Broccoli: Nutrition, Benefits & the Best Ways to Cook It

Broccoli is the rare vegetable where the nutrition press, dietitians and the Canadian Cancer Society all agree: eat more of it. A cup of cooked broccoli (about 91 g) gives you ~135% of an adult’s daily vitamin C, more than half a day’s vitamin K, fibre, folate and a phytochemical called sulforaphane that is being studied for everything from cardiovascular health to chemoprevention.

What a cup of broccoli actually gives you

Per 91 g (one cup, cooked, no added fat): roughly 55 calories, 4 g protein, 5 g fibre, 102 mg vitamin C, 92 µg vitamin K, 84 µg folate, plus useful amounts of potassium, calcium and iron.

Broccoli is a complete-protein vegetable for its calorie weight: ~7 g protein per 100 calories, comparable to lentils. It’s also exceptionally low on the glycemic index, making it a good carbohydrate companion at any meal.

Where the headline benefits actually come from

Sulforaphane is the compound responsible for most of broccoli’s “superfood” reputation. It is not present in raw broccoli — it forms when you crush, chew or chop the florets, which lets an enzyme called myrosinase convert glucoraphanin into sulforaphane.

Cardiovascular evidence: a 2020 meta-analysis pooling 17 cohort studies (~775,000 people) linked higher cruciferous-vegetable intake with a 16% lower risk of cardiovascular mortality. Cancer evidence is more nuanced; the strongest data are for stomach, colon and lung cancers in observational cohorts, not yet trial-replicated.

Fibre and folate make broccoli a useful pregnancy and gut-health food, and Health Canada lists it among the everyday vegetables Canadians should aim for half their plate to come from.

How to cook it without destroying the good stuff

Steam, don’t boil. Boiling broccoli for 5 minutes can leach 30–40% of its vitamin C and most of its glucoraphanin into the cooking water. A 4-minute steam preserves both.

Microwave is fine — surprisingly. A 2007 University of Warwick study found that 2–3 minutes of microwaving with a small amount of water retains more sulforaphane than boiling.

Two tricks for extra sulforaphane: (1) chop the broccoli and let it sit for 10 minutes before cooking — this gives myrosinase time to do its job. (2) Add a sprinkle of mustard seeds, raw daikon or arugula at the end of cooking; their myrosinase reactivates conversion that the broccoli’s heat-deactivated enzyme can no longer do.

How much, how often

Health Canada and the Dietitians of Canada recommend 7–10 servings of vegetables and fruit per day for adults; one cup of broccoli counts as 1–2 servings depending on cooking. Most population studies that found cardiovascular benefit used 3–5 servings of cruciferous vegetables per week as the threshold.

You don’t need to eat broccoli every day. Rotating through the cruciferous family — broccoli, cauliflower, kale, Brussels sprouts, bok choy, cabbage — gives you the same sulforaphane backbone with different micronutrient profiles.

The bottom line

Broccoli is not hype. A cup a few times a week is one of the best dollar-for-nutrient choices on a Canadian grocery list. Steam it, chop it ahead, and rotate through its cruciferous cousins.

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