin C (~11% DV).

Is fennel keto-friendly?

Yes — it fits comfortably in most keto plans. A 85 g serving has about 3.6 g of net carbs (6.2 g total minus 2.6 g fiber).

When is the best time to eat fennel?

Best in the midday. Consuming fennel at lunch or dinner alongside protein and fat sources maximizes nutrient absorption and digestive enzyme stimulation when digestive capacity is highest; the diuretic effect is less disruptive during daytime than evening

How much fennel should I eat?

A typical serving is around 85 g (~26 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 fennel alongside several other vegetable sources.

What pairs well with fennel?

Fennel pairs nicely with: Pair with olive oil because fat-soluble vitamin K (62.8mcg) requires dietary lipids for optimal absorption, and polyphenols are enhanced by lipid co-ingestion; Combine with citrus (lemon, orange) because vitamin C enhances iron bioavailability from fennel while supporting collagen synthesis and antioxidant status; Eat with fatty fish (salmon, mackerel) because omega-3 fatty acids synergize with fennel's anti-inflammatory compounds to reduce systemic inflammation and support cardiovascular function; Pair with leafy greens (spinach, kale) because both are vitamin K-rich, creating a potent combination for bone mineralization and vascular health.

Related supplements

Supplements that mirror Fennel's nutrient profile

Encyclopedia entries that supply the same signature nutrients fennel contributes. Click through to see clinical dose ranges, evidence quality, and bioavailable forms.

Connect the dots

Signature nutrients in Fennel

These are the nutrients fennelcontributes 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.