Why you should eat your greens (and purples)

The term ‘superfood’ is often used to describe exotic foods that are relatively new to our diet, with exotic names like acai, goji or chia, but there are a group of green (and purple) super-duper foods that the Irish have been eating for generations that promise a myriad of health benefits.

Brassicas or cruciferous vegetables are packed with nutritional benefits, but perhaps because they are more everyday, and a little less glamourous, they don’t get the same adoration as other, more novel ingredients.

What are they?

The brassica family of vegetables has more to offer than just broccoli, cabbage and cauliflower. It is a diverse group of vegetables, so even if you don’t like the taste of cabbage, there is sure to be something from the list below that you will enjoy.

Broccoli; Brussels sprouts; Cabbage; Cauliflower; Turnip; Kale; Pak choi; Kohlrabi; Romanesca; Purple sprouting broccoli; Cress; Rocket; Radishes; Mizuna; Horseradish

Why should we be eating them?

Like all vegetables, the brassicas are low fat, high in fibre and packed with vitamins A, C, E and K and minerals like calcium, magnesium, iron, potassium and phosphorus, but it seems that it could be the more subtle phytochemicals that sets this group ahead in terms of their nutritional impact.

Many of the health benefits of this group of veggies has been attributed to their high content of sulphur-containing ingredients, like indole-3-carbinol and sulforaphane. These phytochemicals contribute to the distinctive bitter, or mustard flavour of these veggies and have been linked to their reputation has having potential anti-cancer effects.

Many of these vegetables are a rich source of carotenoids like lutein and zeaxanthin. These antioxidants have been researched for their effects on immune function, cardiovascular health and eyesight.

How often should we eat them?

Generally speaking, the more vegetables we pack into our diet the better. It is recommended that we eat one to two portions of brassica vegetables every day.

Are there any side effects?

Some people find the brassica vegetables difficult to digest, so if you have IBS, or are following a FODMAP diet, you may have been advised to restrict your intake of these vegetables. Usually that is for a short time, and many people find they are easier to tolerate if they are cooked, rather than raw.

This group of vegetables may also impact on thyroid function. Sometimes referred to as ‘goitregens’, they may affect iodine uptake by the thyroid. The good news is that cooking your brassicas will counteract this effect, so replace green smoothies and coleslaw with steamed broccoli and cauliflower soup and the effects are likely to be minimal.

Any ideas for how I eat more greens?

Yes! Here are five ways to get more brassicas into your diet:

:: Try kale crisps (see recipe below).

:: Make cauliflower interesting – roast it with spices, chop it into salads, or grate it and stir fry with a little coconut oil to make ‘cauliflower rice’.

:: Replace iceberg and cos lettuce with rocket and watercress in salads.

:: Transform steamed broccoli by adding a pinch of sea salt and a drizzle of olive oil. Not only will you enjoy a flavour transformation, but you will benefit by absorbing a lot more of the fat-soluble antioxidants.

:: Roast your sprouts!


Ingredients: All you need is a bunch of kale.

Optional extras: smoked paprika, lemon zest, sea salt, black pepper.


Preheat your oven to 160C. Rinse and dry your kale. Tear into small, bite-size pieces.

Spread over a couple of baking sheets. Bake for five minutes. Give it a shake, check it is not going brown and bake for another five minutes. Allow to cool and serve immediately with some lemon zest, a pinch of sea salt and some smoked paprika – or naked, just as it is.

This blog post first appeared as an article in The Irish News on Saturday 9 March 2019.