Asparagus: Rich in prebiotic fibre

18th Apr 2023

As the weather warms up, we welcome a much-anticipated spring ritual: asparagus season. Look out for these delicate verdant stalks at farmers’ markets – they’re packed with polyphenols and bursting with flavour.

Key points

• In a Nutshell
• Plant Tales
• Health Benefits
• Ways to enjoy
• Recipes
• Dive Deeper

In a Nutshell

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Plant Tales

Why so short? In the UK, asparagus season runs from the end of April to Summer Solstice on June 21st. The spears grow rapidly, using a huge amount of energy which can only be sustained for a few weeks. Farmers stop harvesting when spears start to thin out to preserve energy for the next growing season.

White gold: Have you ever tried white asparagus? It’s a slightly sweeter version of asparagus that is grown underground to prevent chlorophyll from developing and turning the spears green. Germany has a special affection for it, where it’s known as “white gold” and celebrated each year with Spargel festivals.

Origin story: Its cultivation dates back to the Romans over 2,000 years ago. It’s said that the emperor Augustus had dedicated ships called Asparagus Fleets for transporting asparagus around the empire! The word Asparagus originates from the Persian “asparag”, meaning sprout or shoot.

Traditional uses: The vegetable we know is garden asparagus (Asparagus officinalis). But the genus Asparagus contains up to 300 species. Some are used in traditional herbal medicine to aid digestion and treat pneumonia, like Chinese asparagus (Asparagus cochinchinensis).

Health Benefits

Beyond its delicate flavour, adding asparagus to your plate may…

1. Improve your gut microbiome, thanks to its ‘prebiotic’ fibres like xylose and inulin.
2. Help lower your risk of chronic disease by giving you lots of fibre and polyphenols. People who eat more fibre and vegetables have a lower risk of heart disease and a wide range of cancers. (Fu et al. 2022; Veronese et al. 2018)
3. Help lower your levels of stress. A (very) small trial found that an asparagus extract lowered participants’ levels of cortisol and improved their sleep quality, compared to placebo. (Ito et al. 2014)

Asparagus is a source of…

• Dietary fibre
• Vitamins and minerals, especially potassium, vitamin C and folate. 6-8 cooked spears provide ~122 micrograms of folate or ~30% of the recommended intake for adults.
• Bioactive compounds, especially phenolic acids, like caffeic acid and rutin, a flavonoid with remarkable anti-inflammatory, antioxidant and anticancer activities.

How does it work? Together, these compounds show beneficial effects in lab models like improving the composition of the gut microbiota, modulating the immune system and improving antioxidant capacity. (Guo et al. 2020)

Ways to enjoy

How much? A portion of asparagus is 80g or about 5 spears.

Buy it fresh: Locally-grown asparagus is more flavourful and lowers the global warming potential by almost 5x compared to imported asparagus. Find UK farm shops here.

Skip the organic section: Asparagus doesn’t carry much of a pesticide load as it emerges from the ground and grows quickly. It’s often cited as one of the foods with the lowest amounts of pesticide residues in the US, according to the Environmental Working Group.

If you’re not a fan (yet)

• Try white asparagus – it usually has a milder and more delicate taste
• Prep it – Cut out the woody bottom portion of each stalk and don’t peel it
• Pair it with strong flavours – Try roasting it with parmesan cheese or grilling it with lemon and garlic.
• Don’t overcook it – Choose thicker stalks and only cook for a few minutes or enjoy it raw in a salad.

We enjoy it…

• Gently grilled or roasted with olive oil, garlic and lemon juice.
• With eggs in an omelette, quiche or the Belgian way in Asperges à la Flamande.
• In a soup with onions, leeks, peas, broth, lemon juice and fresh herbs. Or in Spanish Crema de Espárragos, served with croutons and grated cheese.
• In a salad with lettuce leaves, edamame or crispy chickpeas, crunchy walnuts, feta and a zesty lemon dressing.
• On toast with extra virgin olive oil, fresh tomatoes, basil and parmesan shavings.

Recipes

• Grilled Harissa Asparagus Salad
• Spring Vegetables with Miso Butter and Teriyaki Rice
• Tenderstem, Asparagus and Swede Spicy Pancakes
• Creamy Butter Beans with Asparagus, Mushrooms and Leeks
• Pea, Asparagus and Dill Salad with Feta and Spiced Walnut Crumb

Dive Deeper

Human studies: Ito et al. 2014 - Aune et al. 2017 - Fu et al. 2022 - Veronese et al. 2018

History, compounds & biological activities: Redondo-Cuenca et al. 2023. - Iqbal et al. 2017

Environment: Frankowska et al. 2019 - The University of Arkansas System Division of Agriculture