Broccoli is often hailed as a cancer-fighting food. What gives broccoli its cancer-fighting power is sulforaphane, a naturally occurring plant compound with a whole host of benefits (antioxidant, anti-inflammatory, and anti-cancer properties, to name a few).
This phytochemical has been shown in studies to support detoxification, reduce inflammation, and protect cells from DNA damage – all factors linked to reduced cancer risk. It boosts the body’s protective enzymes and flushes out cancer-causing chemicals. A University of Michigan study on mice found that sulforaphane targets cancer stem cells – those that aid in tumour growth.
This cancer-fighter is present in all cruciferous veggies (eg: cauliflower, cabbage, kale), but broccoli is the only one with a sizable amount of this potent compound.
Sulforaphane is formed when broccoli is chewed, chopped, or otherwise “damaged”. When this happens, a chemical in broccoli called glucoraphanin mixes with an enzyme called myrosinase and forms sulforaphane.
Preparing and cooking broccoli the right way can help you reap the full benefits of its cancer fighting properties.
Chop Broccoli – and Let it Rest
Prolonged and harsh cooking methods can significantly reduce sulforaphane levels in broccoli. To increase its amount, chop broccoli ahead of time before cooking, and use light cooking methods, like stir-frying. Gentle cooking methods like steaming (up to 5 minutes) preserve more nutrients than boiling or frying.
The advice comes from a 2018 report, published in the Journal of Agricultural and Food Chemistry, that examined the effects cooking has on the potent plant compound in broccoli.
“Our results suggest that after broccoli florets are cut into small pieces, they should be left for [approximately] 90 [minutes] before being cooked,” the study authors wrote. Although they hadn’t experimented with a shorter time, they said, “we believe that hydrolysis for 30 [minutes] would also be helpful.”
It’s amazing how small preparation habits can amplify the health benefits of everyday foods. It’s an easy, cost-free adjustment that can turn a common vegetable into a stronger nutritional ally.
How Sulforaphane Protects Against Cancer
An article in the Cancerwise Blog on the UT MD Anderson website explains how sulforaphane prevents cancer.
REDUCES inflammation. Because sulforaphane neutralises toxins, it also calms inflammation in your body. Inflammation has been linked to several kinds of cancer.
MAY protect your DNA. Some studies have shown that sulforaphane blocks mutations in DNA that lead to cancer.
MAY slow tumour growth. Sulforaphane has been shown to reduce the ability of cancerous cells to multiply. That means it may slow tumour growth or reduce its ability to spread to other parts of your body.
MAY help regulate your hormone levels. Sulforaphane may have a modulating effect on estrogen, potentially reducing the risk of estrogen-related cancers, such as breast cancer. But more research is needed to determine its long-term effects and efficacy.
What Other Vegetables Have It?
Sulforaphane is present in all cruciferous vegetables, including: arugula, bok choy, Brussels sprouts, cabbage, cauliflower, collard greens, horseradish, kale, kohlrabi, mustard greens, radish, rutabaga, Swiss chard, turnip, wasabi and watercress. Eating these veggies steamed or raw, and chopped and left to rest before cooking, confers more health benefits.
Sulforaphane is best eaten in its plant form, along with a variety of other vegetables, fruits, nuts and whole grains. That’s because many other nutrients are present in plant foods, too – and it’s likely they all work together.
Usually, sulforaphane is associated with leafy green vegetables, but they can also be purple, white or red. Plants of other colours contain different phytochemicals and antioxidants, too.
And many different phytochemicals have been shown to have anti-cancer properties.
Broccoli is a wonderful addition to your arsenal of cancer fighting foods but you should eat it as part of a balanced diet. No one fruit or vegetable will provide everything your body needs, says UT MD Anderson.
The best way to ensure you get all the benefits of your food is to eat a wide variety of different-coloured plants. Supplements are out because they isolate nutrients and remove many of the benefits of plants. Eat real food.


