Broccoli: Easing the effects of air pollution?

In a Nutshell

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Research Digest

One of your cruciferous vegetables: Large analyses link them to various health benefits, including a reduced risk of all-cause mortality, cancers, depression, type 2 diabetes and improved cardiovascular health. (Li N et al. 2022; Zurbau et al. 2020; Wang et al. 2016)

Smaller studies link broccoli intake to:

• Gut health: Broccoli consumption increased gut microbiota diversity in healthy adults. (Kaczmarek et al. 2019)
• Detoxification of pollutants: Two clinical trials conducted in China found that daily broccoli sprout beverages increased the excretion of benzene, an important airborne pollutant. (Chen et al. 2019)
• Improved autism symptoms: Treatment with broccoli extract improved the social and cognitive function of participants with Autism Spectrum Disorders. (McGuinness et al. 2020)

What’s the mechanism behind this? Broccoli provides many nutrients and bioactive compounds, including:

• Glucosinolates, such as glucoraphanin, which is converted to sulforaphane
• Carotenoids
• Dietary fibre
• Vitamins C and K
• Potassium and iron

Pathway zoom: Glucosinolates in broccoli and cruciferous vegetables are particularly interesting. They are converted to sulforaphane, which is absorbed and acts on various cells. An important target of sulforaphane is the ‘Nrf2 signalling pathway’. It regulates the expression of genes involved in antioxidant and detoxification defences.

Food combinations: The conversion of glucosinolates to sulforaphane occurs thanks to a special enzyme called ‘myrosinase’ that is released when broccoli is cut or chewed. Foods that contain myrosinase like mustard seed powder and daikon radish could be good pairings for broccoli.

So, you don’t like broccoli? Your liking for broccoli and other Brassica vegetables could be influenced by the composition of your saliva and oral microbiome. In the mouth, compounds in Brassicas can be converted into unpleasant sulfur volatiles by oral bacteria. Large differences in sulfur volatile production were found between individuals, depending on their saliva composition and oral microbiome activity. Children whose saliva produced high amounts of sulfur volatiles disliked raw Brassica vegetables the most, but this relationship was not seen in adults, who might acquire a taste over time. (Frank et al. 2021)

In daily life: Try adding at least one portion of cruciferous vegetables to your daily meals. One portion of broccoli is 2 spears or 8 florets. Diversify with different varieties depending on what’s available and in season.

Plant Tales

Broccoli’s origin: Broccoli (from the Italian ‘brocco,’ arm or branch) originated in the eastern Mediterranean and Asia Minor regions. It was known to be cultivated in Italy during ancient Roman times through the writings of the Roman botanist Pliny (first century CE).

Is broccoli man-made? While there are many edible plants that can be foraged in the wild, broccoli is not one of them. It was developed from the flower of the cabbage plant (Brassica oleracea). Through many generations of selective breeding, farmers modified the bright yellow blooms of the wild plant into the enlarged bud clusters we know today as broccoli.

A flower-vegetable! Broccoli is a form of cabbage, grown for its edible flower buds and stalk. In the realm of cabbage, the loose leaves go by kale, tightly folded leaves form head cabbage or Brussels sprouts, and the flowers and thickened stalks give us broccoli and cauliflower.

The right time for fresh broccoli: It grows well in cool late summer and fall. If you can, try it fresh from a local farmer or vegetable box and test out the different varieties they offer like calabrese, Romanesco and tenderstem broccoli.

Tasty Tips

Why we like it: Broccoli adds a textural contrast and a subtle bitterness that balances rich and savoury dishes. It’s the ultimate wingman for all things salty like anchovies, hard cheese or soy sauce.

Our favourite ways to enjoy broccoli

• Oven-roasted or air-fried with olive oil, chopped garlic, chilli flakes and nuts. Top with walnuts and lemon juice or a miso sauce.
• Broccoli soup: Sauté chopped broccoli with olive oil, onion, carrot, celery and spices. Add broth, red lentils or white beans and a handful of spinach. Simmer until tender, blend and top with a swirl of pesto, fresh herbs or roasted nuts.
• Omelettes and egg muffins: Together with chopped sundried tomatoes, spring onions, feta and seasoning.
• Stir-fries: Sauté with sesame oil, spring onions, chopped cabbage, garlic, ginger and a splash of water if needed to soften. Add cooked rice or noodles, tofu, soy sauce and rice vinegar.
• Curries: Add chopped broccoli to your go-to curry.

Use the stems: They appear tough but become tender when you chop them into matchsticks and roast them in a hot oven. You can also peel them and throw them in a stir fry, frittata or soup.

Mix it up: Broccoli comes in various forms, each offering a unique taste profile. Broccoli rabe introduces a touch of bitterness, while Calabrese and Chinese broccoli are on the sweeter end of the scale.

Recipes to try

• Salmon, Broccoli & Quinoa Salad with Miso Dressing
• Chilli and Lime Peanut Broccoli Curry
• Prawn Pad See Ew (free in the app)
• One Pot Creamy Broccoli, Pea & Leek Rice