Broccoli Nutrition Facts: Calories, Vitamin C, Vitamin K, and Sulforaphane

One cup of raw broccoli (about 91 grams) packs 34 calories, 89.2mg of vitamin C (nearly meeting your daily need in one serving), 102µg of vitamin K, 2.8g of protein, and 2.6g of fiber. Despite being a cruciferous vegetable often stereotyped as “rabbit food,” broccoli is a nutrient-dense powerhouse with concentrations of certain protective compounds that rival or exceed other celebrated foods.

This guide pulls every number from USDA FoodData Central (raw broccoli, NDB 11090) and explains how cooking method, storage, and timing affect the compounds you actually absorb.

Broccoli Nutrition Facts (per 100g, raw)

Nutrient	Amount	% Daily Value*
Calories	34 kcal	2%
Total Fat	0.4 g	<1%
— Saturated Fat	0.1 g	<1%
— Polyunsaturated Fat	0.2 g	—
Carbohydrates	6.6 g	2%
— Dietary Fiber	2.6 g	9%
— Sugars	1.4 g	—
Protein	2.8 g	6%
Vitamin C	89.2 mg	99%
Vitamin K	102 µg	85%
Folate	63 µg	16%
Potassium	316 mg	9%
Calcium	47 mg	4%
Vitamin A (RAE)	31 µg	3%
Sulforaphane	22–90 mg	—

*Daily Values based on a 2,000-calorie reference diet (FDA). Individual needs vary.

For one medium broccoli head (600g raw), multiply each value by 6. For a single floret (~50g), divide by 2.

Why Broccoli’s Vitamin C Density Matters

Broccoli contains 89.2mg of vitamin C per 100g raw — that’s 99% of the adult daily value and more per gram than a medium orange (69.7mg per 100g). Vitamin C is essential for collagen formation, immune function, and iron absorption, and because it’s water-soluble, fresh, raw, or minimally cooked broccoli preserves the most.

One cup of raw broccoli (91g) delivers approximately 81mg of vitamin C. In comparison:

• Medium orange (154g): ~70mg vitamin C
• One kiwi (69g): ~56mg vitamin C
• One bell pepper (119g): ~95mg vitamin C

If you’re using broccoli as your primary vitamin C source, raw consumption or steaming for just 2–3 minutes preserves the nutrient best. Boiling leaches 25–50% of vitamin C into the cooking water — a significant loss if you’re relying on broccoli for this micronutrient.

Vitamin K and Bone Health

Broccoli delivers 102µg of vitamin K per 100g, meeting 85% of the daily adequate intake (120µg for adult men, 90µg for women). Vitamin K activates osteocalcin, a bone-matrix protein crucial for bone mineralization and strength. Epidemiological studies consistently link higher vitamin K intake to stronger bones and lower fracture risk, particularly in older adults.

One study in the Journal of Bone and Mineral Research (Kanellakis et al., 2012) found that higher dietary vitamin K intake was associated with higher bone mineral density in postmenopausal women. Another meta-analysis (Theuwissen et al., 2014) showed that vitamin K supplementation reduced bone loss in older women.

Cooked broccoli retains most vitamin K — heat does not degrade it the way it destroys vitamin C. Steaming broccoli for 5 minutes retains ~95% of its vitamin K content.

Sulforaphane: The Cancer-Protective Compound

Sulforaphane is an isothiocyanate produced when broccoli cells are damaged and the enzyme myrosinase activates glucoraphanin (a glucosinolate). This compound has been extensively studied for potential anti-cancer, anti-inflammatory, and neuroprotective properties.

How to Maximize Sulforaphane

The pathway to activate sulforaphane is simple but precise:

1. Chop or chew — Damage the cell walls to expose glucoraphanin to myrosinase
2. Wait 30–40 minutes — Allow the enzyme to fully convert glucoraphanin to sulforaphane at room temperature
3. Then cook, or eat raw — If cooking, use steaming (do not boil)

Raw, freshly chopped broccoli sitting for 40 minutes before eating maximizes sulforaphane content. Research from Johns Hopkins University (Fahey et al., 1997) established that this preparation method increases sulforaphane yield by up to 2–3 fold compared to immediate consumption.

Cooking Method Dramatically Affects Sulforaphane

Raw broccoli contains approximately 22–90mg of sulforaphane per 100g (high variance depends on variety and growing conditions). Once cooked:

• Steaming (5 min): Preserves 50–60% of sulforaphane (myrosinase is inactivated by heat but sulforaphane itself is heat-stable)
• Microwaving: Similar to steaming; preserves 40–50%
• Boiling: Destroys 80–90% of sulforaphane — heat inactivates myrosinase before conversion is complete, and heat-labile sulforaphane leaches into water
• Roasting/stir-frying: Mixed results; high-heat oxidation may degrade sulforaphane

Optimal protocol for sulforaphane: Raw, chopped, consumed within 40 minutes OR lightly steamed (2–3 min max) after chopping.

Broccoli Sprouts: A Sulforaphane Superfood

Broccoli sprouts (immature plants, 3–5 days old) contain 50–100 times more sulforaphane than mature broccoli, according to research by Paul Talalay at Johns Hopkins. This extreme concentration makes sprouts useful for targeted supplementation, though they have not yet replaced mature broccoli in large-scale dietary recommendations — portion sizes and cost differ.

A single ounce (28g) of broccoli sprouts can deliver as much sulforaphane as 1–2 kg of mature broccoli, but sprouts are typically consumed in small amounts (small handfuls on salads, sandwiches) rather than as a main vegetable.

Raw vs. Steamed vs. Boiled: Comparative Nutrient Retention

Cooking Method	Vitamin C Retention	Vitamin K Retention	Sulforaphane Retention	Best For
Raw (chopped, 40 min)	100%	100%	100% (fully activated)	Maximum sulforaphane
Steamed (5 min)	80–90%	95%	50–60% (myrosinase inactivated)	Balanced nutrition + digestibility
Microwaved (3 min)	75–85%	95%	40–50%	Quick, nutrient-preserving
Boiled (5–10 min)	40–50%	95%	5–10%	Lowest nutrient retention
Roasted (15–20 min)	60–80%	95%	20–40%	Flavor, but nutrient loss

For maximum protection and nutrient density, prepare broccoli raw and finely chopped, then allow it to sit for 30–40 minutes before eating — or steam lightly (under 5 minutes) immediately after chopping. Avoid prolonged boiling.

Gas, Digestion, and FODMAP Sensitivity

Raw broccoli, especially in large quantities, can cause bloating, gas, and cramping in some people due to:

1. Raffinose — a trisaccharide that resists digestion in the small intestine and is fermented by colonic bacteria, producing gas
2. FODMAP content — Broccoli is high in fructans and other oligosaccharides, making it problematic for IBS and FODMAP-sensitive individuals

Cooking (steaming, boiling, or roasting) breaks down raffinose and reduces FODMAP content, making broccoli far more tolerable. People with IBS should cook broccoli thoroughly rather than eat it raw.

Alternatively, eating raw broccoli slowly, with adequate hydration, and in smaller portions (under 1 cup at a time) can help acclimate the digestive system — the microbiota adapt to regular consumption within 2–4 weeks.

When Broccoli Might Not Fit Your Diet

• Warfarin (Coumadin) users: Broccoli’s high vitamin K (102µg per 100g) can reduce warfarin’s anticoagulant effect. Consistent intake is safe; sudden increases or decreases alter INR. Consult your doctor and maintain steady broccoli consumption.

• Extreme hypothyroidism or iodine deficiency: Cruciferous vegetables contain goitrogens — compounds that, at very high intake (over 200g raw daily, sustained), may suppress thyroid hormone synthesis. This is only a concern in iodine-deficient populations or those consuming gram quantities daily. Normal portions pose no risk in iodine-sufficient individuals (including anyone using iodized salt).

• IBS or FODMAP sensitivity: Raw broccoli can trigger bloating and cramping. Cook thoroughly and test portion size tolerance — cooked broccoli is usually well-tolerated.

• Severe kidney disease: Potassium restriction may require limiting broccoli (316mg per 100g). Consult a nephrologist.

The Bottom Line

Raw broccoli is among the most nutrient-dense vegetables available: 34 calories, 89.2mg of vitamin C (99% DV), 102µg of vitamin K (85% DV), 2.8g of protein, and 2.6g of fiber per 100g. Sulforaphane, a compound with emerging anti-cancer and neuroprotective properties, is maximized when broccoli is chopped and allowed to rest for 30–40 minutes before eating. Steaming (under 5 minutes) preserves both vitamin C and sulforaphane far better than boiling. The only notable watch-outs are vitamin K interaction with warfarin, potential gas or FODMAP issues for sensitive individuals, and the need to cook rather than eat raw if you have digestive trouble. For most people, daily broccoli consumption — raw in salads, steamed as a side, or lightly roasted — is evidence-based nutrition.